Several studies have found a high incidence of injuries to the knee and ankle in young players in team handball. One prevention study from Danish team handball found a reduction of injuries to the knee and ankle among young female players. However, the number of injuries was not high enough to find a statistical reduction. The purpose of this study was to investigate the effect of an intervention program designed to reduce the incidence of knee and ankle injuries among young players in Norwegian team handball. Methods: Players aged 16-17 years (120 clubs, 1837 players) from the central and eastern Norway took part in the study. Half of the participants were randomized to an intervention group (61 clubs, 958 players) and asked to follow a 15-20 minutes programme of exercises with the ball, including the use of the wobble board and balance mat for warm up, technique, balance, and strength. Instructors from the Norwegian Handball Federation visit the clubs at the start of the season, with a follow up midway through the season. The other half of the participants (59 clubs, 879 players) were asked to do their training as usual during the season. Ten research physiotherapists who were blinded to group allocation recorded injuries in both groups in a web based database in which all the data were coded anonymously. Information about personal data, the injury situations and mechanisms was requested in each case. In addition, a compliance registering was done to evaluate the clubs follow-up of the intervention.
This randomized controlled trial, published in the British Medical Journal, shows that a structured programme of warm-up exercises can prevent knee and ankle injuries in young people playing sports. During the eight month season, 262 (14%) of the 1837 players who were included in the study contracted a total of 298 injuries. Of these, 241 (81%) were acute injuries and 57 (19%) were overuse injuries. The most common body part injured was the ankle (26%), followed by the knee (23%) and finger (11%). A total of 129 acute knee or ankle injuries occurred, 81 injuries in the control group (0.9 injuries per 1000 player hours; 0.3 in training v 5.3 during matches) and 48 injuries in the intervention group (0.5 injuries per 1000 player hours; 0.2 in training v 2.5 during matches). Fewer knee or ankle injured players were in the intervention group than in the control group (46 (4.8%) v 76 (8.6%); relative risk intervention group v control group 0.53, 95% confidence interval 0.35 to 0.81, p=0.004). The same figure for all injuries was 95 (9.9 %) v 167 (19 %) (RR=0,49, 95% CI=0,36-0,68, p<0,0001). A significant reduction in 46-80 % for moderate and major injuries was found. This study is the first randomised controlled trial among adolescents with a sufficient sample size to show that acute knee or ankle injuries can be reduced by 50% and severe injuries even more. On comparison with a previous study that investigated the prevention of injuries to the anterior cruciate ligament at the senior female level, we found a considerably higher compliance (87%) among the youth clubs than they found in the senior clubs (29% compliance). This indicates that it may be easier to implementing prevention training among younger players. It also seems reasonable to assume that the warm-up programme also could be modified to be used in other similar sports such as football, basketball, and volleyball, and in players as young as 10-12 years. These sports have a high incidence and similar pattern of knee and ankle injuries, and the injury mechanisms are also comparable (most injuries resulting from pivoting and landing movements). Therefore, we suggest that programmes focusing on technique (cutting and landing movements) and balance training (on wobble boards, mats or similar equipments) are implemented in players as young as 10-12 years.