Changes in blood lactate and muscle activation in elite rock climbers during a 15-m speed climb

PurposeThe purpose of this study was to investigate the changes in blood lactate concentration (BL) and muscle activity patterns during a 15-m speed climbing competition that consisted of ten consecutive climbing actions on a standardized artificial wall in trained rock climbers.MethodsTwelve trained rock climbers participated in this study. Surface electromyography (sEMG) and video signals were synchronized and recorded during climbing. The blood lactate was also tested 3min after completing the climb.ResultsThe average climbing time was 8.12.1s for the 15-m speed climb across all subjects, accompanied by a BL of 7.6 +/- 1.9mmol/L. The climbing speed and power firstly increased and then slightly decreased relative to peak value during the 15-m speed climbing. The results showed there was a positive correlation between the BL and the climbing time, r=0.59, P=0.043. The sEMG showed the flexor digitorum superficialis (FDS) electric activity was the highest, followed by the biceps brachii (BB) and latissimus dorsi. The instantaneous median frequency of sEMG of FDS and BB significantly decreased during the 15-m speed climbing. All the participants showed the higher sEMG RMS (%) in the terminal phase than that in the initial phase, especially with a greater increase in the left upper limbs. However, the lower limbs muscles presented no significant changes in the sEMG amplitude during climbing.Conclusions The FDS and BB play an important role in completing the 15-m speed climbing. The median frequency of arm EMG decreased more than that of legs, suggesting more fatigue. The blood lactate concentration increases in the current study suggest that a certain amount of glycolysis supplies energy in completing 15-m speed rock climbing. Based on the current data, it is suggested that muscular endurance of FDS and BB muscles in upper limbs should be improved for our climbers in this study.