Postactivation potentiation effects on squat performance and EMG in resistance trained men of different levels of expertise

Postactivation potentiation (PAP) is defined as an increased muscle contractile response following a stimulation called conditioning activity (CA) characterized by intense voluntary contraction. The generation of PAP has been speculated to be caused by the enhancement of the neuromuscular structure following CA. Indeed CA is shown to affect the peak and rate of a muscle contraction. This study aims to evaluate the effectiveness of PAP following CA in squat performance in experienced (EXP) and intermediate (INT) resistance trained men, by measuring the correlation between the increase in strength performance on the total tonnage lifted in the test and the electrical activity of the specific involved muscles. Following an initial evaluation of their one repetition maximum (1RM) of squat, after 4 days subjects were instructed to performed a protocol with CA, which involved performing 1 set of 2 repetitions at 90% of 1RM, after 7 minutes of rest 4 sets at 70% were proposed until concentric exhaustion with 3 minutes rest between sets. The EMG analysis used root mean square amplitude parameter normalized with maximum voluntary contraction and was evaluated on the vastus medialis, vastus lateralis, gluteus maximus and hamstring muscles. From the data analysis we can hypothesize that the subjects could show greater EMG activity in both groups, but the EXP group may present greater EMG activity than the INT group. We also assume that the total volume of work in the EXP group will be greater than the INT group.