Greater Association of Relative Thresholds Than Absolute Thresholds With Noncontact Lower-Body Injury in Professional Australian Rules Footballers: Implications For Sprint Monitoring

• Published in: International journal of sports physiology and performance 2020-02, Vol.15 (2), p.1-212
• Main Authors: O'Connor, Fergus, Thornton, Heidi R, Ritchie, Dean, Anderson, Jay, Bull, Lindsay, Rigby, Alex, Leonard, Zane, Stern, Steven, Bartlett, Jonathan D
• Format: Article
• Language: English
• Subjects: Australian football; Professional soccer; Velocity; Workloads
• ISSN: 1555-0265; 1555-0273
• DOI: 10.1123/ijspp.2019-0015

To examine the relationship between sprint workloads using relative vs absolute thresholds and lower-body soft-tissue and bone-stress injury incidence in professional Australian Rules Football (AF). Fifty-three professional AF athletes' noncontact soft-tissue and bone-stress lower-body injuries (N = 62) were recorded and sprint workloads were quantified over ~18 mo using GPS. Sprint volume (m) and exposures (n) were determined using 2 methods: absolute (>24.9 km·h ) and relative (>75%, >80%, >85%, >90%, >95% of maximal velocity). Relationships between threshold methods and injury incidence were assessed using logistic generalized additive models. Incidence-rate ratios (IRR) and model performances' area under the curve (AUC) were reported. Mean ±SD maximal velocity for the group was 31.5 ±1.4, range 28.6-34.9 km.h . In comparing relative and absolute thresholds, 75% maximal velocity equated to ~1.5 km·h below the absolute speed threshold, while 80% and 85% maximal velocity were 0.1 km·h and 1.7 km·h above the absolute speed threshold, respectively. Model AUC ranged from 0.48 to 0.61. Very low and very high cumulative sprint loads >80% across a 4-wk period, when measured relatively, resulted in higher IRR (2.54-3.29), than absolute thresholds (1.18-1.58). Monitoring sprinting volume relative to an athlete's maximal velocity should be incorporated into athlete-monitoring systems. Specifically, quantifying the distance covered at >80% maximal velocity will ensure greater accuracy in determining sprint workloads and associated injury risk.