Immune Response of Elite Enduro Racers to Laboratory and Racing Environments: The Influence of Training Impulse and Vibration

Kirkwood, Lewis; Ingram-Sills, Lesley; Taylor, Mark Dunlop; Malone, Eva; Florida-James, Geraint

Abstract

Introduction: Understanding the sport-specific immune response elicited during both training and competition is imperative to maximise athlete health and performance. Despite a growing population of professional enduro mountain bike athletes, little is known about the recovery of the immune system following enduro racing events. Methods: Nine international level elite enduro mountain bike athletes (age 24.3 ± 2.4 years, height 178.5 ± 8.7 cm, mass 76.5 ± 12.5 kg) completed a laboratory-based maximal exercise test (LAB) on a cycle ergometer and competed in an international mountain bike enduro race event (RACE). Blood samples were taken before, immediately after, and 1 h after LAB and before, 1 h after, and 17 h after RACE. Leukocyte subsets were enumerated using seven-colour flow cytometry. Lucia’s training impulse (LuTRIMP) and vibration exposure (VIB) were quantified during RACE. Results: Seven participants were included in the final analyses. There was a significant (p < 0.05) increase in neutrophil count alongside a reduction of cytotoxic lymphocyte cell subsets of both the innate (CD3−/CD56+ NK-cells and CD3−/CD56dim NK-cells) and adaptive (CD8+/CD62L−/CD45RA− T-cells and CD8+/CD27+/CD28− T-cells) components of the immune system one hour after RACE. All cell counts returned to baseline values 17 h afterwards (p > 0.05). Cell subset redistribution from pre- to post-one-hour time points (%Δpre-post1h) in cell subsets with potent effector functions (Neutrophils, CD3−/CD56+ NK-cells, CD8+/CD62L−/CD45RA− T-cells, CD8+/CD27+/CD28− T-cells, and CD3−/CD56dim/CD57− NK-cells) was significantly greater at RACE than LAB (p < 0.05). VIB was shown to be a superior predictor of %Δpre-post1h CD4+ T-cells, CD4+ early T-cells, CD4+ naïve T-cells, and NK cells as compared with LuTRIMP on its own (ΔR2 = 0.63 − 0.89, p < 0.05). Conclusions: The race event offers a greater challenge to the immune system than LAB, and potentially, whole body vibration is a key component of training load measurement in mountain bike applications.

• Journal Article Type: Article
• Acceptance Date: Apr 24, 2021
• Online Publication Date: Apr 26, 2021
• Publication Date: 2021-04
• Deposit Date: May 4, 2021
• Publicly Available Date: May 4, 2021
• Journal: International Journal of Environmental Research and Public Health
• Publisher: MDPI
• Peer Reviewed: Peer Reviewed
• Volume: 18
• Issue: 9
• Article Number: 4603
• DOI: https://doi.org/10.3390/ijerph18094603
• Keywords: mountain biking; training load; recovery; leukocyte redistribution
• Public URL: http://researchrepository.napier.ac.uk/Output/2766938