The modified D-max is a valid lactate threshold measurement in veteran cyclists

Abstract

The ageing process has the potential to impact upon the manner in which an athlete responds to training stimuli. This study investigated if power output (PO) and heart rate (HR) at the modified D-max lactate transition threshold (D-max) was comparable with the mean HR and power that could be sustained during a 30-min laboratory time trial (TT30) in veteran athletes. Nine veteran (≥35 years) cyclists performed an incremental exercise test to determine PO and HR at D-max, and peak physiological values. Participants then performed a TT30 during which mean HR and PO were measured for comparison with D-max values. The PO and HR at D-max were significantly correlated with the mean PO and HR during the TT30 (r = 0.95, p < 0.001 and r = 0.88, p = 0.002, respectively). Bland and Altman plots revealed a close agreement between D-max and average values sustained during the time trials for PO (95% CI = -14 to +3 W) and HR (95% CI = -6 to +3 bpm). This study has demonstrated that in veteran cyclists the D-max is accurate in predicting the highest average PO and HR that can be sustained during a 30-min time trial.