Table 6 Summary of study results
First authorSample sizeOutcome measuredInjuries in intervention group (A)Injuries in control group (B)Injury reduction(RR (95% CI))Absolute risk reductionNNT
Emery114Self-reported injury2100.2 (0.03 to 0.72)−0.19 (19%)5
Jung194Injury per player per year0.761.180.73−0.195 (19%)6
Injury per 1000 h exposure6.718.48
Mandlebaum2943ACL injury rate per athlete/1000 exposures/year0.050.470.255−0.18 (18%)6
Olsen1837Number (%) of injured players (all injuries)95 (9.9%)167 (19%)0.49 (0.36 to 0.68)−0.1 (10%)10
Number of acute knee/ankle injuries851560.51 (0.39 to 0.66)
Number of overuse injuries18390.43 (0.25 to 0.75)
Knee and ankle injuries per 1000 player hours0.91.80.53 (0.35 to 0.81)
Wedderkopp (1999)137Number of injuries14660.198−0.26 (26%)4
Injuries per 1000 h practice0.341.17
Injuries per 1000 h game4.6823.38
Wedderkopp (2003)163Incidence of traumatic injury/1000 h practice0.20.60.42 when using ankle disc compared with no ankle disc training−0.11 (11%)9
Incidence of traumatic injury/1000 h match2.46.9
Hewett1263Number of serious knee injuries2/36610/4630.25 (0.06 to 1.15)−0.015 (1.5%)66 (note these data reflect serious injuries; most were season ending)
Knee injury per 1000 exposures0.120.43
Non-contact injuries per 1000 exposures00.35
Heidt300Total number of injured subjects6/4287/2580.42 (0.2 to 0.9)−0.20 (20%)5
Total number of injuries7/42 (16%)91/258 (35%)−0.19 (19%)
Grace580Number of knee injuries (diagnosed by doctor)42/33011/2502.88+ 0.083 (+8.3%) *Higher injury rate in intervention group
MacIntosh294Number of concussions (diagnosed by doctor)7/11792/3571.05+ 0.0003 (+0.03%)*Higher injury rate in intervention group
Webster700Number of injuries per 1000 game exposures1.252.40.52Insufficient dataInsufficient data
Yang1 104 354 athlete exposures (19,728 athletes)Lower extremity injuryUnable to calculateUnable to calculate0.91 (0.72 to 1.15) when use of all protective equipment compared with control9%Insufficient data
  • ACL, anterior cruciate ligament; NNT, number needed to treat; RR, relative risk.

  • *+ indicates increased risk in intervention group.