Getting Defensive about ACL Injuries in Soccer

Soccer players, coaches and families take notice:  two video analysis reviews of Anterior Cruciate Ligament (ACL) injuries confirmed long-time suspected vulnerability with off-balance single-leg landing, but also added a new twist: certain defensive movements may also be a previously unrecognized culprit.

Both the April 2015 British Journal of Sports Medicine (analyzed males only) and May/June 2015 Sports Health (analyzed both males/females) articles found that around 3/4 of all ACL tears occur when the opposing team had the ball and the injured athlete was defending. The Sports Health group found that females were more likely to be defending when they injured their ACL in comparison to male counterparts.

Now, while certain forwards who are reluctant (or lazy) to come back on defense may be silently rejoicing at this news, let's take a deeper look at the particular defensive situations that produced ACL injuries:

• Tackling to separate the ball from an opponent, which often requires last minute adjustments in body position and technique
• Cutting to track an opponent
• Pressing situations where the defending player typically made a sidestep cut in order to reach the ball or to tackle an opponent

Non-contact pressing mechanism (right knee). (A) At−160 ms, the defending player is running forward at high speed towards the opponent in possession of the ball. (B) At initial contact, he strikes the pitch with his right heel and makes a sidestep cut in an effort to reach the ball or to tackle the opponent, but no player contact. (C) At 80 ms, he rotates the trunk towards his left leg and puts the entire load on his right leg. (D) At 240 ms the right hip and knee joints are in abducted positions and the ankle joint is in eversion (dynamic valgus without collapse). From Walden, et al,BJSM, April,2015

In addition to defensive play, being out of balance with single-leg movements was also a more common culprits:

• Regaining balance after kicking
• Landing after heading

In both the defensive or out of balance situations, the injured knee was more apt to be in a valgus (bent inward towards the opposite knee) and straight position.

"Danger position": inward movement (valgus) and straighter right knee relative to right hip and ankle.

So, what teaching points can be made for younger soccer players?

No, we are not going to give any excuses justifying not playing defense (probably much to the chagrin to some players....).

The results of both studies indicate that ACL injury preventive interventions should place focus on keeping the knee in a flexed (bent) position and having the kneecap centered right under the hip and over the foot without any collapsing inward through:

• General postural and neuromuscular control of the core and lower extremities;

• Footwork and running technique during changes of direction in defensive playing actions, mimicking the pressing situation;

• Maintaining balance during shooting, passing and ball clearing;

• Jumping and landing technique during heading duels;

• Promoting fair play in order to avoid fierce tackling from behind

The findings of these two studies further underscore the importance of evidence based ACL injury prevention studies that can readily be found without charge on the web.

Players and parents, do you ask your coaches and trainers to include these training techniques? Coaches and trainers, are you adding value to your program by emphasizing injury prevention? Any other drills that you think would contribute to proper balance, defensive postures, landing and tackling techniques?

How to Keep Volleyball Knees Healthy

Kudos to accomplished writer and volleyball coach Eric Hammond for an insightful article on keeping knees healthy in volleyball players. I appreciated the opportunity to work with him and USA Women's National Team ATC Jill Wosmek on this important article.

The following table summarizes some key points, but I highly recommend you click here to read the entire piece originally published in VolleyballUSA.

Healthier knees: 5 tips
 - Avoid landing on straight knees. Always land and move "softly" 
 with hips, knees and ankles bent.
 - Try to land in good alignment, with the hips and knees lined up 
 with the second toe. Don't let your knees collapse in or rotate.
 - The best time to stretch is after practice or after a match when the 
 muscles are warm. Focus on hamstrings, quadriceps, hip adductors/abductors 
 and calf muscles.
 - Don't hesitate to ice sore knees for 20 minutes after practices 
 or matches.
 - Knee pads help reduce bruises and pounding, especially 
 with repetitive diving drills. 

