Effect of high-speed running on hamstring strain injury risk.
BACKGROUND
Hamstring strain injuries (HSIs) are common within the Australian Football League (AFL) with most occurring during high-speed running (HSR). Therefore, this study investigated possible relationships between mean session running distances, session ratings of perceived exertion (s-RPE) and HSIs within AFL footballers.


METHODS
Global positioning system (GPS)-derived running distances and s-RPE for all matches and training sessions over two AFL seasons were obtained from one AFL team. All HSIs were documented and each player's running distances and s-RPE were standardised to their 2-yearly session average, then compared between injured and uninjured players in the 4 weeks (weeks -1, -2, -3 and -4) preceding each injury.


RESULTS
Higher than 'typical' (ie, z=0) HSR session means were associated with a greater likelihood of HSI (week -1: OR=6.44, 95% CI=2.99 to 14.41, p<0.001; summed weeks -1 and -2: OR=3.06, 95% CI=2.03 to 4.75, p<0.001; summed weeks -1, -2 and -3: OR=2.22, 95% CI=1.66 to 3.04, p<0.001; and summed weeks -1, -2, -3 and -4: OR=1.96, 95% CI=1.54 to 2.51, p<0.001). However, trivial differences were observed between injured and uninjured groups for standardised s-RPE, total distance travelled and distances covered whilst accelerating and decelerating. Increasing AFL experience was associated with a decreased HSI risk (OR=0.77, 95% CI 0.57 to 0.97, p=0.02). Furthermore, HSR data modelling indicated that reducing mean distances in week -1 may decrease the probability of HSI.


CONCLUSIONS
Exposing players to large and rapid increases in HSR distances above their 2-yearly session average increased the odds of HSI. However, reducing HSR in week -1 may offset HSI risk.
School of Exercise and Nutrition Sciences and Institute of Health and Biomedical Innovation, Queensland University of Technology, Brisbane, Queensland, Australia.
Steven
S
Duhig
School of Exercise and Nutrition Sciences and Institute of Health and Biomedical Innovation, Queensland University of Technology, Brisbane, Queensland, Australia.
Anthony J
AJ
Shield
Faculty of Health Sciences, School of Exercise Science, Australian Catholic University, Melbourne, Victoria, Australia.
David
D
Opar
School of Human Movement Studies, The University of Queensland, Brisbane, Queensland, Australia.
Tim J
TJ
Gabbett
Gold Coast Suns Australian Football Club, Gold Coast, Queensland, Australia.
Cameron
C
Ferguson
Faculty of Life Sciences and Education, University of South Wales, Wales, UK.
Morgan
M
Williams
D000328:Adult; D001265:Athletic Injuries / Q000453:epidemiology*; D001315:Australia; D000070633:Hamstring Muscles / Q000293:injuries*; D006801:Humans; D008297:Male; D011446:Prospective Studies; D012420:Running; D012916:Soccer / Q000293:injuries*; D013180:Sprains and Strains / Q000453:epidemiology*; D055815:Young Adult
Australian football; Global positioning system; Sprinting; Training