title: Intramuscular temperature changes during and after 2 different cryotherapy interventions in healthy individuals.
abstract: METHODS
  Crossover.
  
  
  OBJECTIVE
  To compare the time required to decrease intramuscular temperature 8°C below baseline temperature, and to compare intramuscular temperature 90 minutes posttreatment, between 2 cryotherapy modalities.
  
  
  BACKGROUND
  Cryotherapy is used to treat pain from muscle injuries. Cooler intramuscular temperatures may reduce cellular metabolism and secondary hypoxic injury to attenuate acute injury response, specifically the rate of chemical mediator activity. Modalities that decrease intramuscular temperature quickly may be beneficial in the treatment of muscle injuries.
  
  
  METHODS
  Eighteen healthy subjects received 2 cryotherapy conditions, crushed-ice bag (CIB) and cold-water immersion (CWI), in a randomly allocated order, separated by 72 hours. Each condition was applied until intramuscular temperature decreased 8°C below baseline. Intramuscular temperature was monitored in the gastrocnemius, 1 cm below subcutaneous adipose tissue. The primary outcome was time to decrease intramuscular temperature 8°C below baseline. A secondary outcome was intramuscular temperature at the end of a 90-minute rewarming period. Paired t tests were used to examine outcomes.
  
  
  RESULTS
  Time to reach an 8°C reduction in intramuscular temperature was not significantly different between CIB and CWI (mean difference, 2.6 minutes; 95% confidence interval: -3.10, 8.30). Intramuscular temperature remained significantly colder 90 minutes post-CWI compared to CIB (mean difference, 2.8°C; 95% confidence interval: 2.07°C, 3.52°C).
  
  
  CONCLUSIONS
  There was no difference in time required to reduce intramuscular temperature 8°C 1 cm below adipose tissue using CIB and CWI. However, intramuscular temperature remained significantly colder 90 minutes following CWI. These results provide clinicians with information that may guide treatment-modality decisions.
authors.affiliation: Curry School of Education, University of Virginia, Charlottesville, VA, USA. kar7m@virginia.edu
authors.forename: Kimberly A
authors.initials: KA
authors.lastname: Rupp
authors.forename: Daniel C
authors.initials: DC
authors.lastname: Herman
authors.forename: Jay
authors.initials: J
authors.lastname: Hertel
authors.forename: Susan A
authors.initials: SA
authors.lastname: Saliba
mesh_terms: D001831:Body Temperature / Q000502:physiology*; D017679:Cryotherapy / Q000379:methods*; D005260:Female; D006801:Humans; D008297:Male; D018482:Muscle, Skeletal / Q000502:physiology*; D013997:Time Factors; D055815:Young Adult