Polyphenol-Rich Sorghum Bicolor Extract Enhances Strength Recovery after Eccentric Exercise

Clara J. Mitchinson; Minyoung Kwak; Pasquale J. Succi; Brian Benitez; Haley C. Bergstrom

doi:10.1519/JSC.0000000000005144

Polyphenol-Rich Sorghum Bicolor Extract Enhances Strength Recovery after Eccentric Exercise

Clara J. Mitchinson
, Minyoung Kwak
, Pasquale J. Succi
, Brian Benitez
, Haley C. Bergstrom

Kinesiology and Health Promotion

Research output: Contribution to journal › Article › peer-review

Abstract

Polyphenol-rich sorghum bicolor extract enhances strength recovery after eccentric exercise. J Strength Cond Res 39(8): e951-e959, 2025 - This randomized, double-blind, placebo (PL) controlled trial examined the effects of a polyphenol-rich supplement on muscular strength recovery after eccentric exercise. Twenty-nine men (mean ± SD, age = 23.1 ± 3.8 years) were randomly assigned to a high- (500 mg·d^-1; n = 9) or low- (250 mg·d^-1; n = 10) dose polyphenol-rich sorghum bicolor extract, or PL (n = 10) group and completed a 17- to 18-day supplementation period, with eccentric exercise on day 14 + 1. Unilateral forearm flexion strength, muscle thickness (MT), pain pressure threshold (PPT), perceived recovery, and pain ratings were recorded before (baseline) and at 24, 48, and 72 hours after maximal eccentric exercise. Analyses included mixed-model ANCOVAs, ANOVAs, and post hoc Bonferroni corrected pairwise comparisons (p < 0.05). After 18-25% strength losses from baseline to 24 hours, strength increased significantly from 24 to 48 hours for the high-dose group (mean difference [CI_95%] = 5.7 N·m [2.2-9.3]; p < 0.001; d = 0.568) and from 24 to 72 hours for the low-dose group (8.3 N·m [4.4-12.2]; p < 0.001; d = 0.848), while strength remained unchanged from 24 to 72 hours for the PL group (p = 0.101-1.000). There were no changes in MT or PPT from 24 to 72 hours. Pain ratings significantly decreased, and perceived recovery increased at 72 hours relative to 24 and 48 hours for all groups across time (p = 0.001-0.012). Supplementation with a high- and low-dose polyphenol-rich sorghum bicolor extract increased recovery of muscular strength at faster rates than PL after eccentric exercise but had no meaningful effect on muscle swelling, perceived pain, or recovery. A polyphenol-rich supplement may enhance performance in subsequent exercise sessions and promote increased training volume.

Original language	English
Pages (from-to)	e951-e959
Journal	Journal of Strength and Conditioning Research
Volume	39
Issue number	8
DOIs	https://doi.org/10.1519/JSC.0000000000005144
State	Published - Aug 1 2025

Bibliographical note

Publisher Copyright:
© 2025 NSCA National Strength and Conditioning Association. All rights reserved.

Funding

This research was supported by RedLeaf Biologics, Inc. There is an institutional conflict of interest associated with this research that is being managed by the University of Kentucky (University). One of the equity holders and board members of RedLeaf Biologics, Inc. (RedLeaf) is a university professor and director of a university institute, and that university employee is also related by marriage to an officer of RedLeaf. Furthermore, the same university employee and the Kentucky Agricultural Experiment Station, managed by the university, have a financial interest in the amount of Rednatural seed annually planted by RedLeaf in the form of license payment. The associated university employee is uninvolved in the activities associated with the research described in this article. The results of this study do not constitute an endorsement of the product by the authors or the National Strength and Conditioning Association. FUNDING: This study was funded by RedLeaf Biologics (Lexington, KY).

Funders
RedLeaf Biologics, Inc.
Redleaf Biologics Incorporated

Keywords

muscle damage
muscle recovery
supplementation

ASJC Scopus subject areas

Orthopedics and Sports Medicine
Physical Therapy, Sports Therapy and Rehabilitation

Access to Document

10.1519/JSC.0000000000005144

Cite this

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title = "Polyphenol-Rich Sorghum Bicolor Extract Enhances Strength Recovery after Eccentric Exercise",

abstract = "Polyphenol-rich sorghum bicolor extract enhances strength recovery after eccentric exercise. J Strength Cond Res 39(8): e951-e959, 2025 - This randomized, double-blind, placebo (PL) controlled trial examined the effects of a polyphenol-rich supplement on muscular strength recovery after eccentric exercise. Twenty-nine men (mean ± SD, age = 23.1 ± 3.8 years) were randomly assigned to a high- (500 mg·d-1; n = 9) or low- (250 mg·d-1; n = 10) dose polyphenol-rich sorghum bicolor extract, or PL (n = 10) group and completed a 17- to 18-day supplementation period, with eccentric exercise on day 14 + 1. Unilateral forearm flexion strength, muscle thickness (MT), pain pressure threshold (PPT), perceived recovery, and pain ratings were recorded before (baseline) and at 24, 48, and 72 hours after maximal eccentric exercise. Analyses included mixed-model ANCOVAs, ANOVAs, and post hoc Bonferroni corrected pairwise comparisons (p < 0.05). After 18-25\% strength losses from baseline to 24 hours, strength increased significantly from 24 to 48 hours for the high-dose group (mean difference [CI95\%] = 5.7 N·m [2.2-9.3]; p < 0.001; d = 0.568) and from 24 to 72 hours for the low-dose group (8.3 N·m [4.4-12.2]; p < 0.001; d = 0.848), while strength remained unchanged from 24 to 72 hours for the PL group (p = 0.101-1.000). There were no changes in MT or PPT from 24 to 72 hours. Pain ratings significantly decreased, and perceived recovery increased at 72 hours relative to 24 and 48 hours for all groups across time (p = 0.001-0.012). Supplementation with a high- and low-dose polyphenol-rich sorghum bicolor extract increased recovery of muscular strength at faster rates than PL after eccentric exercise but had no meaningful effect on muscle swelling, perceived pain, or recovery. A polyphenol-rich supplement may enhance performance in subsequent exercise sessions and promote increased training volume.",

