Football is a sport with congested calendars, which requires muscle recovery strategies such as cold water immersion (CWI). This recovery technique is well spread through football clubs, although it lacks a profound physiologic investigation to understand its effects on athlete's body. Objectives: The main objective of this study is to evaluate the effect of a long-term CWI exposure in football athlete's.

Study Hypothesis:

H0: The application of Cold water immersion doesn't amend the biomarkers, electromyograph signal, power and perceived of recover when compared with control sample.

H1: The application of Cold water immersion amends the biomarkers, electromyograph signal, power and perceived of recover when compared with control sample.

In order to answer this question, the investigators performed a randomized clinical trial in 23 sub-20 football athletes. All subjects were randomly divided into two groups; a control group (10 minutes seated rest) and a CWI group (10 minutes in a 10 degree C) during seven days in a row. The investigators evaluated creatine kinase (CK) and lactate dehydrogenase (LDH) as molecular biomarkers for muscle damage. The blood samples were collected on the first, second, ninth and tenth days. Yet, the investigators assessed the peak of muscle activity and isometric strength of the knee flexors and extensors, potency of lower limbs, perceived exertion (PE) and total quality recovery perceived (TQRPer) in order to understand the treatment physiological effect on the subjects on the first and last day of experiments (before and after training).

Inclusion Criteria:

• Healthy subjects
• Soccer players

Exclusion Criteria:

• Neurological, vascular or systemic muscle disease