REF-984 · Bleakley & Costello, 2013 · Archives of Physical Medicine and Rehabilitation, Vol. · Paper · PubMed

Do thermal agents affect range of movement and mechanical properties in soft tissues? A systematic review

A-fairly strong evidenceMeasured on non-to trained athletesWritten before October 2026, being re-checked

A systematic review of human studies on thermal interventions and range of movement (ROM) or mechanical properties of soft tissue, searched up to May 2011. Thirty-six studies with a total of 1301 healthy participants were included; all carried a high risk of bias and the results were not pooled because of clinical heterogeneity.

There was evidence that heat increases ROM and that heat combined with stretching is more effective than stretching alone. Data on cold were conflicting for joint ROM, accessory joint movement and passive stiffness, and evidence on whether cold enhances stretching was limited. The effects of heat or ice on other mechanical properties such as passive stiffness remain equivocal.

Participants

Thirty-six studies, comprising a total of 1301 healthy participants.

Protocol

Sources: Cochrane Central Register of Controlled Trials, MEDLINE and EMBASE, from their earliest record up to May 2011; related-articles searches and reference lists.
Selection: human studies reporting how thermal interventions affect ROM and/or soft-tissue mechanical properties; two reviewers screened them independently.
Extraction and quality: by 2 review authors independently; Cochrane risk of bias tool.
Synthesis: meta-analyses not undertaken because of clinical heterogeneity; effect sizes calculated.

Key Results

Heat raises ROM, and heat plus stretching beats stretching on its own.
Cold: conflicting data on joint ROM, accessory joint movement and passive stiffness.
Cold plus stretching: limited evidence on whether acute cold applications enhance the effects of stretching.
Passive stiffness and other mechanical properties: the effects of heat or ice remain equivocal.
High risk of bias across all studies.
Authors' conclusion: heat works well as an add-on to developmental and therapeutic stretching and should be the first-choice treatment for improving ROM in clinical or sporting settings.

Practical Application

"Does a hot bath or heat pack loosen tight muscles?" A systematic review of 36 studies in 1301 healthy participants found that heat increases range of motion and that heat plus stretching beats stretching alone — but whether heat changes tissue stiffness is equivocal, and every included study had a high risk of bias. Heat is a flexibility aid, not a proven way to make the muscle less stiff.
Use: if the goal is range of motion, warming the area before or during stretching is supported. The abstract gives no temperature, duration or method (pack, bath, sauna), so those are not from this paper.
Cold: no consistent effect on range of motion or stiffness; nothing here supports icing to loosen up.
Not from this paper: stretching raised range without changing stiffness in REF-382; the house position that heat after training is not a recovery prescription is SYNTH-70; the tightness framework is SYNTH-11.

Limitations

High risk of bias across all 36 studies; no meta-analysis, so no pooled effect size.
Healthy participants only; search ended May 2011.
The abstract gives no heat modality, temperature, duration or effect sizes, and does not report how long the ROM gain lasts.
Outcomes are ROM and mechanical properties; perceived tightness, soreness, performance and injury are not addressed.
Written from the abstract and record metadata only (full text not read).
How this entry was checked and changed
Why this level

systematic review of 36 studies, but high risk of bias across all studies and not pooled because of clinical heterogeneity