Early Sport Specialization…

Growing up and playing competitive hockey, my goal was always to obtain a college scholarship and maybe, just maybe make it to that next level. So, I did what any other talented young athlete would do, listen to well-meaning coaches and scouts and focus all of my energy on MY sport at a young age. I thoroughly enjoyed playing hockey and was happy to play 2 hours, 5 times a week year-round…

My story of early specialization is all too common in competitive athletics. A recent study by Post and colleagues found that the vast majority of division 1 athletes that specialize early do so because…

The most common reason cited by athletes for choosing to specialize in their college sport was enjoying that sport the most. The second and third most frequent selections were having an opportunity to earn a scholarship to play in college and being the best at that sport, respectively. Only 9.9% (n = 34) of athletes cited parental influence as the most important factor in their decision to specialize in their college sport. — Post et al., 2017

All of these reasons make perfect sense, but do athletes who specialize early actually have more success than multi-sport athletes?

According to the same study, the prevalence of highly specialized athletes (year round training of > 8 months per year, chose a single main sport, and quit all sports to focus on a single sport) increased significantly from freshman (16.9%) to senior year (41.1%) of high school. In a separate study, amongst high school athletes, 29.5% classified themselves as one-sport athletes and 36.4% were considered highly specialized in their chosen sport. Based on this information, there does not seem to be a significant difference between division 1 athletes and the general high school athlete population with regards to specialization.

Furthermore, approximately 90% of 2016 and 2017 NFL draft picks played multiple sports during high school. In agreement with this trend, 100% of 2016 national college football award winners, including all 5 Heisman Trophy finalists, were not highly specialized or single-sport athletes in high school. And looking closer at the two teams who played in Super Bowl LI, approximately 87% of the players on both teams were multi-sport athletes in high school. The current evidence does not necessarily look favorable for the highly specialized athlete.

More importantly, how does early specialization impact risk of injury?

In order to be successful, you need to be healthy and the literature once again does not give favor to specialization. Athletes with high competition volume, who participated in a club sport, or who were highly specialized had 2.08 times greater odds of reporting a previous lower extremity injury than those with low competition volume, 1.50 times greater odds than no club sport participation, and 2.58 times greater odds in comparison to low specialization. Building upon this information, another study found that highly specialized athletes were more likely to report a previous injury of any kind or an overuse injury in the previous year compared with athletes in the low specialization group. Athletes who played their primary sport more than 8 months of the year were 1.68 times more likely to report an upper extremity overuse injury or 1.66 times more likely to sustain a lower extremity overuse injury. When looking at serious overuse injuries, highly specialized athletes were 2.38 times more likely than multi-sport athletes.

When looking closer at ice hockey, one of the most common areas of injury tends to revolve around the hip/pelvic region. Being that highly specialized athletes are 2.74 times more likely to sustain an overuse injury to this region, this should be an area of specific concern… 

Femoroacetabular Impingement Syndrome (FAIS) is an abnormal growth of bone localized to the femoral neck and/or acetabular rim. In the case of Cam morphology (increased bone growth on femoral neck), the prevalence significantly increases in ice hockey players as they age. Even when compared to a similar group of athletes (skiers), the ice hockey group showed a consistent increase in prevalence as age increases. While this altered morphology may not result in a painful condition, as a recent study showed prevalence of FAIS in 68% of ice hockey players with only 22% demonstrating symptoms. This increased prevalence of altered hip/pelvic morphology speaks to the repetitive nature of the sport (especially among goaltenders) and may predispose them to hip/groin pathology as their career progresses.

Moving to the psychological impact of sport specialization, there is also evidence to support increased levels of drop out in those highly specialized athletes.

Among ice hockey players, those who began off-ice training earlier and those that invested a larger number of hours training at a younger age were more likely to drop-out of their sport. This study showed that hockey players started playing at 5 years old and the athletes that ended up dropping out began off-ice training at 11.75 years old in comparison to 13.8 years old in those who continued playing. Additionally, those that continued playing their sport invested an average of 6.8 hours to off-ice training versus 107 hours per year in the drop out group.

