Goals. To: (1) activate and develop neuromuscular control of deep segmental and global spinal stabilizing muscles to support the spine against external loading; (2) develop endurance and strength in the muscles of the axial skeleton for functional activities; and (3) develop control of balance in stable and unstable situations.
This section is divided into two main sections. The first section presents principles and techniques of stabilization exercises for the cervical and lumbar spinal regions with a subsection on motor control exercises for segmental muscle activation and a subsection on global muscle stabilization. The second section presents principles and techniques of general isometric, dynamic, and functional exercises for the neck and trunk.
Stabilization Training: Fundamental Techniques and Progressions
"Proximal stability for distal mobility," a well known phrase, is an underlying principle of intervention with therapeutic exercise. The primary functions of the muscles of the trunk are to provide stability, so upright posture can be maintained against a variety of forces that disturb balance and to provide a stable base, so the muscles of the extremities can execute their function efficiently and without undue stress to the spinal structures. Several studies have demonstrated altered or delayed neuromuscular recruitment patterns in the deep stabilizing muscles of the lumbar spine during active movement in individuals with low back pain.21,24,25,44 Results of other studies have shown improved ability to recruit these muscles with specific training43 and improved outcomes compared with individuals not receiving the training.20,43,44 Studies have also demonstrated improved outcomes in patients with cervical pain and cervicogenic headaches with recruitment of the deep stabilizing musculature in the cervical spine in conjunction with total trunk stabilization.30,37
The functions of the deep segmental musculature and the superficial global (multi-segmental) spinal musculature were identified and described in Chapter 14. Both muscle systems are necessary for spinal stability and function. Therefore, one of the primary areas of emphasis during rehabilitation after spinal problems is recruiting the segmental muscles and training them to respond along with the global musculature to various forces and demands imposed on the spine to improve coordination of their overall function. Activation of the stabilizing musculature is then reinforced when progressing to muscular endurance and strengthening exercises, when performing aerobic exercises, and when practicing functional activities throughout the rehabilitative process with the anticipation that muscle activation for stabilization will become automatic during all daily activities and functional challenges (Fig. 16.37).
Exercises to improve muscle performance, cardiopulmonary endurance, and functional activities are integrated over a background of activating the deep segmental and global multi-segmental spinal stabilizing musculature.
Stabilization training follows the basic principles of learning motor control first by developing awareness of muscle contractions and spinal position, then by developing control in simple patterns and exercises, then progressing to complex exercises, and finally by demonstrating automatic maintenance of spinal stability and control in a progression of simple functional activities to complex and unplanned situations.55 Many of the exercises can be used to accomplish more than one purpose; there is definite overlap with kinesthetic training, muscle performance, and functional training. The choice and progression of exercises described in each of the sections rely on clinical judgment of the patient's response and attainment of goals, not on a strict, time-based protocol or number of days from injury. The ability of the patient to control the spine in a neutral or nonstressful position is paramount for all the exercises.
Stabilization training follows basic principles of learning motor control.
Patient develops awareness of muscle contractions and spinal positions.
Patient develops control of spine when performing simple extremity patterns and exercises.
Patient demonstrates control of spine when progressing to complex exercises.
Patient demonstrates automatic maintenance of spinal stability and control in a progression of simple functional activities to complex and unplanned situations.
There is considerably more research on muscle function and its stabilization action in the lumbar spine than the cervical spine. The cervical spine requires more mobility to position the head, yet relies on the thoracic and lumbar spinal regions to provide a base for stability and postural control. Even though there are unique anatomical considerations in the cervical spine, there is overlap between stabilization training for cervical and lumbar problems.
Guidelines for Stabilization Training
It is important to understand and use the principles and progression of stabilization training for effective instruction.6,41,51,52,53 The following guidelines are summarized in Box 16.2.
BOX 16.2 Guidelines for Stabilization Training: Principles and Progression
Begin training with awareness of safe spinal motions and the neutral spine position or bias.
Have patient learn to activate the deep stabilizing musculature while in the neutral position.
Add extremity motions to load the superficial global musculature while maintaining a stable neutral spine position (dynamic stabilization).
Increase repetitions to improve holding capacity (endurance) in the stabilizing musculature; increase load (change lever arm or add resistance) to improve strength while maintaining a stable neutral spine position.
Use alternating isometric contractions and rhythmic stabilization techniques to enhance stabilization and balance with fluctuating loads.
Progress to movement from one position to another in conjunction with extremity motions while maintaining a stable neutral spine (transitional stabilization).
Use unstable surfaces to improve the stabilizing response and improve balance.
Kinesthetic training for awareness of safe motion and positions must precede stabilization training. The functional range and functional position in which symptoms are minimal or absent are used for stabilization exercises.41 When the condition is not acute, most people find the mid-range (the neutral position) to be their functional position. It is important to recognize that this position or range is not static; nor is it the same for every person. In addition, it may change as the tissues heal, nociceptive stimuli decrease, and flexibility improves.41
Activation of the deep segmental muscles of the trunk, specifically the transversus abdominis (TrA) and multifidus (Mf), is often delayed or absent in patients with back pain.21,25,44 In addition, ultrasound imaging studies on individuals with unilateral low back pain have shown decreased activation of these deep muscles on the side of symptoms compared to the uninvolved side when performing voluntary contractions.59
Learning conscious activation of the deep segmental muscles without contracting the global trunk musculature is the first step in developing habitual activation for spinal stability in patients with pain related to poor spinal control and segmental instability. Once the individual learns correct activation of the segmental stabilizers using the "drawing-in" maneuver, this maneuver is used prior to all exercises and activities to develop the activation and stabilizing function and eventually automatic feedforward stabilization from the muscles.26 A study involving 42 subjects demonstrated that it is possible to alter abdominal muscle activation consciously and automatically with specific exercises.43
In the cervical region, the deep cervical flexors, the longus colli and longus capitis, and the deep cervical and upper thoracic extensors are activated to stabilize the cervical spine in a neutral spinal position (axial extension with mild lordosis).
Extremity motions are added to the stabilization program to coordinate segmental muscle activity with the global stabilizing musculature. Loading via the extremities increases the stabilizing challenge to the musculature. The patient positions the spine in the neutral position (using pelvic tilt motions in the lumbar region and gentle head nodding in the cervical region), performs the drawing-in maneuver, and then begins moving one or several extremities while maintaining the neutral position. Extremity motions are performed within the tolerance of the trunk or neck muscles to control the neutral or functional position. This is called dynamic stabilization, because the stabilizing muscles in the spinal area must respond to the changing forces coming from the dynamic movement of the extremities. Exercises that require stabilization against transverse plane rotational forces on the pelvis more consistently activate the oblique abdominal and deep spinal stabilizers than sagittal plane resistive forces.50
Increase muscular endurance and strength once control of the spinal position is established and the patient can activate the stabilizing muscles. Repetitions of extremity motions are increased, and resistance is applied to the extremities. The intent is to challenge the trunk muscles to stabilize against these increased forces yet stay within their tolerance and ability to control the spinal position. Repetitions also help develop habit; therefore, it is important to use careful instructions and provide feedback. Fatigue is determined by the inability of the trunk or neck muscles to stabilize the spine in its functional position or by increased pain. For example:
Begin at a resistance force that the patient can repeat for 30 to 60 seconds and maintain the neutral position of the spine; progress the repetitions to 3 minutes.
Progress by adding resistance to or increasing the lever arm of the extremities; initially, reduce the time and again progress to doing the new activity for 1 to 3 minutes.
Another way to develop endurance in the trunk muscles is to begin exercising at the most difficult level for that patient, then shift to simpler levels of resistance as fatigue begins in order to keep moving. It is important that the patient does not lose control of the functional position or experience increased symptoms.
