Since studies carried out with basketball players show that over half of the time missed from practices and games is due to ankle injury ('A Comparison of the Injuries Sustained by Female Basketball and Netball Players,' Australian Journal of Science and Medicine in Sport, vol. 28, pp. 12-17, 1996), it's clear that players, coaches, and team doctors need to identify the key risk factors for ankle injuries and develop strategies to limit the likelihood of ankle damage during play.
Traditionally, researchers have suggested that ankle injury history, ankle taping, ankle bracing, playing-shoe construction and quality, warm-up strategy, and position played on the court (forward, guard, centre) all play a role in determining whether an injury will occur, but no one has known which of these factors are most important (or even if all of the factors really do have an impact on the likelihood of injury).
To gain more understanding of how ankle injuries occur and how they can be prevented, researchers at three universities in Australia recently observed 10,393 basketball players (3421 men and 6972 women) during competition. 78 % of these athletes were recreational players, while 22 % qualified as 'elite' (i. e., able to play successfully on competitive teams, rather than merely during informal games). The athletes averaged two games a week, and an injury was defined as 'an action in which a player perceived that bodily harm had been sustained necessitating stoppage of play, substitution, or a display of obvious disability' ('Ankle Injuries in Basketball: Injury Rate and Risk Factors,' British Journal of Sports Medicine, vol. 35, pp. 103-108, 2001).
The rate of ankle injury turned out to be 3.85 per 1000 participations (about one injury for every 260 games). The average time missed due to injury was 2.2 weeks, and 46 % of the injuries prevented players from returning to action for one week or more. Interestingly enough, almost half of the ankle injuries were sustained during landing, with half of these injuries (about 25 % of the total) occurring as a result of landing on another player's foot. Sharp twists or turns (30 %), collisions (10 %), falls (5 %), sudden stopping (2.5 %), and tripping (2.5 %) accounted for the other ankle injuries.
As it turned out, a history of ankle injuries was the best predictor of ankle injury. In fact, players who had previously injured an ankle were almost FIVE times more likely to injure an ankle during the study period, compared to previously uninjured athletes. 73 % of the players who reported an ankle injury during the research had suffered a previous ankle problem (the average number of prior injuries was 3.5). In contrast, a random sample of players who were uninjured during the study revealed that just 33 % had at one time suffered at least one ankle injury (the average for the uninjured players was 2.4 previous injuries).
What does this actually tell us? As is the case in many sports, injuries are usually not unexpected 'lightning bolts'; they are very often simply recurrences of previous problems. Basketball players who suffer ankle injuries usually experience them again and again, not because they are unlucky but because they lack the basic ankle strength and coordination to stay out of trouble. It's logical that a strengthening programme, especially one that emphasises the development of improved strength during landing, 'cutting', and sudden stopping, should help lower the high rate of recurrence. The Australian researchers reported that only 56 % of the ankle injured players received physiotherapy, and it is unlikely that these individuals were given basketball-specific strengthening routines for the lower parts of their legs.
In the Australian investigation, the second-best predictor of ankle injury for basketball players turned out to be the presence of air cells in the heels of the shoes worn for practice and competition. In fact, players wearing shoes with air cells were 4.3 times more likely to hurt an ankle, compared to athletes without the cells.
What should we make of this? First of all, it's quite reasonable to think that mid-sole construction and composition in basketball shoes should play a role in preventing/producing injuries. Basketball-shoe midsoles tend to be quite thick, for one thing. In theory, this exaggerated thickness provides better cushioning, but it also makes the foot and ankle more unstable, compared to a situation in which the foot is closer to the ground. In particular, it makes the foot and ankle more prone to the violent side-to-side tipping motions which produce ankle sprains and other ankle injuries.
If you doubt this, simply stand in your bare feet and try to turn one of your ankles over by rolling it to the outside. You'll find that this simple action is actually fairly difficult to carry out; your bare foot resists this dangerous motion, and much of your foot's sole stays in contact with the ground, even as your ankle turns considerably. Now, strap on a pair of basketball shoes and try the same movement. Note how your foot rolls more easily to the side as the bottom of the shoe lifts off the ground, and note that you fairly quickly reach a point at which the shoe tips over suddenly, stretching the ligaments on the outside of your ankle. This is why some experts call modern basketball shoes 'automatic ankle-spraining devices'.
'He had no hesitation in agreeing that players with a history of ankle injuries were more likely to be hurt that those with no previous ankle problems'
In a similar vein, if basketball-shoe midsoles contain materials or structures which facilitate or enhance this side-to-side motion, then the risk of ankle injury should increase. Are the air cells just such structures, providing less resistance to ankle-twisting movements than traditional midsole materials? In a March 27 interview with Keith Mulvihill provided by Reuters Health, Dr Mario Lafortune of the Nike Sports Research Laboratory in Beaverton, Oregon, said: 'I completely disagree with this hypothesis'. Lafortune suggested that the Australian study provided more questions than answers, and that it was difficult to interpret the results. However, he had no hesitation in agreeing that players with a history of ankle injuries were more likely to be hurt than athletes with no previous ankle problems, which was the other key Aussie result.
The Australians did find one other injury factor (in addition to prior history and air cells): players who did not 'complete a general stretching programme' before the game were 2.6 times more likely to injure an ankle, compared to players who did. This finding is a little difficult to interpret, since few details were provided concerning the stretching. We don't know whether the stretches were carried out before or after a movement-oriented segment of warm-up (lay-ups, jogging, etc.), for example, nor do we know whether the stretches were dynamic and basketball-specific, or perhaps static and general in nature.
Interestingly enough, players with a history of ankle injury were more likely to wear an ankle brace, compared to athletes with no prior injury; however, wearing an ankle brace did not significantly reduce the risk of injury. Other factors which were not significantly related to the occurrence of injury were sex, age, height, weight, games played per week, amount of training per week, shoe cut (high- or low-top), position played (guard, forward, or centre), or quarter of the game (some observers have suggested that ankle injuries tend to be skewed toward the fourth quarter, when players are most fatigued).
Overall, the Australian study was well done, including - as it did - over 10,000 basketball participations, about four times the number of court-side observations made during previous research. Although the detected injury rate was high, there was some good news: almost 80% of ankle injuries are sustained during landing or during sudden cutting or twisting movements, which suggests that if basketball players improve their landing/cutting skill and strength, they can significantly reduce their risk of getting hurt. Various hopping and jumping exercises, sprint drills which include very rapid turns and numerous changes in direction, one-leg squatting activities, and balance-board routines should help to drag down injury rates. Research carried out with volleyball players found a two-fold reduction in ankle injuries after correct landing techniques and body-movement strategies had been learned ('A Twofold Reduction in the Incidence of Acute Ankle Sprains in Volleyball after the Introduction of an Injury-Prevention Program: A Prospective Cohort Study,' Scandinavian Journal of Medicine and Science in Sports, vol. 7, pp. 172-177, 1997). Basketball players with previous ankle injuries should be acutely attentive to these strengthening activities.