The aim of this study was to determine whether prepubertal children are metabolically comparable to well-trained adult endurance athletes and if this translates into similar fatigue rates during high-intensity exercise in both populations. On two different occasions, 12 prepubertal boys (10.5 ± 1.1 y), 12 untrained men (21.2 ± 1.5 y), and 13 endurance male athletes (21.5 ± 2.7 y) completed an incremental test to determine the power output at VO2max (PVO2max) and a Wingate test to evaluate the maximal anaerobic power (Pmax) and relative decrement in power output (i.e., the fatigue index, FI). Furthermore, oxygen uptake (VO2), heart rate (HR), and capillary blood lactate concentration ([La]) were measured to determine (i) the net aerobic contribution at 5-s intervals during the Wingate test, and (ii) the post-exercise recovery kinetics of VO2, HR, and [La]. The Pmax-to-PVO2max ratio was not significantly different between children (1.9 ± 0.5) and endurance athletes (2.1 ± 0.2) but lower than untrained men (3.2 ± 0.3, p < 0.001 for both). The relative energy contribution derived from oxidative metabolism was also similar in children and endurance athletes but greater than untrained men over the second half of the Wingate test (p < 0.001 for both). Furthermore, the post-exercise recovery kinetics of VO2, HR, and [La] in children and endurance athletes were faster than those of untrained men. Finally, FI was comparable between children and endurance athletes (−35.2 ± 9.6 vs. −41.8 ± 9.4%, respectively) but lower than untrained men (−51.8 ± 4.1%, p < 0.01). To conclude, prepubertal children were observed to be metabolically comparable to well-trained adult endurance athletes, and were thus less fatigable during high-intensity exercise than untrained adults.
The aim of this study was to test (a) three methods to estimate the quantity of lactate accumulated (QLaA ) in response to supramaximal exercise and (b) correlations between QLaA and the nonoxidative energy supply assessed by the accumulated oxygen deficit (AOD). Nine rowers performed a 3-min all-out test on a rowing ergometer to estimate AOD and lactate accumulation in response to exercise. Peak blood lactate concentration [(La)peak ] during recovery was assessed, allowing QLaA(m1) to be estimated by the method of Margaria et al. Application of a bicompartmental model of lactate distribution space to the blood lactate recovery curves allowed estimation of (a) the net amount of lactate released during recovery from the active muscles (NALR max ), and (b) QLaA according to two methods (QLaA(m2) and QLaA(m3)). (La)peak did not correlate with AOD. QLaA(m1), QLaA(m2) and QLaA(m3) correlated with AOD (r = 0.70, r = 0.85 and r = 0.92, respectively). These results confirm that (La)peak does not provide reliable information on nonoxidative energy supply during supramaximal exercise. The correlations between AOD and QLaA(m2) and QLaA(m3) support the concept of studying blood lactate recovery curves to estimate lactate accumulation and thus the contribution of nonoxidative pathway to energy supply during supramaximal exercise.
Our results highlight the importance of considering the contribution of total muscle mass and anaerobic energy pathways to 1,500-m rowing performance in competitive adolescent rowers. Therefore, the modified Wingate test could be used by rowing coaches to potentially identify talented young rowers.
Rowing races require developing high level of force and power output at high contraction velocity. This study determined the force-velocity and power-velocity (F-P-V) profiles of lower and upper limbs of adolescent rowers and their relationships with a 1,500-m rowing ergometer performance. The power developed during the 1,500-m (P) was evaluated in fourteen national-level male rowers (age: 15.3±0.6 yrs). F-P-V profiles were assessed during bench pull (BP) and squat jump (SJ) exercises. The theoretical maximal values of force (F), velocity (V), power output (P) and the F-V relationship slope (S ) were determined. The body mass (BM) influence on these relationships was considered using an allometric approach. F was 720±144 and 2146±405 N, V was 1.8±0.1 and 1.8±0.3 m·s, P was 333±83 and 968±204 W and S was -391±54 and -1,200±260 N·s·m for BP and SJ, respectively. Upper and lower limb F and P were significantly related. P was significantly (<0.05) correlated to V, F, S, P, F and P (r²=0.29 to 0.79). BM accounted for more than 90% of these relationships. Rowers' F-P-V profiles reflect adaptations to chronic rowing practice. F-P-V profiles and rowing performance correlations suggest that BP and SJ exercises are relevant to evaluate young rowers' explosive abilities.
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