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Chapter Outline
Biomechanics of Sitting
Treatment Strategies for Improving Postural Control in Sitting
Interventions to Improve Stability in Sitting
Interventions to Improve Dynamic Stability in Sitting
Sitting, Active Weight Shifts
Active Weight Shifts Against Resistance
Voluntary Movements and Task-Oriented Practice
Resisted Limb Movements
Interventions to Improve Transitional Mobility in Sitting
Scooting in the Short-Sitting Position
Scooting in the Long-Sitting Position
Scooting Off a High Table Into Supported Unilateral Standing
Interventions to Improve Balance Control in Sitting
Interventions to Promote Reactive Balance Control
Promoting Balance Control Using Mobile and Compliant Surfaces
Computerized Platform/Feedback Training
Ball Activities
Promoting Adaptive Balance Control
Seated Integrative Medicine Exercises
Seated Tai Chi
Seated Yoga
Outcome Measures of Sitting Ability
Summary
Student Practice Activities
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This chapter focuses on sitting control and interventions that can be used to improve sitting and sitting balance skills. Careful examination of the patient’s overall status in terms of impairments and activity constraints that limit sitting control is necessary. This includes examination of musculoskeletal alignment, range of motion (ROM), and muscle performance (strength, power, and endurance). Examination of motor function (motor control and motor learning) focuses on determining weightbearing status, postural control, and neuromuscular synergies required for static and dynamic control. It also examines use of sensory (somatosensory, visual, and vestibular) cues for sitting balance control and central nervous system (CNS) sensory integration mechanisms. Finally, the patient must be able to safely perform functional movements (activities of daily living [ADL]) in sitting and in varying environments (clinic, home, work [job/school/play], and community).
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BIOMECHANICS OF SITTING
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It is important to understand the foundational requirements of sitting. Sitting is a relatively stable posture with a moderately high center of mass (COM) and a moderate base of support (BOS) that includes contact of the buttocks, thighs, and feet with the support surface. The pelvis is the foundation for sitting and strongly influences postural alignment of the entire axial skeleton. A neutral pelvic position is optimal for sitting. This is characterized by (1) an anterior superior iliac spine (ASIS) that is level or slightly lower than the posterior superior iliac spine (PSIS) (sagittal plane) and (2) a level position of both ASISs (frontal plane). Both ischial tuberosities should be equally weight-bearing. The lumbar spine has a natural lumbar lordosis accompanied by extension throughout other areas of the spine. The head and trunk are vertical, maintained in midline orientation over the pelvis with a “chin-in” position of the head. During active erect sitting, the line of gravity (LoG) passes close to the axes of rotation of the head and spine. During relaxed, erect sitting, the LoG is slightly anterior to these axes of rotation, whereas during slumped or slouched sitting, the LoG is well forward of these axes (Fig. 6.1).1
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