A ‘ramp-sprint’ protocol to characterise indices of aerobic function and exercise intensity domains in a single laboratory test

Abstract

Purpose

The lactate threshold (LT), critical power (CP) and maximum oxygen uptake ($\dot{V}{\text{O}}_{2\text{max} }$) together partition exercise intensity domains by their common physiological, biochemical and perceptual response characteristics. CP is the greatest power output attainable immediately following intolerance at $\dot{V}{\text{O}}_{{2{\text{peak}}}}$, and the asymptote of 3 min all-out exercise. Thus we reasoned that a maximal ‘sprint’ immediately following standard ramp-incremental exercise would allow characterisation of the three aerobic indices in a single test.

Methods

Ten healthy men (23 ± 3 year, mean ± SD) performed 9 cycle-ergometry tests on different days: (A) two ramp-incremental tests to intolerance (20 W min⁻¹), immediately followed by a 3 min maximal, variable-power effort ramp-sprint test (RST) for LT, $\dot{V}{\text{O}}_{{2{\text{peak}}}}$ and sprint-phase power (SP) determination; (B) four constant-power tests for CP and $\dot{V}{\text{O}}_{2\text{max} }$ determination; (C) constant-power tests at 10 W below LT, and 10 W below and above SP to verify intensity domain characterisation. Capillary [lactate] and breath-by-breath $\dot{V}{\text{O}}_{2}$ were measured.

Results

Reproducibility of LT, SP and $\dot{V}{\text{O}}_{2\text{max} }$ measurements between RST repeats was within 5 % or less (r ≥ 0.991, p < 0.001). CP (257 ± 46 W) was not different (p = 0.72) from SP (258 ± 42 W). Exercise 10 W below LT and SP resulted in steady state $\dot{V}{\text{O}}_{2}$ and [lactate]. $\dot{V}{\text{O}}_{2\text{max} }$ (4.0 ± 0.6 L min⁻¹), peak [lactate] (11 ± 2 mM) and intolerance were reached 19 ± 5 min into exercise at 10 W above SP.

Conclusions

These data suggest that the key indices of aerobic function may be accurately and reliably estimated during a single exercise test. This test may provide a basis for simplifying assessment and prescription of exercise training and experimental interventions.