Williams Craig A, Dekerle Jeanne, McGawley Kerry, Berthoin Serge, Carter Helen
Children's Health and Exercise Research Centre, School of Sport & Health Sciences, University of Exeter, Exeter, UK.
Appl Physiol Nutr Metab. 2008 Dec;33(6):1105-11. doi: 10.1139/H08-096.
The purpose of the study was to identify critical power (CP) in boys and girls and to examine the physiological responses to exercise at and 10% above CP (CP+10%) in a sub-group of boys. Nine boys and 9 girls (mean age 12.3 (0.5) y performed 3 constant-load tests to derive CP. Eight of the boys then exercised, in random order, at CP and CP+10% until volitional exhaustion. CP was 123 (28) and 91 (26) W for boys and girls, respectively (p < 0.02), which was equivalent to 75 (6) and 72 (10) % of peak oxygen uptake, respectively (p > 0.47). Boys' time to exhaustion at CP was 18 min 37 s (4 min 13 s), which was significantly longer (p < 0.007) than that at CP+10% (9 min 42 s (2 min 31 s)). End-exercise values for blood lactate concentration (B[La]) and maximal oxygen uptake were higher in the CP+10% trial (5.0 (2.4) mmol.L-1 and 2.15 (0.4) L.min-1, respectively) than in the CP trial, (B[La], 4.7 (2.1) mmol.L-1; maximal oxygen uptake, 2.05 (0.35) L.min-1; p > 0.13). Peak oxygen uptake (expressed as a percentage of the peak value) was not attained at the end of the trials (94 (12) and 98 (14) % for CP and CP+10%, respectively). These results provide information about the boundary between the heavy and severe exercise intensity domains in children, and have demonstrated that CP in a group of boys does not represent a sustainable steady-state intensity of exercise.
本研究的目的是确定男孩和女孩的临界功率（CP），并在一组男孩中检查在CP以及高于CP 10%（CP + 10%）时运动的生理反应。9名男孩和9名女孩（平均年龄12.3（0.5）岁）进行了3次恒定负荷测试以得出CP。然后，8名男孩以随机顺序在CP和CP + 10%强度下运动，直至自愿力竭。男孩和女孩的CP分别为123（28）W和91（26）W（p < 0.02），分别相当于峰值摄氧量的75（6）%和72（10）%（p > 0.47）。男孩在CP强度下的力竭时间为18分37秒（4分13秒），显著长于在CP + 10%强度下的力竭时间（9分42秒（2分31秒））（p < 0.00）。在CP + 10%试验中，运动结束时的血乳酸浓度（B[La]）和最大摄氧量的值高于CP试验（分别为5.0（2.4）mmol·L-1和2.15（0.4）L·min-1），而CP试验中B[La]为4.7（2.1）mmol·L-1，最大摄氧量为2.05（0.35）L·min-1；p > 0.13）。试验结束时未达到峰值摄氧量（以峰值的百分比表示）（CP和CP + 10%分别为94（12）%和98（14）%）。这些结果提供了有关儿童重度和极重度运动强度领域之间界限的信息，并表明一组男孩的CP并不代表可持续的稳定运动强度。
