Comparison between maximal power in the power-endurance relationship and maximal instantaneous power

Abstract

The purpose of this study was to analyze the relevance of introducing the maximal power (P(m)) into a critical-power model. The aims were to compare the P(m) with the instantaneous maximal power (P(max)) and to determine how the P(m) affected other model parameters: the critical power ( P(c)) and a constant amount of work performed over P(c)(W'). Twelve subjects [22.9 (1.6) years, 179 (7) cm, 74.1 (8.9) kg, 49.4 (3.6) ml/min/kg] completed one 15 W/min ramp test to assess their ventilatory threshold (VT), five or six constant-power to exhaustion tests with one to measure the maximal accumulated oxygen deficit (MAOD), and six 5-s all-out friction-loaded tests to measure P(max) at 75 rpm, which was the pedaling frequency during tests. The power and time to exhaustion values were fitted to a 2-parameter hyperbolic model (NLin-2), a 3-parameter hyperbolic model (NLin-3) and a 3-parameter exponential model (EXP). The P(m) values from NLin-3 [760 (702) W] and EXP [431 (106) W] were not significantly correlated with the P(max) at 75 rpm [876 (82) W]. The P(c) value estimated from NLin-3 [186 (47) W] was not significantly correlated with the power at VT [225 (32) W], contrary to other models ( P <0.001). The W' from NLin-2 [25.7 (5.7) kJ] was greater than the MAOD [14.3 (2.7) kJ, P < 0.001] with a significant correlation between them (R = 0.76, P <0.01). For NLin-3, computation of W (P > P c), the amount of work done over P(C), yielded results similar to the W' value from NLin-2: 27.8 (7.4) kJ, which correlated significantly with the MAOD (R = 0.72, P <0.01). In conclusion, the P(m) was not related to the maximal instantaneous power and did not improve the correlations between other model parameters and physiological variables.

Modelling of aerobic and anaerobic energy production in middle-distance running

“…In this case, P c was found to be correlated with various estimates of the ventilatory and lactate thresholds obtained using a single incremental exercise or a series of long duration exercises (Lechevalier et al 1989;Sid-Ali et al 1991;McLellan and Cheung 1992;Pringle and Jones 2002;Moritani et al 1981;Bulbulian et al 1986;Gaesser et al 1995;Smith et al 1999;Chatagnon et al 2005). However, some authors reported that P c was higher than the power at maximal lactate steady state (Pringle and Jones 2002;Dekerle et al 2003).…”

A comparison of modelling procedures used to estimate the power–exhaustion time relationship

“…The power chosen for the tests could also explain the conflicting findings concerning the interpretation of W 0 . When using power lower than maximal aerobic power to establish the power-time to exhaustion relationship, W 0 was almost twice the maximal oxygen deficit, although a significant correlation was observed between them (Chatagnon et al 2005). This led us to propose a segmented model with a break point (P t ) corresponding to the lowest power required to achieve the maximal aerobic power Chatagnon and Busso 2006), whereas P c remained the power asymptote for time tending towards infinity.…”

Esforço percebido durante o treinamento intervalado na natação em intensidades abaixo e acima da velocidade crítica

“…Uma possível explicação para o fenômeno seria que o esforço percebido nas intensidades severas (9) seria regulado pela velocidade de utilização da capacidade de trabalho anaeróbio (CTA). Esse segundo parâmetro do modelo é representativo da capacidade de transferência energética a partir dos estoques de fosfagênios e da glicólise anaeróbia (7,17,18) . Assim, o esforço percebido em intensidades acima da VC seria uma conseqüência dos distúrbios periféricos associados à depleção de fosfagênios e acidose metabólica, concomitante à mobilização crescente da atividade neuromotora eferente (6) .…”

“…Quando o indivíduo realiza exercí-cios acima da VC, há a utilização da CTA para complementar a demanda necessária do exercício que não consegue ser suprida pelo sistema aeróbio, e quando ocorre o esgotamento dessa reserva, o indiví-duo entra em exaustão. Alguns estudos têm demonstrado que CTA está relacionada ao máximo déficit acumulado de oxigênio (7,14) . Esses pressupostos confirmam parte das previsões inicialmente delineadas para este estudo baseadas em nossos estudos recentes (19,20) , em que observamos que a taxa de aumento do esforço percebido, em cargas severas de trabalho (9) , era proporcional à intensidade do exercício.…”