Fifty swimmers from São Paulo state swimming teams will be initially assessed to investigate movement patterns at rest and after a fatigue protocol by means of inertial sensors. The participants will be assessed regarding their perceptions by the Swimmer's Perception of Effort Questionnaire (SPEQ), muscle stiffness by a myotonometer, skin temperature by a thermographic infrared camera and coordination by the Coordination Index and Continuous Relative Phase (CRP). Then, the athletes will perform the fatigue protocol again followed by five interventions in a crossover design separated by 24hr: i) superficial massage, ii) deep massage iii) cold-water immersion iv) immersion in thermoneutral water and v) control (no intervention). All procedures will be performed for an experimental task of shoulder elevation and the sport-specific gesture (front crawl simulation in swim bench). The statistical analysis will be conducted in SPSS software. To analyze fractal properties of time series the detrended fluctuation analysis (DFA) will be used where (α) varies from 0,5 to 1,5, interpreted as random series and Brownian noise, respectively. To compared pre and post assessments from initial testing the paired t test will be used. To compare perceptions, muscle stiffness and temperature between groups after fatigue protocol and intervention a Mixed ANOVA will be used with Greenhouse-Geisser corrections and Bonferroni post-hoc if necessary. Descriptive data will be presented as mean and standard deviations. All analysis will assume level of significance of P< 0,05.
Training prescription is planned considering recovery periods to enhance performance. To assess recovery, a complexity model can be used, in which the main variable would correspond to a fractal of performance. To assess the effectiveness of post-exercise massage and cold-water immersion under a new prism of recovery by means of muscle stiffness and movement variability analysis regarding the sport-specific gesture and an experimental task of shoulder elevation in swimmers.