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Back and hip extensor muscle function during therapeutic exercises
J P Arokoski1, M Kankaanpää, T Valta
1Department of Physical and Rehabilitation Medicine, Rehabilitation Clinic, Kuopio University Hospital, Finland.
Archives of Physical Medicine and Rehabilitation
|July 22, 1999
Summary
Surface electromyography (EMG) can effectively assess multifidus muscle function during therapeutic exercises. These simple exercises activate lumbar paraspinal muscles, with higher activity in women at the L5 level.
Area of Science:
- Biomechanics and Exercise Physiology
- Musculoskeletal Rehabilitation
- Neuroscience
Background:
- Therapeutic exercises are common for low back pain, but precise load targeting remains unclear.
- Understanding paraspinal and gluteal muscle activation during exercises is crucial for effective treatment.
- This study investigated multifidus muscle function using electromyography (EMG).
Purpose of the Study:
- To assess paraspinal and gluteus maximus muscle activity at L2 and L5 levels during therapeutic exercises.
- To determine the validity of surface EMG for measuring multifidus muscle function.
- To compare muscle activation between sexes and spinal levels.
Main Methods:
- Eleven healthy subjects (5 men, 6 women) performed 18 therapeutic exercises.
- Intramuscular and surface EMG recorded paraspinal muscle activity.
- Normalized EMG amplitudes (peak and average) were calculated as a percentage of maximal voluntary contraction (MVC).
Main Results:
- High correlations (0.928–0.950) observed between intramuscular and surface EMG at L2 and L5.
- Exercise EMG amplitudes remained below 50% (peak) and 25% (average) of MVC.
- Women showed higher L5 multifidus activation than men; women also had higher L5 than L2 multifidus activation.
Conclusions:
- Surface EMG is a viable method for assessing multifidus muscle function.
- Simple therapeutic exercises effectively activate lumbar paraspinal muscles.
- Sex-based differences in multifidus activation exist at the L5 level.