Abstract:
Objective: Cryotherapy is commonly used to treat orthopedic pain because it induces numbness. Longer and colder immersion treatments result in greater numbness. We were unable to find numbness data for other cryotherapy modes. The purpose of this study was to compare numbness, cold discomfort, and skin temperature in uninjured ankles using ice bag and cold water immersion therapies. Design and Settings: A 2 x 6 repeated measures design guided this laboratory study. Independent variables were cryotherapy mode (20 minute 1 °Cold water immersion & 20 minute, 1 kg, ice bag application) and time (1 min pre-treatment & 2,4,6,8, 10 min post-treatment). Dependent variables were cold discomfort (visual analog scale), skin temperature (OC), and sensation of pressure (Monofilaments, grams of pressure). Subjects: Twenty, healthy college students (M:6 F:14, age:20.6 yrs, ht:162 cm, wt:63.2kg) volunteered. Subject exclusion criteria included: allergies to cold (including Raynaud's phenomenon), cardiovascular disease, neurological disorders, abnormal sensation in their extremities, or lower extremity injury in the last 6 months. Measurements: We measured discomfort with a 10 em visual analog scale; skin, room and water temperatures with Copperconstant thermocouples connected to an Iso-Thermex unit; and sensation of pressure with Semmes-Weinstein nylon monofilaments. Measurements were taken 1 min pre-, and 2, 4, 6, 8, 10 min post-treatment. Subjects were treated with a 20 minute ice bag application or ice water immersion (1°C) on 2 days separated by a minimum of24 hours. Treatment order was randomized. Group means and standard deviations were calculated for each time. A repeated measures ANOV A determined differences and Tukey-Kramer comparisons located those differences. Our P-level was .05. Results: For both treatments, sensation was reduced at 2 min post-treatment (5.7 ± 4.3g) compared to 1 min pre-, 4, 6, 8, & 10 min-post (3.6 ± 2.1 g; 3.7 ± 2.1 g; 3.2 ± 1.8 g; 3.3 ± 1.7 g; 3.0 ± 1.9 g respectfully) (FS,9S=13.94, P<.OOOOI; Tukey-Kramer <.05). For both conditions, skin temperature was lowest at 2 and 4 min post-immersion (11.2 ± 1.5°C, 12.6 ± 3.1 °C, respectfully) (FS.9S=6.38, P=.00004; Tukey-Kramer, p<.05). There was more discomfort at 2 min post-immersion (17.5 ± 23.5 mm) than all other pre-and post-ice bag and immersion measurements, except for 4 min post-immersion (12.7 ± 19.1 mm)(Fs.9s=5.93, p=.00008). Conclusions: Decreases in skin temperature are related to sensation loss for both conditions. Immersion is more uncomfortable than ice bag treatment, and both are most uncomfortable at 2 min post-treatment. Despite differences in temperature decreases, both cryotherapy treatments caused numbness. Ice bag treatments appear to induce numbness without as much discomfort as immersion treatment.
