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

Synopsis

Commentary

Summary of: Olsen OE, Myklebust G, Engebretsen L, HolmeI and Bahr R (2005): Exercise to prevent lower limb injuriesin youth sports: Cluster randomised controlled trial. BMJ:330: 449. (Prepared by Gro Jamtvedt and Kre Birger Hagen,CAP Editors).

Question What is the effect of a structured warm-up programfor reducing knee and ankle injuries in young peopleparticipating in sport? Design Cluster randomised controlledtrial, with clubs as the unit of randomisation. Setting 120handball club teams in Norway. Patients 1837 players (1586female, 251 male), aged 1517 years. Interventions Astructured warm-up program to improve running, cutting, andlanding technique as well as neuromuscular control, balance,and strength used at the beginning of every training sessionfor 15 consecutive sessions and then once a week during therest of the eight-month season. Each club received one visitfrom an instructor and they received an exercise book, fivewobble boards, and five balance mats. The main focus of theprogram was to improve awareness and control of knee andankle by use of equipment. The program included four sets ofexercises: warm-up exercises, technique, balance, and

strength and power. The players were instructed to spend 45minutes on each exercise group for a total duration of 1520minutes. The instructor did one follow-up visit midwaythrough the season. Outcomes Primary outcome was rate ofacute injuries to the knee or ankle. Secondary outcomes wereany injury to the lower limb and overall injuries. Injuries wererecorded by 10 physiotherapists blinded to group allocation.Result 13% of the clubs in the intervention group did not usethe program, whereas 22% of the clubs in the control groupused specific warm-up exercises to prevent injuries during thestudy period. During the eight month season 14% of the 1837players had an injury. The intervention group hadsignificantly fewer acute knee and ankle injuries, 4.8% ofsubjects experienced injuries in the intervention group versus8.6% in the control group (relative risk 0.53, 95% CI 0.35 to0.81, number needed to treat (NNT) = 26. Injuries overall andupper limb injuries were also lower in the intervention group(NNT for all injuries = 11, NNT for upper limb injuries = 38).Conclusion A structured warm-up exercise program focusingon awareness and control of knees and ankle prevented acuteknee and ankle injuries in young team handball players.

Through a long term research program on injury preventionOslo Sports Trauma Research Centre has published severalhigh quality studies. In this large study, lower limb injurieswere reduced by more than 50% in the exercise group. Aspointed out in a letter responding to this article (Webborn2005) we do not know whether the results can be transferredto other sports, and there might be seasonal variations.

The intervention focused on handball-specific exercises, butthey are also exercises that are important for other athletes toimprove performance. Awareness and control of hips, knees,and ankles during activities has been shown to be vital forknee joint loading. But we still dont know what exercises arethe most important for injury prevention: is it just theawareness part of the program or is it the combination of allexercises? Until we know we should motivate players to usethis program and implement it in all pivoting sports to preventknee injuries and long-term knee degeneration. The programseems to be easy to organise and does not require costlyequipment. Therefore the program is applicable to a largepopulation.

The study contributes significant new knowledge. However,

the most important question is how these findings can beimplemented in programs for team handball players in theyears to come. Compliance is a key point in studiesmeasuring effects of exercise programs. This study adds toexisting knowledge that supervision and coach involvment iscrucial to achieve high compliance. Clubs, coaches, players,and medical teams should be made aware of these results andimplement the programme as an integrated part of everydaytraining. Teaching activities and dissemination of the resultsthrough collaboration with the different federations will beimportant to achieve this.

Thomas T. degaardNorwegian Institute of Sports Medicine (NIMI), Oslo, Norway

May Arna RisbergNAR, Orthopedic Center Ullevaal University Hospital, Oslo, Norway

ReferenceWebborn N (2005): Rapid Response to Olsen E et al. Exercises

to prevent lower limb injuries in youth sports: clusterrandomised controlled trial BMJ 330: 449.(http://bmj.bmjjournals.com/cgi/eletters/330/7489/449)

Critically Appraised Paper

Australian Journal of Physiotherapy 2005 Vol. 51 131