Physiological determinants of climbing-specific finger endurance and sport rock climbing performance
MacLeod, D.; Sutherland, D.L.; Buntin, L.; Whitaker, A.; Aitchison, T.; Watt, I.; Bradley, J.; Grant, S.
Journal of Sports Sciences 25(12): 1433-1443
The aim of the study was to examine several physiological responses to a climbing-specific task to identify determinants of endurance in sport rock climbing. Finger strength and endurance of intermediate rock climbers (n = 11) and non-climbers (n = 9) were compared using climbing-specific apparatus. After maximum voluntary contraction (MVC) trials, two isometric endurance tests were performed at 40% (s = 2.5%) MVC until volitional exhaustion ( continuous contractions and intermittent contractions of 10 s, with 3 s rest between contractions). Changes in muscle blood oxygenation and muscle blood volume were recorded in the flexor digitorum superficialis using near infra-red spectroscopy. Statistical significance was set at P < 0.05. Climbers had a higher mean MVC (climbers: 485 N, s = 65; non-climbers 375 N, s = 91) (P = 0.009). The group mean endurance test times were similar. The force-time integral, used as a measure of climbing-specific endurance, was greater for climbers in the intermittent test ( climbers: 51,769 N center dot s, s = 12,229; non-climbers: 35,325 N center dot s, s = 9724) but not in the continuous test ( climbers: 21,043 N center dot s, s = 4474; non-climbers: 15,816 N center dot s, s = 6263). Recovery of forearm oxygenation during rest phases ( intermittent test) explained 41.1% of the variability in the force -time integral. Change in total haemoglobin was significantly greater in non-climbers ( continuous test) than climbers (P = 0.023-40% test timepoint, P = 0.014-60% test timepoint). Pressor responses were similar between groups and not related to the force -time integral for either test. We conclude that musclere-oxygenation during rest phases is a predictor of endurance performance.