Relação entre economia de corrida e força muscular: análise pelo modelo de dano muscular induzido pela corrida em declive
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2017-08-07
Autores
Lima, Leonardo Coelho Rabello de [UNESP]
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Universidade Estadual Paulista (Unesp)
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Introdução: Alguns estudos longitudinais têm mostrado que a força pode influenciar a economia de corrida (EC). Entretanto, outros modelos [p.ex., dano muscular (DM) induzido por corridas em declive (CrED)] mostram que a magnitude e a cinética de recuperação da EC e da força máxima medida em exercícios de cadeia cinética aberta [pico de torque isométrico de extensão do joelho (PTI)] podem ser diferentes. Fatores como o tipo de exercício usado para medir a força e a forma pela qual a força se manifesta (máxima e explosiva), podem explicar, pelo menos em parte, estes dados antagônicos. O objetivo geral deste estudo foi utilizar o modelo de DM induzido pela CrED para analisar a relação entre força máxima e explosiva e a EC. Método: Para isso, foram empregadas três intervenções para modular o DM induzido pela CrED e verificar seus efeitos sobre a força e a EC. Participaram do estudo 85 sujeitos ativos (22,3 ± 2,4 anos, 78 ± 9,4 kg, 176,9 ± 5 cm) que foram aleatoriamente separados em grupo controle (CON), placebo (PLA), suplementação (SUP), isométrico (ISO) e combinado (COMB). CON foi dividido em indivíduos com presença e ausência da α-actinina-3, resultante de polimorfismo do gene ACTN3. Todos os grupos realizaram uma CrED (-15%) por 30 min a 70% VO2max. SUP ingeriu um suplemento rico em compostos flavonoides antes e após a CrED, PLA ingeriu um placebo nos mesmos períodos, ISO realizou 10 contrações isométricas máximas (CIM) dois dias antes da CrED e COMB ingeriu o suplemento e realizou 10 CIM antes da CrED. Foram avaliados marcadores indiretos de DM (força, dor, amplitude de movimento e circunferência da coxa, e atividade sérica de CK) e EC antes e imediatamente, 24, 48, 72 e 96 horas após a CrED. Alterações ao longo do tempo e entre grupos foram analisadas por meio de ANOVA de dois caminhos com post-hoc de Bonferroni. Resultados: Os resultados obtidos demonstraram comprometimento significante da EC após a CrED, assim como alterações significantes em marcadores de DM. Foi identificado um efeito de aceleração da recuperação nas alterações no DM e EC para os grupos SUP e COMB (que apresentaram retorno do VO2 e PTI a níveis basais no dia seguinte e dois dias após a CrED, respectivamente) em relação ao grupo CON. Os grupos que consumiram o suco antioxidante também apresentaram atenuação significante da dor muscular após a CrED. Entretanto, a diferença de cinética de recuperação entre força e EC se manteve mesmo frente aos tratamentos. O grupo ISO apresentou aceleração da recuperação do PTI, mas não da EC, assim como atenuação da dor muscular em relação ao grupo CON. Alterações na altura de saltos foram significantes, sendo que os valores retornaram a níveis basais antes dos valores de PTI. Em relação aos polimorfismos do gene ACTN3, não houve influência do genótipo nas alterações na EC. Entretanto, como esperado, houve maior perda de força para indivíduos RR (que sintetizam a α-actinina-3). Conclusão: Em conjunto, os resultados obtidos sugerem que há, sim, uma relação entre aspectos neuromusculares e a EC. Entretanto, outros fatores, que não a capacidade de produção de força isoladamente, parecem contribuir para essa relação. Ademais, as estratégias de atenuação do DM investigadas no presente estudo parecem ser eficazes na aceleração da recuperação da EC e da força muscular e o polimorfismo do gene ACTN3 parece ser um dos fatores que explicam a susceptibilidade ao DM.
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.
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.
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Palavras-chave
Força muscular, Economia de corrida, Dano muscular, Profilaxia, ACTN3, Strength, Running economy, Exercise-induced muscle damage, Prophylaxis