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) and blood metabolic responses (lactate and pH) resulting from high-intensity exercise change during growth, and (ii) how lean body mass (LBM) influences AOD 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 and its relationship with the extreme post-exercise blood values of lactate ([La]) and pH (pH) obtained during the recovery period.

Results: AOD and [La] increased while pH decreased linearly with LBM and MO (r = 0.46 to 0.72, p < 0.001). Moreover, AOD was positively correlated with [La] (r = 0.75, p < 0.001) and negatively correlated with pH (r = 0.77, p < 0.001). When AOD was scaled for LBM, the coefficients of the relationships with blood markers drastically decreased by three to four times ([La]: r = 0.24, p = 0.002; pH: r = 0.30, p < 0.001). Furthermore, by scaling AOD for LBM + MO, the correlation coefficients with blood markers became even lower ([La]: r = 0.12, p = 0.037; pH: r = 0.18, p = 0.009). However, MO-related additional changes accounted much less than LBM for the relationships between AOD 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.