This study evaluates different performance, physiological and neuromuscular changes after acute and chronic resistance training intervention in physically active men. The participants will train with a single exercise (full squat) and will be monitored with a linear encoder. The experiment will consist of between 3 to 6 sets between 70% to 85% of 1RM in the full squat exercise. Two main groups will form the intervention: one group will perform inter-set repetitions until there will be a 20% of velocity loss compared to the first repetition, while the second group will have a 40% of velocity loss.

The main dependent variables and instruments will be:

1. Tensyomiography: neuromuscular properties of the vastus lateral (VL), rectus femoris (RF) and vastus medialis (VM) from the dominant leg.
2. Force platform: kinetic variables in relation to a countermovement jump.
3. Near-infrared spectrography: oxygen saturation in the VL and VM.
4. Termographic camera: low limbs temperatura.
5. Linear encoder: mean propulsive velocity from each repetition
6. Electromyography: amplitude and frequency parameters related to a knee extension maximum voluntary contraction test.
7. Strain gauge: maximum isometric force.

Inclusion Criteria:

• To be healthy
• Without injuries or actual illnesses
• More than 2 years of experience in resistance training or federative sports

Exclusion Criteria:

• To be sick or injured
• To have programmed during the intervention phase a dramatic change in the lifestyle