Dropout can occur for any number of reasons spanning from psychological to physical factors. Studies looking into reasoning behind burnout in competitive tennis players found burned-out players had less input into training and sport-related decisions and practiced fewer days with decreased motivation. While sport specialization has not necessarily been linked to burnout, the underlying stressors related to the early and highly specialized athlete mimic those reasons for dropout.

Knowing the negative impact of early and high specialization in one sport, what can we as athletes, coaches, parents, and healthcare providers do? 

  1. Take a break. Actually take the off-season off and find another sport or passion during this time.
  2. Develop overall athleticism. There is a reason multi-sport athletes are generally more successful at higher levels. They have been exposed to different movements and stresses that their primary sport does not provide them.
  3. Listen to your body and your mind. Are you feeling burnt out or are you suffering from a nagging injury? Take the time to have these factors addressed… See a physical therapist, see a sports psychologist, or see the appropriate medical professional.
  4. HAVE FUN. Sports are meant to be a positive influence on your life, not a drain on you physically and mentally.

We as a culture need to make a change in how youth and competitive sports are positioned. The highly specialized athlete is not necessarily more successful, is more likely to sustain an overuse or serious injury, and demonstrates the psychological profile of those that drop-out of their sport. We need to embrace the need for varying experiences and movement activities. The literature is fairly definitive and we need to push our children, athletes, and coaches to focus on the enjoying their athletic career and on developing overall athleticism during this timeframe.


1. Bell DR, Post EG, Trigsted SM, Hetzel S, McGuine TA, Brooks MA. Prevalence of Sport Specialization in High School Athletics: A 1-Year Observational Study. Am J Sports Med. 2016;44(6):1469-1474. doi:10.1177/0363546516629943.
2. Brunner R, Maffiuletti NA, Casartelli NC, et al. Prevalence and Functional Consequences of Femoroacetabular Impingement in Young Male Ice Hockey Players. Am J Sports Med. 2015;44(1):46-53. doi:10.1177/0363546515607000.
3. Fabricant PD, Lakomkin N, Sugimoto D, Tepolt FA, Stracciolini A, Kocher MS. Youth sports specialization and musculoskeletal injury: a systematic review of the literature. The Physician and Sportsmedicine. 2016;44(3):257-262. doi:10.1080/00913847.2016.1177476.
4. Feeley BT, Agel J, LaPrade RF. When Is It Too Early for Single Sport Specialization? Am J Sports Med. 2016;44(1):234-241. doi:10.1177/0363546515576899.
5. Gould D, Tuffey S, Udry E, Loehr JE. Burnout in competitive junior tennis players: III. Individual differences in the burnout experience. Sport Psychol. 1997;11:257-276.
6. Gould D, Tuffey S, Udry E, Loehr JE. Burnout in competitive junior tennis players: II. Qualitative analysis. Sport Psychol. 1996;10:341-366.
7. Gould D, Udry E, Tuffey S, Loehr JE. Burnout in competitive junior tennis players: I. A quantitative psychological assessment. Sport Psychol. 1996;10:322- 340.
8. Jayanthi NA, LaBella CR, Fischer D, Pasulka J, Dugas LR. Sports-specialized intensive training and the risk of injury in young athletes: a clinical case-control study. Am J Sports Med. 2015;43(4):794-801. doi:10.1177/0363546514567298.
9. Myer GD, Jayanthi N, Difiori JP, et al. Sport Specialization, Part I: Does Early Sports Specialization Increase Negative Outcomes and Reduce the Opportunity for Success in Young Athletes? Sports Health: A Multidisciplinary Approach. 2015;7(5):437-442. doi:10.1177/1941738115598747.
10. Myer GD, Jayanthi N, Difiori JP, et al. Sports Specialization, Part II: Alternative Solutions to Early Sport Specialization in Youth Athletes. Sports Health: A Multidisciplinary Approach. 2016;8(1):65-73. doi:10.1177/1941738115614811.
11. Pasulka J, Jayanthi N, McCann A, Dugas LR, LaBella C. Specialization patterns across various youth sports and relationship to injury risk. The Physician and Sportsmedicine. April 2017:1-9. doi:10.1080/00913847.2017.1313077.
12. Philippon MJ, Ho CP, Briggs KK, Stull J, LaPrade RF. Prevalence of Increased Alpha Angles as a Measure of Cam-Type Femoroacetabular Impingement in Youth Ice Hockey Players. American Journal of Sports Medicine. April 2013. doi:10.1177/0363546513483448.
13. Post EG, Bell DR, Trigsted SM, et al. Association of Competition Volume, Club Sports, and Sport Specialization With Sex and Lower Extremity Injury History in High School Athletes. Sports Health: A Multidisciplinary Approach. 2017;34:1941738117714160. doi:10.1177/1941738117714160.
14. Post EG, Thein-Nissenbaum JM, Stiffler MR, et al. High School Sport Specialization Patterns of Current Division I Athletes. Sports Health: A Multidisciplinary Approach. 2017;9(2):148-153. doi:10.1177/1941738116675455.
15. Post EG, Trigsted SM, Riekena JW, et al. The Association of Sport Specialization and Training Volume With Injury History in Youth Athletes. Am J Sports Med. 2017;45(6):1405-1412. doi:10.1177/0363546517690848.
16. Wall M, Côté J. Developmental activities that lead to dropout and investment in sport. Physical Education & Sport Pedagogy. 2007;12(1):77-87. doi:10.1080/17408980601060358.

