Abstract
Elite athletes in varied sports typically combine ergogenic strategies in the hope of enhancing physiological responses and competitive performance, but the scientific evidence for such practices is very scarce. The peculiar characteristics of speed skating contribute to impede blood flow and exacerbate deoxygenation in the lower limbs (especially the right leg). We investigated whether combining preconditioning strategies could modify muscular oxygenation and improve performance in that sport. Using a randomized, single-blind, placebo-controlled, crossover design, seven male elite long-track speed skaters performed on-ice 600-m time trials, preceded by either a combination of preconditioning strategies (COMBO) or a placebo condition (SHAM). COMBO involved performing remote ischemic preconditioning (RIPC) of the upper limbs (3 × 5-min compression at 180 mmHg and 5-min reperfusion) over 3 days (including an acute treatment before trials), with the addition of an inspiratory muscle warm-up [IMW: 2 × 30 inspirations at 40% maximal inspiratory pressure (MIP)] on the day of testing. SHAM followed the same protocol with lower intensities (10 mmHg for RIPC and 15% MIP). Changes in tissue saturation index (TSI), oxyhemoglobin–oxymyoglobin ([O2HbMb]), deoxyhemoglobin–deoxymyoglobin ([HHbMb]), and total hemoglobin–myoglobin ([THbMb]) in the right vastus lateralis muscle were monitored by near-infrared spectroscopy (NIRS). Differences between COMBO and SHAM were analyzed using Cohen’s effect size (ES) and magnitude-based inferences. Compared with SHAM, COMBO had no worthwhile effect on performance time while mean Δ[HHbMb] (2.7%, ES 0.48; -0.07, 1.03) and peak Δ[HHbMb] (1.8%, ES 0.23; -0.10, 0.57) were respectively likely and possibly higher in the last section of the race. These results indicate that combining ischemic preconditioning and IMW has no practical ergogenic impact on 600-m speed-skating performance in elite skaters. The low-sitting position in this sport might render difficult enhancing these physiological responses.
Highlights
Elite speed skaters adopt a crouched position that is both aerodynamically and biomechanically favorable to performance (Noordhof et al, 2014)
Considering the potential cumulative impact of such techniques, the fact that elite athletes combine different methods, and in the spirit of answering a specific research question that was raised in preparation for the Olympic trials and competitions, the primary purpose of this study was to examine whether the combination of chronic remote ischemic preconditioning (RIPC) with inspiratory muscle warm-up (IMW) could improve performance and modify muscular oxygenation during a 600-m speed-skating time-trial in elite speed skaters
This study examined the impact of the combination of RIPC and IMW, two preconditioning strategies that were found to modify peripheral oxygenation (Cheng et al, 2013; Kido et al, 2015; Tanaka et al, 2016) in some context, on the vascular and metabolic effects induced by the crouched position adopted by elite speed skaters in race
Summary
Elite speed skaters adopt a crouched position that is both aerodynamically and biomechanically favorable to performance (Noordhof et al, 2014). The combination of this low-sitting position, the isometric gliding phase and high intramuscular forces results in impeded blood flow to working muscles (Konings et al, 2015). Comparison of oxygenation patterns in short- vs long-track speed skating demonstrates that the former discipline leads to a more severe muscle deoxygenation (Hettinga et al, 2016). Blood flow occlusion and tissue deoxygenation occur during the gliding and push-off phases in longtrack speed skating (Hettinga et al, 2016), thereby implicating physiological drawbacks, such as accentuated local hypoxic stress that may hasten peripheral fatigue development (Konings et al, 2015). The exact impact of the deoxygenation severity during speed-skating performance is not clearly understood
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