10 Interesting Facts About Lower Body Injuries in Youth Soccer

1.       In youth soccer, most lower body injuries come from non-body contact and occur more in competition than training or practice sessions.  While training injury incidence rates usually do not change with increased player age, match injury incidence tends to increase with age through all age groups

2.       The time of the adolescent growth spurt (girls usually age 12-14 and boys usually age 13-16) seems to have an increased vulnerability for traumatic injuries.  Afterwards athletes seem to be susceptible to cumulative overuse injuries.

3.       Knee injuries occur in 7% to 36% of injured players and are seen more frequently in females  Middle school soccer playing females have a higher rate of anterior knee pain issues than volleyball or basketball players. Any single-sport adolescent female has a higher risk of anterior knee pain issues.

4.       Adolescent female soccer players suffer a roughly 3-6 times increased risk of ACL rupture compared to boys playing the same sport. Several factors have been proposed for the increased risk, such as anatomic differences, hormonal contributions with menstrual cycles, and higher-risk single-leg landing, turning, and jumping positions.

5.       Female adolescent players who completed certain Neuromuscular Training Programs intended to reduce knee injuries have been shown enjoy significantly reduced ACL injury rate compared with players with low compliance.

6.       Ankle injuries account for 16% to 29% of injuries and are more frequent in male and older players   Ankle contusions more common in younger players due to the more ground-oriented game, while in older players ankle sprain tend to occur due to the more aggressive and faster game.

7.       Taller players are more likely report more overall injuries than shorter players, and more apt to suffer knee injuries often by playing more physically demanding positions with jumping and abrupt turning.

8.       Shorter players are often recipients of intense and often violent direct contact to the foot and ankle regions.

9.       Greater exposure to training and competition leads to a greater risk of injury due to the high intensity of the activities.

10.   The higher incidence of injury during matches than training highlights the need for education and prevention programs in youth soccer. These programs should focus on coach education aimed at improving skills, techniques, and fair play during competitions with the goal of reducing injuries.

What ideas do I have to help reduce these risks?

• Find ways to make evidence-based injury prevention programs standard practice for all young players
• Ensure proper Certified Athletic Trainer or other medical coverage
• Place large emphasis on fair play and rule enforcement
• Caution with players tending  toward year-round or single-sport emphasis at/near their peak growth periods

What ideas would you add to help young soccer players reduce lower body injuries?

Let's Second the Importance of ACL Injury Prevention Programs

As if tearing an Anterior Cruciate Ligament (ACL) the first time isn't wonderful enough, the risk of a similar second injury within 24 months of returning to sport is frighteningly high, according to a recent study published in the American Journal of Sports Medicine.

In the population of 78 patients (mean age 17.1 years) who underwent surgical ACL reconstruction and made a return to cutting and twisting sports:

• 29.5% of athletes suffered a second ACL injury with 24 months of returning to sport
• Just over 2/3 of those second tears involved the opposite knee
• Those opposite knee tears were more seen in female athletes

in my opinion, this high rate of second injury, especially in the opposite knee, adds even more evidence to the already strong suggestions that improper lower extremity mechanics play a significant role in ACL tears and that neuromuscular training programs are absolutely essential for prevention especially in female participants in high risk activities such as soccer, volleyball, basketball, gymnastics and lacrosse. 

Thankfully, there are several evidence-based programs readily found at no charge:

• Lurie Children's Institute for Sports Medicine Knee Injury Prevention Program (KIPP)
• Santa Monica Sports Medicine Foundation PEP Program
• Sportsmetrics ACL Injury Prevention Program

Best started as athletes reach early puberty (age 12-14), all of these programs feature stretching, strengthening, plyometric training and sport-specific agility exercise that all together take no more than 15 minutes and can easily be integrated into a regular warm-up routine that has been effectively taught to coaches both in-person and on-line.

No reasonable excuses exist for not utilizing these programs. The supporting science is solid, the programs aren't difficult to find or learn, and the time commitment for athletes and coaches is minimal.  

Parents and players need to demand these programs and reduce the risk of the ACL injury downward spiral that plagues far too many athletes.

Does your team incorporate neuromuscular training programs? If not, does this information make you more eager to encourage starting a knee injury reduction program? Would the presence of absence of the training program influence selection of a particular team?