SPORTS MEDICINE HYPERMOBILITY

prevalence of hypermobility of 32% and 42%, respectively (10,12). Both of these studies used a BS cut-off point of

≥4 and might have been expected to report a lower incidence than our study

given our higher cut-off point. It is of note that the football study had a high proportion of African–Caribbean participants, who are known to have a higher incidence of hypermobility than Caucasians (12). The authors of the rugby study argued that hypermobile players would self-select out of rugby, yet they reported a higher prevalence than that found in our study, which is difficult to explain without anthropometric data.

HM and risk of injury As expected, the prevalence of hypermobility was greater in females than males in this study. If hypermobility in female hockey players of this age had been shown to be an independent risk factor for injury, then some policy change might be suggested, for example the introduction of athlete screening for hypermobility. An association with injury was suggested by this study but it was not possible to establish a causative link. Stewart and Burden (10) found that muscle strength does not protect hypermobility players from injury and it is suggested that movement patterning is more important than peak torque. It would be interesting to conduct a study to evaluate the efficacy of a movement control/load transfer strategy programme for hypermobile players with the aim of injury prevention.

Injury and missed training As this was a retrospective study, exposure time was not available to aid data analysis of injuries, thus limiting robust comparison with other hypermobility sport studies. However, injury trends for the group as a whole, and the two genders taken separately, did emerge. Boys were more likely to sustain contact injuries than girls, and girls more commonly reported chronic overuse injuries and injuries sustained in other sports. This difference might arise because when boys play the game the ball moves considerably faster than it does in the girls’ game (so they need faster reaction times to avoid such injuries) and because the boys might be greater risk-takers. Both of these factors might account for the

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PREDISPOSE THEM TO INJURY – IN FACT, IT MIGHT BE CONSIDERED A PERFORMANCE ADVANTAGE IN TERMS OF REACH AND FLEXIBILITY.

greater number of contact injuries in the male group. Despite twice-weekly core stability training, girls were more prone to overuse injuries. This would be interesting to explore further in terms of exercise adherence and skill level, as well as the relevance of the programme to the players. Boys reported more groin injuries, which might be related to their participation in sprint training as noted in their weekly training programmes.

Contact injuries resulting from

impact by a ball or stick are common in hockey and an accepted risk of the game. A limitation of this study was that the participants were not asked to record if they had been wearing protective equipment when they sustained their injury. Gloves can provide protection for hand injuries, and different types of footwear afford different degrees of protection from foot injuries, both in terms of grip on the playing surface and shielding of the foot by the upper part of the shoe. We found that goalkeepers tended

to have greater joint hypermobility but this did not predispose them to injury. In fact, it might be considered a performance advantage in terms of reach and flexibility.

Time missed from training has a significant impact on player development within the national squad and can hamper chances of selection. There were 1,615 days lost from training in this population, an average of 28.3 days per injury. Our results show that girls missed more days than boys, however two girls in particular skewed these results. The first of these girls sustained an ankle fracture–dislocation while throwing the discus, followed a couple of months later by a lumbar pars fracture; together these resulted in 7 months out of play. The other sustained an ankle ligament rupture while playing netball that required 6 months’ rehabilitation. If these two

subjects were removed the number of days lost by the girls would have dropped from 575 to 366.

It is probable that the injury data underestimates the actual injury rate because minor injuries such as contusions are an accepted part of the game and likely to be forgotten about by players when they complete the questionnaire, perhaps some two years later.

Limitations and future investigation The authors acknowledge several limitations in the current study design. The sample population was drawn from players in under-16 and under-18 age groups who presented to assessment and training camps. Players who were injured and did not attend were not included, which may have biased the sample towards the more physically robust players and therefore skewed the results. However the testing period was conducted over three seasons to maximise exposure to all eligible players.

Information about injury history

was collected retrospectively, thus exposing the study to recall bias. Less significant injuries may have been forgotten by some players and thus not included in the analysis. Injury history was recorded for just two seasons to minimise the effect of recall bias, but a longer period of injury history would have been preferable.

Information on exposure hours

was not collected; rather a sample weekly schedule was collected. Thus the relationship between training load and injury prevalence may be alluded to, but compared to injury surveillance studies in rugby and football, for example, this study is less robust. The type of training was not recorded; high-risk training drills (such as drag- flicking, short-corner routines and diving towards the goal) are practiced in greater repetitions in training than ever

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GOALKEEPERS TEND TO HAVE GREATER HYPERMOBILITY BUT THIS DOES NOT