Alternating isometric contractions between antagonists and rhythmic stabilization of the trunk muscles against manual resistance also enhance stabilizing contractions. When performed while sitting and standing, the alternating contractions and co-contractions also develop control of balance.
Transitional stabilization develops as the patient moves from one position to another in conjunction with extremity motions. This requires graded contractions and adjustments between the trunk flexors and extensors and requires greater awareness and concentration.6,41 For example, any motion of the arms or legs away from the trunk tends to cause the spine to extend. The abdominals (trunk flexors) must contract to maintain control of the functional spinal position. This occurs, for example, when lifting a load from the floor to overhead. Then, as the arms or legs move anteriorly toward the center of gravity, the spine tends to flex, which requires the extensors to contract to maintain the functional position (as would occur when lowering a weight to the floor). Greater concentration on maintaining the functional spinal position is necessary when doing more advanced functional activities.
Perturbation (balance) training, exercising against destabilizing forces or on unstable surfaces, develops neuromuscular responses to improve balance.
Deep Segmental Muscle Activation and Training
The function of the deep musculature (TrA and Mf in the lumbar spine and longus colli and other deep musculature in the cervical spine) is described in Chapter 14, and the results of impaired function in these muscles are described in Chapter 15. Techniques for activation of the segmental musculature are described in this section.
FOCUS ON EVIDENCE
Methods for testing and training activation of the deep segmental musculature have been developed and used in both research and clinical settings.47 Placement of fine-wire electrodes with ultrasound guidance has provided valuable information regarding the muscle function and recovery in research settings,26,27 and ultrasound imaging has provided a valuable tool for biofeedback in training.19,22,23,60 As of 2012, use of ultrasound biofeedback imaging has been prohibitively expensive to use clinically for training activation of the deep musculature. As an alternative device, a pressure biofeedback unit (StabilizerTM; © 2006 Encore Medical, L.P.) was developed and has been shown to have clinical usage in training activation and control of the stabilizing musculature of the trunk and neck.28,56
In the cervical region, the goal is to activate and control the muscles that control axial extension (cervical retraction). This requires capital flexion, slight flattening of the cervical lordosis, and flattening of the upper thoracic kyphosis (Fig. 16.38).
Axial extension (cervical retraction) involves the motion of capital flexion and movement of the lower cervical and upper thoracic spine toward extension, resulting in slight flattening of the cervical lordosis and "lifting" of the head.
Deep Neck Flexors: Activation and Training
Patient position and procedure: Supine VIDEO 16.12 . For craniocervical flexion and gentle axial extension, teach the patient to perform slow, controlled nodding motions of the head on the upper cervical spine ("yes" motion). If the patient has a significant forward head posture, place a folded towel under the occipital area, so extension of the head on the neck does not occur. Facilitate the motion with manual cues to ensure the longus colli is contracting, or the sternocleidomastoid is at a relative state of rest. Once the patient is able to activate the motion, the StabilizerTM (or blood pressure cuff) may be used to monitor the amount of cervical flattening and measure the muscular endurance for holding the contraction (Fig. 16.39). The protocol for use of the StabilizerTM is summarized in Box 16.3.
Spinal Stabilization - Activation and Training Deep Cervical Flexor Muscles
(A) The StabilizerTM pressure biofeedback unit (© 2006 Encore Medical, L.P.) is used to provide visual feedback to the patient while training for spinal stabilization. (B) Stabilizer folded into thirds under the cervical spine to test and train capital flexion with neutral spine axial extension.
BOX 16.3 Testing and Training Deep Segmental Muscle Activation in the Cervical Spine
Place blood pressure cuff or the folded StabilizerTM pressure biofeedback unit (folded into thirds) under the upper cervical spine and inflate to 20 mmHg.
Instruct the patient to nod and increase pressure on the cuff to 22 mm Hg and hold the pressure steady for 10 seconds.
If the patient is successful (i.e., can hold the position with minimal superficial muscle activity), have him or her relax and repeat the flexion, this time increasing pressure to 24 mm Hg. Repeat this incremental activation up to 30 mm Hg (total 10 mm Hg increase).
The final pressure is the one at which the patient can hold steady for 10 seconds.
Muscle endurance (holding or tonic capacity) of the deep neck flexors is measured by the number of 10-second holds (up to 10) at the final pressure.
A performance index can be used to document an objective measure. Multiply the pressure increase by the number of times the patient can repeat the 10-second holds—with 100 reflecting the holding of a 10-mm Hg increase for 10 repetitions.31
FOCUS ON EVIDENCE
Jull and associates31 reported that the controlled performance of upper cervical flexion increases the pressure in the StabilizerTM to 30 mm Hg and that the test-retest reliability of the craniocervical flexion test (conducted on 50 asymptomatic subjects 1 week between tests) was an ICC of 0.81 for the activation score and 0.93 for the performance index (see Box 16.3).
Lower Cervical and Upper Thoracic Extensor Activation and Training
Patient position and procedure: Prone with forehead on the treatment table and arms at the sides. Have the patient lift the forehead off the treatment table, keeping the chin tucked and eyes focused on the table to maintain the neutral spinal position (reinforces the craniocervical flexion motion learned in the supine position). Lifting the head is a small motion (Fig. 16.40).
Axial extension (cervical retraction) exercises.
Once the patient learns to activate the deep musculature and assume the neutral posture in the cervical spine, practice throughout the day is encouraged in order to develop good postural control. Stabilization training is initiated by coordinating control of the neutral spinal position with upper extremity loading. The extremity motions are used to stimulate muscular endurance as well as strengthen the stabilizing musculature in the spine. These exercises are described in the next section 'Global Muscle Stabilization Exercises.'
Three techniques for abdominal muscle activation have been described and used in clinical practice: the drawing-in maneuver; abdominal bracing; and posterior pelvic tilt (Fig. 16.41). Each technique differs in the stabilization activity of the abdominal and multifidus muscles.49 Studies have demonstrated that the drawing-in maneuver is more selective in co-activating the transversus abdominis and multifidus muscles than the abdominal bracing and posterior pelvic tilt techniques,28,49 and that the drawing-in maneuver leads to improvement in feedforward postural strategies.62 The drawing-in maneuver also functions to increase intra-abdominal pressure by inwardly displacing the abdominal wall. Because of this, the drawing-in maneuver is recommended for stabilization training; the other two methods are also described, primarily so the reader can recognize the differences.
Three methods to activate the stabilizing musculature in the lumbar spine. (A) Drawing-in maneuver in which the patient hollows the abdominal region ("draws" the belly button toward the spine). (B) Abdominal bracing in which setting the abdominal muscles results in flaring laterally around the waist. (C) Posterior pelvic tilt in which the pelvis is actively tilted posteriorly and the lumbar spine flattens.
Drawing-In Maneuver (Abdominal Hollowing Exercise) for Transverse Abdominis Activation
Patient positions: Training may be easiest in the quadruped position in order to use the effects of gravity on the abdominal wall VIDEO 16.13 . Hook-lying (with knees 70° to 90° and feet resting on an exercise mat), prone-lying, or semireclined positions may be used if more comfortable for the patient. It is important to progress training to sitting and standing as soon as possible.38,40
Spinal Stabilization - Cervical Stabilization Progressions Emphasizing Core Flexors
Procedure: Teach the patient using demonstration, verbal cues, and tactile facilitation. Explain that the muscle encircles the trunk, and when activated, the waistline draws inward (see Fig. 16.41 A).
Palpate the transversus abdominis (TrA) muscle just distal to the anterior superior iliac spine (ASIS) and lateral to the rectus abdominis (RA) (Fig. 16.42). When the internal oblique (IO) contracts, a bulge of the muscle is felt; when the TrA contracts, flat tension is felt. The goal is to activate the TrA with minimal or no contraction of the IO. This is a gentle contraction.
