EMG Activation of Gluteal Musculature During Exercises With and Without Resistance (GlutEMG02)

EMG Activation of Gluteal Musculature and Perceived Exertion During Therapeutic Exercises With and Without Thera-Band® Resistance

The gluteus medius (Gmed) and gluteus maximus (Gmax) muscles are important components in the treatment of many lower limb injuries. Recent studies have evaluated a myriad of exercises which activate the Gmed and Gmax, but limited research remains on exercises involving resistance and the role of the TFL. The purpose of this study is to evaluate Gmed, Gmax, and TFL percent maximal voluntary isometric contraction (%MVIC) and perceived exertion in healthy and low back pain patients while performing exercises with and without resistance. Methods: A convenience sample of healthy subjects and patients diagnosed with non-radicular low back pain will be recruited. Exclusionary criteria will include: current low back or lower extremity injury (healthy group), pregnancy, history of hip surgery, and radicular symptoms. Surface electromyography will be used to quantify the activity level of the gluteal muscles and TFL while performing a series of 8 exercises with and without Thera-Band® Resistance Tubing and Stability Trainer. The maximal voluntary isometric contraction (MVIC) will be established for each muscle group and the order of exercises performed will be randomized to minimize the effect of fatigue. Following the completion of each exercise, the patient will rate their perceived exertion level on the Thera-Band® Resistance Intensity Scale for Exercise (RISE). The EMG signals will be smoothed and rectified and analyzed using a root-mean-square algorithm. Clinical Relevance: The results of this study will allow clinicians to better prescribe exercises, proven to activate the gluteal muscles and limit the TFL involvement, in the treatment of low back pain.

Percent of Maximal Voluntary Isometric Contraction was measured by placing EMG leads on selected muscles. Data was collected and analyzed with the MyoResearch XP Masters Edition (Noraxam Inc., Scottsdale, AZ). The EMG signals were smoothed and rectified and analyzed using a root-mean-square algorithm. We used visual onset and offset of the EMG signal amplitude to select the middle 3 of 5 trials. The middle three repetitions were analyzed. Average activation and peak activation were determined and then compared to the maximum voluntary isometric contraction (MVIC), captured during a manual muscle test, for each muscle group, and expressed as a %MVIC. The %MVIC can be greater than 100% since the MVIC is captured in a stationary, isometric position using manual force and all other activities are performed in motion against elastic or gravity resistance.

Thera-Band(R) RISE (Resistance Intensity Scale for Exercise) Scale to measure amount of perceived exertion during resistance band exercises. This is a scale 0 to 10, 0 being extremely easy and 10 being extremely hard. The subject rated the intensity or resistance felt on each exercise on this scale. The ideal range for an exercise is in the middle of the scale (4-7) where the subject is feeling resistance but is not maximally exerted.

Inclusion Criteria: healthy, physically active subjects patients diagnosed with non-radicular low back pain 18-65 Exclusion Criteria: current low back or lower extremity injury (healthy group) pregnancy history of hip surgery radicular symptoms