Lactate kinetics in handcycling under various exercise modalities and their relationship to performance measures in able-bodied participants

Purpose
The aim of this study was to expand exercise testing in handcycling by (1) examining different approaches to determine lactate kinetics in handcycling under various exercise modalities and (2) identifying relationships between parameters of lactate kinetics and selected performance measures.

Methods
Twelve able-bodied nationally competitive triathletes performed a familiarisation, a sprint test, an incremental step test, and a continuous load trial at a power output corresponding to a lactate concentration (La) of 4 mmol l−1 (PO4) in a racing handcycle that was mounted on an ergometer. During the tests, La and heart rate (HR) were determined. As performance measures, maximal power output during the 15-s All-Out sprint test (POmax,AO15) and maximal power output during the incremental test (POmax,ST) were determined. As physiological parameters, coefficients of lactate kinetics, maximal lactate accumulation rate (VLamax), maximal La following the sprint test and incremental test (Lamax,AO15, Lamax,ST) and the increase in La within the last 20 min of the continuous trial (LaCrit,CT) were determined.

Results
Mean values of POmax,AO15 (545.6 ± 69.9 W), POmax,ST (131.3 ± 14.9 W), PO4 (86.73 ± 12.32 W), VLamax (0.45 ± 0.11 mmol l−1 s−1), Lamax,AO15 (6.64 ± 1.32 mmol l−1), Lamax,ST (9.64 ± 2.24 mmol l−1) and LaCrit,CT (0.74 ± 0.74 mmol l−1) were in accordance to literature. VLamax was positively correlated with Lamax,AO15 and POmax,AO15 and negatively correlated with POmax,ST. POmax,ST was negatively correlated with Lamax,AO15. PO4 was negatively correlated with Lamax,ST.

Conclusions
VLamax was identified as a promising parameter for exercise testing in handcycling that can be supplemented by other parameters describing lactate kinetics following a sprint test.