The Effects of Quercetin Supplementation on Eccentric Exercise-Induced Muscle Damage
What this study found
Quercetin improved resistance to eccentric exercise-induced muscle damage and preserved neuromuscular performance versus placebo. Maximal voluntary isometric contraction increased by +4.7% from baseline with quercetin, and torque and muscle fiber conduction velocity decayed less during the eccentric protocol than with placebo (both p < 0.001). After exercise, quercetin also reduced the loss of torque and muscle fiber conduction velocity, and CK and LDH rose less at 24, 48, and 72 hours; for example, CK differed from placebo at 48 h and 72 h (p = 0.047 and p = 0.026) and LDH was lower with…
- Study & population
- Randomized, double-blind, placebo-controlled crossover trial in 12 moderately active healthy young men from Rome, Italy.
- Intervention
- Oral quercetin aglycone in crystalline powder, 500 mg per capsule, taken as 2 capsules daily for 14 consecutive days (1000 mg/day total), with one dose at breakfast and the second 12 hours later.
- Key limitation
- Very small sample size and short 14-day intervention limit certainty and generalizability.
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Open PDFOriginal abstract
The aim of the present investigation was to test the hypothesis that quercetin (Q) may prevent the strength loss and neuromuscular impairment associated with eccentric exercise-induced muscle damage (EEIMD). Twelve young men (26.1 ± 3.1 years) ingested either Q (1000 mg/day) or placebo (PLA) for 14 days using a randomized, double-blind, crossover study design. Participants completed a comprehensive neuromuscular (NM) evaluation before, during and after an eccentric protocol able to induce a severe muscle damage (10 sets of 10 maximal lengthening contractions). The NM evaluation comprised maximal voluntary isometric contraction (MVIC) and force–velocity relationship assessments with simultaneous recording of electromyographic signals (EMG) from the elbow flexor muscles. Soreness, resting arm angle, arm circumference, plasma creatine kinase (CK) and lactate dehydrogenase (LDH) were also assessed. Q supplementation significantly increased the isometric strength recorded during MVIC compared to baseline (+4.7%, p < 0.05). Moreover, the torque and muscle fiber conduction velocity (MFCV) decay recorded during the eccentric exercise was significant lower in Q compared to PLA. Immediately after the EEIMD, isometric strength, the force–velocity relationship and MFCV were significantly lower when participants were given PLA rather than Q. Fourteen days of Q supplementation seems able to attenuate the severity of muscle weakness caused by eccentric-induced myofibrillar disruption and sarcolemmal action potential propagation impairment.