Rate of force development and maximal force: reliability and difference between non-climbers, skilled and international climbers.

The goal of this study was to assess (i) test-retest reliability between sessions and within sessions, and (ii) the difference among three skill levels (international = 12, skilled = 10 and non-climbers = 9) for finger flexor maximal force (Fmax) and rate of force development (RFD) at different time scales. Each climber performed a maximal finger flexion on a dynamometer in two different conditions: half crimp and slope crimp. The inter-session revealed no difference with low to high correlation from 0.56 to 0.94. Intra-session reliability reveals intraclass correlation ranging from 0.40 to 0.98 for all groups. The coefficients of variation ranged from 7.77% to 28.34% for RFD and 2.90% to 9.99% for Fmax. Maximal force, expressed as an absolute or normalised value, reveals a significant difference between all samples (22.11% difference between international and 38.58% between skilled and non-climbers). Finally, the difference in RFD and RFD among the three groups suggests that the practice of intensive climbing causes many changes in neural and structural factors. Last, RFD and RFD are highly reliable and can be used to discriminate samples, suggesting that these variables could be used in monitoring training.