Muscle oxygen dynamics in elite climbers during finger-hang tests at varying intensities

The aim of this study was to measure muscle oxygen saturation (SmO(2)) dynamics during a climbing specific task until failure in varying conditions. Our prediction was that SmO(2) should be a good marker to predict task failure. Eleven elite level climbers performed a finger-hang test on a 23 mm wooden rung under four different weighted conditions, 1. body weight (BW), 2. body weight +20% (BW +20), 3. body weight −20% (BW −20) and 4. body weight −40% (BW −40), maintaining half crimp grip until voluntary exhaustion. During each trial SmO(2) and time to task failure (TTF) were measured. TTF was then compared to the minimally attainable value of SmO(2) (SmO(2)min) and time to SmO(2)min (TTmin). There is a considerable degree of agreement between attainable SmO(2)min at high intensity conditions (M(BW) = 21.6% ± 6.4; M(BW)(+20) = 24.0% ± 7.0; M(BW−20) = 23.0% ± 7.3). Bland-Altman plot with an a priori set equivalency interval of ±5% indicate that these conditions are statistically not different (M(BW-BW + 20) = −2.4%, 95% CI [1.4, −6.2]; M(BW−Bw−20) = −1.3, 95% CI [2.5, −5.1]). The fourth and lowest intensity condition (M(BW −40) = 32.4% ± 8.8) was statistically different and not equivalent (M(BW-BW −40) = −8.8%, 95% CI [−5.0, −12.6]). The same agreement was found between TTF and TTmin for the high intensity conditions plotted via Bland-Altman. While the rate with which oxygen was extracted and utilised changed with the conditions, the attainable SmO(2)min remained constant at high intensity conditions and was related to TTF.