New Study: Core Stability, Athletic Performance, and ACL Injury Risk across a Soccer Season

Jenneva Rogers prepares to kick the ball for FC Pride.

Soccer isn’t a risk-free sport. While most soccer-related injuries happen in the lower body area, an injury to the ACL is particularly serious, and has a long recovery time.

Between 45-65% of ACL injuries are non-contact and occur most often during single-leg landing and side-step cutting (1). These risk factors aren’t just associated with the knee joint, itself, but also the muscles and joints surrounding the knee - like the position and rotation of the hips and trunk, and the strength and symmetry of the hamstrings, quadriceps, hip flexors, and hip external rotators (2).

We’ve been measuring the performance and symmetry of those muscles groups in our athletes for over a year now. You can read about that more in Measuring the 4 Components of Athlete Knee Health

Research has demonstrated that improved core stability has decreased ACL injury risk in both male and female soccer players (3, 4, 5). This makes sense. Having good core stability means that an athlete’s body is optimally positioned to transfer energy through the body. It influences how the trunk and hips are positioned during force production and absorption.

However, core stability and ACL injury risk hadn’t been studied together over the course of a soccer season. Let’s dig into this new study published this month that featured participants from the French U17 and U19 national championships.

Sammie King controls possession during a high school game.
Photo credit: Julie L. Brown Photograpy

Evolution of Core Stability, Athletic Performance, and ACL Injury Risk across a Soccer Season

Authors: Théo A. Weber, Youri Duchene, Frédéric R. Simon, Guillaume Mornieux, and Gerôme C. Gauchard

Read the Full Article (Free)

This study focused on how athletes’ core stability might change over the duration of a soccer season in comparison to their ACL injury risks. They hypothesized that (1) core stability and performance would evolve (in one way or another) and (2) that core stability and ACL injury risk would change in opposition to each other.

Thirty-five players were recruited. They participated in 6-8 training sessions per week and were healthy with no injuries during the two months prior to the study. Over the course of the study, athletes participated in a periodized training regimen that was programmed appropriately to the phase of the season (Pre, Start, Middle, and End). Each of these phases included performance measurements and core stability evaluations, and ACL injury prevention-based programming was implemented as a part of their training program.

Three tests were used to measure core stability:

  1. Chain Lower Extremity Stability Test
    The athlete is in a fore-arm plank position, with a small box between the feet. The athlete had to cross one foot over the other and touch the ground as many times as possible, alternating legs during 15 seconds.

  2. Lower Quarter Y-balance Test
    Athletes performed this with their dominant (kicking) leg. While standing on their planting leg, athletes placed their hands on their hips and had to move an object (likely a cone) as far as possible with the free leg and come back to the starting position. They repeated this three times— to the side, forward, and backwards. In order to count an attempt as successful they had to (1) not touch the ground with their free leg, (2) push, and not kick, the object, (3) keep their hands in place on their hips, and (4) return back to the starting point. Athletes performed each direction three times. Scores were calculated by accounting for the maximum reach. The three best distances were divided by three times the leg length.

  3. Lateral Step Down
    This test is very similar to a modified pistol squat. Athletes stood on their dominant leg while on an approximately 1 foot tall box. They touched the ground with the heel of their free leg and return to the start position without transferring any weight to their free leg. This was repeated 5 times and recorded using a video camera and scored according an assessment of dynamic balance, knee valgus/hip internal rotation, and pelvic control.

Key Takeaways:

  • Sprinting speeds improved when sprint training was present in the programming, and decreased when athletes spent less dedicated time sprint training towards the end of the season.

  • The Chain Lower Extremity Stability and Lower Quarter Y-balance tests showed the significantly positive score changes over the season.

  • Lateral Step Down evaluation scores showed no significant change over the season, meaning that it might be best suited as a general movement screening test.

  • Lower ACL injury risk and increased core stability scores were observed over the course of the study, but there wasn’t a significant correlation between improved core stability and decreased injury risks. This may be because all participants had different injury risks inherit to how their bodies bended and moved, which could blur the lines on the results.

  • Core motor control performance decreased between the middle and end of the season, which drives home how important it is to maintain regular training during the season.

What’s Next

Core stability has been a “core” tenet of our training for years. But measuring and tracking improvement in that specific area has not been.

Pouring over new research challenges us to evolve how we measure athletic performance while reducing risk of injury. At Raymer Strength & Rehab, we’ve implemented validated (and some novel) methods to measure performance related to knee health, and we’re always looking for ways to make that more comprehensive.

My challenge to my staff now is to brainstorm ways we can introduce core stability evaluations as a part of our normal athletic training programming in ways that not only keeps training fun, but allows us to collect data without significant time lost. Our quarterly Knee Evaluation Week give our athletes a built-in de-load week… but we aren’t looking to stretch that into two.

Looking for sports performance training or physical therapy?

If you’re a Central Indiana athlete looking for a place to improve your strength, speed, and agility and reduce your risk of injury, contact us!

Coach Eddie demonstrates one of our knee evaluation tests.

References

  1. Weber, T.A.; Duchene, Y.; Simon, F.R.; Mornieux, G.; Gauchard, G.C. Evolution of Core Stability, Athletic Performance, and ACL Injury Risk across a Soccer Season. Appl. Sci. 2024, 14, 4116. https://doi.org/10.3390/app14104116

  2. Raymer, J. (2023, March 1). Measuring the 4 components of Athlete Knee Health. Raymer Strength & Rehab. https://raymerstrength.com/blog/2023/3/1/4-components-of-knee-health-for-soccer-athletes

  3. Waldén, M. Return to Sports After ACL Reconstruction Surgery: A Risk for Further Joint Injury? In The ACL-Deficient Knee: A Problem Solving Approach; Sanchis-Alfonso, V., Monllau, J.C., Eds.; Springer: London, UK, 2013; pp. 183–188. ISBN 978-1-4471-4270-6. [Google Scholar]

  4. Silvers-Granelli, H.J.; Bizzini, M.; Arundale, A.; Mandelbaum, B.R.; Snyder-Mackler, L. Does the FIFA 11+ Injury Prevention Program Reduce the Incidence of ACL Injury in Male Soccer Players? Clin. Orthop. Relat. Res. 2017, 475, 2447–2455. [Google Scholar] [CrossRef]

  5. Azhar, N.I.; Othaman, N.N.C.; Zainuddin, S.Z.; Justine, M.; Kamarulzaman, M.F.; Bukry, S.A. FIFA 11+ Prevention Programme in Preventing Anterior Cruciate Ligament Injury among Soccer Players: A Scoping Review. Malays. J. Med. Health Sci. 2022, 18, 374–385. [Google Scholar]

Coach J