Have the patient assume a neutral spinal position and attempt to maintain it while gently drawing in and hollowing the abdominal muscles.47 Instruct the patient to breathe in, breath out, then gently draw the belly button in toward the spine to hollow out the abdominal region. When done properly, there are no substitute patterns; that is, there is minimal to no movement of the pelvis (posterior pelvic tilting), no flaring or depression of the lower ribs, no inspiration or lifting of the rib cage, no bulging out of the abdominal wall, and no increased pressure through the feet. Performing the drawing-in maneuver with the spine in a neutral position results in increased TrA response (measured as increased thickness in ultrasound imaging) compared to slouched sitting or slouched standing postures.46
Palpation of the transversus abdominis (TA) muscle just distal to the ASIS and lateral to the rectus abdominis muscle. The TA feels like a tense sheet (a bulge is the internal oblique) when performing a gentle drawing-in maneuver.
If a patient has difficulty activating the TrA, the following two feedback techniques have been shown to assist with learning.17,48,49
Pressure biofeedback for clinical testing and visual feedback. With the patient prone, the StabilizerTM (or blood pressure cuff) is placed horizontally under the abdomen (centered under the navel). Inflate the StabilizerTM to 70 mm Hg. Have the patient perform a drawing-in maneuver, as described above. A decrease of 6 to 10 mm Hg during the drawing-in maneuver (without substitutions) indicates proper activation of the deep abdominal muscles. The dial on the unit is large and easily read by the patient for immediate feedback.
Biofeedback with surface electrodes. Surface electrodes placed over the rectus abdominis and external obliques (near its attachment on the eighth rib) may be used in conjunction with the inflatable cuff. There should be minimal to no activation of these muscles if the drawing-in maneuver is done correctly.
As with the cervical spine, the StabilizerTM can be used not only to train and reinforce activation of the TrA but also to measure control for a measured period of time as well as number of repetitions. The protocol is summarized in Box 16.4.
BOX 16.4 Testing and Training Deep Segmental Muscle Activation (Transversus Abdominis) in the Lumbar Spine
Patient is prone lying.
Place a blood pressure cuff or the StabilizerTM pressure biofeedback unit horizontally under the abdomen with the lower edge just below the anterior superior iliac spine (ASIS) (navel at center of unit).
Inflate to 70 mm Hg and instruct the patient to perform the drawing-in maneuver.
If done properly, the pressure drops 6 to 10 mm Hg.
See if the patient can maintain the pressure drop for up to 10 seconds.
Muscle endurance (holding or tonic capacity) of the transversus abdominis (TrA) is measured by the number of 10-second holds (up to 10).
Adapted from the instruction manual that accompanies the StabilizerTM © 2006 Encore Medical, L.P., with permission.
In contrast to the drawing-in maneuver, abdominal bracing occurs by setting the abdominals and actively flaring out laterally around the waist (see Fig. 16.41 B). There is no head or trunk flexion, no elevation of the lower ribs, no protrusion of the abdomen, and no pressure through the feet. The patient should be able to hold the braced position while breathing in a relaxed manner. This technique has been taught for a number of years as the method to stabilize the spine; it has been shown to activate the oblique abdominal muscles consistent with their global stabilization function.49
Posterior pelvic tilt exercises (see Fig. 16.41 C) principally activate the rectus abdominis muscle, which is used primarily for dynamic trunk flexion activity. It is a superficial muscle that does not have segmental attachments; therefore, it is not emphasized in the training for stabilization.49 Pelvic tilt exercises are used to teach awareness of the movement of the pelvis and lumbar spine as the patient explores his or her lumbar ROM to find the functional spinal range and the neutral position.
Multifidus Activation and Training
Patient position and procedure: Prone or side-lying VIDEO 16.14 . Place your palpating digits (thumbs or index fingers) immediately lateral to the spinous processes of the lumbar spine (Fig. 16.43).
Spinal Stabilization - Cervical Stabilization Progressions Emphasizing Extensors
Palpation of the multifidus muscle lateral to the spinous processes in the lumbar spine, (A) bilaterally in the supine position and (B) unilaterally in the side-lying position.
Palpate each spinal level so comparisons in the activation of the multifidus (Mf) muscle can be made between each segment as well as from side-to-side.
Instruct the patient to "swell the muscle" out against your digits. Palpate for consistency of muscle contraction at each level.
Facilitation techniques include using the drawing in maneuver and gently contracting the pelvic floor muscles (as in Kegel exercises, described in Chapter 24).
In the side-lying position, facilitate by gently applying manual resistance to the thorax or pelvis to activate the rotation function of the Mf.
The patient may be taught to self-palpate a Mf contraction in the following manner. Sit and rock the pelvis to find the neutral position; with the fingers or thumbs placed along the lumbar spinous processes, lean forward a couple degrees. The Mf is thus activated. Differentiate a Mf contraction from tension in the aponeurosis of the global erector spinae.
Once the patient learns to activate the deep segmental musculature, practice throughout the day is encouraged. Segmental muscle activation is then coordinated with stabilization training, using the global musculature and extremity loading. Extremity motions are added and used to stimulate muscle endurance as well as strengthen the trunk muscles. Global stabilization exercises are described in the next section.
Global Muscle Stabilization Exercises
Even though this section is divided into cervical and lumbar regions, many of the same exercises may be used for impairments in either region because of the functional relationships of the entire axial skeleton.
Stabilization Exercises for the Cervical Region
Stabilization with Progressive Limb Loading
In general, stabilization exercises begin in the recumbent position and progress to sitting, sitting on a large gym ball, standing with the back supported against a wall, and finally standing without support. For advanced training, exercises are progressed to standing on an unstable surface.
Begin all exercises with gentle craniocervical nods and axial extension to the neutral spinal position to activate the deep segmental muscles as described in the previous section. During the early phases of training, if the patient has difficulty maintaining a neutral spinal position, a small towel roll may be placed under the neck for passive support.
Initially, the only resistance load comes from simple upper extremity movements. When the patient can perform multiple repetitions of the upper extremity motions without losing control of the spinal position or causing an increase in symptoms, resistance is added with handheld weights or elastic resistance.
The principles of muscle endurance and strengthening described in Chapter 6 are used to challenge the spinal stabilizing musculature.
Table 16.3 summarizes limb-loading exercises that emphasize the flexor muscles, and Figure 16.44 illustrates the basic exercise progression in the supine position.
Table 16.4 summarizes limb-loading exercises that emphasize the lower cervical/upper thoracic extensor muscles, and Figure 16.45 illustrates a basic exercise progression in the prone position. It is important to note that these exercises do not isolate the flexors or extensors, but the designation is primarily for emphasis due to the effects of gravity.
Spinal Stabilization - Activating and Training the Transversus Abdominis Muscle
Limb loading for basic stabilization progression of cervical musculature in the supine position. Maximum protection phase: (A) shoulder flexion to 90°; (B) shoulder abduction to 90°; (C) shoulder external rotation arms at the side. Moderate protection phase: (D) shoulder flexion and abduction to end-range; (E) diagonal patterns.
