Four Weeks of Supplementation With Isolated Soy Protein Attenuates Exercise-Induced Muscle Damage and Enhances Muscle Recovery in Well Trained Athletes: A Randomized Trial

Abstract

BackgroundThe effects of consumption of isolated soy protein (ISP) for a chronic period (4 weeks) on exercise induced muscle damage (EIMD) in athletic population have never been explored.ObjectivesTo examine the effects of ISP on muscle damage indices elicited via a bout of damaging exercise.Patients and MethodsForty males (20 boxers, 20 cyclists) aged 18 - 28 years were randomly assigned to two groups (ISP and Placebo) (n = 20). All participants who engaged themselves in specific, regular training of 30 hours a week during the competitive season were included in the study. Participants consumed the supplement and the placebo for 4 weeks. The damaging exercise consisted of 100 consecutive drop-jumps. Pre and post supplementation readings of the criterion variables, highly sensitive C reactive protein (hs-cRP), creatine Kinase (CK), myeloperoxidase (MPO), isometric muscle strength, maximum aerobic capacity (VO2 max), heart rate (HR) and muscle soreness were obtained at baseline (Day 1), at 24 hours (Day 2) and at 48 hours (Day 3) following EIMD.ResultsDifferences were observed in pre and post supplementation values (P < 0.05) indicating the effectiveness of soy protein in attenuating muscle damage and enhancing muscle recovery.ConclusionsOur findings suggest that soy protein; a vegetable based supplement is effective, in ameliorating the negative effects of EIMD in trained athletic population.

Post-Game High Protein Intake May Improve Recovery of Football-Specific Performance during a Congested Game Fixture: Results from the PRO-FOOTBALL Study

“…Oxidative burst of leukocytes is the main source of reactive oxygen species (ROS) generation during recovery after EIMD [ 13 ]. A reduction of myeloperoxidase activity in response to protein feeding under conditions of EIMD further supports this possibility [ 75 ]. This may be mediated by a protein-induced increase of antioxidant reserves.…”

“…Protein-induced attenuation of the inflammatory response may offer a possible explanation for the improvement in recovery kinetics of football-specific performance in PRO. Findings from previous studies have been highly inconclusive reporting both attenuation [ 70 , 74 , 75 , 76 ] and no change [ 63 , 77 , 78 , 79 , 80 ] of muscle damage markers in response to various exercise protocols. The mechanisms linking protein intake with muscle soreness and CK responses are largely unknown, and only speculations can be made.…”

“…The positive effects of increased protein intake on performance recovery may be related to anti-inflammatory actions rather than EIMD-related mechanisms. In fact, it has been shown that augmented protein intake induces an attenuation of C reactive protein and myeloperoxidase elevation following a muscle damaging protocol [ 75 ]. Administration of protein and/or BCAAs may also interfere with the acute phase response of the immune system following damaging exercise [ 81 , 82 ], probably via the mammalian target of rapamycin (mTOR) intracellular signaling pathway [ 83 ] or through the modulation of neutrophils’ oxidative burst [ 84 ].…”

Greater volumes are required to reduce muscle performance in well-trained individuals

“…To study the effect of protein ingestion in muscle performance recovery after a strenuous exercise, Shenoy et al 19 applied 100 drop jumps in well trained athletes in order to induce muscle damage. Their results showed a slight reduction in knee extensors strength (~15%).…”

“…In the same way, other studies that included non-athletes and individuals who had little or no experience in strength and/or power training showed a decrease of 20% to 40% in force production capacity and a decrease of 13% to 20% in power production capacity immediately after protocol [14][15][16][17] . On the other hand, Bridgeman et al 18 and Shenoy et al 19 had applied different DJs protocol in strength trained or power trained athletes and showed a small decrease in maximal strength and muscle power immediately and 24 hours after protocol.…”