Reliability of Force Application to Instrumented Climbing Holds in Elite Climbers.

Multiaxial force sensors were applied to measure interaction forces during dynamic movements, such as climbing. When interaction forces are interpreted, minimal detectable changes, typical errors, and coefficients of variation of related performance metrics should be quantified. Thus, the presented study evaluated absolute and relative between-trial reliability with and without previous familiarization trials. Eleven Swiss elite climbers (5 females, 6 males) were tested during 2 repetitive climbing sequences (including 4 instrumented holds: 2 crimps, 1 undercling, 1 sloper). To ensure comparable relative intensity, females climbed at 20°, 25°, 30°, 25°, and 20° wall inclination, while males climbed at 25°, 30°, 35°, 30°, and 25°. Contact time, maximal resultant force, mean resultant force, impulse, and the number of load changes were analyzed at the lowest inclination. Acceptable to good between-trial reliability was found for nearly all holds and performance metrics. Performance analyses after 5 minutes of familiarization on the unknown boulder, which equals up to 3 trials, yielded to higher variability compared with performance analyses after several familiarization trials. Accordingly, the majority of absolute and relative reliability data improved after familiarization trails. Thus, to be detectable, interventional changes have to exceed higher biological variability during on-sight conditions than during red-point conditions.