Abstract
Purpose W′ balance ( W′ BAL ) modelling is becoming an important tool to monitor intermittent cycling performance. This study assessed the ability of different time constant ( τ W ′ ) equations for W′ reconstitution ( W′ rec ) to predict exhaustion during intermittent exercise and the relationship between parameters of W′ rec with established determinants of endurance performance. Methods Thirteen cyclists performed cycling performance tests to determine: lactate threshold (LT), critical power (CP), W′ , V̇ O 2max , maximal aerobic power (MAP) and maximal sprint power ( P max ). Participants subsequently performed three intermittent Wʹ depletion trials to volitional exhaustion involving different work and recovery periods: 20:10; 3 × 20 s intervals separated by 10 s recoveries before a final continuous effort, 60:30; 3 × 60 s intervals separated by 30 s recoveries before a final continuous effort, 20:10 TE ; repeated 20 s intervals each separated by 10 s recoveries. W′ BAL was determined via five different τ W ′ equations and an individualised equation ( τ W′INDV ) calculated from the 20:10 TE under the assumption that the point of task failure represents 0 kJ. Results Current τ W′ equations failed to predict exhaustion during intermittent exercise protocols to exhaustion. Total work done above CP for the 20:10 TE ( Wʹ total 20:10 TE ) was positively correlated with absolute and relative LT, CP, V̇ O 2max , MAP, and P max ( r = 0.64–0.80; P < 0.05). The τ W′INDV was negatively correlated with relative CP ( r = − 0.69), and LT 1 ( r = − 0.58), and Wʹ total 20:10 TE ( r = − 0.63). Conclusion Individualised τ W′ should be utilised for the accurate prediction of Wʹ BAL . W′ rec is influenced primarily by aerobic performance parameters, including LT 1 and CP.