Differences in Forearm Strength, Endurance, and Hemodynamic Kinetics Between Male Boulderers and Lead Rock Climbers

This study examined differences in the oxygenation kinetics and strength and endurance characteristics of boulderers and lead sport climbers. Using near infrared spectroscopy, 13-boulderers, 10-lead climbers, and 10-controls completed assessments of oxidative capacity index and muscle oxygen consumption (m⩒O) in the flexor digitorum profundus (FDP), and extensor digitorum communis (EDC). Additionally, forearm strength (maximal volitional contraction MVC), endurance (force-time integral FTI at 40% MVC), and forearm volume (FAV and ΔFAV) was assessed. MVC was significantly greater in boulderers compared to lead climbers (mean difference = 9.6, 95% CI 5.2-14 kg). FDP and EDC oxidative capacity indexes were significantly greater (p = .041 and .013, respectively) in lead climbers and boulderers compared to controls (mean difference = -1.166, 95% CI (-3.264 to 0.931 s) and mean difference = -1.120, 95% CI (-3.316 to 1.075 s), respectively) with no differences between climbing disciplines. Climbers had a significantly greater FTI compared to controls (mean difference = 2205, 95% CI= 1114-3296 and mean difference = 1716, 95% CI = 553-2880, respectively) but not between disciplines. There were no significant group differences in ΔFAV or m⩒O. The greater MVC in boulderers may be due to neural adaptation and not hypertrophy. A greater oxidative capacity index in both climbing groups suggests that irrespective of climbing discipline, trainers, coaches, and practitioners should consider forearm specific aerobic training to aid performance.