SPORTS REHABILITATION

ACL prevention in female football

– Written by Kathrin Steffen, Roald Bahr and Grethe Myklebust, Norway

“TARPLEY TEARS RIGHT ACL, WILL MISS could have been prevented and in this players have a two to three times higher WOMEN’S WORLD CUP paper we will tell you how. ACL injury risk compared to their male United States Women’s National Team counterparts. Females also tend to sustain midfielder tore her right HOW BIG IS THE PROBLEM? an ACL injury at a younger age than males1. anterior cruciate ligament in the 75th minute Severe knee injuries, such as ACL injuries, Protecting the health of the athlete by of Saturday night’s 2-0 win over Japan and constitute a serious problem. Unfortunately, establishing prevention routines early is the will miss this summer’s Women’s World Cup they are frequent in many sports. Treatment responsibility of everyone involved in sports in Germany. She is expected to miss six-to- is costly and it often takes 12 months or including coaches, medical personnel, eight months. more to return to sport or in worst case, lead referees and the athletes themselves. To This is the same ACL that Tarpley tore in to early retirement. The long-term outcome maximise the health benefits for players the final game of the 2009 WPS season with is also a concern. A majority of athletes and to minimise the direct and indirect costs the . She slowly recovered will develop osteoarthritis within 15 to associated with injuries, early identification from that and made a strong comeback in 20 years after an ACL injury, regardless of of players at high injury risk is key. 2010 with and, more treatment. Consequently, injuries represent notably, with the . Tarpley a considerable problem for the athlete, their RISK FACTORS was recalled to the US team in November and team and, given the popularity of sport, for As for most other types of injury, recent had scored two goals in just four appearances society at large. studies have suggested that a history of knee with the team in 2011.” In football, as in other team sports ligament injury is the predominant risk – equalizersoccer.com characterised by sudden changes of factor for a subsequent injury2,3. However, direction, pivoting accelerations and the reasons for the obvious gender gap in Unfortunately, we hear of numerous sad decelerations, ACL injuries are a particular the risk of ACL injury are not completely stories like this, especially among women concern, especially for female athletes. clear. Various researchers have suggested competing in pivoting sports. Many of these A recent literature review, including 23 differences in anatomy, hormonal and anterior cruciate ligament (ACL) injuries studies, demonstrated that female football neuromuscular function as potential

178 reasons for the higher injury risk in women no direct player contact to the knee, many factor in many cases. This implies that than in men. To date, however, there is little cases involve some sort of perturbation by avoiding valgus knee motion is important evidence linking all these potential intrinsic an opponent (e.g. being pushed slightly for preventing injuries5,7. risk factors to noncontact ACL injuries and off-balance just before landing). The a great deal of controversy exists on the mechanisms for non-contact ACL injuries PREVENTION relative importance of the different factors4. are widely debated. What seems clear from A variety of injury-specific and sport- The main external risk factor that has several studies from various team sports specific preventive exercise programmes been advanced is the effect of friction and even alpine skiing is that knee valgus exist. Also, a growing number of between shoes and the playing surface. (where the knee collapses inwards into programmes have been developed to reduce Investigations from Australian Rules a ‘knock-knee’ position) is an important the risk of knee injuries in general and ACL Football and European handball suggest injuries in particular. Studies from various that a high shoe surface friction is associated sports typically show that establishing with an increased risk of ACL injury. For such programmes as standard warm-up example, when friction is high, the foot can majority of athletes programmes for teams can reduce the risk abruptly stop while the athletes are out for of injury by as much as 30 to 50%8-14. a cutting or turning manoeuvre. This will will develop Typically, these programmes consist of cause the knee to twist suddenly at foot osteoarthritis exercises focusing on core stability, balance, strike and collapse5,6. dynamic stabilisation and muscle strength within 15 to 20 years of the lower extremities. The exercises are MECHANISMS often designed as structured warm-up ACL injuries usually occur without after an ACL injury programmes to ensure that all players use contact between players and typically the programme regularly. One essential during cutting and turning or when landing part is to emphasise the ‘hip-knee-toe in on one foot after a jump. Even if there is line position’ in all types of exercises, both

