Lee, Young-Ran., Kwon, Soon-Mi., Yoon, A-Ram., Min, Kyung-Eun., Lee, Wang-Lok. Effects of either aerobic exercise training or quercetin supplementation with a low-fat diet on lipid metabolism, mitochondrial biogenesis, and inflammatory cytokine in skeletal muscle of high fat diet-induced obese mice. Exercise Science, 22(2):113-123, 2013. The aim of this study was to compare the effectiveness of aerobic exercise training or quercetin supplementation with a low fat diet on lipid metabolism, mitochondrial biogenesis and inflammatory cytokine in skeletal muscle of high fat diet-induced obese mice. C57BL/6J mice(5 weeks old, n=28) were fed high fat diet (45 % fat) for 12 weeks first and then fed low fat diet for 8 weeks later. The mice were divided into 4 groups:low-fat diet control (HLC; n=7), low fat diet with quercetin(HLQ; n=7), low fat diet with exercise (HLE n=7) and low fat diet with exercise plus quercetin (HLEQ; n=7). The exercise groups (HLE, HLEQ) performed treadmill running for 30-60 min/day at 10-22 m/min, 0 % grade, 5 times/week for 8 weeks and the quercetin groups (HLQ, HLEQ) received a daily dose of quercetin (10 mg/kg of body weight), 5 days/week for 8 weeks. In the results, the low fat diet with exercise training was significantly reduced in body weight, Lee-index, and blood lipid profile. Also, The low fat diet with exercise training was significant improvements in lipid metabolism (FAS, ACC, LEPTIN, ACOX), mitochodrial biogenesis (PGC-1α, Tfam) and inflammatory cytokines (TNF-α, IL-6). In conclusion, low fat diet with exercise training has a positive effects to ameliorate the metabolic disturbance in obese mice. However, it seems that the effect of low fat diet with quercetin was limited in lipid metabolism, mitochondria biogenesis and anti-inflammatory cytokines