Introduction A high incidence of anterior cruciate ligament (ACL) injuries related to sports activities has been reported; however, the injury situation of ACL injury in badminton has not been elucidated. This study investigated the mechanism of ACL injury in badminton using a questionnaire.
Methods Information on injury mechanism was gathered from interviews with six male and 15 female badminton players who received a non-contact ACL injury playing badminton and underwent ACL reconstruction.
Results The most common injury mechanism (10 of 21 injuries) was single-leg landing after overhead stroke. Nine of 10 players had injured the knee opposite to the racket-hand side. The second most frequent injury mechanism (eight of 21 injuries) was plant-and-cut while side-stepping or backward stepping. All eight players injured the knee of the racket-hand side. Eleven injuries occurred in the rear court, and six of the 11 injuries occurred during single-leg landing after an overhead stroke.
Conclusion The knee opposite to the racket-hand side tended to sustain the ACL injuries during single-leg landing after a backhand overhead stroke, whereas the knee of the racket-hand side tended to be injured by plant-and-cut during side or backward stepping. These injury patterns appear to be due to specific movements during badminton.
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Most anterior cruciate ligament (ACL) injuries occur during sports activity, and up to 70% of all incidents are non-contact injuries.1,–,3 Non-contact ACL injuries often occur during landing or deceleration before a change of direction; the mechanism of ACL injuries remain poorly understood and very little is known about the effect of sports-specific factors.4 Competitive badminton requires frequent quick starts, stops and changes of direction. Players hold a racket in their dominant hand, which limits their arm position and leads to asymmetric posture. In badminton, overuse injuries and acute injuries in the lower extremities are generally the most frequent.5,–,7 From the data of 141 badminton players who underwent surgical treatment for overuse or acute injuries, ACL injuries accounted for 37% of all injuries.8 To our knowledge, however, there have been no published reports of the incidence or mechanisms of ACL injury related to badminton. Therefore, the purpose of this study was to investigate the mechanisms of ACL injury in badminton players.
Materials and methods
All data were collected through interviews and retrospective review of the medical records for the period from January 2002 to December 2007. During the period, 314 primary ACL reconstructions were performed in our institute; 95% of injuries occurred while playing sports and 91% were non-contact injuries. Information on injury mechanism was collected from medical records and interviews with injured players that were obtained within 1 month after the injury. The patients who had visited our institution for the first time over 1 month after the injury were excluded. All the players consented to participate in a personal interview. Demographic data such as age, gender and subject characteristics, such as years of badminton experience, dominant hand (racket hand), and the event during which the injury occurred (practice or game) and which knee was injured: right or left, were collected from medical records. The players were interviewed by a physician using a standardised questionnaire (table 1).
They were asked to describe the circumstances (playing situation, motion, handling the shuttle) and court position and floor type when the injury occurred. The court position showed the combination of row (front, middle or rear) and side (forehand or backhand). Based on the results obtained from questionnaires filled out by the patients, the mechanisms of injuries were grouped as a single-leg landing from overhead stroke (smash or clear) (figure 1), plant-and-cut during stepping (figure 2) and others.
Twenty-one badminton-related ACL injuries were recorded during the period, representing 7% of all the registered ACL injuries. Six male and 15 female badminton players were injured (figure 3). The mean age of injured players was 21.9±7.9 (mean±SD) years (13–38); 18.6±5.3 years (15–34) for women and 27.4±9.6 years (18–38) for men. Twenty players were right-hand dominant, and one player was left-hand dominant, which corresponded with the racket-hand side. Twelve and nine players injured the knees that were the opposite side and same side as the dominant hand, respectively. All players participated in various levels of a badminton club, except one player who was injured during a gym class. The playing experience of injured participants averaged was 5.8±5.8 (mean±SD) years (0.4–21) (figure 4). The injury was prevalent during games (14 of 21, 67%).
The most common injury event was a single-leg landing after an overhead stroke (smash or clear shot) following a backward step by 10 players (47.6%); six injuries in the backhand side of the rear corner; two injuries in the forehand side of the rear corner; one injury in the backhand side of the middle court and one injury mechanism in an unknown court position (figures 5 and 6). Nine of 10 players injured the knee opposite to the racket-hand side.