Ice Hockey Injuries: Who Gets Hurt and Why Does it Matter?

Ice hockey is an inherently physical sport and as such creates situations where injury is possible and often likely. With the influence that injuries can have on a team’s success, research has started to focus on our ability to assess injury risk and prevent injuries before they occur. However, these strategies cannot be effectively laid out until we first understand who gets hurt, when they get hurt, and how they get hurt.

Who gets hurt?

According to a prospective cohort study performed by Flik et al., there is a significant disparity in injury incidence depending upon player position in NCAA Division 1 ice hockey. Only 6.2% of injuries were sustained by goaltenders, whereas 32.7% were defensemen and 61.1% were forwards. In agreement with this distribution, Agel et al found 9.6% of injuries effected goaltenders, 40.8% were defensemen, and 48.3% were forwards. This information also correlated with a recent study investigating injury incidence during the World Championship and Olympic tournaments, where goaltenders were once again the least injured followed by defensemen and forwards. However, when evaluating injuries in the National Hockey League (NHL), the only significant difference found was a higher likelihood of defensemen missing gametime due to injury in comparison to forwards. This study also found that a significant predictor of missing at least 5 games due to injury included being a goaltender (odds ratio = 1.68). So, while goaltenders do not get injured as often, their return to play is often more extended in comparison to other players. These numbers are likely not as drastically position dependent due to the disparity of position players on the ice at one time (3 forwards, 2 defensemen, and 1 goaltender), which may account for a significant amount of the variance reported in the literature at the collegiate, international, and professional levels.

When do they get hurt?

Understanding when injuries occur during the course of an individual game and throughout the course of the season allows us to understand when an athlete is at an increased risk of injury. With regards to the collegiate level, 65.5% of injuries occur during games and 35.5% during practice. Additionally, preseason practice rates were more than twice as high as in season injury rates. Two studies looked into the distribution of injuries during game play and found drastically different results. Agel and colleagues found that most injuries occurred in the 2nd and 3rd periods, which is likely due to athlete fatigue and intensity of gameplay increasing as the game progresses. In contrast to this report, amongst NHL regular season injuries, the vast majority occur in the first period (48.1%). Intuitively, as the NHL season progresses, the likelihood of injury also increases. This increase in injury rate is likely due to player fatigue and increased intensity of play as teams are fighting for a playoff spot.

How do they get hurt?

