Timing and Dose Matter: Late High-Speed Exposure and Higher High-Intensity Acceleration Volumes Reduce Hamstring Reinjury Risk in Elite Male Football (Soccer).
Pecci J, Castilla-López C, et al. • The Journal of orthopaedic and sports physical therapy • 2026
Delaying the introduction of high-speed running, sprinting, and accelerations until later in rehabilitation (≥60% of rehabilitation progression), followed by a structured and progressive build-up, was associated with lower risk of hamstring reinjury without compromising subsequent match performance in elite male football players.
Key Findings
Results
Late introduction of high-speed running during on-field rehabilitation was associated with significantly lower hamstring reinjury risk at both 2 and 6 months.
Late introduction was defined as introducing HSR at or after ≥60% of rehabilitation progression
Relative risk range at 2 months: RR = 0.948–0.969 (P < .01)
Relative risk range at 6 months: RR = 0.964–0.979 (P < .05)
Study used modified Poisson regression to assess associations between rehabilitation load characteristics and reinjury risk
Data came from 95 elite male football players across five professional clubs in major European and Middle Eastern leagues
Results
Late introduction of sprinting during rehabilitation was associated with significantly lower hamstring reinjury risk at both 2 and 6 months.
Late introduction defined as ≥60% of rehabilitation progression
RR range at 2 months: 0.948–0.969 (P < .01)
RR range at 6 months: 0.964–0.979 (P < .05)
Association held across both short-term and medium-term follow-up periods
Results
Late introduction of high-intensity accelerations during rehabilitation was associated with significantly lower hamstring reinjury risk.
Late introduction defined as ≥60% of rehabilitation progression
RR range at 2 months: 0.948–0.969 (P < .01)
RR range at 6 months: 0.964–0.979 (P < .05)
Higher daily exposure to high-intensity accelerations once introduced was also protective (RR = 0.861, 95% CI: 0.778–0.951)
Results
Higher daily exposure to high-intensity accelerations once introduced into rehabilitation was independently associated with lower reinjury risk.
RR = 0.861 (95% CI: 0.778–0.951)
This suggests a dose-dependent protective effect after the delayed introduction of high-intensity accelerations
This finding indicates that both the timing of introduction and the subsequent volume of exposure matter for reinjury prevention
Results
Total volume of high-speed running or sprinting during rehabilitation was not meaningfully associated with hamstring reinjury risk.
No significant associations were found between total HSR volume and reinjury risk
No significant associations were found between total sprinting volume and reinjury risk
This contrasts with the significant protective effect seen for timing of introduction and high-intensity acceleration dose
Results
Match running performance metrics did not differ significantly between pre-injury and post-return-to-play matches.
Metrics compared included HSR distance, sprint distance, and high-intensity accelerations per minute
Comparisons made across the five matches before injury and the first five matches after return to play
All comparisons yielded P > .05, indicating no statistically significant differences
Changes in performance were not correlated with rehabilitation load characteristics
This suggests that delaying high-intensity exposure in rehabilitation did not compromise subsequent match performance
Methods
The study analyzed rehabilitation load profiles from 95 elite male football players with hamstring strain injuries across five professional clubs.
Retrospective cohort study design
Clubs competed in major European and Middle Eastern leagues
Players with complete rehabilitation load profiles were included in both 2-month and 6-month reinjury analyses
Modified Poisson regression was used to assess associations between rehabilitation load characteristics and reinjury risk
Paired t-tests were used to compare match running performance pre-injury versus post-return to play
What This Means
This research suggests that when professional soccer players recover from hamstring muscle injuries, waiting until later in the rehabilitation process before introducing high-speed running, sprinting, and explosive acceleration exercises is associated with a meaningfully lower chance of re-injuring the hamstring. The study tracked 95 elite male players from five professional clubs across European and Middle Eastern leagues, finding that delaying these high-intensity activities until at least 60% of the rehabilitation program had been completed was linked to reinjury risk reductions of roughly 3–5% over both a 2-month and 6-month follow-up period. Once high-intensity accelerations were introduced, doing more of them each day was also associated with additional protection against reinjury.
Importantly, this research suggests that taking a more cautious, gradual approach to reintroducing high-intensity running during rehabilitation did not come at a cost to performance. When players returned to competitive matches, their high-speed running distances, sprint distances, and acceleration counts per minute were statistically similar to what they had achieved in matches before they were injured. The amount or timing of high-intensity training during rehabilitation was not linked to how well players performed after returning to play.
This research suggests that for elite soccer players recovering from hamstring injuries, the sequencing and timing of when demanding running activities are introduced during on-field rehabilitation may matter more than the total amount of high-speed running done overall. A 'less is more, then build up' approach to high-intensity running exposure — rather than an early aggressive approach — appears linked to safer outcomes, without sacrificing the physical capacities players need to compete at a high level.
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Pecci J, Castilla-López C, di Michele R, Benedetti L, Aiello P, Prandelli N, et al.. (2026). Timing and Dose Matter: Late High-Speed Exposure and Higher High-Intensity Acceleration Volumes Reduce Hamstring Reinjury Risk in Elite Male Football (Soccer).. The Journal of orthopaedic and sports physical therapy. https://doi.org/10.2519/jospt.2026.14077