Oxygen uptake and heart rate kinetics of body mass-based squat exercise in children and adults

Abstract

This study aims to clarify oxygen uptake (VO₂) and heart rate (HR) kinetics of body mass-based squat exercise (SQ_BM) with relation to age. Fourteen healthy adults and 19 healthy children performed SQ_BM 200 times as well as an incremental loaded bicycle test to determine maximal VO₂ and HR. The VO₂ and HR during SQ_BM were normalized to maximal VO₂ (%VO₂peak) and HR (%HRmax), respectively. Electromyograms (EMGs) were recorded from the vastus lateralis, rectus femoris, vastus medialis and biceps femoris muscles from the right leg. In the VO₂ and HR during SQ_BM, the time constant in children was faster than adults, whereas the physiological load (%VO₂peak and %HRmax) was almost the same between children and adults. In both groups, %VO₂peak was significantly related to %HRmax during SQ_BM. The slope of the %VO₂peak-%HRmax relationship was 0.92 for children, and 0.73 for adults. The current results demonstrate that, compared to adults, the rise in VO₂ and HR after initiation of SQ_BM is faster in children, and the physiological load during SQ_BM partially depends on individual maximal aerobic capacity.