Due to the physical nature of ice hockey, the vast majority of injuries are contact-related, however non-contact injuries tend to make up a higher proportion of practice injuries. According to Agel and colleagues, non-contact injuries make up 9.7% of injuries during games, whereas they make up 32% of injuries during practice. During games, approximately 50% of injuries are due to contact with another player and 39.6% are due to contact with another object (boards, puck, etc.). In agreement with these trends, in the NHL body checking made up 28.6% of injuries, while incidental contact (14.3%), hit by puck (13.5%), contact with environment (9.4%), and other intentional player contact (7.4%) made up the bulk of injuries incurred. Aside from these mechanisms, non-contact injuries made up 14.8% of all injuries and accounted for 11.7% of man games lost due to injury (1,921 games) between 2009 and 2012. This gives good insight into the general cause of injury, but what types of injury are most common amongst ice hockey players?

Over a 16 season timeframe, injures most often sustained during gameplay included internal derangement of the knee (13.5%), concussion (9.0%), acromioclavicular joint injury (8.9%), upper leg contusion (6.2%), and musculotendinous strain of the hip/groin region (4.5%). However, distribution of injuries during practice shows a slightly different distribution. The most common injuries during practice were musculotendinous strain of the hip/groin region (13.1%), internal derangement of the knee (10.1%), ankle ligament sprain (5.5%), concussion (5.3%), and acromioclavicular joint injury (4.4%). Looking further at this data, during games, the highest prevalence of severe injuries was knee internal derangement and the most common mechanism of injury was due to player contact. Of the most common severe injuries reported, musculotendinous injuries of the pelvis/hip was the only pathology (6.2%) that had a non-contact mechanism as the most common cause. In agreement with these findings, amongst NHL players, the most common sites of injury include the head (17%), thigh (14%), knee (13%), and shoulder (12%). Additionally, with regards to man games lost, these regions also comprised the largest impact on their respective teams. Unfortunately, this study did not break the body regions into specific injuries/pathologies.

Given the fairly vague description of the injuries reported in these large epidemiological studies, it is also important to look more in depth to determine which specific injuries are actually reported in the literature. With regards to knee ligamentous injuries, Sikka and colleagues found that between 2006 and 2010, only 47 players sustained an anterior cruciate ligament tear in the NHL, which is significantly lower than most professional contact team sports. These injuries included 3 goaltenders, 8 defensemen, and 36 forwards. Of these 47 injuries, the reported mechanism for all but one injury was contact with another player and/or with the boards. In addition to the primary ACL rupture, 68% of injuries reported a concomitant meniscal or medical collateral ligament injury as well. Looking at the more commonly injured MCL, from 2003-04 to 2010-11, 13 MCL injuries were reported within one collegiate ice hockey program. This resulted in ten different players being injured (12.7%) and an incident rate of 0.44 per 1,000 athlete exposures. Of these injuries, 77% were contact related and an acute non-contact injury was reported in 15% of cases.

Looking at the most common non-contact injury, hip/pelvic pathology has also been investigated in the literature for this population. Over a four year span, 890 hip or groin injuries were reported in the NHL. Of those reported, 10.6% were found to be intra-articular in nature. There was a very small difference between injury occurring during games (44.6%) and during practice (41.4%), but the vast majority occurred during the regular season (71.2%). The most frequent intra-articular hip diagnosis made in this cohort was hip labral tear (69.1%), followed by hip osteoarthritis (13.8%), hip loose body (6.3%), femoroactebular impingement (5.3%), other hip injury (3.1%), and hip chondromalacia (2.12%). With regards to player position, injuries per 1000 player-game appearances were significantly higher in goaltenders compared with all other players.

Why does it matter?

Having a successful team depends on multiple factors, but regardless of coaching or talent, injuries can have a significant impact on a team’s ability to win. Unfortunately, the NHL does not readily provide injury data to the general public, however ManGamesLost.com has provided data supporting the negative impact of injuries on a team’s success. Over the past five seasons, the Stanley Cup champion has been among the top five least injured teams throughout the regular season. Along those same lines, this season’s President’s Trophy (best regular season record) winning Washington Capitals also had the least man games lost due to injury. Additionally, with the exception of the Pittsburgh Penguins, none of the top five most injured teams have had consistent success over the past five years. In fact, two of those included in the top five most injured also had the two of the worst overall records over this timeframe (Columbus Blue Jackets and Edmonton Oilers).

