title: Microvascular perfusion and intramuscular temperature of the calf during cooling.
abstract: OBJECTIVE
  The study's purpose was to examine how the microvascularity of the gastrocnemius changed after a cryotherapy intervention based on subcutaneous tissue thickness. A secondary purpose was to compare intramuscular temperature change to subcutaneous tissue thickness.
  
  
  METHODS
  This was a single-blinded crossover study; each subject received both conditions (cryotherapy or sham). Subjects had baseline measurements of blood flow, blood volume, and intramuscular temperature recorded at 1 cm into the muscle belly of the medial gastrocnemius. The randomized condition was applied for 10, 25, 40, or 60 min, depending on subcutaneous tissue thickness. Immediate posttreatment microvascular measures were taken. After a designated rewarming period, again based on subcutaneous tissue thickness, measurements were retaken. At least 48 h separated the two conditions.
  
  
  RESULTS
  There were significant condition × time interactions for blood flow (P = 0.01), blood volume (P = 0.022), and intramuscular temperature (P < 0.001). For blood flow and volume, the cryotherapy condition maintained baseline levels, whereas the sham condition increased immediately after treatment and rewarming. For intramuscular temperature, the cryotherapy condition caused a decrease in intramuscular temperature from baseline compared with no change in the sham condition from baseline. Intramuscular temperature change was significantly correlated to subcutaneous tissue thickness (r = 0.49, P = 0.05).
  
  
  CONCLUSIONS
  Cryotherapy did not decrease blood flow and blood volume from resting levels, although the intramuscular temperature decreased. An intramuscular change of 7°C-9°C may not be cold enough to cause local vasoconstriction.
authors: School of Kinesiology and Recreation, Illinois State University, Normal, IL 61761, USA. nselkow@ilstu.edu
authors: Noelle M
authors: NM
authors: Selkow
authors: Carly
authors: C
authors: Day
authors: Zhenqi
authors: Z
authors: Liu
authors: Joseph M
authors: JM
authors: Hart
authors: Jay
authors: J
authors: Hertel
authors: Susan A
authors: SA
authors: Saliba
mesh_terms: D000293:Adolescent; D000328:Adult; D000704:Analysis of Variance; D001783:Blood Flow Velocity; D001810:Blood Volume; D001831:Body Temperature; D018592:Cross-Over Studies; D017679:Cryotherapy; D005260:Female; D006801:Humans; D007866:Leg / Q000098:blood supply* / Q000000981:diagnostic imaging; D008297:Male; D008833:Microcirculation; D018482:Muscle, Skeletal / Q000098:blood supply* / Q000000981:diagnostic imaging; D017694:Rewarming; D016037:Single-Blind Method; D014463:Ultrasonography