The second most common mechanism (eight players; 38.1%) was plant-and-cut; four injuries occurred during a backward step to turn the body towards the rear corner to make a forehand stroke, and four and one injuries during a side-step to receive the shuttle on the forehand side of the middle and front court, respectively. All eight players had injured the knee on the racket-hand side. In these situations, the players land the leg of the racket-hand side by transferring their body weight while taking the shot, and then they push off the leg of the racket-hand side for recovery of the body to return to the centre of the court immediately in preparation for the next shot.
One player hyperextended and injured the knee opposite to the racket-hand side when receiving the shuttle from a forehand stroke at the front of the court. One player who was injured on the forehand side could not remember the event. One other player could not remember the inciting event nor the court location at the time of the injury. She ruptured the ACL in a gym class and did not have much experience in competitive badminton.
The main observation of this investigation was that ACL injuries in competitive badminton result predominantly from one of two injury mechanisms: (1) single-leg landing after overhead stroke and (2) plant-and-cut during short steps. Following an overhead stroke, players transfer their body weight from backward to forward, and land on the leg opposite to their racket-hand side to balance and push their body from the back to the base position. In right-handed players, the right foot was used for takeoff and the left foot was used for landing (figure 1). In an overhead stroke on the backhand side it is more difficult to keep the body in balance than on the forehand side, because they have to bend their trunk to their backhand side laterally as their arm comes through. In addition, quick footwork in a diagonal direction may also result in imbalance. Therefore, many players were injured during single-leg landing after an overhead stroke in the rear court, usually involving the knee opposite to the racket-hand side. On the other hand, plant-and-cut injuries occurred during side or backward steps towards the forehand side. In these situations, players placed stress on the leg of the racket-hand side to receive a shot and push back the upper body into a recovery position (figure 2). Therefore, many injuries occurred to the knees of the racket-hand side. In racket sports such as badminton, players always hold the racket in their dominant hand, which limits their arm position to balance their body with an asymmetric posture. Chaudhari et al9 examined the effect of sports-dependent variations in arm position on the valgus loading of the knee during a side-stepping manoeuvre. It was reported that a significant increase at the knee valgus moment occurred when the arm position was constrained by a ball or racket-carry posture compared with an unconstrained arm position. Single-leg landing after an overhead stroke in badminton may influence lower limb dynamics.
The key limitation in this study is that data are self-reported by the patients. However, Olsen et al10 compared the video analysis and questionnaire, and the results were very similar. We obtained video images from only one patient who ruptured the ACL of left knee with a single-leg landing after an overhead stroke (figure 7; see online video). She stepped backwards to her left and landed full weight on the left leg immediately after an overhead stroke, all the time being off balance. The upper body was bent forward and to her left with the left hip abducted. The left knee was slightly flexed and internally rotated with valgus alignment and left foot pronation. The observation in the video images matched her memory and answers in the questionnaire.
ACL injuries in badminton were primarily the result of two injury mechanisms; the knee opposite to the racket-hand side was injured during a single-leg landing after an overhead stroke and it usually occurred in the backhand side of the court. The knee of the racket-hand side was injured by plant-and-cut during side or backward stepping in the forehand side of the court.
What is already known on this topic
▶. Anterior cruciate ligament injuries frequently occurred with a non-contact mechanism during jump landing and plant-and-cut in sports activities.
▶. Few studies have examined sports-specific factors, and the mechanism of badminton has not been investigated.
What this study adds
▶. Anterior cruciate ligament injuries in badminton mainly occurred by two major injury mechanisms.
▶. The knee opposite to the racket-hand side was injured during a single-leg landing after an overhead stroke.
▶. The knee of the racket-hand side was injured by plant-and-cut during side-stepping.
Competing interests None.
Patient consent Obtained.
Ethics approval This study was conducted with the approval of the Hirosaki University Graduate School of Medicine Institutional Review Board.
Provenance and peer review Not commissioned; externally peer reviewed.
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