Effects of step exercise on human physiological variables, physical fitness, and muscle oxygen saturation in women with sarcopenia: a pilot study

This pilot randomized controlled trial (RCT) aimed to determine whether an 8-week progressive step exercise program improves sarcopenic outcomes compared with treadmill exercise and a nonexercise control condition in women with sarcopenia. The primary outcomes were appendicular skeletal muscle mass (ASM), grip strength, calf circumference, and five-times sit-to-stand (5×STS) performance. As secondary objectives, we examined the effects of the intervention on body composition, cardiorespiratory fitness, and skeletal muscle oxygen saturation (SmO₂). Thirty-six women were randomly assigned, but 30 were included in the analysis across three groups: a control group (CON, n=10), a treadmill exercise group (TEG, n=10), and a step exercise group (SEG, n=10). Compared with the CON and TEG, the SEG demonstrated significant between-group differences in calf circumference (<i>P</i>=0.001, <i>η</i>²=0.422), grip strength (<i>P</i>=0.003, <i>η</i>²=0.393), 5×STS (<i>P</i><0.001, <i>η</i>²=0.617), and ASM (<i>P</i>=0.046, <i>η</i>²=0.194). Significant between-group differences were observed for postintervention maximal oxygen uptake (<i>P</i><0.001, <i>η</i>²=0.571) and maximal heart rate (<i>P</i>=0.018, <i>η</i>²=0.193). During graded exercise, significant between-group differences in SmO2 emerged from level 4 (<i>P</i><0.05) and persisted through level 10 (<i>P</i><0.01). These preliminary findings suggest that step exercise may be a promising and practical intervention for improving sarcopenic outcomes, aerobic capacity, and muscle oxidative adaptation in women with sarcopenia. However, larger adequately powered RCTs are required to confirm these findings and establish the efficacy of this intervention.