Medicine & Science in Sports & Exercise:
A17t Free Communication/Poster Sport Biomechanics
Browder, K D.1; Dolny, D G.1
1University of Idaho, Moscow, ID
To date, no research has examined muscle activation during exercise on the elliptical trainer. However, many exercisers use the device to train specific muscles by altering resistance and direction of travel. A new prototype recently introduced to the market allows the exerciser to alter stride length, which may provide more flexibility in targeting specific muscles for toning.
To evaluate the effects of stride length (SL) and direction of travel on lower extremity muscle activation during elliptical trainer exercise.
Ten males volunteered as subjects (Age: 24 ± 4 yrs; Height: 175.5 ± 7.9 cm; Weight: 84.1 ± 24.2 kg). Each subject exercised at 5 stride lengths (6.7, 7.5, 8.3, 9.1, and 9.8 cm) in a forward (F) and backward (B) direction for 1 min. Direction was randomized, and SL within direction was randomized. EMG activity of the gluteus maximus (GM), vastus lateralis (VL), and biceps femoris (BF) was sampled continuously at 500 Hz for 6 consecutive strides at the end of each minute of exercise. A two-way repeated measures ANOVA (Direction X Stride Length) was calculated to determine differences in peak and average EMG activity across direction and SL.
No significant differences were found for muscle activation across SL, although trends for increased peak BF EMG (+15% overall) and decreased peak VL EMG (−16% overall) were observed with increasing SL in the forward direction. Significant differences (p < .05) were found in peak and average GM and VL activation across directions. Muscle activation was greater for GM and less for VL in the forward direction (VLFpeak: 98 ± 34 μV; VLBpeak: 139 ± 61 μV; VLFavg: 16 ± 12 μV; VLBavg: 24 ± 18 μV; GMFpeak: 65 ± 30 μV; GMBpeak: 27 ± 24 μV; GMFavg: 7 ± 5 μV; GMBavg: 2 ± 3 μV.
These results suggest that manipulation of direction and stride length during elliptical trainer exercise may promote differential use of lower extremity muscles. Supported, in part, by Sport Art, Inc.