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

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

doi:10.3390/ijerph18094603

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

Int J Environ Res Public Health. 2021 Apr 26;18(9):4603. doi: 10.3390/ijerph18094603.

Authors

Lewis Kirkwood^{1

2}, Lesley Ingram-Sills^{1

2}, Mark Dunlop Taylor³, Eva Malone¹, Geraint Florida-James^{1

2}

Affiliations

¹ School of Applied Sciences, Edinburgh Napier University, Edinburgh EH11 4BN, UK.
² Mountain Bike Centre of Scotland, Peel Tower, Glentress EH45 8NB, UK.
³ School of Engineering and the Built Environment, Edinburgh Napier University, Edinburgh EH10 5DT, UK.

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^-/CD56^dim 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^-/CD56^dim/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.

Keywords: leukocyte redistribution; mountain biking; recovery; training load.

MeSH terms

Flow Cytometry
Immunity
Killer Cells, Natural
Laboratories*
Lymphocyte Subsets
Vibration*