Effects of Sex, Training, and Maturity Status on the Cardiopulmonary and Muscle Deoxygenation Responses during Incremental Ramp Exercise

Abstract

Whilst participation in regular exercise and sport has generally increased over recent decades globally, fundamental questions remain regarding the influence of growth, maturation, and sex on the magnitude of training response throughout adolescence. Trained (108 participants, 43 girls; age: 14.3 ± 1.8 years) and untrained (108 participants, 43 girls; age: 14.7 ± 1.7 years) adolescents completed an incremental ramp test to exhaustion during which breath by gas exchange, beat-by-beat heart rate (HR), stroke volume (SV) and cardiac output (Q̇) and muscle deoxygenation were assessed. Device-based physical activity was also assessed over seven consecutive days. Boys, irrespective of training status, had a significantly higher absolute (2.65 ± 0.70 L min−1 vs. 2.01 ± 0.45 L min−1, p < 0.01) and allometrically scaled (183.8 ± 31.4 mL·kg−b min−1 vs. 146.5 ± 28.5 mL·kg−b min−1, p < 0.01) peak oxygen uptake (V̇O2) than girls. There were no sex differences in peak HR, SV or Q̇ but boys had a higher muscle deoxygenation plateau when expressed against absolute work rate and V̇O2 (p < 0.05). Muscle deoxygenation appears to be more important in determining the sex differences in peak V̇O2 in youth. Future research should examine the effects of sex on the response to different training methodologies in youth.

The associations of physical activity, sedentary time, and sleep with V˙O2max in trained and untrained children and adolescents: A novel five-part compositional analysis

“…These equivocal findings may be related to a reliance on techniques that fail to account for the inter-related and inherently constrained nature of PA behaviours, leading to spurious conclusions [18,25,26]. Moreover, the reliance on ratio scaled peak _ VO 2 potentially creates erroneous associations [15,42]. Of note, in the present study when _ VO 2max was allometrically scaled by body mass, the overall PA composition explained ~11% less variance compared to absolute _ VO 2max .…”

The joint associations of physical activity, sedentary time, and sleep on VO2max in trained and untrained children and adolescents: A novel five-part compositional analysis

“…These equivocal findings may be related to the reliance on techniques that fail to account for the inter-related and inherently constrained nature of PA behaviours, leading to spurious conclusions [18,25,26]. Moreover, the reliance on ratio scaling VO 2max potentially creates spurious associations [15,42]. Of note, when VO 2max was allometrically scaled by body mass, the overall PA composition explained ~11% less variance compared to absolute VO 2max .…”