Reliability and Validity of a Shoulder Fatigue Test Using Two Tools: Elastic Resistance and Isokinetic Dynamometer.

Tests applied

1RM test The 1 RM test in the elastic band is based on the study by ANDERSEN et al. (2016). Elastic bands of the brand Theraband® CLX (Hygienic, Corporation, Akron, Ohio, USA) with a standard length of 1.47m, ranging from very low to very high strength (yellow, red, green, blue, black, silver, gold). Due to possible changes in the mechanical properties of elastic bands during the initial stretching cycles, all elastics will be pre-stretched 100 times.

Initially the research assistant will instruct the participants to sit on a chair, and place their feet together on the elastic band without shoes. Starting with the least elastic resistance (yellow), the research assistant will instruct the participants to perform a shoulder abduction of a unilateral (dominant) shoulder up to 90 ° and hold such a position for 3 seconds (statically). Thus, participants will have to perform the concentric contraction phase without the help of the research assistant before reaching the static test position. Through visual inspection, the search assistant will control the correct positioning of the movement. Two-minute intervals will be taught between resistance levels until it is not possible for the participant to reach and / or hold the position for 3 seconds. When there is a failure, two more attempts to reach and maintain the desired position will be accomplished. During the essay, the research assistant will provide verbal encouragement. The obtained torque will be calculated by a formula based on the study of ANDERSEN et al. (2016).

Isokinetic muscle strength test For the MVIC test, the participant will be seated with the dominant upper limb on the Biodex System Pro 4 isokinetic dynamometer (Biodex Medical System, Shirley-NY, USA). Prior to the test, the participant will undergo a warm-up consisting of 10 repetitions of concentric contraction of abduction-adduction of the shoulder at 180º / s throughout the range of motion. After the warm-up will be given a two-minute rest break to the start of the MVIC. The CIVM will be considered as the Of torque obtained between three 5 second repetitions of abduction, with the dominant upper limb positioned at 90º horizontal abduction of the shoulder. A two-minute interval between replicates will be administered in order to minimize possible fatigue effects. The participant will be instructed to perform their maximum power performance and will be verbally encouraged by the evaluator in each attempt made. Such protocol is based on the one used by BARONI et al., (2010) for lower limb.

Fatigue Resistance Test (TRF) TRF - Elastic Tube: To perform the fatigue resistance test on the elastic tube the participant will initially be positioned sitting on a chair with their feet together stepping on the elastic band without shoes. He will then perform a 20-second abduction-adduction heating of the shoulder from the neutral position to 90 °. The interval of 2 minutes will then be given to start the TRF. This will consist of performing the maximum of the possible repetition with a load of 50% of the 1RM (1½ second in the concentric phase and 1½ second in the eccentric phase).