This study examined the effects of trunk exercise on unstable surfaces on trunk control and balance for persons in the sub-acute stage of stroke. The hypothesis was that, compared to upper limb exercises in well supported sitting position, this exercise would lead to better trunk control and sitting and standing balance. The results supported the hypothesis.

Inpatients in the sub-acute stage of stroke were randomly assigned to receive upper limb range of motion exercises in well supported sitting position or trunk exercises on unstable surfaces in supine and sitting, 30 min per session, 2 sessions per week for 6 weeks, in addition to their daily conventional stroke rehabilitation. Sensorimotor functions, including hand grip strength, plantar sensitivity, stroke rehabilitation assessment of movement and Fugl-Meyer lower extremity motor scale, and clinical outcome assessments, including Trunk Impairment Scale and 6-meter walk test, were conducted by a blinded assessor. Biomechanical outcome measures included center of pressure area while maintaining static posture and peak displacement while leaning forward, and the average speed of the unaffected arm raising (to represent the ability to provide a stable foundation for focal movement). These measures were taken in sitting without foot support, sitting with foot support and standing to reflect trunk control, sitting balance and standing balance, respectively.

Inclusion Criteria:

• age: between 20-80 years old
• first time stroke
• could sit without back support at least 20 seconds
• could understand and follow experimental instructions

Exclusion Criteria:

• medically unstable
• other neuromuscular/musculoskeletal problems that would affect balance

Outcome assessor not aware of group assignment