WORKLOAD SPIKES COMBINED WITH HIGH CUMULATIVE LOAD IS ASSOCIATED WITH INCREASED INJURY RISK IN ELITE RUGBY SEVENS PLAYERS

Background Match and training demands differ between seven and fifteen-a-side rugby. The association between training load and injury risk has not been examined in elite Rugby Sevens. Objective To explore the association between training load measures and injury risk in elite Rugby Sevens players. Design Two-season (2014/15 and 2015/16) prospective cohort study. Setting The England men9s Rugby Sevens squad. Participants 42 players (31 players followed over one-season, 11 players over two-seasons). Assessment of Risk Factors Training loads were recorded for all sessions using the session-Rating of Perceived Exertion method. A generalised linear mixed effects model examined the association between training load measures and injury risk in the subsequent week. The acute:chronic workload variable (one-week load divided by four-week average load) was parsed into tertiles: low= 1.45. Main Outcome Measurements Injury and the relative risk (RR) associated with increases in training load measures. Results 152 training and 30 match injuries were recorded. The incidence rate was 91/1000 player-match-hours (90% CI: 68–123) and 14/1000 player-training-hours (90% CI: 12–16). Mean severity (day9s absence) of injuries was 31 days during matches and 21 days during training. There was a substantial interaction between four-week cumulative load and acute:chronic workloads, such that typically high versus typically low four-week cumulative loads (i.e., a 7140 AU difference) coupled with high acute:chronic workloads were clearly associated with injury risk (RR: 2.08, 90% CI 1.17–3.68). This effect was unclear in the low (RR: 1.02, 90% CI: 0.62–1.68) and medium (RR: 1.44, 90% CI: 0.81–2.55) acute:chronic workload ranges. Conclusions The injury incidence rate in elite Rugby Sevens training is substantially higher than in the 15-a-side game. The coupling of high cumulative loads with high acute:chronic workloads was associated with an increased injury risk, therefore practitioners should avoid high acute:chronic workloads during periods of high cumulative load.