REF-1730 · Öncü et al., 2026 · Scientific Reports, · Paper · PubMed

In 16 adolescent male soccer players tested 60 min after waking, a 45-min nap cut Pro Agility time from 5.40 s (no nap) to 4.98 s and the mean RPE over the six sprints by 1.4 points, a 25-min nap gave 5.18 s, and neither nap changed repeated-sprint ability (no significant condition effect), in a crossover after a normal night. Read in full

Main caveat: 16 players; order assigned by a fixed table that is not fully balanced (no nap first for 6), no analysis of order effects, and no blinding is possible for…
limited evidenceMeasured on trained athletesRead in full

Öncü, Eken and Aldhahi compared no nap, a 25-min nap and a 45-min nap in 16 male soccer players aged 16-19 from a club's U17 and U19 teams, all intermediate chronotypes and none habitual nappers.

After three familiarisation sessions, each player completed the three conditions 48 h apart: a nap (or no nap) in a quiet dark room at about 22 °C, 60 min of seated passive rest after waking, a short warm-up, the Pro Agility (5-10-5 yard) test, 3 min rest and a repeated-sprint test (6 × 30 m, 20 s rest), with RPE after each sprint.

Agility time improved with nap length, from 5.40 s with no nap to 5.18 s after 25 min and 4.98 s after 45 min (p < 0.001, partial eta squared 0.57), and every pairwise step was significant. Mean RPE fell from 9.90 with no nap to 8.48 after the 45-min nap (difference 1.42, 95% CI 0.64-2.19); the 25-min nap did not differ significantly from either.

No repeated-sprint index changed significantly overall; best sprint was fastest after the 45-min nap (4.33 s) and sprint decrement largest after it (8.72%), but the overall tests gave p = 0.074 and 0.093. Hooper wellness and self-rated alertness did not change significantly.

The authors conclude that a 45-min early-afternoon nap helped agility and lowered perceived exertion without improving fatigue resistance in repeated sprints.

Participants

n = 16 male soccer players, U17 and U19 squads of one professional club (Yeni Malatyaspor), age 17.18 ± 1.04 y (16-19), height 179.06 ± 3.17 cm, body mass 71.50 ± 7.16 kg, BMI 22.28 ± 1.98 kg/m²; competitive play since 9.06 ± 2.0 y.
All intermediate chronotypes (Morningness-Eveningness Questionnaire); no regular napping (fewer than 3 naps a week over the previous 3 months); PSQI 5.37 ± 2.62.
Tested at the end of the competitive season, in the off-season.

Protocol

Three conditions, 48 h apart: no nap (N0), 25-min nap (N25), 45-min nap (N45); order from a fixed sequence table (N0 first for 6 players, N25 first for 5, N45 first for 5); the authors describe it as randomised and as quasi-experimental.
Night before: instructed to sleep at least 7 h (not measured); no caffeine for 6 h before arrival.
Nap: 10-min adaptation, quiet darkened room at about 22 °C; Fitbit Charge 6 used to confirm sleep in the nap conditions and wakefulness in N0; minutes slept and sleep stages not reported.
Clock time of the nap: not stated in the Methods (the abstract and Discussion call it early afternoon and say the 13:00-16:00 window was adhered to).
After waking: 60 min seated passive rest, water only; then a warm-up (light jogging and 3 min of mobility), the Pro Agility test (18.28 m), 3 min rest, and the repeated-sprint test (6 × 30 m, 20 s rest) with Borg 6-20 RPE after each sprint (session mean used).
Hooper Index after each condition; alertness on a visual analogue scale after the naps; POMS referring to the past week.

Key Results

OutcomeNo nap25-min nap45-min napOverall test
Pro Agility time (s)5.40 ± 0.345.18 ± 0.234.98 ± 0.29F(2,30) = 19.88, p < 0.001, ηp² 0.57; N0 slower than both naps (p < 0.01), N25 slower than N45 (p < 0.05)
RPE, mean of 6 sprints (6-20)9.90 ± 1.659.07 ± 1.668.48 ± 1.35F(2,30) = 12.16, p < 0.001, ηp² 0.45; N0 vs N45: 1.42 (95% CI 0.64-2.19), p = 0.001; other pairs not significant
Best sprint (s)4.42 ± 0.264.53 ± 0.204.33 ± 0.19p = 0.074, ηp² 0.11 (not significant)
Mean sprint (s)4.70 ± 0.264.78 ± 0.314.70 ± 0.25p = 0.162 (not significant)
Sprint decrement (%)6.36 ± 3.045.64 ± 4.158.72 ± 4.49p = 0.093, ηp² 0.10 (not significant)
Hooper Index13.25 ± 3.3115.50 ± 4.0614.87 ± 4.73p = 0.072 (not significant)
Alertness (visual analogue scale)not measured5.18 ± 2.485.37 ± 3.00p = 0.819
The abstract and Discussion report best sprint faster after N45 than N25 (p < 0.01) and sprint decrement higher after N45 than N0 (p < 0.05); these are post hoc comparisons after non-significant overall tests, and the Results section itself reports no significant condition effects for these indices.
Exploratory correlations: POMS fatigue with RPE r = 0.584 (N0) and 0.564 (N25); POMS vigour with RPE r = −0.507 (N45); PSQI with best sprint r = −0.504 (N0 only).

Practical Application

In adolescent soccer players after a normal night, a 45-min early-afternoon nap followed by 60 min awake gave faster agility and lower perceived exertion than no nap, and did not improve repeated-sprint ability. The 25-min nap sat in between on agility and did not significantly lower RPE.
Against SYNTH-07: both naps sit inside the guide's 20-90 min, and the longer one did better on agility, which supports the length range. The study does not test the guide's 30 min awake: every test came 60 min after waking, and the authors chose 60 min to avoid sleep inertia. It does not test the short-night trigger either: players were told to sleep at least 7 h the night before.
Inference, not tested here: the agility gain (5.40 to 4.98 s, about 8% by our arithmetic) is large for a change-of-direction test; with the order only partly balanced and three familiarisation sessions, part of it may be order or learning, so treat the size as uncertain.
No benefit for repeated sprints; the 45-min nap went with the largest sprint decrement, a non-significant trend that the authors read as a possible fatigue trade-off.
Inference, not tested here: the result transfers to adult or endurance athletes only by analogy; the base's adult nap evidence is REF-1672 and REF-1673.

Limitations

16 players; order assigned by a fixed table that is not fully balanced (no nap first for 6), no analysis of order effects, and no blinding is possible for napping.
The sleep obtained in each nap (minutes, stages) and the clock time of the nap are not reported, so the dose behind "25" and "45" min is unknown; Fitbit actigraphy cannot stage sleep (the authors).
The prior night was instructed, not measured.
Repeated-sprint post hoc differences are reported despite non-significant overall tests.
Adolescent males, intermediate chronotypes, non-habitual nappers only (the authors).
RPE on a 6-20 scale averaged near 9-10 after maximal sprints, and the alertness scale is described as 100 mm but reported near 5, which the paper does not explain.
Funding from Princess Nourah bint Abdulrahman University and a university research project; the funder had no role in the study; no competing interests declared. The study is the first author's MSc thesis.
How this entry was checked and changed
Why this level

a crossover of 16 would reach the rubric's B+ band, held one step because the order was only partly balanced with no test for order effects, the sleep obtained in each nap and the nap clock time are not reported, and the repeated-sprint post hoc claims follow non-significant overall tests