Benefits of Flywheel and Eccentric Training After ACL Surgery
Introduction
ACL injuries are common and often career-threatening, especially in female athletes. Once surgery is done, the real challenge begins: regaining performance. Recent approaches now include flywheel training, known for its role in developing eccentric strength, balance, and reactive control—critical elements in post-ACL rehabilitation.
In this article, we’ll look at how eccentric training, plyometric training, and a combination of both influence recovery and functional return in elite female athletes after ACL reconstruction.
Background: Why combine eccentric and plyometric work?
Traditionally, post-ACL rehab focuses on concentric strength and range of motion. However, recent studies highlight the importance of neuromuscular control, stability, and reactive strength for full return to sport.
Eccentric training is effective in:
- Increasing hamstring and quadriceps strength
- Promoting tendon remodeling
- Improving control during deceleration
Plyometric training enhances:
- Elasticity and explosiveness
- Coordination and balance
- Readiness for rapid direction changes
The combination, according to the evidence, may offer synergistic benefits: building strength while restoring speed and reactivity.
The study: How was it conducted?
Forty elite female athletes (~20 years old), all members of national teams, were enrolled 14 weeks after ACL surgery. They had already completed standard early-stage rehab.
They were divided into four groups for six weeks of training:
- ECC Group: eccentric training only
- PLYO Group: plyometric training only
- COMB Group: combined eccentric + plyometric training
- CON Group: control (no specific added training)
Training frequency: 2x per week
Assessments pre- and post-program:
- Dynamic balance (Y-Balance Test)
- Lysholm Knee Score (functional knee stability)
- Return to Sport Index (RSI)
- Leg Symmetry Index (LSI) via single-leg hop
Results: What worked best?
All groups started with similar baseline measures. After six weeks:
- The COMB group showed the greatest improvements in all tests.
- Significant gains in Y-BAL, LKS, and RSI (all p < 0.001).
- Better LSI (symmetry in single-leg hop) than all other groups.
Compared to single-mode training, the combined approach produced:
- Better knee stability
- More symmetrical leg power output
- Higher psychological readiness for return to sport
Practical insights for coaches and therapists
When to introduce eccentric and plyometric work post-ACL?
- Around 3–4 months post-surgery, after basic mobility and strength are reestablished.
- Begin with low-impact eccentric and low-intensity plyometrics.
- Gradually increase intensity and complexity over time.
Sample progression:
- Eccentric training
- Step-downs
- Slow tempo squats
- Flywheel hip extension
- Nordic curls (late-stage only)
- Plyometric training
- Jump and stick (landing control)
- Double-leg hops
- Bounding drills
- Deceleration and COD tasks
- Combine movements
- Eccentric squats → jump squats
- Nordic curls → sprint drills
- Lunge drop + reactive hops
Keep the athlete involved: Use RSI and Y-BAL to give feedback on progress. These are simple, reliable tools.
Key takeaways
- Eccentric and plyometric training target different yet complementary neuromuscular systems.
- Combined programs improve balance, symmetry, and confidence, essential for safe return to play.
- Early integration (after foundational rehab) accelerates recovery of performance traits, not just healing.
This isn’t just about returning athletes to the field. It’s about preparing them to stay there—healthy, confident, and effective.
Final thoughts
Injury rehab is evolving. Gone are the days of just “getting strong again.” Now we need to rebuild athletes who can absorb force, react quickly, and move with confidence.
In the next article, we’ll look at how different inertial loads in flywheel training affect muscle contractile properties, especially in the hamstrings. Let’s keep going.
