The paper
Systematic scoping review, 66 studies (from 5135 screened) on internal/external loading of soccer substitutes during warm-up, match play and training.
Found
Substitutes' pre-pitch-entry body temperature (~37°C) sits well below in-match temperatures (>38°C); they cover lower absolute distances but higher relative total distance (~109-137 m·min-1), high-speed running (~9.8-13.5 m·min-1) and sprint distance (~3.8-5.0 m·min-1) than starters, with second-half substitutes reaching 84% max HR versus 81% for full-match players (but still below starters' 86% first-half HR).
Appraisal
The temperature and relative-intensity findings are physiologically plausible and consistent across studies, but this is a descriptive synthesis of associations, not a test of any intervention, so it cannot establish that lower core temperature causes the higher relative running outputs or vice versa, nor can it quantify how much a ~1°C temperature gap actually degrades sprint or power performance in practice. Statistically the agreement between included studies is reassuring, but clinically the magnitude of real-world impact (injury risk, performance decrement) remains unquantified.
The gap
No study in this review tests whether a specific substitute warm-up or re-warm-up protocol actually normalises core temperature or running output before pitch entry, this is a map of the problem, not a test of a fix. Soccer physical-performance research skews heavily male, so treat any extrapolation to female squads with extra caution until sex-specific data are confirmed. That intervention-efficacy evidence is what's needed before changing warm-up practice with confidence.
Landmark
This extends the broader literature on match-running demands and half-time/substitute re-warm-up strategies (the well-established finding that core temperature and sprint performance decline during passive rest periods in soccer), by mapping substitute-specific data rather than testing a new re-warm-up intervention itself.
On Monday
Reinforces prioritising a late, active, substitute-specific warm-up or re-warm-up close to pitch entry to limit the temperature/readiness gap, but since no protocol here was tested for efficacy, don't adopt a specific new regimen off this paper alone, use it to justify auditing your current substitute warm-up timing.
