Researchers at the University of Kentucky evaluated electromyographic (EMG) levels of 4 exercises in total hip patients between 7 and 32 weeks post-operative. Dr. Cale Jacobs and colleagues were interested to see if there was a progression of muscle activation to guide clinical decisions about hip abduction exercise prescription. They published their findings in the Journal of Arthroplasty. The 4 exercises included 2 non-weight bearing and 2 weight-bearing exercises:

• Standing hip abduction with cuff weight at 1% of bodyweight, lifted to 30 degrees
• Sidelying hip abduction with cuff weight at 0.5% of bodyweight, lifted to 50% of leg length
• Standing hip abduction with uninvolved leg to 30 degrees
• Lateral walk with Thera-Band resistance band attached with extremity straps around ankle

Researchers used a level of Thera-Band resistance that created the same torque as the standing hip abduction exercise (1% body weight) with stretch on the band at 50% elongation. The researchers used this chart of Thera-Band elastic resistance pull forces to prescribe the appropriate color of band.

Both the sidelying abduction and weight-bearing standing abduction with the other leg produced an average of 67% maximum voluntary isometric contraction (MVIC).  The Thera-Band resisted lateral walk exercise produced an average of 63% MVIC and the non-weight bearing standing abduction produced 58%. There was no significant difference in activation between exercises, indicating no clear order of exercise progression.  The researchers suggested these exercises can be used interchangeably, particularly when balance impairment or postural position may be an issue.

In conclusion, non-weight bearing exercises involving open-chain hip abduction provide no additional benefit of gluteus medius activation compared to more functional closed-chain exercises. Thera-Band loop resisted walking provides moderate (>60% MVIC) of gluteus medius activation in post-operative total hip replacement patients.

REFERENCE: Jacobs CA, et al. Electromyographic analysis of hip abductor exercises performed by a sample of total hip arthroplasty patients. J Arthroplasty. 2009 Oct;24(7):1130-6. Epub 2008 Aug 30.

Disclosure: Thera-Band Academy provided the bands used in this study, but did not provide monetary funding.

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• 1-leg balance, 15-30 seconds for 5 reps on each leg
• 1-leg balance with opposite leg movement for 1 to 3 sets of 15-25 reps
• Hip lift for 3 sets of 15-25 reps
• 2-leg calf raise with 2-second hold, 1 to 3 sets for 15 to 25 reps.
• Patients progress from a stable surface to Thera-Band Stability Trainers.

In a paper published in the Journal of Geriatric Physical Therapy, German researchers wanted to compare their Hip School participants with a non-exercising control group of hip patients. Each group was tested before and after 3 months using an oscillating platform (Posturomed®) to measure their static and dynamic balance. The Posturomed quantified the participants’ center of pressure excursion and balance recovery after platform perturbation.

The Hip School training group had a significantly lower percentage of failures and movements to maintain their balance on the Posturomed, particularly in the medial-lateral direction. The authors concluded that the Hip School exercise program utilizing Thera-Band Stability Trainers for 12 weeks significantly improved dynamic balance in older adults with hip osteoarthritis and replacement compared to a non-exercising control group. In particular, exercise participants also improved their reaction to perturbation, which is a primary contributor to falls.

Reference: Boeer J, et al. 2010. Effects of a sensory-motor exercise program for older adults with osteoarthritis or prosthesis of the hip using measurements made by the Posturomed oscillatory platform. J Geriatric Phys Ther. 33(1):10-15

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By Michal Novotny PT and Todd Ellenbecker DPT, MS, SCS, OCS, CSCS

Injuries to the lower extremities in elite tennis players are prevalent due to the multidirectional movements inherent in tennis play coupled with the repetitive loading and often extreme ranges of motion incurred in some tennis strokes. Tennis is unique in that it is played on many surfaces with very different coefficient of friction and traction demanding different responses at the court/shoe interface affecting traction, lower body loading, and ultimately functional performance. An increase awareness of hip injuries in including hip impingement and labral tears has necessitated clinical strategies aimed at reducing intra-articular hip injury. Descriptive study of hip internal and external rotation range of motion have shown bilateral symmetry in elite level tennis players. Additionally, tennis players and other multidirectional sport athletes have long been plagued with muscular injury in the form of strains particularly of the two joint musculotendinous structures of the hip and groin. Finally, recent emphasis has been places on dynamic stretching and warm-up prior to athletic performance due to the finding of short term decreases in acute high intensity muscular power and explosiveness following traditionally applied static stretches in athletes.

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