TABLE 16.4Cervical Stabilization with Progressive Limb Loading—Emphasis on Cervical and Thoracic Extensors VIDEO 16.16 ||Download (.pdf) TABLE 16.4 Cervical Stabilization with Progressive Limb Loading—Emphasis on Cervical and Thoracic Extensors VIDEO 16.16
|Instructions: Determine amount of support needed and amount of protection. Begin each exercise with axial extension to the neutral spinal position and maintain it while exercising; increase extremity repetitions, then increase resistance before progressing to a new challenge. ||Maximum Support || ||Minimum Support |
|Prone forehead on treatment table—lift forehead off table (Fig. 16.19) ||Quadruped over padded stool or gym ball—maintain eyes focused on floor ||Standing back supported by wall (ball behind head for less stability) ||Standing, no support, (standing on unstable surface for less stability) |
|Deep segmental muscle activation—gentle craniocervical flexion/axial extension ||Lift forehead off exercise mat; hold 10 seconds × 10 repetitions |
|Minimum limb loading ||Maximum to moderate protection phase ||Arms at side: laterally rotate shoulders and adduct scapulae |
| ||Arms in 90/90 position (abducted and laterally rotated), horizontally abduct shoulders and adduct scapulae |
| ||Moderate to minimum protection phase ||Elevate shoulder in full flexion |
|Arms abducted to 90° and laterally rotated, elbows extended: horizontally abduct shoulders and adduct scapulae |
|Upper extremity diagonal patterns |
|Maximum limb loading ||Minimum to no protection phase || |
Standing, no support → standing on unstable surface:
Reaching forward, outward, upward in functional patterns
Pushing/pulling and lifting activities
|Standing on unstable surface: |
Spinal Stabilization - Activating and Training the Multifidus Muscle Contraction
Limb loading for basic stabilization progression of cervical musculature in prone position. Maximum protection phase: (A) arms at side, shoulder lateral rotation, and scapular adduction; (B) arms at 90/90, horizontal abduction, and scapular adduction. Moderate protection phase: (C) shoulder elevation full range, (D) shoulders 90° with lateral rotation and elbow extended, horizontal abduction, and scapular adduction.
Variations and Progressions in the Stabilization Program
Remind the patient to find and maintain the neutral spinal position when doing these exercises.
Extremity loading. During the early phases of training, limit shoulder flexion to 90° flexion and abduction. Once the patient can maintain stability and symptoms are not provoked, greater challenges occur with elevating the upper extremity full ROM. Unilateral and asymmetrical upper extremity motion require greater control than bilateral motion.
External resistance. Tables 16.3 and 16.4 summarize progressions based on position changes. In addition, use of resistance loads (free weights, elastic resistance, or manual resistance) to any of the exercises adds to the stabilizing challenge. Even though external resistance applied through the extremities has the benefit of increasing strength in the extremity musculature, the primary goal is to increase the stabilizing response of the cervical musculature. Therefore, any loss of the neutral spinal posture or increase in cervical symptoms signals the need to decrease the intensity of the resistance force.
Unstable surfaces. The application of external resistance while on an unstable surface, such as sitting on a large ball (Fig. 16.46 A), lying prone over a ball (Fig. 16.46 B), or standing supporting the ball between the head and the wall (Fig. 16.46 C), provides additional challenges to the muscles as they respond to perturbations. Many variations of these exercises can be used to challenge the stabilizing muscles so long as the patient is able to maintain control.
Muscular endurance and strength. Determine the maximum level of resistance tolerated by the cervical-stabilizing musculature that does not reproduce symptoms. Decrease the intensity and have the patient exercise with multiple repetitions at that level (20 to 30 repetitions or for 1 minute). Resistance can then be added for strengthening (decrease the number of repetitions) at that level before progressing to endurance training at the next level.
Unstable surfaces provide increased challenges to the cervical stabilizing musculature, requiring greater control. Examples include performing upper extremity motions, such as diagonal patterns (A) while sitting on a gym ball, (B) while quadruped over a gym ball, and (C) while pressing a ball against the wall. Use of external resistance is also illustrated.
Integration of Stabilization Exercises and Posture Training
Good postural alignment of the neck begins with the pelvis and lumbar spine and moves up to the scapular and thoracic regions. The thorax must be lifted up from the pelvis and scapula retracted in a comfortable position for the cervical spine to assume an efficient position of axial extension (cervical retraction). Therefore, begin with lumbopelvic control if necessary and develop thoracic extension and scapular retraction. While the patient is performing the extremity motions to develop stability, reinforce good scapulohumeral alignment. It is important to remember that strengthening alone does not correct faulty posture and, therefore, to utilize the reinforcement techniques and environmental adaptations that are discussed in Chapter 14.
Progression of Isometric and Dynamic Strengthening in Conjunction with Functional Activities
When the patient demonstrates good cervical stabilization and response to various upper extremity resistance changes, isometric and dynamic exercises are integrated into the program. These are described in the 'Isometric and Dynamic Exercise' section following this section.
Stabilization Exercises for the Lumbar Region
Once the patient learns to activate the deep segmental muscles in the lumbar region, explain that prior to each exercise the patient is to find the neutral spinal position, perform the drawing-in maneuver, and then maintain control while applying an exercise load with extremity motions. The drawing-in maneuver develops the pattern of setting the deep abdominal and multifidus muscles in a feedforward pattern and then trains their holding capacity in coordination with the global muscles.17
Stabilization with Progressive Limb Loading
Begin with the patient supine for greatest support, adding quadruped exercises when able. If the patient cannot control the position, pre-position him or her using pillows or supports (see Box 15.6).
BOX 16.5 Instructions for use of StabilizerTM for Stabilization Training with Leg Loading
Patient position: Supine, hook lying.
Place the three-chamber pressure cell under the lumbar spine horizontally across low back area.
Position the spine in neutral.
Inflate the pressure cell to a baseline of 40 mm Hg.
Draw in the abdominal wall without moving the spine or pelvis.
Pressure should remain at 40 mm Hg (±10 mmHg) while performing the lower extremity loading exercises.
Adapted from the instruction manual that accompanies the StabilizerTM © 2006 Encore Medical, L.P., with permission.
To improve the holding capacity of the stabilizing muscles, increase the amount of time the patient does the exercises. It is important that no exercise is continued if the patient cannot maintain the stable position. If the deep abdominals cannot stabilize, substitute patterns in the superficial muscles that override the deep muscle activation.
The StabilizerTM Pressure Biofeedback unit (or blood pressure cuff) may be used for feedback during this early training (see Box 16.5 for guidelines).
Table 16.5 summarizes basic limb-loading exercises in the supine position that emphasize the abdominal muscles, and Figures 16.47 and 16.48 illustrate the exercise progression.
Table 16.6 summarizes limb-loading exercises in the quadruped and prone positions that emphasize the extensor muscles, and Figure 16.49 illustrates a basic exercise progression.
