Comparative Analysis of Muscle Synergy between Patients with Shoulder Impingement Syndrome and Healthy Controls: A Preliminary Study.

Shoulder impingement syndrome can be caused by a muscle imbalance around the shoulder joint. It would be beneficial for therapy to implement rehabilitation exercises based on intermuscular coordination in order to achieve muscle balance. This study presents the muscle synergy characteristics of patients with shoulder impingement syndrome, which can be used to develop rehabilitation exercises. During pick and place task, the muscle synergy obtained from eight shoulder muscles in patients and healthy subjects was compared. The experimental results revealed that patients have low contributed muscle synergy structures for the serratus anterior and infraspinatus.Clinical relevance- This proposes that patients with shoulder impingement syndrome may have abnormal muscle synergy structure which can be used for assessment.

Altered Biomechanics in Individuals With Chronic Ankle Instability Compared With Copers and Controls During Gait.

CONTEXT: Given that motions of 1 segment affect those of an adjacent segment, the authors of biomechanical studies must thoroughly investigate the kinematics and kinetics of the proximal joints (hip and knee) as well as the ankle joints in patients with chronic ankle instability (CAI). However, few researchers have investigated the altered movement strategies of the lower extremities of patients with CAI compared with lateral ankle-sprain (LAS) copers and control participants throughout the full gait cycle of walking and jogging. OBJECTIVE: To evaluate lower extremity biomechanical differences in patients with CAI, LAS copers, and control individuals during gait. DESIGN: Case-control study. SETTING: Controlled laboratory setting. PATIENTS OR OTHER PARTICIPANTS: A total of 54 participants, consisting of 18 patients with CAI (age = 24.6 ± 2.8 years, height = 173.0 ± 8.0 cm, mass = 67.8 ± 14.6 kg), 18 LAS copers (age = 26.0 ± 4.6 years, height = 173.4 ± 7.5 cm, mass = 66.9 ± 10.3 kg), and 18 control individuals (age = 26.2 ± 2.3 years, height = 172.2 ± 8.2 cm, mass = 63.3 ± 11.2 kg). MAIN OUTCOME MEASURE(S): Three-dimensional kinematics and kinetics of the lower extremity during walking and jogging. RESULTS: The CAI group exhibited dorsiflexion deficits and more inverted ankles compared with the LAS coper and control groups during walking and jogging. In addition, the LAS coper group generated greater knee internal-rotation moments than did the CAI group during jogging. The other variables did not differ among groups. CONCLUSIONS: Participants with CAI demonstrated altered biomechanics, which need to be addressed via intervention programs.