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In addition to the obvious impact on team performance, when a player returns from a significant injury, their productivity and durability has the potential to decline in the seasons following their return to play. The presence of a meniscal injury was associated with a decreased length of career for all positions. Furthermore, for wings and centers, the number of games played decreased in the first full season after ACL injury from 71.2 to 58.2 and in the second full season to 59.29. With regard to offensive production, there was a 31% reduction in goals scored per season, 60% reduction in assists, and 42% reduction in total points compared with an uninjured control group. Only 37.5% of players who were previously selected as All-Stars were able to regain this honor upon their return to play.

Finally, there is also a financial impact as well. According to Donaldson and colleagues, between the 2009-10 and 2011-12 seasons, 50.9% of NHL players missed at least one game, which translated to a total salary cost of $218 million per year.

With the substantial impact on team performance and the associated financial implications, understanding how to identify those at risk and develop programs to lessen the likelihood of injury are paramount to a successful organization. Part 2 of this series will delve into the evidence regarding injury risk assessment and prevention in this population of athletes.


1. Agel J, Dompier T, Dick R, Marshall S. Descriptive Epidemiology of Collegiate Men’s Ice Hockey Injuries: National Collegiate Athletic Association Injury Surveillance System, 1988–1989 Through 2003–2004. Journal of Athletic Training. 2007;42(2):241-248.

2. Flik K. American Collegiate Men’s Ice Hockey: An Analysis of Injuries. American Journal of Sports Medicine. 2005;33(2):183-187. doi:10.1177/0363546504267349.

3. Currier, Nathan. “The Most Injured NHL Teams Since the 2009-2010 Season.” ManGamesLost.com. N.p., 12 Apr. 2016. Web. 22 Apr. 2016.

4. Donaldson L, Li B, Cusimano MD. Economic burden of time lost due to injury in NHL hockey players. Inj Prev. 2014;20(5):347-349. doi:10.1136/injuryprev-2013-041016.

5. Epstein DM, McHugh M, Yorio M, Neri B. Intra-articular Hip Injuries in National Hockey League Players: A Descriptive Epidemiological Study. American Journal of Sports Medicine. 2013;41(2):343-348. doi:10.1177/0363546512467612.

6. Grant JA, Bedi A, Kurz J, Bancroft R, Miller BS. Incidence and Injury Characteristics of Medial Collateral Ligament Injuries in Male Collegiate Ice Hockey Players. Sports Health. 2013;5(3):270-272. doi:10.1177/1941738112473053.

7. McKay CD, Tufts RJ, Shaffer B, Meeuwisse WH. The epidemiology of professional ice hockey injuries: a prospective report of six NHL seasons. British Journal of Sports Medicine. 2014;48(1):57-62. doi:10.1136/bjsports-2013-092860.

8. Sikka R, Kurtenbach C, Steubs JT, Boyd JL, Nelson BJ. Anterior Cruciate Ligament Injuries in Professional Hockey Players. American Journal of Sports Medicine. 2016;44(2):378-383. doi:10.1177/0363546515616802.

9. Tuominen M, Stuart MJ, Aubry M, Kannus P, Parkkari J. Injuries in men’s international ice hockey: a 7-year study of the International Ice Hockey Federation Adult World Championship Tournaments and Olympic Winter Games. British Journal of Sports Medicine. 2015;49(1):30-36. doi:10.1136/bjsports-2014-093688.

Research Review: Immediate Effects of Real-Time Feedback on Jump-Landing Kinematics

In the next instalment of the Research Review Series, we discuss the impact of real-time feedback in addition to post-response feedback compared to post-response feedback alone on jumping-landing mechanics in a young female population1

Study Design

Randomized controlled trial.


Thirty-six pain-free females were recruited from the general student population at the University of Toledo and assigned to either the real-time feedback (RTF), RTF plus post-response feed-back (RTF+), or the no feedback control group (CG).

