Comparison of climbing-specific strength and endurance between lead and boulder climbers

Albeit differences in climbing-specific strength of the forearms have been demonstrated between lead and boulder climbers, little is known about the potential differences in force and power output of the upper body pulling-apparatus between disciplines. The aim of this study was to compare the climbing-specific upper-body strength and finger flexor endurance between lead and boulder climbers, as well as to examine the relative utilization of force when testing on a ledge hold compared to a jug hold. Sixteen boulder climbers (red-point climbing grade 17.9 ± 3.3) and fifteen lead climbers (red-point climbing grade 20.5 ± 3.5) performing on an advanced level volunteered for the study. Peak force, average force and rate of force development (RFD) were measured during an isometric pull-up, average velocity in dynamic pull-up, and finger flexor endurance in an intermittent test to fatigue. The isometric pull-up was performed on a ledge hold (high finger strength requirements) and on a jug hold (very low finger strength requirements). Boulder climbers demonstrated a higher maximal and explosive strength in all strength and power measurements (26.2-52.9%, ES = 0.90-1.12, p = 0.006-0.023), whereas the finger flexor endurance test showed no significant difference between the groups (p = 0.088). Both groups were able to utilize 57-69% of peak force, average force and RFD in the ledge condition compared to the jug condition, but the relative utilization was not different between the groups (p = 0.290-0.996). In conclusion, boulder climbers were stronger and more explosive compared to lead climbers, whereas no differences in finger flexor endurance were observed. Performing climbing-specific tests on a smaller hold appears to limit the force and power output equally between the two groups.