Warm-up exercise prevents acute knee and ankle injuries in young handball players

QuestionWhat is the effect of a structured warm-up program for reducing knee and ankle injuries in young people participating in sport?DesignCluster randomised controlled trial, with clubs as the unit of randomisation.Setting120 handball club teams in Norway.Patients1837 players (1586 female, 251 male), aged 15–17 years.InterventionsA structured warm-up program to improve running, cutting, and landing technique as well as neuromuscular control, balance, and strength used at the beginning of every training session for 15 consecutive sessions and then once a week during the rest of the eight-month season. Each club received one visit from an instructor and they received an exercise book, five wobble boards, and five balance mats. The main focus of the program was to improve awareness and control of knee and ankle by use of equipment. The program included four sets of exercises: warm-up exercises, technique, balance, and strength and power. The players were instructed to spend 4–5 minutes on each exercise group for a total duration of 15–20 minutes. The instructor did one follow-up visit midway through the season.OutcomesPrimary outcome was rate of acute injuries to the knee or ankle. Secondary outcomes were any injury to the lower limb and overall injuries. Injuries were recorded by 10 physiotherapists blinded to group allocation.Result13% of the clubs in the intervention group did not use the program, whereas 22% of the clubs in the control group used specific warm-up exercises to prevent injuries during the study period. During the eight month season 14% of the 1837 players had an injury. The intervention group had significantly fewer acute knee and ankle injuries, 4.8% of subjects experienced injuries in the intervention group versus 8.6% in the control group (relative risk 0.53, 95% CI 0.35 to 0.81, number needed to treat (NNT) = 26. Injuries overall and upper limb injuries were also lower in the intervention group (NNT for all injuries = 11, NNT for upper limb injuries = 38).ConclusionAstructured warm-up exercise program focusing on awareness and control of knees and ankle prevented acute knee and ankle injuries in young team handball players