Protect Your Athletes: Proven Methods to Reduce ACL Injury Risks

             Craig Twentyman

How can ACL injuries be prevented in youth sports?

No injuries can be prevented, especially when you are working in the chaotic environments which are team field sports. Injuries are multifaceted so it’s important to understand the risk factors that may lead to an injury, the types of injuries that your athletes may be at most risk of suffering in their chosen sport (injury risk profile) & as an individual (previous injury history) & then planning training interventions which are geared toward lessening the risk of these injuries.

Priority needs to be placed on developing the key aspects of physical performance & capability with an important consideration being the biological age & capability of the individual athletes. Especially during puberty there will be a broad range of developmental stages & the programs assigned must reflect these differences.

• Movement ability- appropriate ranges of motion & multi-planar coordinative abilities developed.
• Controlled high force producing & reducing ability on 1 & 2 legs which aims to enhance the ability to accelerate, decelerate & change direction. Need to consider strength development in key major muscle groups- both relative (as in moving their own body mass) as well as absolute (especially where they are involved in contact sport where they need to act against an external force & mass).
• Multi-planar high force producing & reducing ability with varying movement velocities, through varied ranges of motion on 1 & 2 legs. Sport movements happen at very high velocities & many serious injuries occur as a result of movement errors associated with time constraints. It is important to include appropriately prescribed plyometric exercises as a consistent feature of any strength & conditioning program. Plyometric exercises are any exercise involving the stretch-shortening cycle, they are quick powerful movements involving a pre-stretch of the muscle-tendon unit followed by an amortization phase & a subsequent powerful concentric contraction. Examples include sprinting, hopping, bounding & jumping & incorporating these types of exercises in a multi-planar way into athletes’ training programs has many benefits including developing coordinated movement patterns, building tissue tolerance to very high forces, enhancing acceleration/deceleration/change in direction ability & enhancing the movement ‘bandwidth of individuals’. When you look at kids playing in the playground they are performing plyometric exercises over & over so the fear by some of youth athletes performing this type of exercise is unnecessary & robs the individuals of an important developmental tool. The catch is they need to be appropriately coached & prescribed to ensure they compliment but not compete with all the other training these individuals may be undertaking.  
• Appropriately managed workload needs to be a priority which is a difficult thing to do when you are 1 of 3 or 4 sports the athlete may be playing. Coordinating between staff & sports in a school environment should be able to be well managed but this may become more challenging when it is school & club involved. You would hope that everyone involved has the best interests of the athlete in mind but unfortunately this is not always the case. In my experience in these situations this is where it’s important to park the ego, do your best to understand what each individual in your group overall training & playing load looks like & ensure your training environment isn’t the straw that breaks the camel’s back!

Are there any tests that can help in assessing ACL injury risk?

These injuries are multi-faceted in nature which means screening individuals for risk needs to incorporate a broad range of tests to build a picture of lower body strength & dynamic movement capability. In the youth sport context it is important to observe general movement skills of your group & acknowledge especially at the younger age group levels there will be many individuals you will probably identify as “poor” or “at-risk” movers. This is where some basic coordinative & movement pattern work incorporated into trainings can help to start teaching these athletes about body control & stability. In more detail the best screening & return to play assessments I have seen which are supported by different studies & research include these commonalities-

• Previous injury history understanding
• ROM assessment of ankle/knee/hip
• Knee & mid-thigh girth measures
• Quad strength assessment
• Hamstring strength assessment
• Quad to hamstring strength ratio
• Combination of dynamic hopping assessments ie: forward hop for distance, triple cross-over hop for distance, repeated lateral line hop
• Combination of force plate single leg assessments ie: single leg jump & land, single leg drop off box into hop (RSI- contact time & flight time)
• Unplanned reactive change in direction assessment ie: acceleration into a reactive cut

Which exercises do you find particularly helpful in ACL injury prevention?

The exercise prescription principles that I use with male & female athletes of all ages can be summarised by the following-

• Move heavy loads through full range of motion
• Move moderate loads as explosively as you can
• Use light loads to jump with, sprint with & throw
• Sprint/jump/bound/hop regularly
• Challenge your reaction time & coordination

Each point will look different depending on the age & capability of the individuals you are working with but the principles can be applied to all-

Individuals within your groups will have different strengths & weaknesses so prioritising different components will be required but if you build a program with these considerations in mind you can be confident of covering the majority of what matters in your physical development program.

What kind of warm-up do you recommend for young athletes?

The structure of the warm-up will change as the age & level of the athletes change. With younger athletes I think it is really important to base the content around them having fun while exploring many different movements. Play games, have races, make obstacle courses, get them doing forward rolls, jumping & landing on 1 & 2 feet, jumping from 1 object to another & add some competitive element to it. All “trainings” for kids should be fun as this will engage them, have them leaving wanting to “keep playing” & excited to come back. If you try to make things too serious or structured you will lose engagement. Goals for trainings & playing will change as they move up through the grades & age groups but I don’t think the emphasis on fun should ever leave. Warm-ups can become a little more directed but should always consist of some unstructured play, competition & fun. Warm-ups are a great opportunity to get some detailed coaching around some of the plyometric exercises you are hopefully programming for the group as well as some exposures to high intensity acceleration/deceleration/change in direction. This high output component will lead nicely into the session itself. Sometimes it can be overwhelming for practitioners when trying to decide what to actually focus on when they have so many “key points” they want to deliver on. This is where I think a useful approach can be to think of a theme for each warm-up across the week which enables you to narrow your focus & organise the priorities for each training ie: Training day 1- acceleration/deceleration + horizontal jump/bound/hop; Training day 2- curve running/change in direction + lateral jump/bound/hop, Training day 3- max velocity + vertical jump/hop. Collaborate with the coaches to incorporate skill components as well.

How can coaching practices be improved to ensure that their programs simultaneously protect young athletes from injuries?

An understanding & consideration of 2 main points by coaches of youth athletes can help to avoid many of the injuries that occur at this level.

• An understanding of load management considerations

This is not a call to start tracking training or playing minutes of young athletes or fitting them all out with GPS monitors, but many injuries related to bone stress & tendinopathy occur as a result of a chronic overload of physical stress on the developing body. Multi-sport athletes' weekly training & playing picture must be understood. Everyone will want a piece of them & the younger athletes are often too scared to speak up & say if they feel fatigued or feel a chronic issue starting to arise & then they often end up with an avoidable injury that keeps them out of training & playing for a long period of time.

• Allow training time across the week for general preparatory work & unstructured exploratory play

Especially at the younger levels any opportunity to continue to develop coordination & movement patterns is invaluable. General preparatory work built into obstacle courses & lots of games focussed on developing different physical capacities & competencies as well as field scanning & decision making will ensure the group’s focus, fun & buy-in & will be more beneficial than trying to run an overly structured, discontinuous, information-heavy technical session.  

Considering the 2 points above your athletes will likely leave training feeling energised having had fun with their mates & looking forward to next time rather than walking away feeling tired physically & mentally & not looking forward to the next session.