Critical power in adolescents: physiological bases and assessment using all-out exercise

This study examined whether critical power (CP) in adolescents: (1) provides a landmark for maximal steady-state exercise; and (2) can be determined using ` allout' exercise. Nine active 14-15 year olds (6 females, 3 males) performed five cycling tests: (1) a ramp test to determine (V)over dotO(2peak); (2) up to four constant power output tests to determine CP; (3-4) constant power output exercise 10% above and 10% below CP; and (5) a 3 min all-out cycle test to establish the end power (EP) at 90 and 180 s of exercise. All participants completed 30 min of exercise below CP and were characterized by steady-state blood lactate and (V)over dotO(2) profiles. In contrast, time to exhaustion during exercise above CP was 15.0 +/- 7.0 min and characterized by an inexorable rise in blood lactate and a rise, stabilization (similar to 91% (V)over dotO(2peak)) and fall in (V)over dotO(2) (similar to 82% (V)over dotO(2peak)) prior to exhaustion. Eight out of nine participants completed the 3 min test and their EPs at 90 s (148 +/- 29 W) and 180 s (146 +/- 30 W) were not different from CP (146 +/- 27 W) (P = 0.98). The typical error of estimates for establishing CP using EP at 90 s or 180 s of the 3 min test were 25 W (19.7% CV) and 25 W (19.6% CV), respectively. CP in active adolescence provides a valid landmark for maximal steady-state exercise, although its estimation on an individual level using the 3 min all-out test may be of limited value.