The effects of prioritizing lead or boulder climbing among intermediate climbers

This study compared the effects of prioritizing lead climbing or boulder climbing on climbing-specific strength and endurance, as well as climbing performance. Fourteen active climbers were randomized to a boulder climbing training group (BCT: age = 27.2 ± 4.4 years, body mass = 65.8 ± 5.5 kg, height = 173.3 ± 3.8 cm) or a lead-climbing training group (LCT: age = 27.7 ± 6.1 years, body mass = 70.2 ± 4.4 kg, height = 177.7 ± 4.4 cm). The groups participated in a 5-week training period consisting of 15 sessions, performing either two weekly bouldering sessions and one maintenance-session of lead-climbing (BCT) or two weekly lead-climbing sessions and one maintenance-session of bouldering (LCT). Pre- and post-training, maximal force and rate of force development (RFD) were measured during isometric pull-ups performed on a jug hold and a shallow rung, and during an isolated finger-strength test. Lead-climbing and bouldering performance were also measured, along with an intermittent forearm endurance test. The pre-to-post changes were not significantly different between the groups for any of the parameters (P = 0.062–0.710). However, both the BCT (ES = 0.30, P = 0.049) and LCT (ES = 0.41, P = 0.046) groups improved strength in the isometric pull-up performed using the jug, whereas neither group improved force in the rung condition (P = 0.054 and P = 0.084) or RFD (P = 0.060 and P = 0.070). Furthermore, climbing and bouldering performance remained unchanged in both groups (P = 0.210–0.895). The LCT group improved forearm endurance (ES = 0.55, P = 0.007), while the BCT group improved isolated finger strength (ES = 0.35, P = 0.015). In addition to isometric pull-up strength, bouldering can increase isolated finger strength while lead-climbing may improve forearm endurance. A 5-week period prioritizing one discipline can be safely implemented for advanced to intermediate climbers without risking declined performance in the non-prioritized discipline