Reliability and Validity of Functional Grip Strength Measures Across Holds and Body Positions in Climbers: Associations With Skill and Climbing Performance.

In climbing, exceptional levels of fingertip strength across different holds and body positions are considered essential for performance. There is no commonly agreed upon way to measure such "grip strength variability." Furthermore, the accurate and reliable monitoring of strength is necessary to achieve safe, progressive improvement in strength. Therefore, this study aimed to develop reliability and criterion validity for assessment of grip strength across multiple holds and body positions. Twenty-two advanced toelite climbers (age = 28.5 ± 8.6 years) performed maximal voluntary isometric contractions on two occasions (for test-retest reliability). Conditions included two hold types (edge and sloper) tested in two postures (elbow flexion [90°] and self-preferred). Climbing performance was determined on two "difficulty" routes (difficulty increases with each hold): one route composed of only edges and another only of slopers. Test-retest reliability was high (ICC between 0.94-0.99). Significant positive correlations were observed for the forces produced on the sloper test and climbing distance on the sloper route (r = 0.512,p < .05), and for the forces produced on the edge test and climbing distance on the edge route (ρ = 0.579, p < .01). These findings support reliability and validity of the method used to measure grip strength variability with different holds and body positions and suggest that improving strength across different grasping types supports adaptive climbing performance.