Relative electromyographic activity in trunk, hip, and knee muscles during unilateral weight bearing exercises: Implications for rehabilitation.

BACKGROUND: Clinicians routinely prescribe unilateral weight bearing exercises to strengthen the lower extremity. Researchers have primarily examined thigh muscle activation with minimal attention to the hip and trunk muscles. The purpose of this study was to quantify trunk, hip, and thigh muscle activation during these types of exercises. METHODS: Electromyographic (EMG) activity was collected for the abdominal obliques (AO), lumbar extensors (LE), gluteus maximus (GMX), gluteus medius (GM), and vastus medialis (VM) as subjects performed four unilateral weight bearing exercises. Data were expressed as 100% of a maximum voluntary isometric contraction (% MVIC). Separate analyses of variance with repeated measures were used to identify muscle activity differences across exercise. The sequentially-rejective Bonferroni test was used for all post-hoc analyses. RESULTS: EMG activity for the AO, LE, and GMX was low (5.7-18.9% MVIC) during all the exercises. The GM activity was moderate (21.4-26.5% MVIC) while VM activity was high (40.0-45.2% MVIC). CONCLUSION: Lower AO and LE activation most likely resulted from subjects maintaining a vertical trunk position over the stance limb during each exercise. The fact that the exercises required greater frontal plane control (from balancing on a single limb) most likely accounted for lower GMX activity. The exercises would provide little, if any, benefit for individuals with AO, LE, or GMX weakness. The unilateral weight bearing exercises would be beneficial for GM neuromuscular re-education and endurance and VM strengthening.

POSTERIOR STERNOCLAVICULAR JOINT DISLOCATION IN A DIVISION I FOOTBALL PLAYER: A CASE REPORT.

UNLABELLED: Posterior dislocation of the sterno-clavicular (SC) joint is a rare injury in athletes. It normally occurs in high collision sports such as American football or rugby. Acute posterior dislocations of the SC joint can be life-threatening as the posteriorly displaced clavicle can cause damage to vital vascular and respiratory structures such as the aortic arch, the carotid and subclavian arteries, and the trachea. The potential severity of a posterior SC joint dislocation provides multiple challenges for clinicians involved in the emergency care and treatment of this condition. Integration of clinical examination observations, rapid critical thinking, and appropriate diagnostic imaging are often required to provide the best management and outcome for the injured athlete. The criterion for return-to-play and participation in collision sports after suffering a posterior dislocation of the SC joint are unclear due to the rarity of this injury. The purpose of this case report is to describe the management, from the initial on-field evaluation through the return-to-sport, of a collegiate Division I football player following a traumatic sports-related posterior SC joint dislocation. The rehabilitation process and the progression to return to participation are also presented and briefly discussed. LEVEL OF EVIDENCE: 4-Single case report.