Increased Gait Speed Changes Knee Mechanics Following Anterior Cruciate Ligament Reconstruction: Implications and Caution for Treadmill Training in Early Rehabilitation.
Sara Y Almansouri, Susan M Sigward
PMID 40041529WHAT IT FOUND
Walking 25% faster than self-selected speed on a treadmill increased knee loading in people 12-20 weeks post-ACL reconstruction.
However, walking 50% faster worsened limb symmetry and triggered compensatory patterns. Use moderate speed increases for gait retraining; avoid large jumps.
Key findings
01Increasing treadmill speed by 25% improved knee extensor moment and power absorption in the surgical limb, but did not improve limb symmetry.
02Increasing treadmill speed by 50% caused limb symmetry to worsen significantly across all measured variables compared to the 25% increase.
03Self-reported function and strength indices indicated the ACL group was on a typical recovery path, yet significant biomechanical deficits persisted.
STILL TO COME
How it was doneWhat they foundWhat it means for PTs
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What it does not show
The study was cross-sectional, so it observed immediate responses to speed changes rather than long-term adaptations to a training program. The sample size was small (10 in the ACL group), limiting the generalizability of the findings. Participants were only 12-20 weeks post-surgery, so results may not apply to later stages of rehabilitation. Fatigue or practice effects could have influenced performance across the three speed conditions, although order was randomized.
Declared interests
The authors declare no conflict of interest.
The easy way to misread this
Do not assume that walking faster on a treadmill automatically improves gait symmetry. While a 25% speed increase improved knee loading in the surgical limb, it did not fix the asymmetry between legs. A 50% increase actively worsened symmetry, meaning faster is not always better for gait retraining.