Effect of two load escalation methods using a supine ergometer on the cardiorespiratory system and lower limb muscle activity

[Purpose] This study aimed to determine the effects of two load escalation methods, such as pedal weight increasing method and pedal speed raising method using a supine ergometer, on the cardiorespiratory system and lower limb muscle activity. [Participants and Methods] The study included 20 healthy adult males (age: 21 ± 1 years). Two different parameters were modulated during exercise intervention. Pedal load progression was applied in the load group (28.9 N, 72.3 N, 101.3 N), and pedal rate progression was applied in the speed group (60 rpm, 80 rpm, 100 rpm). Each group performed 5 minutes of exercise at their respective level of progression, for a total duration of 15 minutes. [Results] Oxygen consumption, carbon dioxide output, and minute ventilation were significantly increased as exercise intensity increased in both groups. Significant differences in muscle activity were found between the highest exercise intensities (101.3 N and 100 rpm). The activities of the biceps femoris and gastrocnemius were significantly higher with exercise at 100 rpm than at 101.3 N. [Conclusion] Increasing the number of revolutions per minute may significantly increase the activity of the lower limb muscles at comparable exercise intensities, despite the low work load.