|Support type:||Scholarships in Brazil - Scientific Initiation|
|Effective date (Start):||July 01, 2015|
|Effective date (End):||June 30, 2016|
|Field of knowledge:||Health Sciences - Physical Education|
|Principal Investigator:||Cleiton Augusto Libardi|
|Grantee:||Lucas Pintanel Rodrigues|
|Home Institution:||Centro de Ciências Biológicas e da Saúde (CCBS). Universidade Federal de São Carlos (UFSCAR). São Carlos , SP, Brazil|
Resistance training (RT) is the main method utilized for increasing skeletal muscle strength and mass, where intensities higher than 60% of one-repetition maximum (1-RM) are commonly applied. However, such RT model does not take in account concentric muscle failure. Studies evaluating muscle activation levels using electromyography (EMG) indicate a muscle activation plateau in which activation becomes maximal previously to concentric failure point. Thus, it's possible that the exercise performed up to voluntary fatigue (i.e. before concentric failure) promotes muscular activation similar to exercise performed to concentric failure. This way, the objective of the current study is to compare the acute effects of high (HIRT) and low (LIRT) intensity resistance training performed to volitional fatigue and concentric failure on muscle activation. For this, 15 young untrained men will be recruited and will undergo four different experimental conditions of RT in a randomized crossover design in order to reduce inter-individual variability: 1) High Resistance Training performed to volitional fatigue (TFAI-Volun); 2) High Resistance Training performed to concentric failure (TFAI-Falha); 3) Low Resistance Training performed to volitional fatigue (TFBI-Volun); e 4) Low Resistance Training performed to concentric failure (TFBI-Falha). The interval between RF sessions will be of 72h. One repetition maximum (1-RM) test will be assessed in the knee extensor machine to quantify the intensity of the RT sessions. Muscle activation will be assessed by surface electromyography (EMG) of the rectus femoris (RF), vastus lateralis (VL) and vastus medialis (VM) in each RT session.