TABLE 16.5Basic Lumbar Stabilization with Progressive Limb Loading—Emphasis on Abdominals ||Download (.pdf) TABLE 16.5 Basic Lumbar Stabilization with Progressive Limb Loading—Emphasis on Abdominals
|Instructions: Patient position hook lying (knees 90°). Place pressure cuff under lumbar spine and inflate to 40 mm Hg. Begin each exercise with drawing-in maneuver to activate deep segmental muscles. Determine level at which patient can maintain pressure constant (stable pelvis) while performing either A, B, or C limb load activity. For endurance, decrease load and perform repetitive motion for 1 minute or longer. For strength, progress load. ||Progressive Limb Loading || |
|A. Lift bent leg to 90° hip flexion ||B. Slide heel to extend knee ||C. Lift straight leg to 45° |
|Minimum external support ||Level 1: deep segmental muscle activation ||Draw in and hold 10 seconds |
|Maximum external support ||Level 2: ||Opposite LE on mat; bent leg fall out |
| ||Level 3: A, B, or C ||Opposite LE is on table |
|Level 4: A, B, or C ||Hold opposite LE @ 90° of hip flexion with UE |
|Level 5: A, B, or C ||Hold opposite LE @ 90° of hip flexion (no UE assistance) |
|Minimum external support ||Level 6: A, B, or C ||Bilateral LE movement |
Bent-leg fall out. Level 2 limb loading for basic stabilization of the abdominal muscles in the supine position. This requires control to prevent pelvic rotation; stability is assisted by the opposite lower extremity while hook-lying. VIDEO 16.17
Spinal Stabilization - Abdominals at Levels 1 and 2
Limb loading for basic stabilization progression of the abdominal muscles in the supine position, levels 3 to 6. Level 3, stability assisted by opposite extremity in hook-lying position; level 4, stability assisted by patient holding opposite leg at 90°; level 5, stability challenged with both lower extremities moving. (A) Bent leg lift to 90°. (B) Heel slide to extend knee. (C) Straight-leg lift to 45°. VIDEO 16.18
Spinal Stabilization - Abdominal Levels 3 and 6
TABLE 16.6Basic Lumbar Stabilization with Progressive Limb Loading: Emphasis on Trunk Extensors ||Download (.pdf) TABLE 16.6 Basic Lumbar Stabilization with Progressive Limb Loading: Emphasis on Trunk Extensors
|Instructions: Patient position quadruped or prone. Patient assumes neutral spine in lumbar and cervical regions (keeping eyes focused toward floor or exercise mat), performs drawing-in maneuver, and moves extremities. Motions are repeated or alternated from side to side. ||Position ||Load |
|Lower intensity ||Quadruped position ||Flex one upper extremity (UE) |
| ||Extend one lower extremity (LE) by sliding it along the exercise mat |
|Extend one LE and lift 6–8 inches off exercise mat |
|Flex one UE and extend contralateral LE |
|Greater intensity and spinal compression ||Prone lying position—near end of range of motion, requiring greater control of neutral spine ||Extend one LE |
|Extend both LE |
|Lift head, arms, and LE |
Limb loading for basic stabilization progression of the lumbar extensors. Begin in the quadruped position and progress the intensity by (A) flexing one UE; (B) extending one LE with a leg slide; (C) extending one LE by lifting it off the mat; (D) flexing one UE while extending contralateral LE and then alternate to opposite extremities. Progress to prone: (E) extending one LE; (F) extending both LE; and (G) lifting head, arms, and trunk. VIDEO 16.19
Spinal Stabilization - Erector Spinae with Limb Loading
Performance of extremity loading in the prone position places a greater compressive load on the lumbar spine5,39 and is not possible if there are hip flexion contractures; therefore, initiate extension exercises in the quadruped position, so the lumbar spine can be positioned more easily in neutral, and the patient can learn control.
If the patient cannot bear weight on the extremities or maintain balance in the quadruped position, use a padded stool or gym ball for additional support.
It is important to maintain the cervical spine in its neutral position during quadruped exercises. The patient should be able to align the head and focus the eyes on the floor. As the exercises progress, there is a greater challenge on co-activation of all of the stabilizing musculature.
NOTE: The exercise progressions described in Table 16.5 are adapted from several research studies that investigated the reliability, validity, and sensitivity to change one exercise level with abdominal muscle stabilizing ability using lower-limb loading.16,17,29 The exercise progressions described in Table 16.6 are adapted from electromyography (EMG) studies that documented extensor activity with limb loading in the quadruped and prone-lying positions.5,39
Variations and Progressions in the Stabilization Exercise Program
For all exercises, reinforce the importance of first finding the neutral spine (cervical and lumbar regions), performing the drawing-in maneuver, and then maintaining the neutral spine while superimposing any extremity motions. It is critical to instruct the patient to stop the exercises (or decrease the intensity) as soon as loss of control of the stable spinal position is sensed. It is important not to progress the patient beyond what he or she is able to control in order to develop the proper muscle response. The emphasis is first on improving the static holding capacity (endurance) of the trunk muscles followed by strengthening. Endurance training of the trunk extensor muscles is related to decreased pain and improving function during the early stages of recovery in patients with subacute low back pain.10
Emphasis on muscle endurance. Determine a level of exercise that the patient can perform for several repetitions while maintaining a stable spine in the neutral position. Have the patient exercise at that level with the goal of increasing the number of repetitions or the time. Once the patient can perform repetitions for 1 minute, add weights, decrease the repetitions, and emphasize strength. Progress to the next level of difficulty for muscular endurance.
Use of external props. Use of the StabilizerTM pressure biofeedback unit to help the patient learn control while doing the abdominal stabilization exercises was described earlier (see Box 16.5). For exercises in the quadruped position, if the patient has difficulty controlling the trunk rotation, use a prop, such as a dowel rod, placed along the spine. Have the patient attempt to keep it balanced while performing the arm and leg exercises (Fig. 16.50). It may be helpful to cue the patient not to shift his or her weight as the extremity is moved—this is difficult to do but is effective in bringing in the stabilizing trunk muscles.
Extremity loading. Boxes 16.5 and 16.6 identify a progression of exercises in supine and quadruped/prone positions with extremity loading. Initially, have the patient do the motions repetitively; then progress to alternating the extremities or moving all four extremities simultaneously (Fig. 16.51). This requires the stabilizing musculature to adjust to the shifting loads. Motions begin in the sagittal plane and then progress to the transverse plane and diagonal patterns (unilateral and bilateral), in which movement away from the midline adds a rotational component and increases the challenge to the stabilizing musculature.
External resistance. Use weights, elastic resistance, or pulleys for strengthening. Several suggestions are illustrated in Figures 16.52, 16.53, and 16.54. Even though the extremities benefit from the exercises, the primary purpose is to improve performance in the stabilizing muscles of the trunk; therefore, when signs of fatigue occur, such as poor control of spinal stability (seen as movement of the pelvis or lumbar spine), reduce the intensity or stop the exercise and allow recovery.
Position changes. Apply the extremity-loading exercises in the sitting (supported then unsupported), kneeling, and standing positions. Also, use modified bridging to challenge the stabilizing function of the trunk musculature. Exercises, such as wall slides and partial lunges and bridging with extremity motions, use the extremities and trunk during weight bearing and prepare the muscles for functional activities. These exercises are described in the final section under Functional Activities but also serve the purpose of challenging the stabilizing muscles.
Unstable surfaces. Use a large gym ball, foam roller, or wobble board to challenge the patient's balance and develop the stabilizing musculature. With the ball, a variety of positions can be used, such as sitting upright on the ball with the feet on the floor (Fig. 16.55), lying supine with the trunk on the ball and feet on the floor (see Fig. 16.60 B) or with the feet on a low mat or wobble board. The foam roller can can be used with the patient supine (Fig. 16.56), kneeling, quadruped (with hands on one roller and knees on another), or standing. Use handheld weights or elastic or pulley resistance secured at various heights (see Fig. 16.54) to increase the challenge. VIDEOS 16.20 and 16.21
Spinal Stabilization - Supine on Unstable Surfaces
Spinal Stabilization - Stabilization Progressions Cervical and Lumbar Regions
Balancing a rod on the back while doing quadruped exercises provides reinforcement that the trunk is not twisting. (A) Single leg slides. (B) Lifting the opposite arm and leg simultaneously, then alternating extremities.
(A) Alternating LE motions with the "modified bicycle" or (B) reciprocal and alternating patterns using the UE and LE simultaneously require a strong controlling action in the abdominals.
Developing the stabilizing action of the abdominal muscles by using pull-down activities against a resistive force from pulleys or elastic bands. This exercise can also be done sitting or standing to increase the challenge to the muscles in less stable positions.
Using elastic resistance to train and strengthen the abdominal muscles in the upright position. The drawing-in maneuver to set the deep segmental stabilizing muscles precedes the movement of the arms forward against the resistance.
Using elastic resistance to train and strengthen the back extensor muscles to stabilize in the upright position (A) diagonal patterns while sitting on an unstable surface and (B) while standing.
BOX 16.6 Summary of Aerobic Conditioning Principles
Establish the target heart rate and maximum heart rate.
The maximum heart rate is generally 220 minus the individual's age or may be the symptom-limiting heart rate (the rate at which cardiovascular symptoms appear).