SPORTS MEDICINE IN FOOTBALL TARGETED TOPIC 179 SPORTS REHABILITATION

Figure 1: Proper and poor knee lower limb alignment.

in plyometric, co-ordination and strength Balance training alone and home-based To identify the minimal effective dose exercises. The primary goal of this strategy training without instruction and feedback to reduce ACL injury risk is a daunting task. is to maintain posture and lower limb on proper movement technique (i.e. lower Also, we question: Which exercises are the balance in an attempt to teach players limb alignment, two-leg landings) is key exercises in a programme: strength, how to control their knee position as far as probably ineffective16,17 unless combined balance, plyometric or agility are actually all possible in all situations (Figure 1). with other types of exercises for core and of them? A recent comprehensive review of lower-limb strength, perturbation and the scientific literature15 focused on jumping, with a continuous focus on knee When to start? neuromuscular training programmes control. Most clinicians and researchers suggest developed to alter risk factors associated Another important challenge is to that focus on injury prevention should start with an ACL injury and to reduce injury risk convince coaches and athletes to use the as soon as children start participating in in football players. The authors conclude programmes. “Are the exercises really organised sports. Generally, injury risk is low that neuromuscular training appears to worth doing?” “The programme takes 20 under the age of 1218. Even so, from a motor be effective in reducing ACL injury risk minutes; do we need to do this programme learning perspective, including exercises and that lower extremity strength and every training session?” These are common to prevent injuries early can help develop balance exercises, in combination with core questions. And the answers are yes and yes! ‘good habits’ and less vulnerable movement and trunk control, seem to be necessary If done properly, as many as every second patters, in addition to establishing correct components of a successful ACL injury injury can be prevented. Perhaps one day, playing technique and fair play attitudes. prevention programme. Since Alentorn-Geli through continued research, programmes et al15 finished their thorough review, new can be developed which take less time and studies in football have been published are even more effective. (Continued on page 184) which reinforce their message: injuries can 9,11-13 be prevented . Figure 2: Prevention of ACL injuries We have selected three knee/ACL injury in team sports (Page 181) prevention programmes to present all have been proven to prevent 30 to 50% of all injuries (Figures 2 to 4). Two of the exercise A 5-phase 15 min programme with 3 different balance exercises focusing programmes presented here have been on neuromuscular control and planting/landing skills was developed and 9,12 developed for football , while the other is introduced to female elite handball players. Injury risk was significantly reduced for handball10. These and other successful for those players who highly complied with the exercises10. Balance exercises knee/ACL injury prevention programmes are usually done on a balance board or on an unstable balance pad, with the have several key aspects in common and knees and hips slightly flexed. Ball or partner exercises may also be included keeping these in mind, they can easily be to make the training more challenging and fun. While proper hip and knee adapted to other sports. control is always emphasised, the exercises for balance, jumping and landing can be adjusted to suit all sports that are characterised by cutting and landing PRACTICAL IMPLICATIONS - HOW, WHAT, movements. These exercises can also be incorporated into a warm-up program. WHEN? Though this programme seems to focus much on balance, there are also strength What type of exercises? elements included, such as two and one-leg squats. Remember, always use proper ACL injury prevention works. However, hip - knee – toe control. During an initial training period of at least 5 weeks, we still do not know how to optimise injury the exercise should be done a minimum of 3 times per week, training for 10–15 prevention programmes to make them time minutes per session. Maintenance training once or twice a week should continue efficient, which exercises are the ‘right ones’ throughout the competitive season. or if such a thing exists at all.

180 Right Wrong Prevention of ACL injuries in team sport athletes

Level 1

Floor exercises Mat exercises Wobble board exercises Running and planting, Two players standing on one Two players standing two partner running backwards leg on the mat throwing to legged on the board and giving feedback on the each other. throwing to each other. quality of the movement, change position after 20 s.

