Abstract
The aim of this study was to measure muscle oxygen saturation (SmO2) dynamics during a climbing specific task until failure in varying conditions. Our prediction was that SmO2 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 SmO2 and time to task failure (TTF) were measured. TTF was then compared to the minimally attainable value of SmO2 (SmO2min) and time to SmO2min (TTmin). There is a considerable degree of agreement between attainable SmO2min at high intensity conditions (MBW = 21.6% ± 6.4; MBW+20 = 24.0% ± 7.0; MBW−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 (MBW-BW + 20 = −2.4%, 95% CI [1.4, −6.2]; MBW−Bw−20 = −1.3, 95% CI [2.5, −5.1]). The fourth and lowest intensity condition (MBW −40 = 32.4% ± 8.8) was statistically different and not equivalent (MBW-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 SmO2min remained constant at high intensity conditions and was related to TTF.
Highlights
The aim of this study was to measure muscle oxygen saturation (SmO2) dynamics during a climbing specific task until failure in varying conditions
If oxidative capacity is an individual, but constant volume, the rate of muscle deoxygenation should increase but SmO2min would remain constant near to the point of task failure. This highlights two research hypothesis; 1. during a sport specific performance task SmO2min remains constant over varying workloads; and 2. time to SmO2min (TTmin) is equal to time to task failure (TTF)
Statistical equivalency can not be clearly discerned as confidence intervals (CI) expand beyond the the a priori set equivalency intervals (EI)
Summary
The aim of this study was to measure muscle oxygen saturation (SmO2) dynamics during a climbing specific task until failure in varying conditions. A greater local oxidative capacity has shown to enhance sport specific strength and endurance when comparing novice and expert climbers[13], with a considerable degree of predictive power to determine climbing level; linear regression model predicting Red-point grade (IRCRA Scale) from tissue oxygen resaturation rate: y = −0.351 + 14.121, R2 = 0.2413 Numerous studies look both at isometric holds and repeated or intermittent isometric holding as performance limiting components and their effect on NIRS dynamics[12,15,17]. Applying this knowledge to simple in vivo and in situ tests during isometric finger-hangs, it is possible that NIRS dynamics could be used to assess task failure during measurement situations, which in turn could be a useful tool for both training and competition For these predictions the minimally attainable muscle oxygen saturation (SmO2min) can be used as a pragmatic surrogate for oxidative capacity[8,14,16,19]. This highlights two research hypothesis; 1. during a sport specific performance task SmO2min remains constant over varying workloads; and 2. time to SmO2min (TTmin) is equal to time to task failure (TTF)
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