Introduction

Rock climbing places a high workload on the forearm flexors (Giles et al., 2006) and observations during intermittent isometric contractions have highlighted the importance of blood flow during the short recovery periods (Fryer et al., 2015). More specifically, higher force time integral values achieved during the intermittent test by elite climbers have been attributed to improved blood flow upon release of an isometric hold (Fryer et al., 2015). Blackcurrant anthocyanin supplementation increased forearm blood flow at rest (Matsumoto et al., 2005) and increased femoral artery diameter during submaximal isometric contraction (Cook et al., 2017). There would appear to be justification for the use of New Zealand Blackcurrant (NZBC) as an ergogenic aid in sports climbing in an attempt to delay the onset of fatigue and enhance rock-climbing performance.

Methods

Twenty experienced climbers (2 females) (age 23±5 yrs; height 177±8 cm; mass 71±8 kg) were tested on 3 occasions; familiarisation, after 7 days of NZBC extract (600mg∙day-1 CurraNZ containing 210mg anthocyanin), and placebo (PL) (double-blind, randomized, crossover design, 14 days washout). The number of pull-ups on a finger-board (Metolius ® Finger Board) until failure, 90° lock off hang time was followed by 3 climbs to volitional exhaustion on a Treadwall (Brewer Ledge M6) self-selected pace at 90° with a 20-min recovery period between climbs. Heart rate (Polar®H7), rate of perceived exertion (RPE) (Borg, 1982), climbing duration and distance were recorded.

Results

NZBC extract resulted in an 8% increase in hang time (p=0.035), and an 11% increase in climb duration between climb 1 and 3; a 23% decrease climb duration was observed in the placebo condition: interaction effect (p=0.003). There was a main effect for climb with the mean heart rate declining across the three (p<0.001). No effect was seen for pull-ups, maximum heart rate, RPE and distance climbed.

Conclusion

Data indicate that NZBC extract improves sports climbing endurance, possibly through improved local blood flow. The improved hang time suggests that this was not dependent on release of the isometric hold as seen in previous work by Fryer et al. (2015). Future work may explore the effect of anthocyanin-rich NZBC extract on other types of climbing and conditions.

References
Borg GA et al. (1982). Med Sci Sports Exerc 14(5), 355-381.
Cook MD et al (2017) Nutrients. 9(6), 556.
Fryer S et al. (2015). Int J Sports Med, 36(2), 137-142.
Giles LV et al. (2006). Sports Med, 36(6), 529-545.
Matsumoto H et al. (2004). Eur J Appl Physiol, 94(1-2), 36-45.