Characterization of the work-time relationship during cross-country ski ergometry

Area of Science:

• Exercise Physiology
• Sports Science
• Biomechanics

Background:

• The critical power (CP) test is a standard method for determining the work-time relationship in endurance exercise.
• The 3-minute all-out test (3MT) offers a potentially more time-efficient alternative for assessing exercise capacity.

Purpose of the Study:

• To evaluate the validity and reliability of the 3MT compared to the traditional multi-trial CP test for estimating key physiological and biomechanical parameters during cross-country ski ergometry.
• To assess the concurrent validity and reliability of parameters like critical power (CP), work above end-test power (WEP), and critical stroke rate (CSR) derived from both testing protocols.

Main Methods:

• Fourteen recreationally active males underwent three testing sessions on a ski ergometer (SkiErg).
• Methods included a graded exercise test for maximal oxygen uptake (VO2peak), two 3MT sessions for oxygen uptake (VO23MT), end-test power (EP), WEP, and end stroke rate (ESR).
• Three time trials (300m, 650m, 1000m) were used to estimate CP, W', and critical stroke rate (CSR).

Main Results:

• VO2peak and VO23MT were not significantly different.
• The 3MT demonstrated good reliability for EP and ESR, and moderate reliability for WEP.
• CP and EP were not significantly different and highly correlated (r=0.780).
• WEP and W' were similar but not correlated (r=0.119).
• ESR and CSR were not significantly different and moderately correlated (r=0.498).

Conclusions:

• The 3MT is a valid and reliable method for estimating CP and CSR during ski ergometry.
• The 3MT is not a valid measure for W' or WEP when compared to the traditional CP test.
• Both testing protocols elicited similar maximal oxygen uptake values.