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author = "Mitchinson, \{Clara J.\} and Minyoung Kwak and Succi, \{Pasquale J.\} and Brian Benitez and Bergstrom, \{Haley C.\}",

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T1 - Polyphenol-Rich Sorghum Bicolor Extract Enhances Strength Recovery after Eccentric Exercise

AU - Mitchinson, Clara J.

AU - Kwak, Minyoung

AU - Succi, Pasquale J.

AU - Benitez, Brian

AU - Bergstrom, Haley C.

PY - 2025/8/1

Y1 - 2025/8/1

N2 - Polyphenol-rich sorghum bicolor extract enhances strength recovery after eccentric exercise. J Strength Cond Res 39(8): e951-e959, 2025 - This randomized, double-blind, placebo (PL) controlled trial examined the effects of a polyphenol-rich supplement on muscular strength recovery after eccentric exercise. Twenty-nine men (mean ± SD, age = 23.1 ± 3.8 years) were randomly assigned to a high- (500 mg·d-1; n = 9) or low- (250 mg·d-1; n = 10) dose polyphenol-rich sorghum bicolor extract, or PL (n = 10) group and completed a 17- to 18-day supplementation period, with eccentric exercise on day 14 + 1. Unilateral forearm flexion strength, muscle thickness (MT), pain pressure threshold (PPT), perceived recovery, and pain ratings were recorded before (baseline) and at 24, 48, and 72 hours after maximal eccentric exercise. Analyses included mixed-model ANCOVAs, ANOVAs, and post hoc Bonferroni corrected pairwise comparisons (p < 0.05). After 18-25% strength losses from baseline to 24 hours, strength increased significantly from 24 to 48 hours for the high-dose group (mean difference [CI95%] = 5.7 N·m [2.2-9.3]; p < 0.001; d = 0.568) and from 24 to 72 hours for the low-dose group (8.3 N·m [4.4-12.2]; p < 0.001; d = 0.848), while strength remained unchanged from 24 to 72 hours for the PL group (p = 0.101-1.000). There were no changes in MT or PPT from 24 to 72 hours. Pain ratings significantly decreased, and perceived recovery increased at 72 hours relative to 24 and 48 hours for all groups across time (p = 0.001-0.012). Supplementation with a high- and low-dose polyphenol-rich sorghum bicolor extract increased recovery of muscular strength at faster rates than PL after eccentric exercise but had no meaningful effect on muscle swelling, perceived pain, or recovery. A polyphenol-rich supplement may enhance performance in subsequent exercise sessions and promote increased training volume.

AB - Polyphenol-rich sorghum bicolor extract enhances strength recovery after eccentric exercise. J Strength Cond Res 39(8): e951-e959, 2025 - This randomized, double-blind, placebo (PL) controlled trial examined the effects of a polyphenol-rich supplement on muscular strength recovery after eccentric exercise. Twenty-nine men (mean ± SD, age = 23.1 ± 3.8 years) were randomly assigned to a high- (500 mg·d-1; n = 9) or low- (250 mg·d-1; n = 10) dose polyphenol-rich sorghum bicolor extract, or PL (n = 10) group and completed a 17- to 18-day supplementation period, with eccentric exercise on day 14 + 1. Unilateral forearm flexion strength, muscle thickness (MT), pain pressure threshold (PPT), perceived recovery, and pain ratings were recorded before (baseline) and at 24, 48, and 72 hours after maximal eccentric exercise. Analyses included mixed-model ANCOVAs, ANOVAs, and post hoc Bonferroni corrected pairwise comparisons (p < 0.05). After 18-25% strength losses from baseline to 24 hours, strength increased significantly from 24 to 48 hours for the high-dose group (mean difference [CI95%] = 5.7 N·m [2.2-9.3]; p < 0.001; d = 0.568) and from 24 to 72 hours for the low-dose group (8.3 N·m [4.4-12.2]; p < 0.001; d = 0.848), while strength remained unchanged from 24 to 72 hours for the PL group (p = 0.101-1.000). There were no changes in MT or PPT from 24 to 72 hours. Pain ratings significantly decreased, and perceived recovery increased at 72 hours relative to 24 and 48 hours for all groups across time (p = 0.001-0.012). Supplementation with a high- and low-dose polyphenol-rich sorghum bicolor extract increased recovery of muscular strength at faster rates than PL after eccentric exercise but had no meaningful effect on muscle swelling, perceived pain, or recovery. A polyphenol-rich supplement may enhance performance in subsequent exercise sessions and promote increased training volume.

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Polyphenol-Rich Sorghum Bicolor Extract Enhances Strength Recovery after Eccentric Exercise

Abstract

Bibliographical note

Funding

Keywords

ASJC Scopus subject areas

Access to Document

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