Author(s): PROTZEN, G., MATOSO, B., DOMA, K., DE OLIVEIRA JR, S., BOULLOSA, D., Institution: UNIVERSITY OF LEÓN, Country: BRAZIL, Abstract-ID: 1473

INTRODUCTION:
High-intensity eccentric exercises may cause exercise-induced muscle damage (EIMD). However, a prior session of a similar exercise can alleviate EIMD symptoms in the next sessions, a phenomenon called repeated bout effect (RBE) (1). Athletes typically improve jump performance through post-activation performance enhancement (PAPE) after a high-intensity running exercise (2). Meanwhile, it is not known if the attenuation of EIMD may enhance the magnitude of the PAPE (3). Therefore, we hypothesized that the execution of two bouts of an eccentric-oriented exercise could promote RBE, thus providing protection against EIMD, and subsequently enhancing jump potentiation after a high-intensity running exercise in recreational runners.
METHODS:
Twenty male recreational runners (32.1 ± 2.8 years; 173.4 ± 6.1 cm; 73.3 ± 11.5 kg; 57.8 ± 7.2 ml.kg.min-1) were randomly assigned to either experimental (EXP; N = 10) or control (CON; N = 10) groups. Both groups underwent evaluations of jump capacity before and after a shuttle-run test until exhaustion in the first and fourth weeks. The EXP group, in addition to their regular training, performed one low-volume (3 × 10 reps.) session of an eccentric-oriented lunge exercise (i.e., Kudashov lunge) in the second and third weeks to induce RBE. The CON group maintained their regular training without any intervention. Muscle damage markers were assessed 48 hours after the tests and exercise sessions.
RESULTS:
The first training session effectively induced muscle damage, which was reduced following the second session (p<0.05), thus confirming the RBE. However, no PAPE in jump capacity was observed following the shuttle-run test, regardless of the presence of RBE. In addition, there was an increase in countermovement jump height after the intervention in the experimental group when compared to the control group (p=0.008).
CONCLUSION:
The results suggest that the completion of two low-dose bouts of an eccentric-oriented exercise may induce an RBE, leading to reduced muscle damage, and possibly increasing jumping capacity in recreational runners. However, the RBE may not directly influence PAPE after high-intensity running exercises.

1. Doma et al. (2023); 2. Boullosa et al. (2018); 3. Souza et al. (2022).