Most exercise machines restrict motion to the midline, thereby engaging flexor-extensor muscles selectively. However, most sports require changes of direction involving lateral leg motion (mediated by abductor-adductor muscles) as well as flexion-extension. A recent study seeking to identify the“optimal” equipment for indoor energy expenditure evaluated midline devices exclusively. Therefore, we compared responses to midline vs. nonmidline exercise using a new device (a “stepswing”) that permits independent lateral and vertical foot travel by mounting astep mechanism at the lower ends of 2 side-by-side pivot arms, thus freeing the legs to also swing laterally. Eight normal subjects performed 3 flexion-extension exercises - stepping (S), hopping (H), and light hopping (LH) (step heights 24±4, 24±4, and 13±1 cm, respectively) - in both midline and abducted stances (feet 32±3 vs. 53±7 cm apart). All 6 bouts of exercise were performed for 3 minutes at constant frequency (70±3 steps/min) and resistance. Shown are mean±SD for peak HR (bpm) and VO2 (ml/kg/min).*P<0.05, †p<0.06 (midline vs. abducted stance) Table
Addition of an abducted stance increased the intensity of each flexion-extension exercise on the stepswing. For S and LH, these differences were significant, while the greater difficulty of full hopping may have limited the effect. We conclude that exercises combining motion along both lateral and vertical axes may further “optimize” energy expenditure by recruiting more muscle groups, while they also provide more sport-specific training.
B-22 POSTER APPLIED EXERCISE PHYS