Haemodynamic Kinetics and Intermittent Finger Flexor Performance in Rock Climbers

Abstract

Currently it is unclear whether blood flow (BF) or muscle oxidative capacity best governs performance during intermittent contractions to failure. The aim of this study was to determine oxygenation kinetics and BF responses during intermittent (10 s contraction: 3 s release) contractions at 40% of MVC in rock climbers of different ability (N=38). Total forearm BF, as well as de-oxygenation and re-oxygenation of the flexor digitorum profundus (FDP) and the flexor carpi radialis (FCR) were assessed. Compared to the control, intermediate and advanced groups, the elite climbers had a significantly (p<0.05) greater force time integral (FTI), MVC and MVC/kg. Furthermore, the elite climbers de-oxygenated the FDP significantly more during the first (7.8, 11.9, 12.4 vs. 15.7 O2%) and middle (7.3, 8.8, 10.4 vs.15.3 O2%) phases of contractions as well as for the FCR during the first phase only (8.3, 7, 11.7 vs. 13.3 O2%). They also had a significantly higher BF upon release of the contractions (656, 701, 764 vs. 971 mL ∙ min(-1)). The higher FTI seen in elite climbers may be attributable to a greater blood delivery, and an enhanced O2 recovery during the 3 s release periods, as well as a superior muscle oxidative capacity associated with the greater de-oxygenation during the 10 s contractions.

Forearm muscle oxidative capacity index predicts sport rock-climbing performance

“…Despite minor over-and underestimations in male and females respectively, there were no significant or meaningful differences between self-reported grade and the grade achieved. As such, the self-report method has been used for on-sight and red-point performance extensively within the literature for both red-point and on-sight (Dickson et al 2012a;Dickson et al 2012b;Draper et al 2011a;Fryer et al 2012;Fryer et al 2015a;Fryer et al 2015b;Fryer et al 2015c). The current study used a self-reported best red-point grade achieved in the 6 months prior to laboratory testing.…”

“…In turn, the endurance of the FDP would be expected to be dependent on the ability to (i) deliver and (ii) use oxygen (Fryer et al 2015b). However, a recent study reported the ability to deliver oxygen at the conduit artery (brachial) level, during contractions to failure does not predict rock climbing performance (Fryer et al 2015c), suggesting that the ability to deliver and use oxygen in the muscle (oxidative capacity) may be a more important determinant of performance.…”

Oxygen Recovery Kinetics in the Forearm Flexors of Multiple Ability Groups of Rock Climbers

“…Figure 1 shows a schematic depicting the protocol used during the study. A rock climbing specific fingerboard designed by MacLeod et al, (14) and modified (addition of climbing holds instead of wooden force plate) by Fryer et al, (10,11) was used to conduct all strength and endurance tests (fingerboard the between-day coefficient of variation was 0.5 %). A schematic and picture of the fingerboard and climbing hold is shown in Figure 2.…”

“…Rock climbing has been shown to involve large periods of time spent cycling between sustained and intermittent isometric forearm contractions (9), and so oxidative capacity in the highly stressed local muscle groups is important, and has become a prominent area of interest (10,11,14,17). Previous studies have used near infra-red spectroscopy (NIRS) to assess de-oxygenation (the offloading of oxygen from haemoglobin in the muscle tissue) during both sustained and intermittent contractions to failure, but have not been used to assess oxidative capacity per se (10,11,14,17).…”

“…Previous studies have used near infra-red spectroscopy (NIRS) to assess de-oxygenation (the offloading of oxygen from haemoglobin in the muscle tissue) during both sustained and intermittent contractions to failure, but have not been used to assess oxidative capacity per se (10,11,14,17). Tissue oxygen (O2) recovery assessed using NIRS has been shown to have a similar time constant to phosphocreatine (PCr) re-synthesis assessed using magnetic resonance spectroscopy (15), and so the application of NIRS may provide useful information on muscle tissue oxidative capacity in climbers.…”