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| Author(s): |
Leonardo Coelho Rabello de Lima
Total Authors: 1
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| Document type: | Doctoral Thesis |
| Institution: | Universidade Estadual Paulista (Unesp) |
| Defense date: | 2017-08-07 |
| Advisor: | Benedito Sérgio Denadai |
| Abstract | |
Introduction: Longitudinal studies have been showing that strength production capacity might influence running economy (RE). However, other study models [e.g., downhill running (DhR) induced muscle damage (MD)] show different magnitudes of change and recovery kinetics between strength measured with open kinetic chain exercises [knee extension isometric peak torque (IPT)] and RE might differ. Factors such as the type of exercised used to measures strength and its form of manifestation (maximal or explosive) might, at least in part, explain these differences. The aim of the present study was to analyze the association between strength production capacity and RE using an DhR induced MD model. Methods: To do so, three different prophylactic strategies were adopted to modulate MD induced by DhR and also analyze their effects on strength production capacity and RE. Eighty five active subjects (22.3 ± 2.4 years, 78 ± 9.4 kg, 176.9 ± 5 cm) participated in the study and were randomly allocated to control (CON), placebo (PLA), supplementation (SUP), isometric (ISO), and combined (COMB) groups. Participants in CON were separated based on their ACTN3 polymorphisms. All groups ran downhill (-15%) for 30 min at 70%VO2max. SUP ingested a flavonoid-rich supplement before and following DhR, PLA ingested an isocaloric placebo at the same time points, ISO performed 10 maximal isometric contractinons (MIC) two days prior to the DhR, and COMB ingested the supplement and performed the MIC before DhR. MD symptoms (strength, soreness, knee joint range of motion, thigh circumference, and serum CK activity) and RE were assessed before, immediately after, and 1-4 days following DhR. Changes over time and between groups were analyzed with two-way ANOVA followed by Bonferroni’s post hoc tests. Results: Results showed that RE was significantly compromised following DhR and MD markers were also affected. Faster recovery of RE and MD markers was identified for the SUP and COMB groups (which reached full recovery of VO2 and IPT 1 and 3 days following the DhR, respectively), as compared to CON. Both groups that consumed the antioxidant supplement also presented significant attenuation of muscle soreness following DhR. However, the difference in the recovery kinetics of strength and RE was maintained with this treatment. ISO presented faster recovery of IPT, but not RE, and attenuation and faster recovery of soreness, as compared to CON. Significant changes in jump height were found for all groups, with faster recovery when compared to IPT. No influence of the ACTN3 gene polymorphism was found for changes in RE. However, as expected, RR individuals presented significantly greater strength loss following DhR. Conclusion: When put together, our results suggest that there is, indeed, an association between neuromuscular aspects and RE. However, factors other than strength production per se seem to contribute to this association. Moreover, the prevention/recovery strategies investigated in the present study seem to be effective to promote faster recovery of RE and strength following DhR. Also, ACTN3 gene polymorphism seems to be one of the factors contributing to susceptibility to MD, but not changes in RE. (AU) | |
| FAPESP's process: | 13/23585-4 - The relationship between running economy and strength: Utilizing a downhill runnin-induced muscle damage analysis model. |
| Grantee: | Leonardo Coelho Rabello de Lima |
| Support Opportunities: | Scholarships in Brazil - Doctorate |