Importance of dimensional changes on glycolytic metabolism during growth

Purpose The aim of the present study was to investigate (i) how glycolytic metabolism assessed by accumulated oxygen deficit (AOD gly ) and blood metabolic responses (lactate and pH) resulting from high-intensity exercise change during growth, and (ii) how lean body mass (LBM) influences AOD gly and its relationship with blood markers. Methods Thirty-six 11- to 17-year olds performed a 60-s all-out test on a rowing ergometer. Allometric modelling was used to investigate the influence of LBM and LBM + maturity offset (MO) on AOD gly and its relationship with the extreme post-exercise blood values of lactate ([La] max ) and pH (pH min ) obtained during the recovery period. Results AOD gly and [La] max increased while pH min decreased linearly with LBM and MO ( r 2 = 0.46 to 0.72, p < 0.001). Moreover, AOD gly was positively correlated with [La] max ( r 2 = 0.75, p < 0.001) and negatively correlated with pH min ( r 2 = 0.77, p < 0.001). When AOD gly was scaled for LBM, the coefficients of the relationships with blood markers drastically decreased by three to four times ([La] max : r 2 = 0.24, p = 0.002; pH min : r 2 = 0.30, p < 0.001). Furthermore, by scaling AOD gly for LBM + MO, the correlation coefficients with blood markers became even lower ([La] max : r 2 = 0.12, p = 0.037; pH min : r 2 = 0.18, p = 0.009). However, MO-related additional changes accounted much less than LBM for the relationships between AOD gly and blood markers. Conclusion The results challenge previous reports of maturation-related differences in glycolytic energy turnover and suggest that changes in lean body mass are a more powerful influence than maturity status on glycolytic metabolism during growth.