Quercetin ingestion alters motor unit behavior and enhances improvement in muscle strength following resistance training in older adults: a randomized, double-blind, controlled trial.

Taichi Nishikawa, Ryosuke Takeda, Saeko Ueda, Kaito Igawa, Tetsuya Hirono, Masamichi Okudaira, Yukiko Mita, Toshiyuki Ohya, Kohei Watanabe

Journal: European journal of nutrition 2025;64(3):117

PMID: 40063125

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Plain Language Summary

Age-related muscle strength loss, due to muscle wastage or loss of nerve function also known as muscle unit (MU) changes, increases the risk of falls, fractures, physical disability, and lifestyle-related diseases. Resistance training is widely recognised for mitigating these effects. This study aimed to investigate whether daily quercetin supplementation influences MU behaviour during a single resistance training session and enhances long-term adaptations to resistance training. It was a randomised, double-blind, controlled trial involving 30 healthy, physically independent older adults (aged 65–82 years). Participants were randomly assigned to receive either 200 mg/day of quercetin glycosides (QUE) or a placebo (PLA). Results showed that quercetin supplementation enhanced muscle strength improvements following resistance training by promoting adaptations in the muscle. Authors concluded that combining quercetin supplementation with resistance training may be an effective strategy for improving muscle strength in older adults.

Abstract

BACKGROUND

During resistance training, quercetin ingestion can enhance motor unit (MU) with a higher recruitment threshold in older adults.

OBJECTIVE

We investigated the effects of daily quercetin glucoside ingestion on chronic adaptations in muscle strength and MU behavior following resistance training in healthy older adults.

METHODS

Twenty-six older adults were randomly allocated to two groups that completed 6-week resistance training intervention with the ingestion of either placebo (PLA) or quercetin glycosides (QUE) at 200 mg/day. Maximal voluntary force (MVF) during isometric knee extension, muscle mass, and MU firing behavior during ramp task at 70%MVF were measured before (PRE) and after (POST) intervention.

RESULTS

In both groups, knee extensor MVF was significantly increased (both p < 0.001), and the improvement in QUE (115.1 ± 11.0%) was greater than in PLA (105.3 ± 4.8%) (p < 0.001) by the Mann-Whitney test. Muscle mass was not changed from PRE to POST in PLA or QUE (p > 0.050). At POST, firing rates of Mus with relatively moderate (recruited between 20 and 40%MVF) or higher (recruited between 20 and 40%MVF) recruitment thresholds were higher in QUE than PLA (p < 0.050). There was a significant correlation between %change in MVF and %change in firing rates of MUs with a relatively higher recruitment threshold from PRE to POST (p = 0.018, r = 0.642).

CONCLUSIONS

These results suggest that the adaptations of MUs with higher recruitment thresholds explain the greater improvement in muscle strength associated with QUE ingestion.

CLINICAL TRIAL REGISTRY

UMIN000053019 ( https://rctportal.niph.go.jp/detail/um?trial_id=UMIN000053019 ).

Address: Graduate School of Health and Sport Sciences, Chukyo University, Toyota, Japan.; Laboratory of Neuromuscular Biomechanics, School of Health and Sport Sciences, Chukyo University, Toyota, Japan.; Laboratory of Neuromuscular Biomechanics, School of Health and Sport Sciences, Chukyo University, Toyota, Japan.; Laboratory of Neuromuscular Biomechanics, School of Health and Sport Sciences, Chukyo University, Toyota, Japan.; Department of Human Nutrition, School of Life Studies, Sugiyama Jogakuen University, Nagoya, Japan.; Laboratory of Neuromuscular Biomechanics, School of Health and Sport Sciences, Chukyo University, Toyota, Japan.; Human Health Sciences, Graduate School of Medicine, Kyoto University, Kyoto, Japan.; Laboratory of Neuromuscular Biomechanics, School of Health and Sport Sciences, Chukyo University, Toyota, Japan.; Faculty of Education, Iwate University, Morioka, Japan.; Department of Human Nutrition, School of Life Studies, Sugiyama Jogakuen University, Nagoya, Japan.; Laboratory for Exercise Physiology and Biomechanics, Graduate School of Health and Sport Sciences, Chukyo University, Toyota, Japan.; Laboratory of Neuromuscular Biomechanics, School of Health and Sport Sciences, Chukyo University, Toyota, Japan. [email protected].

DOI: 10.1007/s00394-025-03634-9

Patient Centred Factor

Triggers: Quercetin

Clinical Imbalances

Immune and inflammation

Laboratory Testing

Imaging

Modifiable Lifestyle Factors

Diet Exercise and movement

Jadad Score

Allocation Concealment

Yes

Nutrition Evidence Keywords

Supplementation Muscle mass Resistance training Quercetin

Bioactive Substances

Quercetin

Link outs

Free resources

Full Text Sources:

https://pmc.ncbi.nlm.nih.gov/articles/pmid/4006312...

Research Materials:

https://antibodies.cancer.gov/detail/CPTC-GST+Mu1-...

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Full Text Sources:

https://dx.doi.org/10.1007/s00394-025-03634-9

MeSH Terms: Humans, Resistance Training, Muscle Strength, Double-Blind Method, Quercetin, Male, Female, Aged, Muscle, Skeletal, Motor Neurons, Middle Aged