Enhanced understanding of how muscle demands vary across cardiovascular exercises is essential for optimizing treatment and fitness interventions.
PURPOSE: To compare muscle activity patterns in key hip stabilizers during five exercises.
METHODS: Eight healthy adults participated (5 male, 3 female, 25.5±5.9yrs). After completing 3 familiarization sessions, each subject performed 5 exercises in random order: recumbent biking (RB), stair stepping (SS), elliptical training (EL), walking (WK) and jogging (JG). Subjects were instructed to perform each at an intensity that could be maintained for 30-min. Electromyographic (EMG, fine-wire indwelling electrodes: upper gluteus maximus (GM-U), lower gluteus maximus(GM-L), and gluteus medius(GMED)), kinematic and foot-floor contact pattern data were recorded during the final minute of a 5-min workout. Cycle timing was defined by using footswitch (WK, JG) and kinematic (RB, SS, EL) data. EMG peak activity (expressed as % of maximum voluntary contraction), as well as duration (expressed as % of total cycle) were calculated across 10 cycles for each muscle activity. A 5×1 ANOVA with repeated measures identified significant differences in EMG activity (peak and duration) across exercises for each muscle. A Bonferroni adjusted alpha level of p < 0.0167 assessed significance.
RESULTS: Peak EMG activity (Mean ± SD) showed that JG, EL, WK > RB (35+22, 26+16, 20+15 > 3+5, p<0.014) in GM-U, JG, EL, WK > RB (32+16, 25+14, 17+6 > 8+9, p,<0.001) in GM-L, and JG, EL, SS, WK > RB (72+52, 57+30, 42+30, 34+26 > 3+5, p<0.011) and EL >WK (57+30 > 34+26, p=0.009) in GMED. Duration EMG activity showed that JG, EL >WK, RB (37+8, 36+8 > 15+11, 5+9, p<0.001) in GM-U, JG, EL >WK, RB (43+13, 35+10 > 16+6, 13+15, p<0.005) GM-L, and JG, EL, SS, WK > RB (44+21, 41+11, 38+12, 20+10 > 4+8, p<0.009) and EL, SS > WK (41+11, 38+12 > 20+10, p<0.011) in GMED.
CONCLUSION: When maximizing gluteal effort is a desired therapeutic goal, JG and EL should be considered. If protection of weak gluteals is required (e.g., with post polio), consideration of RB appears warranted due to the diminished demand.
