Exercise and quadriceps muscle cooling time

Cryotherapy is commonly used for a variety of purposes; however, the body's response to cryotherapy immediately postexercise is unknown.

To investigate the effect of prior exercise on crushed-ice-bag treatment of a large muscle group.

2 x 3 repeated-measures design on depth (1 cm and 2 cm below adipose tissue) and treatment (exercise followed by ice, exercise followed by no ice, and no exercise followed by ice).

Sports Injury Research Laboratory.

Six physically active, uninjured male volunteers.

For the 2 exercise conditions, subjects rode a stationary cycle ergometer at 70% to 80% of their age-predicted maximum heart rate, as calculated by the Karvonen method. For the no-exercise condition, subjects lay supine on a treatment table. The cryotherapy treatment consisted of a 1-kg ice bag applied to the anterior mid thigh. For the no-ice condition, subjects lay supine on a treatment table.

Time required for the intramuscular temperatures at the 1-cm and 2-cm depths below adipose tissue to return to pre-exercise baseline and time required to cool the 1-cm and 2-cm depths to 10 degrees C below the pre-exercise temperature.

The time to cool the rectus femoris to the pre-exercise temperature using a crushed-ice-bag treatment was reduced by approximately 40 minutes (P < .001). The ice bag cooled the 1-cm and 2-cm depths to the pre-exercise temperature within 7 minutes (P = .38), but the 2-cm tissue depth took nearly 13.5 minutes longer to cool than the 1-cm depth when no ice was applied (P = .001). The 1-cm depth cooled to 10 degrees C below the pre-exercise temperature about 8 minutes sooner than the 2-cm depth, regardless of whether the tissue was exercised or not (P < .001). Exercise shortened the cooling time to 10 degrees C below the pre-exercise temperature by approximately 13 minutes (P = .05).

Exercise before cooling with a crushed-ice bag enhanced the removal of intramuscular heat.