Name: VICTOR MAGALHÃES CURTY
Publication date: 23/04/2018
Advisor:
Name |
Role |
|---|---|
| ELISARDO CORRAL VASQUEZ | Co-advisor * |
| VALERIO GARRONE BARAUNA | Advisor * |
Examining board:
| Name |
Role |
|---|---|
| ELISARDO CORRAL VASQUEZ | Co advisor * |
| JOSE GERALDO MILL | Internal Examiner * |
| RICHARD DIEGO LEITE | External Examiner * |
| VALERIO GARRONE BARAUNA | Advisor * |
Summary: Muscle damage is considered as one of the main mediators of the musculoskeletal adaptations provided by strength exercise (SE). However, it is hypothesized that low intensity PE (20-50% of 1RM) associated with restriction of blood flow (RFS) can provide similar adaptations regardless of whether or not muscle damage occurs. This study aimed to evaluate the effects of RFS associated with different protocols of strength exercise on skeletal muscle damage and cardiovascular system. Three different experimental protocols were evaluated: 1º) High-intensity eccentric strength exercise (HIEC, 130% of 1RM), in which the participants performed 3 sets of 10 maximal repetitions, in two conditions (with or without the BFR); 2º) Low-intensity strength exercise (LISE, 40% of 1RM), in which the participants performed 3 sets until muscle fatigue, also under conditions with or without the BFR; and lastly, 3º) Low-intensity strength exercise (LISE, 40% of 1RM), performed again 3 sets until muscular fatigue under different percentages of BFR (0, 40, 60 and 80%). Of the experimental protocol 1, we observed that the range of motion (ROM) decreased similarly in both exercise conditions immediately after exercise. However, only HIEC presented ROM reduced at the 24-hour post-exercise. Muscle pain on palpation increased similar for both conditions, but for HIEC+BFR condition muscle pain returned to baseline at 48 hours post-exercise. The circumference of the arm (CIR) was increased only for HIEC condition immediately after exercise. For hemodynamic responses, we observed an similar increase in heart rate (HR) for HIEC and HIEC+BFR immediately after exercise. In the results of the experimental protocol 2, we observed that muscle damage markers, as maximal isometric voluntary contraction (MIVC), ROM, muscle pain on palpation, CIR, creatine kinase (CK) and lactate dehydrogenase (LDH) were altered post-exercise in both conditions, but with more expressive changes for the exercise condition without the BFR (LISE). Regarding cardiovascular responses, we observed similar increases in systolic blood pressure (SBP), diastolic (DBP), mean (MBP), and HR at the post-exercise. Finally, in our experimental protocol 3, we observed MIVC, pressure pain threshold (PPT), ROM and CIR changes immediately after the exercise session in all groups. In addition, we observed that the values of the muscle damage biomarkers analyzed (CK, LDH and cell-free DNA) increased more in the exercise condition without the BFR (LISE). Regarding cardiovascular responses, we observed that SBP increased immediately after exercise for all groups. The DBP and MBP increased significantly in the LISE+BFR60 and LISE+BFR80 groups (p<0.05), showing that cardiovascular responses were more altered when higher percentages of BFR were performed. Concluding that BFR has a potential effect on attenuating muscle damage and that this response is proportional to the intensity of BFR applied. However, BFR may promote increased cardiovascular demand during low-intensity strength exercise protocols.
