title: Cryotherapy induces an increase in muscle stiffness.
abstract: Although cold application (ie, cryotherapy) may be useful to treat sports injuries and to prevent muscle damage, it is unclear whether it has adverse effects on muscle mechanical properties. This study aimed to determine the effect of air-pulsed cryotherapy on muscle stiffness estimated using ultrasound shear wave elastography. Myoelectrical activity, ankle passive torque, shear modulus (an index of stiffness), and muscle temperature of the gastrocnemius medialis were measured before, during an air-pulsed cryotherapy (-30°C) treatment of four sets of 4 minutes with 1-minute recovery in between and during a 40 minutes postcryotherapy period. Muscle temperature significantly decreased after the second set of treatment (10 minutes: 32.3±2.5°C; P<.001), peaked at 29 minutes (27.9±2.2°C; P<.001) and remained below baseline values at 60 minutes (29.5±2.0°C; P<.001). Shear modulus increased by +11.5±11.8% after the second set (10 minutes; P=.011), peaked at 30 minutes (+34.7±42.6%; P<.001), and remained elevated until the end of the post-treatment period (+25.4±17.1%; P<.001). These findings provide evidence that cryotherapy induces an increase in muscle stiffness. This acute change in muscle mechanical properties may lower the amount of stretch that the muscle tissue is able to sustain without subsequent injury. This should be considered when using cryotherapy in athletic practice.
authors.affiliation: Laboratory "Sport, Expertise and Performance" (EA 7370), Research Department, French Institute of Sport (INSEP), Paris, France.
authors.forename: M
authors.initials: M
authors.lastname: Point
authors.affiliation: Laboratory "Sport, Expertise and Performance" (EA 7370), Research Department, French Institute of Sport (INSEP), Paris, France.
authors.forename: G
authors.initials: G
authors.lastname: Guilhem
authors.affiliation: NHMRC Centre of Clinical Research Excellence in Spinal Pain, Injury and Health, School of Health and Rehabilitation Sciences, The University of Queensland, Brisbane, Australia.|Laboratory "Movement, Interactions, Performance" (EA 4334), Faculty of Sport Sciences, University of Nantes, Nantes, France.
authors.forename: F
authors.identifier: http://orcid.org/0000-0002-6432-558X
authors.initials: F
authors.lastname: Hug
authors.affiliation: Laboratory "Movement, Interactions, Performance" (EA 4334), Faculty of Sport Sciences, University of Nantes, Nantes, France.
authors.forename: A
authors.initials: A
authors.lastname: Nordez
authors.affiliation: Medical Department, French National Institute of Sport (INSEP), Paris, France.
authors.forename: A
authors.initials: A
authors.lastname: Frey
authors.affiliation: Laboratory "Sport, Expertise and Performance" (EA 7370), Research Department, French Institute of Sport (INSEP), Paris, France.|Laboratory "Movement, Interactions, Performance" (EA 4334), Faculty of Sport Sciences, University of Nantes, Nantes, France.
authors.forename: L
authors.identifier: http://orcid.org/0000-0002-9664-8121
authors.initials: L
authors.lastname: Lacourpaille
mesh_terms: D000328:Adult; D000842:Ankle; D001265:Athletic Injuries / Q000628:therapy*; D017679:Cryotherapy; D055119:Elastic Modulus; D054459:Elasticity Imaging Techniques; D005260:Female; D006801:Humans; D008297:Male; D053581:Muscle Strength Dynamometer; D018482:Muscle, Skeletal / Q000503:physiopathology*; D019415:Torque
keywords: cooling; elastography; muscle temperature; shear modulus; supersonic shear imaging; ultrasound