Level 2 R L R Floor exercises R Mat exercises Wobble board exercises Jumping exercise—right leg– L Jump shot from a box Squats on two legs, right leg over to left leg–left (30–40 cm high) with a then on one leg. L leg and finishing with a two- two-foot landing with foot landing with flexion in L flexion in hip and knees. both hips and knees. R L

Level 3

Floor exercises Mat exercises Wobble board exercises Running and planting “Step” down from box with Two players throwing to (as in week 1), now doing a one-leg landing with flexion each other, one foot on the full plant and cut movement in hip and knee. board. with the ball, focusing on knee position.

Level 4

Floor exercises Mat exercises Wobble board exercises Two and two players together two- Two players both standing One foot on the board, leg jump forward and backwards, on balance mats trying to bounding the ball with their 180° turn and the same movement push partner out of balance, eyes shut. backwards; partner tries to push first on two-legs, then on the player out of control but still one leg. focusing on landing technique. Level 5

Floor exercises Mat exercises Wobble board exercises Expanding the movement The players jump on a mat Two players, both standing from week 3 to a full plant catching the ball, then take on balance boards trying to and cut, then a jump shot a 180° turn on the mat. push partner out of balance, with two-legged landing. first on two legs, then on one leg.

Squats: Imagine that you are sitting down on a chair. Perform squats by bending your hips and knees to 90 degrees, do not let your knees cave inward. Bend slowly and straighten up more quickly.

Nordic Hamstrings: Your body should be completely straight from the shoulder to the knee. Lean forward as far as you can by using the hamstring muscles to resist the forward falling motion.

Squat–walking lunges: As you lunge forward, bend your lead leg until the hip and knee are bent to 90 degrees. Do not let your knee cave inward. Keep your upper body and hips steady.

Lateral jumps: Jump approx. 1m sideways from one leg to the other, like a skater. Land gently on the ball of your foot. Bend your hips and knees slightly and do no let your knee cave inward.

Sprunglauf: Spring as high and far as possible off the supporting leg. Bring the knee of the trailing leg up as high as possible and the opposite arm in front of the body.

©www.skadefri.no

Plakat Forebygging korsbåndskader.indd 1 01.06.10 16.02 Figure 2: Prevention of ACL injuries in team sport (Myklebust et al10).

SPORTS MEDICINE IN FOOTBALL TARGETED TOPIC 181 SPORTS REHABILITATION

Figure 3: Knäkontroll (Waldén et al12).

182 Figure 4: FIFA 11+ (Soligard et al9).

SPORTS MEDICINE IN FOOTBALL TARGETED TOPIC 183 SPORTS REHABILITATION

Who should be targeted? Figure 3: Knäkontroll (knee control) (Page 182) Most prevention programmes today are created as ‘one-size fits all’ package to be performed by all athletes. Perhaps future studies will give more specific knowledge The neuromuscular warm-up program “Knäkontroll” (“knee control”) about which type of exercises different significantly reduces the rate of ACL injuries among adolescent female football sports and different athletes should 12 players (Waldén et al. ). “Knäkontroll” contains of exercises focusing on knee perform. Further evidence is needed to control and core stability similar to other programs in, for example, handball. determine whether a pre-season functional The 6 exercises are one-legged knee squat, pelvic lift, two-legged knee squat, test e.g. by a drop-jump or single-leg squad the bench, lunge, and exercises on jump/landing technique. Each exercise is test, can be used to identify athletes with subdivided into 4 steps of progressive difficulty and a pair exercise (Table 1). higher risk. A study by Soligard et al19 showed The exercises are to be preceded by 5 minutes of low intensity running and take that across different skill attributes, players about 15 minutes to complete after familiarisation. In the project, the teams were with high levels of football skills were at instructed to conduct the exercises during the warm-up at 2 training sessions greater risk of sustaining injuries than their a week throughout the whole season. All players started on the first level of difficulty and proceeded to the next level when exercises were performed with less skilled teammates. In other words, there good control as assessed by the coach. are direct and indirect performance benefits from keeping players free of injury.

