General health complaints and sleep associated with new injury within an endurance sporting population: A prospective study

Objectives: To examine the association between subjective health complaints, sleep quantity and new injury within an endurance sport population. Design: Prospective cohort study. Methods: Ninety-five endurance sporting participants were recruited from running, triathlon, swimming, cycling and rowing disciplines. Over 52-week period participants submitted weekly data regarding subjective health complaints (SHCs) (cardiorespiratory, gastrointestinal and psychological/lifestyle), sleep quantity, training load and new injury episodes. Applying a 7- and 14-day lag period, a shared frailty model was used to explore new injury risk associations with total SHCs and sleep quantity. Results: 92.6% of 95 participants completed all 52 weeks of data submission and the remainder of the participants completed >= 30 weeks. Seven-day lag psychological/lifestyle SHCs were significantly associated with new injury risk (Hazard ratio (HR)= 1.32; CI 95% = 1.01-1.72, p <0.04). In contrast, cardiorespiratory (HR= 1.15; CI 95% = 0.99-1.36, p =0.07) and gastrointestinal (HR= 0.77; CI 95% = 0.56-1.05, p= 0.09) SHCs were not significantly associated with new injury risk. New injury risk had a significant increased association with 14-day lag <7 h/day sleep quantity (HR= 1.51; CI 95% = 2.02-1.13, p <0.01) and a significant decreased association with >7 h/day sleep quantity (HR= 0.63, CI 95%=0.45-0.87, p <0.01. A secondary regression analysis demonstrated no significant association with total SHCs and training load factors (Relative Risk (RR)= 0.08, CI 95%=0.04-0.21, p=0.20). Conclusions: To minimise an increased risk of new injuries within an endurance sporting population, this study demonstrates that psychological/lifestyle subjective health complaints and sleep quantity should be considered. The study also highlights a lag period between low sleep quantity and its subsequent impact on new injury risk. No association was demonstrated between subjective health complaints, sleep quantity and training load factors. (C) 2019 Sports Medicine Australia. Published by Elsevier Ltd. All rights reserved.