Inclusion Criteria: (1) Female gender, (2) No current or previous lower extremity musculoskeletal complaints

Exclusion Criteria: (1) Male gender, (2) previous history of fracture, surgery, or significant orthopaedic injury to the lower extremity


Outcome Measures: Kinematic and kinetic data were collected as participants performed 3 trials of a jump-landing task from a 30-cm box, positioned at a horizontal distance of 50% of the participant’s height from 2 force platforms. Sagittal plane moments and angles at the knee and hip, frontal plane angles at the knee, and vertical ground reaction forces during the jump-landing task were quantified at baseline and post-intervention.

Randomization: Block randomization was used with concealed allocation to assign participants to 1 of the 3 groups. An opaque envelope was used to conceal group assignment until after baseline testing.

Interventions: Prior to the intervention, both the RTF+ and PRF feedback groups were presented with a PowerPoint presentation explaining the goals of the jump-landing task. This presentation outlined the need to (1) land with both feet at the same time, (2) land in neutral valgus/varus position, (3) land with feet shoulder width apart, (4) land on toes and rock onto heels, (5) land with increased bending at the knees and hips, and (6) land softly. After viewing the presentation, participants in both intervention groups performed 3 sets of 6 jumps from the box. Following each set of 6 jumps, the investigator reviewed the goals that the participant failed to accomplish in the previous jumps and showed the participant the corresponding PowerPoint slides to reinforce the correct form.

For the RTF+ group, participants received a live, digital representation of their body segments and were able to see a reference line to assist in making biomechanical corrections in the frontal plane. The RTF+ group was provided the following explanation,

You will now be able to see markers representing your knee and toe on the screen in real time; start with your toe marker in line with the reference line and then line your knee marker up with the reference line. This is the way the markers should line up when you land; we want you to watch the video monitor, focusing on keeping the shank segment in line with the reference line when you land from your jump. You can aim to land with your foot on the tape line, but your main focus should be to keep the shank segment lined up with the line when landing from the jump.

Participants in the no-feedback control group performed the same jump landing sequence as the other two groups, however they received no feedback or PowerPoint presentation on the major goals of jump landing.


Post hoc testing revealed that the RTF+ and PRF groups had a greater increase in knee flexion, hip flexion, and greater decrease with regards to vertical ground reaction forces compared to the control group, but no differences were found between the two groups. Neither the RTF+ or PRF groups demonstrated a significant change in the knee extensor moment, hip extensor moment, or knee abduction angle post-intervention.


This study had several significant limitations that may have impaired the impact of the interventions provided. First of all, there was no “pre-screening” for excessive valgus and due to this fact, the included subjects had very low knee abduction angles at baseline. This limited the ability to make any kind of meaningful impact post-intervention. This is where utilizing a simple lower extremity functional test would have aided in providing a better patient population. Additionally, this study only measured immediate impact of the interventions without looking into long-term retention of the movement pattern, which would be more important in injury risk reduction. With a fairly small, albeit adequately powered, sample-size, the statistical significance of some of the changes may have been hampered.

Clinical Implications

Anterior cuciate ligament injuries have significantly increased from 40.9 to 47.8 per 10,000 patients according to a study looking into trends and demographics of ACL injuries in the United States4. This rising incidence coupled with very high re-injury rates to the contralateral and ipsilateral limb3,5,6 make developing injury risk reduction programs paramount. Due to its importance, several researchers have investigated faulty movement patterns and the incidence of ACL injury. These studies have identified prospective evidence linking decreased knee flexion and increased knee abduction angles as predictive of future injury2. While the aforementioned study did not produce a change to the knee abduction angle (likely due to a ceiling effect), there was a significant change in knee flexion angle, which may aide in decreasing the likelihood of future injury. While this is promising preliminary evidence, in order to have a significant impact, an injury prevention program must be repetitive and participants must have good compliance7,8 to create a long-term change in movement pattern. This study, due to its design, does not capture this aspect.


1. Ericksen HM, Thomas AC, Gribble PA, Doebel SC, Pietrosimone BG. Immediate Effects of Real-Time Feedback on Jump-Landing Kinematics. Journal of Orthopaedic & Sports Physical Therapy. 2015; 45(2): 112–118. doi:10.2519/jospt.2015.4997.

