Did you know that approximately 200,000 anterior cruciate ligament (ACL) injuries occur in the U.S. every year? That's enough to fill a small stadium! These injuries can sideline athletes for months, often leading to a long and complicated road back to full strength. And for those who decide to have surgery, returning to one's sport can feel like climbing a mountain.

Upon returning, many athletes learn the hard way that getting back to their pre–injury level of performance is no simple task. In fact, about 43% of athletes who underwent an ACL reconstruction reported that they never regained their pre–injury vertical leap, with abnormal jumping mechanics persisting in most patients for years after surgery.

But what if there was a new way to ensure a smoother, safer comeback? A recent study looked into this, and the results are promising.

Understanding the ACL recovery journey

The ACL is one of the major ligaments in the knee. It crisscrosses the bones that make up the knee and provides the joint with stability, especially during jumping and pivoting activities. Injuries to the ACL most often result from sudden changes in direction in sports like basketball, soccer, and skiing, which sends athletes to the sidelines with pain, limited mobility, and usually an eagerness to return.

That's why many athletes decide to undergo ACL reconstruction, a surgical procedure that replaces the torn ligament to improve knee stability. Although ACL reconstruction is typically quite effective, many athletes continue to experience lingering issues even after a successful procedure:

• Up to 65% report abnormal jumping mechanics more than 2 years after surgery


• Reconstructed knees have been found to produce 18% less power during jumps than healthy knees


• 1 in 4 patients experience a second ACL injury within 5 years

Weak quadriceps (thigh muscles) and overusing hip muscles can decrease power and increase the odds of a second ACL injury. That's where optimal rehabilitation guided by physical therapists makes all the difference, and a new study suggests a bold way forward.

Flywheel training study breaks new ground

Considering the inherent issues of ACL reconstruction recovery, a team of researchers conducted a study to investigate the effectiveness of an exercise called the flywheel rear–leg elevated split squat (RLESS) in this population. The RLESS, or Bulgarian split squat, is a squat that involves keeping the rear leg elevated and using a flywheel–or spinning wheel–for resistance, and it's intended to increase quadriceps strength and fine–tune jumping form. Prior research has showed that athletes who undergo ACL reconstruction over–rely on their hips instead of their knees while jumping, which can hinder performance and increase injury risk. The team hypothesized that RLESS could balance this, and their goal was to determine if this innovative approach could improve both the biomechanics of jumping and overall performance in athletes who underwent ACL reconstruction. Here's a closer look at how the study was conducted:

• Participants: 11 college athletes between ages 19–28 who underwent an ACL reconstruction on one knee and returned to sports in the past few years


• The intervention: athletes participated in 16 sessions over 8 weeks in which they trained their reconstructed leg with one set of deep–knee RLESS to exhaustion using a flywheel; the resistance gradually increased to keep it challenging


• Outcome measure: single–leg drop jumps from a 30–cm box were tested before and after the intervention, with motion capture and force plates tracking jump height, joint contributions (hip, knee, ankle), and forces

The results were promising. Here's what the researchers found:

• Increased jump heights
  
  
  
  • Participants showed an increase in jump height from their reconstructed leg after training; although they still had not fully matched the performance level of their non–injured leg, the improvements were still significant
  
  
  
  


• Biomechanical Improvements
  
  
  
  • Contributions from the knee joint increased during propulsion, while reliance on the hip joint decreased, which indicates more balanced biomechanics
  
  
  • Leg–to–leg joint differences also decreased
  
  
  • Knee varus moment asymmetry (a sideways force tied to injury risk) disappeared and vertical ground reaction force held steady, hinting at safer landings
  
  
  • The intact leg also showed kinematic shifts, suggesting wider benefits
  
  
  
  

The vital role of physical therapists in ACL recovery

Although patients recovering from ACL reconstruction often struggle with jumping performance, these findings suggest that incorporating flywheel RLESS training into rehabilitation plans can safely enhance their performance and help restore normal joint function.

Physical therapists frequently treat patients recovering from ACL injuries–both before and after surgery–and we play a crucial part in their rehabilitation journey. Through the use of flywheel training and other personalized exercises, we can:

• Help athletes regain lost strength and improve their biomechanics


• Monitor progress closely to assure safety and effectiveness


• Educate patients about their condition, rehabilitation methods, and the specific role of exercises like RLESS in achieving their athletic goals

Ready to get back in the game?

If you've injured your ACL and have already undergone surgery or are considering the procedure, don't navigate recovery alone! Our clinic specializes in tailored rehabilitation programs that incorporate the latest research–backed methods, including flywheel training.

Contact us today to learn more about how we can support you on your path to recovery and help you return the sports you love. Together, we can unlock your full athletic potential!

For more details about the study, check it out here.