The hip joint mobilization with movement technique improves muscle activity, postural stability, functional and dynamic balance in hemiplegia secondary to chronic stroke: a blinded randomized controlled trial.

BACKGROUND: People with stroke generally experience abnormal muscle activity and develop balance disorder. Based on the important role of the proximal joints of the lower extremity in balance maintenance, hip joint mobilization with movement technique can be applied to enhance normal joint arthrokinematics. Therefore, the present study aimed to investigate the effectiveness of hip joint mobilization with movement technique on stroke patients' muscle activity and balance. METHODS: Twenty patients aged between 35 and 65 years old with chronic stroke were randomly assigned either to an experimental group (n = 10) or to a control group (n = 10). Both groups participated in a 30-minute conventional physiotherapy session 3 times per week for 4 weeks. The experimental group received an additional 30-minute's session of hip joint mobilization with movement technique on the affected limb. The muscle activity, berg balance scale, time up and go, and postural stability were measured at baseline, 1-day and 2-week follow-up by a blinded assessor. RESULTS: The experimental group showed a significant improvement in berg balance scale, time up and go, and postural stability (p ≤ 0.05). The rectus femoris, tibialis anterior, biceps femoris, and medial gastrocnemius muscles' activations of the affected limb during static balance test markedly changed along with the biceps femoris, erector spine, rectus femoris, and tibialis anterior muscles during dynamic balance test after hip joint mobilization with movement technique. The mean onset time of rectus abdominus, erector Spine, rectus femoris, and tibialis anterior muscles activity significantly decreased in the affected limb after hip joint mobilization with movement technique compared to the control group (p ≤ 0.05). CONCLUSIONS: The results of the present study suggest that a combination of hip joint mobilization with movement technique and conventional physiotherapy could improve muscle activity and balance among chronic stroke patients. TRIAL REGISTRATION NUMBER: The study was registered in the Iranian Registry of Clinical Trials (No; IRCT20200613047759N1). Registration date: 2/08/2020.

Head and neck extension more than 30° may disturb standing balance in healthy older adults.

Although there is clinical evidence of postural instability at extreme angles of head extension, the effects of lower angles on balance have been not investigated. This study aimed to investigate the effects of different head and neck extension angles on standing balance in older adults, and to determine the critical angle of instability. Twenty-eight healthy older adults were tested at 0°, 20°, 30° and 40° head and neck extension. The center of pressure (COP) parameters were recorded with a force plate. Significant differences were observed between 30° and 40° compared to 0° in anteroposterior and mediolateral COP displacement and total COP velocity, and between 40° and 0° in mediolateral COP velocity. Head and neck extension at 30° was the critical angle associated with the appearance of instability, and this value should be considered in the ergonomic design of work and living spaces, exercise programming and daily activities in older adults.