2. Hewett TE, et al. Biomechanical Measures of Neuromuscular Control and Valgus Loading of the Knee Predict Anterior Cruciate Ligament Injury Risk in Female Athletes: A Prospective Study. American Journal of Sports Medicine. 2005;33(4):492–501. doi:10.1177/0363546504269591.

3. Kamath GV. Anterior Cruciate Ligament Injury, Return to Play, and Reinjury in the Elite Collegiate Athlete: Analysis of an NCAA Division I Cohort. Am J Sports Med. 2014;42(7):1638–1643. doi:10.1177/0363546514530866.

4. Leathers MP, Merz A, Wong J, Scott T, Wang JC, Hame SL. Trends and Demographics in Anterior Cruciate Ligament Reconstruction in the United States. Journal of Knee Surgery. 2015. [Epub ahead of print]

5. Paterno MV, Rauh MJ, Schmitt LC, Ford KR, Hewett TE. Incidence of Second ACL Injuries 2 Years After Primary ACL Reconstruction and Return to Sport. Am J Sports Med. 2014;42(7):1567–1573. doi:10.1177/0363546514530088.

6. Rugg CM, Wang D, Sulzicki P, Hame SL. Effects of prior knee surgery on subsequent injury, imaging, and surgery in NCAA collegiate athletes. Am J Sports Med. 2014;42(4):959–964. doi:10.1177/0363546513519951.

7. Sugimoto D, Myer GD, Bush HM, Hewett TE. Effects of Compliance on Trunk and Hip Integrative Neuromuscular Training on Hip Abductor Strength in Female Athletes. Journal of Strength and Conditioning Research. 2014;28(5):1187–1194. doi:10.1097/JSC.0000000000000228.

8. Sugimoto D, Myer GD, Bush HM, Klugman MF, McKeon JMM, Hewett TE. Compliance With Neuromuscular Training and Anterior Cruciate Ligament Injury Risk Reduction in Female Athletes: A Meta-Analysis. Journal of Athletic Training. 2012;47(6):714–723. doi:10.4085/1062-6050-47.6.10.

What is the Key to the ACL Epidemic? Prevention.

In my previous post, I discussed the current research and concepts with regards to Return to Sport following Anterior Cruciate Ligament Reconstruction (ACLR)… Now it is time to discuss how we, as clinicians, can help to prevent these injuries altogether.

A recent Systematic Review and Meta-analysis of 14 studies and 27,000 participants conducted by Gagnier et al found that neuromuscular and educational interventions appear to reduce the incidence rate of ACL injuries by approximately 50%. Within this systematic review, 109 ACL injuries were prevented; that means 109 athletes will not have to face the unfortunately low return to sport and high re-injury rate associated with ACLR. The first ACL prevention program was published in 1999 by Hewett et al and focused on flexibility, plyometrics, weight training, and emphasized maintaining adequate frontal, transverse, and sagittal plane mechanics throughout each exercise/movement. During this study of 1,263 athletes, there were five non-contact ACL injuries in the untrained female group, one in the untrained male group, and none in the trained female group. This study determined that female athletes who do not undergo neuromuscular training have a 3.6x increased likelihood of sustaining a non-contact ACL injury. Since this initial study, several additional randomized controlled trials have also shown the benefits of injury prevention programs on the incidence of ACL injury (Mandelbaum et al, Gilchrist et al, Olsen et al, Caraffa et al, Myklebust et al, and Petersen et al).

