Sport-specific finger flexor strength assessment using electronic scales in sport climbers

The aim of this study was to assess the validity and reliability of four climbing grip positions during finger flexor strength measurement using electronic scales in sport climbing contexts. Fifty-five climbers with self-reported climbing abilities RP (redpoint) between V and XII– on the Union Internationale des Associations d'Alpinisme scale volunteered to the study. Strength measures were obtained using open grip (OG), crimp grip (CG), index+middle (IM) finger, middle+ring (MR) finger on a 23 mm wide wood-edge climbing hold. The climbers were asked to stand on the scale platform and to progressively load their maximum weight on to the tested arm. Strength for each measurement was calculated by subtracting the lowest value shown during grip hold from the participant's body mass. Intra-session reliability was calculated across three trials and test-retest reliability through a cohort tested in a second testing session on week later. The intra-class correlation coefficients for all grip positions ranged between r = 0.88–0.97 and r = 0.88–0.94 for intra-session and test-retest reliability, respectively, indicating a high level of consistency and stability for the test scores. Criterion validity with regard to RP and on-sight (OS) was highest in OG and CG. The coefficients of correlation ranged from r = 0.788 to r = 0.811 between OG and CG with RP or OS performance. Criterion validity was lower between the MR position RP/OS and lower still for the IM position (r = 0.677–0.753). The use of a climbing fingers board and digital scales appears to represent a relatively inexpensive, straightforward, reliable and valid method to assess climbing-specific finger strength using different grip positions. The OG and CG are most closely related to self-reported climbing performance. In addition, the two-finger grip positions might provide further information on individual variation in grip performance.