The relationship between cadence decline, cardiovascular drift and aerobic decoupling as a marker of fatigue in well trained cyclists

Prolonged steady-state cycling is characterised by gradual neuromuscular and metabolic acute fatigue, which may affect an athlete’s movement patterns. We hypothesize that athletes might unconsciously reduce cadence as a compensatory strategy to maintain power output. To test this theory, we examined changes in cadence and internal load during extended submaximal cycling. To test this theory, 17 trained cyclists performed a monthly standardised 60-minute effort at 75% of their functional threshold power for five months, yielding 85 paired observations. Cadence behaviour was analysed alongside cardiovascular drift and aerobic decoupling in order to ascertain whether cadence decline reflects a surrogate marker of acute fatigue. The results showed that cadence decline in the second half of the test was significantly correlated with both, cardiovascular drift and aerobic decoupling. Linear mixed model regression analysis revealed a robust association between cadence decline and cardiovascular drift (b = 0.61, p = 0.024), and a repeated measures correlation of r = 0.40 (p < 0.001). On average, each additional rpm of cadence decline corresponded to a 0.61% increase in cardiovascular drift. The correlation between cadence decline and aerobic decoupling was also significant (r = 0.38, p = 0.001) and the regression analysis shows that each additional rpm of cadence decline corresponds to a 0.58% increase in aerobic decoupling (b = 0.58, p = 0.007). These findings suggest that cadence decline is linked to both, cardiovascular and mechanical manifestations of acute fatigue. In practice, cadence monitoring offers a simple, non-invasive and widely accessible method of tracking fatigue. Moreover, it allows the design of training plans incorporating cadence-strategies and providing real-time feedback when cardiovascular strain may impair performance.