In addition to these randomized controlled trials, there have also been several systematic reviews detailing the benefit of neuromuscular training in the prevention of serious knee injury. The first of which was a meta-analysis conducted in 2006 by Hewett et al of 6 studies investigating prevention programs for female athletes. This analysis found that 4 out of 6 neuromuscular intervention programs significantly reduced knee injury incidence, and 3 out of 6 significantly reduced anterior cruciate ligament injury incidence. Overall, the meta-analysis of these 6 studies demonstrates a significant effect of neuromuscular training programs on anterior cruciate ligament injury incidence in female athletes. Later in 2010, Yoo et al found that the odds ratio of injury prevention was 0.40 with the implementation of a prevention program. Yoo and colleagues also determined through meta-analysis that pre- and in-season neuromuscular training with an emphasis on plyometrics and strengthening exercises was effective at preventing ACL injury in female athletes, especially in those under 18 years of age. Finally, in 2012, Sadoghi et al found an overall risk reduction following the implementation of a prevention program of 52% for female athletes and 85% for male athletes. This coupled with the overall reduction of 50% stated by Gagnier et al shows more than enough reason to suggest the need for widespread usage of injury prevention programs amongst all athletes.

With all of this readily available evidence, surely these programs are being utilized by coaches at all levels, right? Unfortunately, according to a survey of female soccer coaches conducted by Joy et al, only 19.8% of coaches implement an Injury Prevention Program (IPP). Of these coaches who chose to implement an IPP, they did so for injury prevention (93%) as well as performance enhancement (36%). Performance enhancement is what will drive athletes, coaches, and parents toward IPPs – with the added benefit of a decreased likelihood of a catastrophic season-ending injury. Thankfully, the literature is in favor of IPPs with regards to performance enhancement as well. In 2005, Myer et al conducted a study investigating the performance enhancing effects of their injury prevention program. They found significant improvements in 1-Repitition Maximum Bench Press and Squat, Single-Leg Hop Distance, Vertical Jump, and speed in the 9.1 meter dash. This study also showed an overall decreased knee valgus and varus torque during functional movement as an added benefit. While injury prevention is the end goal, performance enhancement is what will bring clients through your doors and will make coaches change their philosophy. It is up to physical therapists, athletic trainers, strength & conditioning coaches, and physicians to bring this information to coaches and players alike. We have the evidence to support the effectiveness of these programs, but we need to take the time to educate those who will benefit most.

All this being said, what makes a successful program? While specific areas of training have not been adequately differentiated in terms of effectiveness, there is a general consensus as to what aspects should be included. These areas include a dynamic warm-up, restoration of proximal stability, proprioceptive training, plyometric training, neuromuscular re-education, strength training, and education. One area cannot be proven more effective than another, however certain qualities of a program have been deemed indicative of an effective program. The first and likely most important quality is patient/client compliance. Wingfield et al recently conducted a cluster randomized controlled trial to evaluate the effectiveness of a neuromuscular warm-up program in preventing acute knee injury in adolescent female soccer players. Not surprisingly, they found that athletes who performed ≥ 1 exercise session per week had a lower rate of ACL injury, severe knee injury, and of any acute knee injury compared to the control group. Additionally, in a systematic review conducted by Sugimoto et al, it was found that incidence rates of ACL injury were lower in studies with high rates of compliance with neuromuscular training than in studies with low compliance rates. So, this begs the question of, “How do we make our athletes compliant?” In my opinion, we must provide a solid, systematic evaluative and progressive program addressing each individual athlete’s deficiencies.

There are several Injury Prevention Programs available from the simple (FIFA 11+, Santa Monica Prevent Injury and Enhance Performance Program, ect.) to the more advanced systematic programs implemented by trained fitness and healthcare professionals. Of the programs available, there are two that appear to encompass all aspects of injury prevention that therapists and/or strength & conditioning coaches should consider implementing. The first of which is the Dynamic Movement Assessment (DMA) developed by Trent Nessler, DPT. The DMA consists of a thorough functional assessment backed-up by the use of video feedback to provide visual input to both athletes and clinicians alike. This allows for detailed understanding of where these faulty movement patterns are stemming from and how these deficits should be corrected. The second program is seemingly simpler, albeit a much more researched program in the Functional Movement Screen (FMS)/Selective Functional Movement Assessment (SFMA). These systems are comprised of several tests that provide the ability to ‘screen’ athletes for the poor movement patterns often associated with increased likelihood of injury. Regardless of the specific system, the key to any successful program is selecting a solid classification system to identify those at risk and implement exercise programs to improve their specific movement patterns and/or deficient muscular performance.