Movement Regularity and Local Dynamic Stability During Acute and 12-Week Retrained Non-Rearfoot-Strike Running Compared to Habitual Non-Rearfoot-Strike Running.
Wu K, Deng L, et al. • Journal of sports science & medicine • 2026
A gradual 12-week gait-retraining programme may be an appropriate approach for transitioning habitual rearfoot strikers to non-rearfoot-strike running, as retrained runners showed greater movement regularity and local dynamic stability than during acute adoption, though selected differences from habitual non-rearfoot strikers remained.
Key Findings
Results
Habitual rearfoot strikers during acute non-rearfoot-strike adoption (HRFS-AN) demonstrated a more anterior foot strike position compared to both the 12-week gait-retrained state (HRFS-GR) and habitual non-rearfoot strikers (HNRFS).
Thirty-three male recreational runners were enrolled, including 13 habitual rearfoot strikers and 14 habitual non-rearfoot strikers.
All participants ran on a treadmill at 9 km·h⁻¹ while ground reaction forces and lower-limb kinematics were recorded.
The more anterior foot strike during acute adoption suggests that novice NRFS adopters initially overshoot the target foot placement pattern compared to experienced NRFS runners.
After 12 weeks of gait retraining, foot strike position converged toward that of habitual non-rearfoot strikers.
Results
Vertical instantaneous loading rate (VILR) and vertical average loading rate (VALR) were lower in HRFS-AN than in HRFS-GR.
Despite all three groups adopting an NRFS pattern, loading rates differed between the acute adoption and retrained states.
HRFS-AN showed lower VILR and VALR compared to HRFS-GR, indicating that loading rate characteristics changed over the course of retraining.
Peak vertical ground reaction force did not differ significantly among the three states.
Most other spatiotemporal and discrete kinematic outcomes also did not differ among states.
Results
Compared to acute NRFS adoption (HRFS-AN), the 12-week retrained state (HRFS-GR) and habitual non-rearfoot strikers (HNRFS) exhibited lower sample entropy (SampEn) for sagittal-plane knee and ankle motion and vertical center-of-mass (COM) motion.
Sample entropy (SampEn) was used to characterize temporal regularity of movement, with lower SampEn indicating more regular (less complex) motion patterns.
Both HRFS-GR and HNRFS showed lower SampEn than HRFS-AN for sagittal-plane knee motion, sagittal-plane ankle motion, and vertical COM motion.
This suggests that acute adoption of NRFS is associated with more irregular movement patterns compared to both the retrained and habitually trained states.
Coefficient of variation (CV) was used for discrete kinematic variability and largest Lyapunov exponent (LyE) for local dynamic stability.
Results
Compared to acute NRFS adoption (HRFS-AN), both the retrained state (HRFS-GR) and habitual non-rearfoot strikers (HNRFS) showed lower largest Lyapunov exponents (LyE) for sagittal-plane knee and vertical COM motion, indicating greater local dynamic stability.
The largest Lyapunov exponent (LyE) quantifies local dynamic stability, with lower values indicating greater stability.
HRFS-GR and HNRFS both exhibited lower LyE than HRFS-AN for sagittal-plane knee motion and vertical COM motion.
This indicates that 12 weeks of gait retraining improved local dynamic stability in key movement trajectories toward levels seen in habitual non-rearfoot strikers.
The improvement in stability suggests the nervous system adapted to the new gait pattern over the 12-week training period.
Results
After 12 weeks of retraining, HRFS-GR exhibited higher SampEn and LyE than HNRFS for selected hip and knee measures, indicating that selected movement regularity and stability differences from habitual non-rearfoot strikers remained.
Compared to HNRFS, HRFS-GR showed higher SampEn for sagittal-plane knee motion and transverse-plane hip motion.
HRFS-GR also showed higher LyE (less stability) than HNRFS for sagittal-plane knee motion and coronal-plane hip motion.
These persistent differences suggest that 12 weeks of retraining, while beneficial, does not fully replicate the movement patterns of lifelong habitual non-rearfoot strikers.
The residual differences were observed specifically in knee and hip motion planes rather than in ankle or COM trajectories.
Results
Most conventional biomechanical outcomes, including peak vertical ground reaction force and the majority of spatiotemporal and discrete kinematic measures, did not differ significantly among the three running states.
Analyses included ground reaction forces and lower-limb kinematics recorded during treadmill running at 9 km·h⁻¹.
Selected joint angle and coefficient of variation (CV) outcomes did differ among states.
The lack of difference in most conventional biomechanical variables contrasts with the differences observed in nonlinear measures (SampEn and LyE), highlighting the additional discriminatory value of these measures.
The authors noted that movement regularity and local dynamic stability measures revealed differences that conventional biomechanical analysis did not capture.
Discussion
A 12-week gait retraining programme produced movement regularity and local dynamic stability in selected joint and COM trajectories that were intermediate between acute NRFS adoption and habitual non-rearfoot striking.
The retraining programme resulted in improved regularity and stability compared to acute adoption for sagittal-plane knee, ankle, and vertical COM trajectories.
However, the retrained state had not fully converged with habitual non-rearfoot strikers in sagittal-plane knee and hip motion planes.
The study design included 13 habitual rearfoot strikers assessed at two time points (acute and after 12 weeks) and 14 habitual non-rearfoot strikers as a reference group.
The authors concluded that a gradual 12-week gait-retraining programme 'may be an appropriate approach for transitioning habitual rearfoot strikers to NRFS.'
What This Means
This research examined what happens to movement patterns when runners who normally land on their heel (rearfoot strikers) switch to landing on the front or middle of their foot (non-rearfoot striking), both immediately and after 12 weeks of structured retraining. The study compared these two transition stages to runners who had always run with a non-rearfoot strike pattern. Beyond standard measures like forces and joint angles, the researchers used advanced mathematical tools to assess how regular and stable movement patterns were over time — measures that can reveal adaptation differences that traditional analyses might miss.
The study found that when runners first attempt to change their foot strike pattern, their movements are less regular and less stable compared to either trained or habitual non-rearfoot strikers. After 12 weeks of gradual retraining, movement regularity and stability improved substantially and approached the levels of habitual non-rearfoot strikers, particularly in knee, ankle, and whole-body movement patterns. Interestingly, the newly retrained runners initially showed lower loading rates (a common injury risk factor) during the acute phase compared to after retraining, and they also initially landed with a more forward foot position than either the retrained or habitual groups. Some differences from habitual non-rearfoot strikers — particularly in hip and knee movement — persisted even after 12 weeks.
This research suggests that switching running foot strike patterns is a gradual neuromotor learning process, not just a mechanical adjustment. A structured 12-week retraining programme appears to meaningfully improve movement quality and stability in runners making this transition, though the body may need even more time to fully adapt to match someone who has always run that way. These findings support using gradual, supervised retraining programmes rather than abrupt changes when runners seek to modify their foot strike pattern.
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Wu K, Deng L, Zhang X, Suo B, Lu Z, He J, et al.. (2026). Movement Regularity and Local Dynamic Stability During Acute and 12-Week Retrained Non-Rearfoot-Strike Running Compared to Habitual Non-Rearfoot-Strike Running.. Journal of sports science & medicine. https://doi.org/10.52082/jssm.2026.822