Target heart rate is between 60% and 80% of the maximum heart rate.
Perform warm-up exercises for 10 to 15 minutes, including active movements of the neck and trunk.
Individualize the program of exercise.
Select activities that emphasize the patient's spinal bias if necessary (see information in the text).
Not all people are at the same fitness level and therefore cannot perform the same exercises. Any one exercise has the potential to be detrimental if attempted by someone not able to execute it properly.
To avoid overuse syndromes to structures of the musculoskeletal system, appropriate equipment, such as correct footwear, should be used for biomechanical support with weight-bearing exercises.
Increase the pace of the activity to reach the target heart rate and maintain it for 20 to 30 minutes.
Cool-down for 5 to 10 minutes with slow, total body, repetitive motions and stretching activities.
Frequency of aerobic exercise should be three to five times per week.
Always stay within the tolerance of the individual. Overuse commonly occurs when there is an increase in time or effort without adequate rest (recovery) time between sessions. Increase repetitions or time by no more than 10% per week.35 If pain begins while exercising, heed the warning and reduce the stress.
Strength, balance, and coordination are required to maintain spinal stabilization while sitting on a gym ball and moving the extremities. This activity is progressed by adding weights to the extremities.
Activation of the stabilizing trunk muscles occurs to maintain balance on a foam roll while the extremities move in various planes: (A) shoulder horizontal abduction/adduction and (B) ipsilateral hip and shoulder flexion/extension are shown. Weights are added to increase the challenge.
Quadratus Lumborum: Stabilization Exercises
The quadratus lumborum has been identified as an important stabilizer of the spine in the frontal and transverse planes.39 VIDEO 16.22 Strongest activation of this muscle occurs with the side propping (side plank) position. The external obliques are also activated in this position.39
Spinal Stabilization - Alternating Isometrics For Trunk Stabilization
Patient position and procedure: Begin side-lying. Have the patient prop up on the elbow and then lift the pelvis off the mat, supporting the lower body with the lateral side of the knee on the downward side. The position can be maintained for an isometric hold or performed intermittently (Fig. 16.57 A). Progress by having the patient support the upper body with the hand (with the elbow extended) and lateral aspect of the foot on the downward side (Fig. 16.57 B). Arm and leg movements (without then with weights) are added to increase the challenge.
Quadratus lumborum stabilization training using side-propping (side plank) (A) on the elbow and knee and (B) on the hand and foot.
FOCUS ON EVIDENCE
Using ultrasound imaging, Teyhen and associates61 demonstrated that the side support (side propping) exercise resulted in the greatest change in muscle thickness of the TrA and IO muscles with the least amount of lumbar loading compared to five other trunk exercises (abdominal crunch, drawing-in maneuver, quadruped opposite UE and LE lift, supine LE extender, and abdominal sit back).
Progression to Dynamic Exercises
When the patient has developed control, endurance, and strength in the stabilizing muscles in weight-bearing and nonweight-bearing positions, dynamic trunk strengthening exercises are initiated at a low-intensity (see following section). The emphasis is on control and safety.
As the patient returns to his or her instrumental activities of daily living (IADLs) and limited work activities, instruct him or her to incorporate the deep segmental activation and global stabilization techniques into the activities.
Isometric and Dynamic Exercises
Isometric exercises may be considered stabilizing exercises, as there is little or no movement of the spinal segments. They are included in this section with dynamic exercises, however, because of the method of application of the resistive force; that is, the resistive force is applied directly to the axial skeleton rather than through limb loading, as described in the spinal stabilization section. The decision to use the isometric exercises described in this section must be based on the goals of intervention. The exercises may be combined with the stabilization exercises in a home exercise program.
Dynamic exercises with spinal movement are introduced into the patient's exercise program when the patient demonstrates effective segmental and global stabilization techniques and has developed endurance in the stabilizing musculature. Dynamic exercises should not be a substitute for stabilization exercises. Because of the load imposed on the spine, they may exacerbate the patient's symptoms if introduced prior to effective stabilization and control. They are important in the total rehabilitation of the individual with neck, thoracic, or low back pain, as dynamic muscle endurance and strength is required for many daily activities as well as manual labor and athletic performance.
Exercises for the Cervical Region
PRECAUTION: Use of external weights via a cable or pulley system applied directly to the head are contraindicated for cervical strength training due to the compressive loading on the spine and the potential loss of control during the exercise.
Isometric Exercises: Self-Resistance
The intensity of the isometric exercises can range from low to high, depending on the patient's symptoms and tolerance. Patient position and procedure: Sitting.
Flexion. Have the patient place both hands on the forehead and press the forehead into the palms in a nodding fashion while not moving (Fig. 16.58 A).
Side bending. Have the patient press one hand against the side of the head and attempt to side bend, as if trying to bring the ear toward the shoulder but not allowing motion.
Axial extension. Have the patient press the back of the head into both hands, which are placed in the back, near the top of the head.
Rotation. Have the patient press one hand against the region just superior and lateral to the eye and attempt to turn the head to look over the shoulder without allowing motion.
Self-resistance for isometric (A) cervical flexion and (B) axial extension.
Isometric Resistance Activities
Patient position and procedure: Standing with a basketball-sized inflatable ball between the forehead and a wall. Have the patient keep the chin tucked and not go into a forward-head posture. The patient maintains the functional position while superimposing arm motions. Progress by adding weights to the arm motions. (See Fig. 16.46 C)
Often with faulty forward-head postures, the patient substitutes using the sternocleidomastoid (SCM) muscles to lift the head when getting up from the supine position rather than the overstretched, weak, deep cervical flexors. To correct this muscle imbalance, begin training capital flexion as described in the stabilization section (deep segmental muscle activation). For home exercise and when rising from a bed, emphasize "curling" the head and neck, not lifting the head up.
Patient position and procedure: Supine. If the patient cannot tuck the chin and curl the neck to lift the head off the mat, begin with the patient on a slant board or large wedge-shaped bolster under the thorax and head to reduce the effects of gravity (Fig. 16.59). Have the patient practice tucking the chin and curling the head up. Use assistance until the correct pattern is learned. Progress by decreasing the angle of the board or wedge and then adding manual resistance if the patient does not substitute with the SCM.
Training the short cervical flexors while de-emphasizing the sternocleidomastoid for cervical flexion to regain a balance in strength for anterior cervical stabilization.
Manual Resistance: Cervical Muscles
Patient position and procedures: Supine. Stand at the head end of the treatment table, supporting the patient's head for each exercise.
Place one hand on the patient's head to resist opposite the motion. Do not resist against the mandible lest force be transmitted to the temporomandibular joint. Resistance is given to isolated muscle actions or to general ROMs, whichever best gains muscle balance and function.
Isometric resistance can be applied with the head in any desired position before applying resistance. Avoid jerking the neck when applying or releasing the resistance by gradually building up the intensity, telling the patient to match your resistance, holding, and then gradually releasing and asking the patient to relax.
Intermediate and Advanced Training
As the patient progresses in the rehabilitation program, greater challenges to the musculature to stabilize and control motion are emphasized, especially for those individuals returning to work, sports, or recreational activities that place greater demands on the cervical structures.
Transitional Stabilization for the Cervical and Upper Thoracic Regions
Patient position and procedure: Standing with a basketball-sized inflatable ball between the head and the wall. Have the patient roll the ball along the wall, using the head. This requires the patient to turn the body as he or she walks along.
Patient position and procedure: Sitting on a large gym ball. Have the patient walk the feet forward so the ball rolls up the back and the thorax is resting on the ball (Fig. 16.60 A and B). The head and neck are maintained in neutral position, and the cervical flexors are emphasized. Have the patient then walk the ball farther, so it is under the head. The extensors are now emphasized (Fig. 16.60 C). The patient walks the feet forward and backward, alternating stabilization between the flexors and extensors. Progress to advanced training by adding arm motions and then arm motions with weights in each of the positions.
