Quercetin ingestion modifies human motor unit firing patterns and muscle contractile properties

Abstract

Quercetin is a polyphenolic flavonoid that has reported to block the binding of adenosine to A1 receptors at central nervous system and increase calcium release from the sarcoplasmic reticulum at skeletal muscle. The aim of the present study was to investigate the acute effect of quercetin ingestion on motor unit activation and muscle contractile properties. High-density surface electromyography during submaximal contractions and electrically elicited contraction torque in knee extensor muscles were measured before (PRE) and 60 min after (POST) quercetin glycosides or placebo ingestions in 13 young males. Individual motor units of the vastus lateralis muscle were identified from high-density surface electromyography by the Convolution Kernel Compensation technique. Firing rates of motor units recruited at 30-50% of the maximal voluntary contraction torque (MVC) were increased from PRE to POST only with quercetin (9.0 ± 2.3 to 10.5 ± 2.0 pps, p = 0.034). Twitch torque during doublet stimulation was decreased from PRE to POST with placebo (77.1 ± 17.1 to 73.9 ± 17.6 Nm, p = 0.005), but not with quercetin (p > 0.05). For motor units recruited at < 10% of MVC, normalized firing rate were decreased with quercetin (1.52 ± 0.33 to 1.58 ± 0.35%MVC/pps, p = 0.002) but increased with placebo (1.61 ± 0.32 to 1.57 ± 0.31%MVC/ pps, p = 0.005). These results suggest that ingested quercetin has the functional roles to: mitigate reduction in the muscle contractile properties, enhance activations of relatively higher recruitment threshold motor units, and inhibit activation of relatively lower recruitment threshold motor units.

Effects of Quercetin Glycoside Supplementation Combined With Low-Intensity Resistance Training on Muscle Quantity and Stiffness: A Randomized, Controlled Trial

“…Regarding the difference in absorption capacity, over 200 mg of QG may be needed to exert physiological actions similar to 1,000 mg of quercetin aglycone. Of note, a recent study demonstrated increased neuromuscular efficacy by a single ingestion of 500 mg QGs ( 37 ). The present study showed that the combined effects of 200 mg of QGs with low-intensity resistance exercise on muscle quantity and quality are similar to those of 500 mg of QGs.…”

Neuromuscular characteristics of front and back legs in junior fencers

“…During submaximal contractions, individual motor units were identified from the recorded monopolar surface EMG signals by the Convolution Kernel Compensation (CKC) technique using DEMUSE software (Holobar et al 2009 ; Holobar and Zazula 2004 , 2008 ; Merletti et al 2008 ). The procedures for decomposition into individual motor units used in the present study were previously and extensively validated based on HDsEMG signals from various skeletal muscles, including the VL muscle (Farina et al 2010 ; Gallego et al 2015a , b ; Holobar et al 2009 ; Watanabe and Holobar 2021 ; Watanabe et al 2016 ; Yavuz et al 2015 ). Based on Holobar et al ( 2014 ), the pulse-to-noise ratio (PNR) was used as an indicator of the motor unit identification accuracy, and only motor units with PNR > 30 dB (corresponding to an accuracy of motor unit firing identification > 90%) were employed for further analysis; all other motor units were discarded (Holobar et al 2014 ).…”

Accounting Gut Microbiota as the Mediator of Beneficial Effects of Dietary (Poly)phenols on Skeletal Muscle in Aging

“…Quercetin is a rutin derivative that is naturally found in capers, herbs, radish, fennel, onions and berries, or can originate from rutin de-glycosylation carried out by intestinal mucosa enzymes [ 27 , 42 ]. Quercetin is well known for exerting pleiotropic myoprotective actions, being able to stimulate protein synthesis, inhibit apoptosis [ 168 ], reduce oxidative stress [ 169 ], promote mitochondrial biogenesis [ 170 ], regulate fiber type switching [ 171 ], promote the myogenic differentiation of stem cells [ 172 ], attenuate adipogenesis and fibrosis [ 173 ], and regulate motor unit firing patterns [ 174 ] in skeletal muscle cells. For these reasons, quercetin supplementation can help to limit muscle damage and promote recovery after strenuous eccentric exercise in adult subjects [ 175 , 176 , 177 ].…”