“Cleared” Isn’t Always Ready: Vertical Jump Deficits During ACL RTPs
Athletes often return to sport (RTS) after ACL reconstruction (ACLR) using standard discharge tests like strength and horizontal hops.
But do these really tell the whole story?
This study questions whether single and bilateral vertical jump tests can better reveal lingering asymmetries and performance deficits that might otherwise be missed during return to play.
Are athletes ready to return to sport at 9 months post-ACLR? Or are we missing key deficits by relying on outdated RTS criteria?
What did the researchers do?
Researchers tested 126 male athletes post-ACLR and 532 healthy male controls, using dual force plates.
Jump Tests
- Countermovement Jumps ⮕ CMJ, double and single leg
- Drop Jumps ⮕ from 30 cm for double-leg, 15 cm for single-leg
Symmetry and Performance Measures
- Jump height, contact time, Reactive Strength Index (RSI)
- Concentric and eccentric impulses, peak landing force
Used mixed models and subgroup analysis (e.g., graft type, pro vs. recreational athletes)
What were the results?
Symmetry Deficits Persist
- Athletes post-ACLR had significant asymmetries in concentric impulse, especially in single-leg drop jumps
- Concentric phase (propulsive) was most consistently affected across all tests
Performance Gaps Remain
- Jump height and RSI were significantly lower in ACLR athletes vs. controls, even after RTS clearance
- Even the uninvolved limb underperformed compared to controls
Drop Jump Sensitivity
- Single-leg drop jump was most sensitive at detecting asymmetries
- Bilateral CMJ best-exposed landing asymmetries
Symmetry Results
Performance Results
What does this mean?
- Significant kinetic and performance deficits remain even after “passing” the RTS criteria.
- Traditional RTS testing misses critical asymmetries, especially in dynamic, vertical tasks.
- Clinicians and coaches should include phase-specific vertical jump testing in RTS decisions.
- Jump metrics (like RSI and jump height) reflect more profound issues.
Limitations
- Only included male athletes, mostly from one institution
- Normative comparisons are limited to professional football players
Coach's Takeaway
- Beyond hop tests ⮕ use vertical jump tests to assess readiness and deficits.
- The concentric phase is the weak link ⮕ be sure to target this in late-stage rehab.
- Don’t just chase symmetry ⮕ restore both limbs to pre-injury performance