Advanced exercises for strengthening the cervical and upper thoracic flexors and extensors as stabilizers. Begin by (A) sitting on a large gym ball, then (B) walking forward while rolling the ball up the back. With the ball behind the mid-thoracic area, the cervical flexors must stabilize. Continue walking forward until the ball is (C) under the head; the cervical extensors now must stabilize. Walk back and forth between the two positions (B and C) to alternate control between the flexors and extensors. Progress by adding arm motions or arm motions with weights to increase resistance.
NOTE: This activity requires considerable strength in the cervical extensors to support the body weight and should be performed only with advanced training with patients who have been properly progressed to tolerate the resistance.
Design exercises that simulate patient-specific functional activities. Identify what activities stress that individual's neck and have the patient practice modifications of those activities with the spine kept in neutral position. Include pushing, pulling, reaching, and lifting (see the 'Functional Training' section later in this chapter). Challenge the patient with increased repetitions and weight and by using patterns that replicate functional demands.
Exercises for the Thoracic and Lumbar Regions
Alternating Isometric Contractions and Rhythmic Stabilization
Patient positions and procedures: Begin with the patient supine in the most stable position (Fig. 16.61) VIDEO 16.23 . Progress to sitting on a stable surface, sitting on an unstable surface such as a large gym ball, kneeling, and then standing. Sitting, kneeling, and standing require stabilizing action in the hip, knee, and ankle musculature, respectively, as well as the spinal muscles. Apply resistance directly against the patient's shoulders or pelvis, against a rod that is held by the patient (as in Fig. 16.61), or against the patient's outstretched arms.
Spinal Stabilization - Frontal Plane Stabilization Exercises
Alternating isometric resistance applied in the sagittal, frontal, and horizontal planes with the patient supine to stimulate the stabilizing function of the trunk musculature.
Have the patient find the neutral spine position and then activate the stabilizing muscles with the drawing-in maneuver prior to applying the resistive force. Then instruct the patient to "meet my resistance" while applying a force to stimulate isometric contractions. Apply the resistance in alternating directions at a controlled speed while the patient learns to maintain a steady position.
Initially, provide verbal cues, such as "hold against my resistance, but do not overpower me. Feel your abdominal muscles contracting. Now, I'm pulling in the opposite direction. Match the resistance and feel your back muscles contracting."
Progress by shifting the directions of resistance without the verbal cues and then by increasing the speed and force.
Begin with alternating resistance in the sagittal plane; progress to side-to-side and then transverse plane resistance. Isometric resistance to trunk rotation (transverse plane resistance) has been shown to be the most effective in stimulating the oblique abdominals, transversus abdominis, and deep spinal extensor muscles.50
Alternating resistance to pelvic rotation can also be done by having the patient assume a modified bridge position. Apply resistance directly to the pelvis to stimulate rotation while the patient isometrically holds the pelvis and spine in a stable position.
Dynamic Strengthening: Abdominal Muscles
NOTE: Dynamic exercises of the trunk musculature are not initiated until late during the rehabilitation process and not until after the patient has learned to activate the drawing-in maneuver automatically for stabilization in all functional activities.
No one abdominal exercise challenges all of the abdominal muscles39; therefore, a variety of exercises should be included in the patient's exercise program to include the entire region.
FOCUS ON EVIDENCE
EMG studies have looked at abdominal muscle recruitment with various abdominal exercises.4,34,39,64 In summary:
Curl-ups (various types) recruit primarily the rectus abdominis, with low activity in the obliques, transversus abdominis, and psoas.
Sit-ups (straight-leg and bent-knee) show high rectus and external oblique activity, high psoas activity, and high low-back compression. Heel press sit-ups increase psoas activity.
Hanging-leg raises show high external oblique and high spinal compression.
Supine single-leg lifts show negligible global abdominal muscle activity (opposite lower extremity provides stability). Primarily, these exercises are used early in the stabilization exercise routines to train the deep stabilizing muscles under progressive extremity loading.
Supine-bilateral leg lifts show increased activity in the RA, EO, and IO during the first part of the range of hip flexion and increased load on the spine.
Curl-ups on a labile surface doubled the activity of the rectus abdominis and increased the activity of the external obliques fourfold compared with curl-ups on a stable surface.64
Rectus abdominis. There is no clinically significant selective difference between the upper and lower rectus abdominis function.34 Both portions contract strongly in all trunk curl-type and leg lift exercises.34,39
External obliques. External obliques contract strongest in sit-ups and diagonal sit-ups to the opposite side.37
Internal obliques. Internal obliques contract strongest in diagonal sit-ups to the same side and horizontal side propping (see Fig. 16.57).39
Transversus Abdominis. Use of the drawing-in maneuver prior to the abdominal crunch, abdominal sit-back, and lateral side propping activates increased muscle thickness in the transversus abdominis (demonstrated with ultrasound imaging).61
Trunk Flexion (Abdominals): Supine
Patient position and procedures: Supine or hook-lying with the lumbar spine neutral. McGill39 suggested supporting the low back with the hands to maintain slight lordosis. The spine should not be allowed to go into an increased lordosis during the exercise—this indicates weakness of the abdominals and consequently lifting of the trunk occurs from hip flexor action only.32 When training the abdominals, curl-up exercises should be performed at a slow, controlled rate to activate the stabilizing function of the abdominals.65
PRECAUTIONS: If a patient experiences pain or increased radicular symptoms with trunk flexion, these exercises should not be done. Use the stabilization exercises, as described in the previous section, with the spine maintained in a neutral position (slight lordosis).
Curl-ups. First, instruct the patient to perform the drawing-in maneuver to cause a stabilizing contraction of the abdominal muscles61 (see section on 'Stabilization Training: Core Muscle Activation') and then lift the head. Progress by lifting the shoulders until the scapulae and thorax clear the mat, keeping the arms horizontal (Fig. 16.62). A full sit-up is not necessary, because once the thorax clears the mat, the rest of the motion is performed by the hip flexor muscles.
The curl-up exercise to strengthen the abdominal muscles. The thorax is flexed on the lumbar spine. The arms are shown in the position of least resistance. Progress by crossing the arms across the chest and then behind the head.
Curl-downs. If the patient is unable to perform the curl-up, begin with curl-downs by having the patient start in the hook-sitting or long-sitting position and lower the trunk only to the point at which he or she can maintain a flat low back and then return to the sitting position.
Diagonal curl-ups. Have the patient reach one hand toward the outside of the opposite knee while curling up; then alternate. Reverse the muscle action by bringing one knee up toward the opposite shoulder; then repeat with the other knee. Diagonal exercises emphasize the oblique muscles.
Curl-ups on an unstable surface. Progress the above curl-up exercises on an unstable surface, such as a large gym ball (Fig. 16.63), foam roller, or a biomechanical ankle platform system (BAPS) board.
Curl-ups on an unstable surface. The unstable surface increases activity in the oblique and rectus abdominis muscles.
FOCUS ON EVIDENCE
Patients with chronic, unilateral low back pain have been shown to have impaired balance.2 Using unstable surfaces, such as a gym ball (Fig. 16.63) or a balance board, while doing abdominal curl-up exercises has been shown to increase activity in the internal and external obliques and the rectus abdominis.64 The presumption is that these muscles generate increased activity to maintain balance on the unstable surfaces.
Double knee-to-chest. To emphasize the lower rectus abdominis and oblique muscles, have the patient set a posterior pelvic tilt, bring both knees to the chest, and return. Progress the difficulty by decreasing the angle of hip and knee flexion (Fig. 16.64).
