Warm Up I: Potential Mechanisms and the Effects of Passive Warm Up on Exercise Performance
Key Results
Warm-up routines are well accepted despite limited scientific evidence for their effectiveness
Most warm-up effects are attributed to temperature-related mechanisms: decreased stiffness, increased nerve-conduction rate, altered force-velocity relationship, increased anaerobic energy provision, increased thermoregulatory strain
Non-temperature-related mechanisms have also been proposed: effects of acidaemia, elevated baseline oxygen consumption (VO2), increased post-activation potentiation
Possible psychological effects (e.g. increased preparedness)
Two categories of technique: passive warm-up (raising muscle or core temperature by external means) and active warm-up (exercise)
Passive heating obtains the temperature rise of an active warm-up without depleting energy substrates; it is not practical for most athletes, but it lets researchers test how much of the active warm-up effect is temperature alone
Mechanism
As above: a temperature branch (stiffness, nerve conduction, force-velocity, anaerobic energy provision, thermoregulation) and a non-temperature branch (acidaemia, raised baseline VO2, post-activation potentiation), plus psychological preparedness. Any figure for "degrees gained → percent power gained" is from the full text or other sources, not this abstract.
Practical Application
Bishop's 2003 review (Part I): warm-up effects are mostly temperature-driven — less stiffness, faster nerve conduction, a shifted force-velocity relationship, more anaerobic energy provision — with non-temperature contributions from raised baseline VO2, acidaemia and post-activation potentiation; passive heating can raise muscle temperature without spending substrate — the mechanistic basis for warming up at all.
Inference, not tested: passive warming (hot bath, heated garments) is worth using where an active warm-up is impossible or must be kept short, and to hold temperature in a delay before the start — the review's own point is that passive heating does not deplete energy stores.
Inference, not tested: an active warm-up is the default because it adds the non-temperature mechanisms (raised VO2, potentiation) on top of temperature; the review frames this as the reason to compare the two, not as a measured superiority.
Not from this paper; the base's own practice: the working target of an active warm-up is a clear rise in muscle temperature plus a raised baseline VO2 before the first hard effort — how many degrees is not stated in this abstract.
Limitations
Narrative review (not systematic)
Some temperature effects extrapolated from isolated muscle preparations to whole-body exercise
The abstract gives mechanisms and categories, no effect sizes
How this entry was checked and changed
Why this level
regraded 2026-09-27 from A-: narrative review without systematic method, from the leading group on warm-up
Content correction 2026-09-27
Level A- -> B+: narrative review (rubric: authoritative narrative review from the leading group). Sport "cycling, sprint" -> general.
Removed numbers not in the abstract: "↑ muscle temp by 1°C → ~2-5% power" and "raise muscle temperature by ≥1°C"; removed "oxyhemoglobin dissociation curve" and "muscle glycogenolysis/glycolysis" as not in the abstract; mechanism list now the abstract's (stiffness, nerve conduction, force-velocity, anaerobic energy provision, thermoregulatory strain; acidaemia, baseline VO2, PAP; psychological).
Added the passive-vs-active distinction and the substrate-sparing point from the abstract; "active superior" labelled as inference.