Recruitment and activity of the pectineus and piriformis muscles during hip rehabilitation exercises: an electromyography study.

BACKGROUND: The pectineus muscle has been reported to function primarily as a hip flexor and secondarily as a hip internal rotator; the piriformis muscle has been reported to function as an abductor and external rotator of the hip. The recruitment and activations of these muscles during hip rehabilitation exercises have not been detailed. HYPOTHESIS: The authors hypothesized that they would measure the highest pectineus activation during exercises involving hip flexion, with moderate pectineus activation during exercises with hip internal rotation. They also hypothesized that they would measure the highest piriformis activation during exercises involving hip abduction and/or external rotation. STUDY DESIGN: Descriptive laboratory study. METHODS: Ten healthy volunteers completed 13 hip rehabilitation exercises with electromyography (EMG) electrodes inserted under ultrasound guidance into the pectineus and piriformis muscle bellies. The EMG signals were recorded and exercise activation levels were reported as a percentage of a maximum voluntary contraction (MVC). RESULTS: Both the highest peak pectineus activation (62.8% ± 26.6% MVC) and the highest mean pectineus activation (33.1% ± 17.4% MVC) were measured during the supine hip flexion exercise. Moderate activation was found during the single- and double-legged bridge and both phases of the stool hip rotation exercise. The highest peak piriformis activation was observed in the single-legged bridge (MVC, 35.7% ± 25.7%), and the highest mean piriformis activation was observed in the prone heel squeeze (MVC, 24.3% ± 8.2%). Similar moderate activation levels were found for single-legged hip abduction and resisted hip extension. CONCLUSION: The pectineus was highly activated during hip flexion exercises and moderately activated during exercises requiring rotational hip stabilization in either direction, rather than with internal hip rotation only. The piriformis was most activated during static external rotation and abduction while the participants' hips were in slight extension. These observations indicate that the pectineus and piriformis are both muscles that contribute to hip stabilization. CLINICAL RELEVANCE: The findings indicate that the pectineus and piriformis function as hip-stabilizing muscles and can be used to specifically address pectineus and piriformis muscle rehabilitation. The authors believe that strengthening and conditioning of these muscles should aid in the restoration of hip function and stability after injury or arthroscopic surgery.

Rehabilitation exercise progression for the gluteus medius muscle with consideration for iliopsoas tendinitis: an in vivo electromyography study.

BACKGROUND: It is common for hip arthroscopy patients to demonstrate significant gluteus medius muscle weakness and concurrent iliopsoas tendinitis. Restoration of gluteus medius muscle function is essential for normal hip function. HYPOTHESIS: A progression of hip rehabilitation exercises to strengthen the gluteus medius muscle could be identified that minimize concurrent iliopsoas muscle activation to reduce the risk of developing or aggravating hip flexor tendinitis STUDY DESIGN: Descriptive laboratory study. METHODS: Electromyography (EMG) signals of the gluteus medius and iliopsoas muscles were recorded from 10 healthy participants during 13 hip rehabilitation exercises. The indwelling fine-wire EMG electrodes were inserted under ultrasound guidance. The average and peak EMG amplitudes, normalized by the peak EMG amplitude elicited during maximum voluntary contractions, were determined and rank-ordered from low to high. The ratio of iliopsoas to gluteus medius muscle activity was calculated for each exercise. Exercises were placed into respective time phases based on average gluteus medius EMG amplitude, except that exercises involving hip rotation were avoided in phase I (phase I, initial 4 or 8 weeks; phase II, subsequent 4 weeks; phase III, final 4 weeks). RESULTS: A continuum of hip rehabilitation exercises was identified. Resisted terminal knee extension, resisted knee flexion, and double-leg bridges were identified as appropriate for phase I and resisted hip extension, stool hip rotations, and side-lying hip abduction with wall-sliding for phase II. Hip clam exercises with neutral hips may be used with caution in patients with hip flexor tendinitis. Prone heel squeezes, side-lying hip abduction with internal hip rotation, and single-leg bridges were identified for phase III. CONCLUSION/CLINICAL RELEVANCE: This study identified the most appropriate hip rehabilitation exercises for each phase to strengthen the gluteus medius muscle after hip arthroscopy and those to avoid when iliopsoas pain or tendinitis is a concern.

Rehabilitation after arthroscopic repair of intra-articular disorders of the hip in a professional football athlete.

OBJECTIVE: To report the 4-phase rehabilitation progression of a professional athlete who underwent arthroscopic intra-articular repair of the hip after injury during the 2006-07 season. DESIGN: Case study; level of evidence, 4. MAIN OUTCOME MEASURES: Objective values were obtained by standard goniometric measurements, handheld dynamometer, dynamic sports testing, and clinical testing for intra-articular pathology. RESULTS: This case report illustrates improvements in hip mobility, muscle-force output, elimination of clinical signs of intra-articular involvement, and ability to perform high-level sport-specific training at 9 wk postsurgery. At 16 wk postsurgery, the patient was able to return to full preparation for sport for the following season. CONCLUSION: After the 4-phase rehabilitation program, the patient demonstrated improvement in all areas of high-level function after an arthroscopic intra-articular repair of the hip. The preoperative management to return to sport is outlined, with clinical outcomes and criteria for return to competition.