The Coach is the key! Winning and performance are the key factors for coaches and players. Therefore, Figure 4: The FIFA 11+ (Page 183) motivating coaches and players to follow exercise programmes is easier if they do not only to prevent injuries but also is provide direct performance benefit20. It might be In a randomised controlled study by Soligard et al9, the objective was to examine expected that by implementing a 15 to the effect of a comprehensive warm-up program designed to reduce the risk 20 minute injury prevention programme, of lower extremity injuries among female soccer players. Approximately 1900 players participated in the study. The 15-20 min warm-up program, called physical performance should also improve. “The FIFA 11+” includes exercises to improve lower extremity and core strength, However, there is limited research on this 20 awareness and neuromuscular control during static and dynamic movements. with conflicting outcomes . After 8 months of training, the intervention group had a significantly lower Coach education is the key. Well- risk of injuries overall (32%), of overuse injuries (53%) and of severe injuries trained coaches can deliver a new exercise (45%) compared with the controls. The “11+” exercises, as in many of the other programme in the correct way. Knowledge neuromuscular exercise programs, compose a multifaceted program, provide of sports injuries, injury prevention, variation and progression of exercises, and address many training components attitudes and beliefs to the importance of that are thought to be related to ACL and lower extremity injury risk. injury prevention training is quite varied among coaches. Without doubt, injury prevention should be mandatory as part of the coach education and certification at all levels. Key Aspects of Successful Injury Prevention Programmes TAKE HOME MESSAGE It is possible to prevent ACL injuries, however, much research is still needed to Multi-component warm-up programmes, including a combination of balance/ make the current programmes even better co-ordination, technique, lower limb and core strength, plyometric and agility and maybe more athlete-specific. We know exercises. that exercise programmes need to include a combination of balance, co-ordination, Focus on technique: strength, plyometric and agility exercises. • two-leg landings. A better understanding of ACL injury • a more narrow cutting technique. risk factors and mechanisms will help • proper balance with hip, knee and toe in line. us to optimise current injury prevention Include a variety of exercises with a progression from easy to more difficult to programmes. In the meantime, our best continually pose a challenge to athletes (important for motivation!). recommendation is to establish warm-up Include exercises in pairs to make training more fun, but also to maximise routines and put the existing knowledge on movement quality. ACL injury prevention into practice. Spread Include ball exercises when basic exercises are well-established. this knowledge and convince coaches and athletes that ACL prevention works!

