Does exercise-induced muscle damage compromise responsiveness to post-activation potentiation?

• Grant number: 19/17596-0
• Support type: Scholarships abroad - Research
• Effective date (Start): January 09, 2020
• Effective date (End): February 03, 2020
• Field of knowledge: Health Sciences - Physical Education
• Principal Investigator: Leonardo Coelho Rabello de Lima
• Grantee: Leonardo Coelho Rabello de Lima
• Host: Ken Nosaka
• Home Institution: Pró-Reitoria de Gradução. Centro Universitário Hermínio Ometto (UNIARARAS). Fundação Hermínio Ometto (FHO). Araras , SP, Brazil
• Local de pesquisa : Edith Cowan University, Joondalup (ECU), Australia

Abstract

Muscles with greater type II muscle fibre distribution are more responsive to post-activation potentiation (PAP). These muscles also appear to be more susceptible to muscle damage induced by plyometric exercise. Considering that both PAP and muscle damage induced by plyometric exercise are more frequently observed in type II muscle fibers, the aim of this study is to investigate if muscle damage induced by plyometric contractions compromises responsiveness to PAP of lower limb muscles. Fifteen men with no recent experience with resistance training and without a history of lower limb injuries will participate in the study. They will perform a pre-activation protocol consisting of a set of five parallel back squats with a five-repetition maximum load. Fifteen minutes before and four minutes after the pre-activation they will have their counter movement jump height assessed. Fifteen minutes after the last counter movement jump, they will undergo a plyometric training session consisting of five sets of six drop-jumps with an added weight of 20% of their body masses. Fifteen minutes, 24 and 48 hours after the training session, participants will repeat the same pre-activation protocol and assessments performed before the training session. Knee extensors isometric peak torque, muscle soreness, thickness and eco-intensity of ultrasound image will be assessed as markers of exercise-induced muscle damage before, 15 minutes, 1 and 2 days following the plyometric training session. Responsiveness to PAP and changes in markers of exercise-induced muscle damage will be tested by ANOVAs throughout the experimental period with Tukey's post hoc tests. Significance levels will be set as p < 0.05. (AU)