# Morning sprint interval training produces greater physical performance adaptations than evening training in soccer players

PMID: 39979557
Journal: Scientific Reports
Published: 2025-02-20
Authors: Yan B, Li L

## Question

Does the time of day of sprint interval training affect physical and physiological adaptations in trained soccer players?

## Summary

In 30 male college soccer players, adding 7 weeks of supervised sprint interval running to regular soccer practice improved jumping, sprinting, change-of-direction, intermittent running, VO2max, and Wingate power. Morning sprint sessions at 8 AM produced larger gains than evening sessions at 5 PM on several performance outcomes.

## Population

- Male College Division II soccer players
- Sample size: 30
- Age: MSIT 22.6 +/- 2.3 years; ESIT 23.2 +/- 3.1 years; CON 23.5 +/- 2.8 years
- Sex: Male
- Fitness level: Trained soccer players with about 5-6 years of soccer training age
- Health status: Free of lower-body injury in the previous 3 months and medically cleared for participation

## Methodology

- Randomized controlled training study
- 7-week intervention within a 10-week study schedule
- Soccer pitch and performance testing facilities
- Randomized and controlled study design.

## Protocol

- Morning or evening running SIT.
- Modality: Field running.
- Work intervals: 5 seconds all-out.
- Recovery: 1:3 recovery between efforts; 3 minutes between sets.
- Sets or repetitions: 4 x 10 sprints.
- Intensity: All-out.
- Session duration: About 50 minutes including warm-up and cool-down.
- Frequency: 3 sessions/week.
- Program length: 7 weeks.
- Progression: No progression reported.
- Soccer practice control.
- Modality: Technical and tactical soccer practice.
- Intensity: Usual training.
- Frequency: 3 practices/week.
- Program length: 7 weeks.

## Outcomes

### Performance adaptations
Status: improved
Both SIT groups improved jump, sprint, change-of-direction, Yo-Yo IR1, VO2max, and Wingate power versus baseline and control.

Reported p<0.05 for pre-post SIT changes with small to very large effect sizes.

### Morning vs evening
Status: improved
Morning SIT produced greater gains than evening SIT for CMVJ, 20-m sprint, Yo-Yo IR1, peak power, and average power.

Significant interactions were reported for multiple outcomes; CMVJ interaction p=0.001 in the displayed table.

### Safety
Status: no clear change
No training-related injuries were reported.

Descriptive safety reporting only.

## Practical Insights

- For trained, sprint-ready users, very short all-out efforts can be paired with generous recovery and still drive performance gains.
- Time of day may be worth exposing as a scheduling preference, but this study does not justify a general morning-is-best claim.
- A 15-minute warm-up before maximal sprint intervals is a key safety and readiness detail.

## Limitations

- Small sample of male college soccer players.
- Athlete-only, supervised field sprinting protocol limits general fitness translation.
- No post-intervention follow-up.
- One methods sentence appears inconsistent about intervention length, while tables and results describe 7 weeks.

## Safety And Adherence

- No reported injuries related to the training intervention.
- Participants were screened for recent lower-body injury and limiting medical/orthopedic conditions.

## Original Sources

- [PubMed](https://pubmed.ncbi.nlm.nih.gov/39979557/) (pubmed)
- [DOI](https://doi.org/10.1038/s41598-025-89821-4) (doi)
- [PMC full text](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11842626/) (full text)

## Agent Guidance

Preserve the paper-level scope of this note. Do not generalize beyond the population, protocol, measured outcomes, and limitations above.