184 15. Alentorn-Geli E, Myer GD, Silvers HJ, Samitier G, Romero D, Lázaro-Haro C et al. Prevention of non-contact anterior cruciate ligament injuries in soccer players. Part 2: a review of prevention programs aimed to modify risk factors and to reduce injury rates. Knee Surg players with high Sports Traumatol Arthrosc 2009; 17:859- 879. levels of football skills 16. Söderman K, Werner S, Pietila T, Engström B, Alfredson H. Balance board training: are at greater risk of prevention of traumatic injuries of the lower extremities in female soccer players? A prospective randomised sustaining injuries intervention study. Knee Surg Sports Traumatol Arthrosc 2000; 8:356-363. 17. Engebretsen AH, Myklebust G, Holme I, Engebretsen L, Bahr R. Prevention of injuries among male soccer players: a References DS, Knarr JF, Thomas SD, Griffin LY et al. prospective, randomised intervention 1. Waldén M, Hägglund M, Magnusson H, Effectiveness of a neuromuscular and study targeting players with previous Ekstrand J. Anterior cruciate ligament proprioceptive training program in injuries or reduced function. Am J Sports injury in elite football: a prospective preventing anterior cruciate ligament Med 2008; 36:1052-1060. three-cohort study. Knee Surg Sports injuries in female athletes: 2-year follow- 18. Froholdt A, Olsen OE, Bahr R. Low risk Traumatol Arthrosc 2011; 19:11-19. up. Am J Sports Med 2005; 33:1003-1010. of injuries among children playing 2. Waldén M, Hägglund M, Ekstrand J. High 9. Soligard T, Myklebust G, Steffen K, Holme organized soccer: a prospective cohort risk of new knee injury in elite footballers I, Silvers H, Bizzini M et al. Comprehensive study. Am J Sports Med 2009; 37:1155-1160. with previous anterior cruciate ligament warm-up programme to prevent injuries 19. Soligard T, Grindem H, Bahr R, Andersen injury. Br J Sports Med 2006; 40:158-162. in young female footballers: cluster TE. Are skilled players at greater risk randomised controlled trial. BMJ 2008; 3. Steffen K, Myklebust G, Andersen TE, of injury in female youth football? Br J 337:a2469. Holme I, Bahr R. Self-reported injury Sports Med 2010; 44:1118-1123. history and lower limb function as risk 10. Myklebust G, Engebretsen L, Braekken IH, 20. Lindblom H, Waldén M, Hägglund M. factors for injuries in female youth soccer. Skjølberg A, Olsen OE, Bahr R. Prevention No effect on performance tests from a Am J Sports Med 2008; 36:700-708. of anterior cruciate ligament injuries neuromuscular warm-up programme in female team handball players: a 4. Renström P, Ljungqvist A, Arendt E, in youth female football: a randomised prospective intervention study over three Beynnon B, Fukbayashi T, Garrett W et controlled trial. Knee Surg Sports seasons. Clin J Sport Med 2003; 13:71-78. al. Non-contact ACL injuries in female Traumatol Arthrosc 2011; 20:2116-2123. athletes: an International Olympic 11. LaBella CR, Huxford MR, Grissom J, Committee current concepts statement. Kim KY, Peng J, Christoffel KK. Effect of Br J Sports Med 2008; 42:394-412. neuromuscular warm-up on injuries in Kathrin Steffen Ph.D. 5. Olsen OE, Myklebust G, Engebretsen L, female soccer and basketball athletes Grethe Myklebust P.T., Ph.D. in urban public high schools: cluster Bahr R. Injury mechanisms for anterior Research and Knowledge Translation cruciate ligament injuries in team randomised controlled trial. Arch Pediatr handball: a systematic video analysis. Am Adolesc Med 2011; 165:1033-1040. Oslo Sports Trauma Research Center J Sports Med 2004; 32:1002-1012. 12. Waldén M, Atroshi I, Magnusson H, Norwegian School of Sport Sciences 6. Meyers MC, Barnhill BS. Incidence, causes, Wagner P, Hägglund M. Prevention of Oslo, Norway and severity of high school football acute knee injuries in adolescent female Contact: [email protected] injuries on Field Turf versus natural grass: football players: cluster randomised a 5-year prospective study. Am J Sports controlled trial. BMJ 2012; 344:e3042. Roald Bahr M.D., Ph.D. Med 2004; 32:1626-1638. 13. Kiani A, Hellquist E, Ahlqvist K, Gedeborg Sports Medicine Physician 7. Koga H, Nakamae A, Shima Y, Iwasa R, Michaëlsson K, Byberg L. Prevention of J, Myklebust G, Engebretsen L, et al. soccer-related knee injuries in teenaged Aspetar – Qatar Orthopaedic and Sports Mechanisms for noncontact anterior girls. Arch Intern Med 2010; 170:43-49. Medicine Hospital cruciate ligament injuries: knee joint 14. Olsen OE, Myklebust G, Engebretsen L, Doha, Qatar kinematics in 10 injury situations from Holme I, Bahr R. Exercises to prevent female team handball and basketball. lower limb injuries in youth sports: cluster Am J Sports Med 2010; 38:2218-2225. randomised controlled trial. BMJ 2005; 8. Mandelbaum BR, Silvers HJ, Watanabe 330(7489):449.

SPORTS MEDICINE IN FOOTBALL TARGETED TOPIC 185