As a therapeutic modality, cryotherapy is highly used for soft tissue damage control during acute and subacute stages. Cryotherapy is able to reduce pain, inflammatory condition, muscle spasm, nerve conduction, metabolic rate, edema formation and to prevent secondary hypoxic injury. These effects are due to the heat conduction, passing from tissue to different cryotherapy modalities, leading to tissue temperature reduction.

The diversity of cryotherapy modalities in clinical practice, like crushed-ice packs, frozen food, gel packs and wetted ice packs, are widely explored by studies. To achieve anesthesia by cryotherapy it's settled that the skin temperature must reach 13,6 degrees celsius (ºC). Ice packs are the most effective modality of cryotherapy when placed directly on the skin, this effectiveness is accentuated when ice packs are associated with water. To improve the contact area the pack must be wrapped.

Even though wetted ice packs are the most effective modality, there are few studies approaching it. There aren't studies analyzing an ideal percentage of water to ice in this modality either. Also, it isn't observed if the amount of water interferes on the conduction of the heat from the skin to the ice pack, and in rewarming time. Besides neither of the studies measures the amount of pain during cryotherapy application, and if there was any difference between wetted ice packs, and ice packs isolated.

Therefore, the purpose of this study is to analyze the most effective cryotherapy modality for reducing skin temperature, rewarming time, and the amount of discomfort during the application.

The data for the sample size calculation was taken from Kanlayanaphotpron and Janwantanakul (2005), that also approached the cryotherapy application. The software used to calculate the sample was GPower 3.1.9.2. A 16 subjects sample were obtained to reach a power of 90%, needed to detect a difference on the average of the groups in repeated measures with an alpha of 5%. The subjects will be chosen through social media and informal invitations.

The subjects will attend to the laboratory four times, the first day for orientation and measurements (body mass and skinfold), and the data collection will start on the second day.

The room temperature will be set between 23 ° C and 25 ° C, and the humidity around 70%. The subject will be in supine position on the stretcher, relaxed and instructed not to touch the right thigh region for 20 minutes before the intervention to stabilize the body temperature. The thigh will be measured and the center marked to determine the place where the pack will settle and the temperature collected.

The intervention will last 20 minutes, and the order of application will be according to the randomization. The subject will be asked to mark his pain level on the visual analogue scale every minute.

The temperature of the right thigh will be measured by infrared thermography, before the intervention, right after the removal and every minute until the total time of the intervention.

To summarize the data, it will be used descriptive statistics, the values of average, standard deviation and the collected measurements will be identified. Through Shapiro-Wilk test the distribution of data regarding normality will be verified. To compare the initial and the final test values the ANOVA and the post-hoc of Bonferroni will be used. In the case of data being out of the normal standards, a transformation will be used to reach the normality. If the data still don't reach the normality after the transformation, the non-parametric tests will be used (Mann-Whitney e Kruskal Walis). The confidence level adopted for all tests will be 95% (p <0.05).

Inclusion Criteria:

• No orthopedic injury in three months prior to the study;
• A minimum of 18 years of age, and a maximum of 40 years;
• Female;
• Must agree not to practice exercise the day before the study and not ingest caffeine, alcohol, or foods one hour before intervention.

Exclusion Criteria:

• Cold hypersensitivity and urticaria;
• Cold hyposensitivity;
• Raynaud's phenomenon diagnosed;
• Any thigh open wound;
• Muscular or neurological disease;
• Diabetes diagnosed;
• Cigarette smokers.