The effects of theaflavin-enriched black tea extract on muscle soreness, oxidative stress, inflammation, and endocrine responses to acute anaerobic interval training: a randomized, double-blind, crossover study

Abstract

Background

Muscle soreness and decreased performance often follow a bout of high-intensity exercise. By reducing these effects, an athlete can train more frequently and increase long-term performance. The purpose of this study is to examine whether a high-potency, black tea extract (BTE) alters the delayed onset muscle soreness (DOMS), oxidative stress, inflammation, and cortisol (CORT) responses to high-intensity anaerobic exercise.

Methods

College-age males (N = 18) with 1+ yrs of weight training experience completed a double-blind, placebo-controlled, crossover study. Subjects consumed the BTE (1,760 mg BTE·d^-1) or placebo (PLA) for 9 days. Each subject completed two testing sessions (T1 & T2), which occurred on day 7 of the intervention. T1 & T2 consisted of a 30 s Wingate Test plus eight 10 s intervals. Blood samples were obtained before, 0, 30 & 60 min following the interval sessions and were used to analyze the total to oxidized glutathione ratio (GSH:GSSG), 8-isoprostane (8-iso), CORT, and interleukin 6 (IL-6) secretion. DOMS was recorded at 24 & 48 h post-test using a visual analog scale while BTE or PLA continued to be administered. Significance was set at P < 0.05.

Results

Compared to PLA, BTE produced significantly higher average peak power (P = 0.013) and higher average mean power (P = 0.067) across nine WAnT intervals. BTE produced significantly lower DOMS compared to PLA at 24 h post test (P < 0.001) and 48 h post test (P < 0.001). Compared to PLA, BTE had a slightly higher GSH:GSSG ratio at baseline which became significantly higher at 30 and 60 min post test (P < 0.002). AUC analysis revealed BTE to elicit significantly lower GSSG secretion (P = 0.009), significantly higher GSH:GSSG ratio (P = 0.001), and lower CORT secretion (P = 0.078) than PLA. AUC analysis did not reveal a significant difference in total IL-6 response (P = 0.145) between conditions.

Conclusions

Consumption of theaflavin-enriched black tea extract led to improved recovery and a reduction in oxidative stress and DOMS responses to acute anaerobic intervals. An improved rate of recovery can benefit all individuals engaging in high intensity, anaerobic exercise as it facilitates increased frequency of exercise.

Keywords:

• Anaerobic Exercise
• Muscle Soreness
• High Intensity Exercise
• Delay Onset Muscle Soreness
• GSSG Ratio

Electronic supplementary material

The online version of this article (doi:10.1186/1550-2783-7-11) contains supplementary material, which is available to authorized users.

Electronic supplementary material

The online version of this article (doi:10.1186/1550-2783-7-11) contains supplementary material, which is available to authorized users.

Acknowledgements

We would like to extend our gratitude to the subjects that participated in this study. We would also like to thank Cynthia Jaouhari, Joseph Pellegrino, Anthony Lupinacci, and Meryl Epstein for their assistance with recruitment and data collection. This study was funded by a grant from WellGen, Inc (USA). The results of the present study do not constitute endorsement of the product by the authors or by ISSN.

Competing interests

This study was funded by WellGen, Inc. (USA) through an unrestricted research grant to Rutgers, The State University of New Jersey. All researchers involved impartially collected, analyzed, and interpreted the data from this study and have no financial interests concerning the outcome of this investigation. The results from this study do not represent support by the authors and their institutions concerning the supplement investigated.

Authors' contributions

SMA conceived of and designed this study, contributed to the acquisition, analysis and interpretation of data, led the drafting and revising of the manuscript, and gave final approval of the version to be published. MS contributed to the acquisition of data as well as the drafting and revising of the manuscript. DLG contributed to the drafting and revising of the manuscript, and gave final approval of the version to be published. KHM contributed to the design of the study and gave final approval of the version to be published.