The role of arm position during finger flexor strength measurement in sport climbers

The aim of the study was to evaluate the validity and reliability of different arm positions for finger flexor strength measurement in sport climbers. Forty six climbers completed finger flexor strength measurement on a climbing specific device with four different arm positions: 1 - handgrip, shoulder flexed at 0°, elbow fully extended; 2 - shoulder flexed at 90° and externally rotated, elbow flexed at 90° (position 90/90); 3 - shoulder abducted at 130°, elbow flexed at 50° (position 130/50), 4 - shoulder flexed at 180°, elbow fully extended (position 180/0). Intra-session reliability from 3 trials was assessed by an intra-class correlation coefficient (ICC). To assess the criterion related validity repeated analysis of covariance was used (4 x 2 x 2) with the arm position as a within subject factor, sex and climbing ability as between subject factors, and body mass as a covariate. The criterion was represented by self-reported climbing ability. A high ICC was found for all arm positions ranging from 0.95 to 0.98. The highest variability explained by climbing ability in finger strength was found in the 180/0 position (ηp2 = 0.25) and 130/50 position (ηp2 = 0.25). The handgrip test had the lowest validity to the reported climbing ability (ηp2 = 0.05). It was concluded that the positions 180/0 and 130/50 are most suitable to assess finger flexor strength in climbers.