Strengthening the abdominal muscles by flexing the hip and pelvis on the lumbar spine. The legs are shown in the position for least resistance. Progress by decreasing the angle of hip flexion until the legs can be lifted with the knees extended, as in the pelvic lift.
Pelvic lifts. Have the patient begin with the hips at 90° and the knees extended; then lift the buttocks upward off the mat (small motion). The feet move upward toward the ceiling (Fig. 16.65). The patient should not push against the mat with the hands.
Pelvic lifts. Elevating the legs upward toward the ceiling by raising the buttocks off the floor emphasizes strengthening the lower abdominal muscles.
Bilateral straight-leg raising. Have the patient begin with legs extended; then perform a posterior pelvic tilt followed by flexing both hips, keeping the knees extended. If the pelvis and spine cannot be kept stable, the knees should be flexed to a degree that allows control. If the hips are abducted before initiating this exercise, greater challenge is placed on the oblique abdominal muscles.
Bilateral straight-leg lowering. Bilateral straight-leg lowering can be performed if the bilateral SLR is difficult. Have the patient begin with the hips at 90° and knees extended; then, lower the extremities as far as possible while maintaining stability in the lumbar spine (should not increase the lordosis), followed by raising the legs back to 90°. See 'Precaution' under the bilateral SLR exercise.
The strong pull of the psoas major causes shear forces on the lumbar vertebrae. Also, the bilateral straight-leg raising and lowering exercises cause increased spinal compression loads.
If there is any low-back pain or discomfort, especially with spinal hypermobility or instability, the bilateral straight-leg raising and lowering exercises should not be performed even if the abdominals are strong enough to maintain a posterior pelvic tilt.
Be sure the patients avoid holding their breath (valsalva maneuver) as they may try to use their diaphragm to provide the stabilization.
Trunk Flexion (Abdominals): Sitting or Standing
Patient position and procedures: Sitting or standing. Pulleys or elastic material are secured at shoulder level behind the patient. Progress the resistance as the patient's abdominal strength increases.
Have the patient hold the handles or ends of the elastic material with each hand and then flex the trunk, with emphasis on bringing the rib cage down toward the pubic bone and performing a posterior pelvic tilt (Fig. 16.66).
Have the patient perform diagonal motions by bringing one arm down toward the opposite knee with emphasis on moving the rib cage down toward the opposite side of the pelvis. Repeat the diagonal motion in the opposite direction.
Standing trunk flexion against elastic material to strengthen the abdominal muscles. The patient performs a posterior pelvic tilt and then approximates the ribs toward the pubis.
Dynamic Strengthening: Erector Spinae and Multifidus Muscles
FOCUS ON EVIDENCE
Strengthening the extensor muscles and an improved extensor/flexor ratio of the trunk muscles have been found to be important in decreasing symptoms in patients with chronic low back pain (LBP).58 Lee and associates33 determined that the trunk extensor/flexor ratio is a sensitive parameter for predicting LBP. After following 67 asymptomatic individuals for 5 years, they found an increased incidence of LBP in those who had lower extensor strength than flexor muscle strength. Danneels and colleagues13 demonstrated that intensive lumbar resistance training (isometric or dynamic) is necessary to develop paravertebral muscle strength and bulk. The following is a summary of specific exercise outcomes studies.
Dynamic prone extension (prone arch), isometric trunk extension, and isometric leg extensions: high activity in both the multifidus and erector spinae42; stronger contractions when both lower extremities stabilized during trunk extension.14
Quadruped and prone upper and lower extremity lifts: stronger contractions than bridging (including bridging with feet on gymnastic ball or shoulders on gymnastic ball).14
Isolated training of multifidus: requires a low-intensity focus, as described in the stabilization section.47
Extension Exercises in Prone or Quadruped Position
Resistance can be applied to any of the following recumbent exercises by having the patient hold weights in the hands or by strapping weights around the patient's legs.
PRECAUTIONS: Extension exercises in the prone position are performed at the end of the ROM in spinal extension and therefore may not be appropriate for individuals with symptoms from conditions such as arthritis, spondylolisthesis, or nerve root compression. Patients with spondylosis or other flexion bias conditions or patients who develop symptoms under loaded conditions (e.g., with disc lesions) may experience increased symptoms and therefore should not do dynamic end-range extension exercises. If symptoms occur, modify the positioning toward more neutral spinal positions, such as the quadruped position, and emphasize stabilization with isometric holds rather than moving into full extension (see Figs. 16.49 A through D, 16.50, and 16.54).
Thoracic elevation. Begin with the arms at the sides, progress to behind the head or reaching overhead as strength improves. Have the patient tuck in the chin and lift the head and thorax. The lower extremities must be stabilized (Fig. 16.67).
Strengthening the back extensors with the arms in position to provide maximal resistance. Additional resistance can be provided by holding weights in the hands.
Leg lifts. Initially, have the patient lift only one leg, alternate with the other leg, and, finally, lift both legs and extend the spine. (See Fig 16.28 E through G.) Stabilize the thorax by having the patient hold onto the side of the treatment table.
Strengthen the trunk and hip extensors by lifting the trunk and legs off the mat simultaneously. Greater resistance can be provided by abducting the shoulders to 90° or by elevating them to 180° ("Superman").
"Superman." Progress the extension exercises by having the patient lift both upper and lower extremities simultaneously (Fig. 16.68).
Variations. Patient positioned prone on a large gym ball; combine spinal extension with UE and/or LE resistance, similar to exercises described in the stabilization exercise section (see Fig. 16.46 B).
Extension Exercises Sitting or Standing
Elastic resistance or weighted pulleys. Secure pulleys or elastic resistance in front of the patient at shoulder level. Have the patient hold onto the ends of the material or handles and extend the spine (Fig. 16.69).
Using elastic resistance for concentric eccentric back extension.
For trunk rotation, use a pulley or elastic resistance secured under the foot or to a stable object opposite the side being exercised. Have the patient pull against the resistance, extending and rotating the back. Change the angle of pull of the resistance to recreate functional patterns specific to the patient's needs (Fig. 16.70).
Rotation with extension strengthens the back extensors in functional patterns.
Trunk Side Bending (Lateral Abdominals, Erector Spinae, Quadratus Lumborum)
Trunk side-bending exercises are used for general strengthening of the muscles that side bend the trunk.
FOCUS ON EVIDENCE
McGill39 identified the quadratus lumborum as one of the most important stabilizers of the spine and documented the isometric horizontal side support as an effective exercise to strengthen this muscle (see discussion in the 'Stabilization' section and Fig. 16.57).
Side-bending exercises are also used if there is scoliosis, although exercise alone has not been shown to halt or change the progression of a structural scoliosis curve. Exercise in conjunction with other methods of correction, such as bracing, is often employed.8 When there is a lateral curve, the muscles on the convex side are usually stretched and weakened. The following exercises are described for use as strengthening exercises on the side of the convexity, although they may be used bilaterally for symmetrical strengthening. Stabilization exercises for spinal control, as previously described, may be beneficial for strengthening and conditioning when there is scoliosis.
Patient position and procedure: Standing. Place elastic resistance under the foot or have the patient hold a weight in the hand on the side of the concavity; then have him or her side bend the trunk in the opposite direction.
Patient position and procedure: Side-lying on the concave side of the curve with the apex at the edge of the table or mat so the thorax is lowered. If you have access to a split table with one end that can be lowered, begin with the apex of the curve at the bend of the table. Have the patient place the lower arm folded across the chest and upper arm along the side of the body and side bend the trunk up against gravity. Progress by having the patient clasp both hands behind the head (Fig. 16.71). Stabilization of the pelvis and lower extremities must be provided.
Antigravity strengthening of the lateral trunk musculature. (A) There is less resistance if the top arm is at the side and the bottom arm is folded across the chest. (B) Increase resistance by positioning the arms behind the head.