Supplementation with a polyphenolic blend improves post-exercise strength recovery and muscle soreness

Background : Exercise can initiate a cascade of inflammatory and oxidative stress–related events leading to delayed onset muscle soreness. Polyphenols possess antioxidant and anti-inflammatory properties. Objective : The current study examined the effects of a proprietary polyphenolic blend (PB), containing catechins and theaflavins, on exercise performance and recovery following an eccentric exercise challenge. Design : Male participants (18–35 years of age) received placebo or PB at a low dose (PB-L, 1,000 mg/d) or high dose (PB-H, 2,000 mg/d) for 13 weeks. During the 13th week of supplementation, participants completed an eccentric exercise (40 min downhill treadmill run) followed by a strength assessment (peak torque on isokinetic leg extensions) pre-exercise, and 24, 48, and 96 h post-exercise. Muscle soreness (subjective questionnaire), markers of muscle stress (cortisol and creatine phosphokinase [CK]), and antioxidant capacity (ferric reducing ability of plasma [FRAP]) were also assessed. Results : PB-H attenuated the decrease in peak torque observed in the placebo group from pre-exercise to 48 h ( p= 0.012) and 96 h ( p= 0.003) post-exercise. At 48 h post-exercise, PB-H reduced whole body and hamstring soreness ( p =0.029) versus placebo. Chronic consumption of PB improved serum FRAP ( p =0.039). As expected, serum cortisol and CK increased from pre- to post-exercise in all groups; however, by 96 h, cortisol and CK levels returned to pre-exercise levels following PB supplementation. At 96 h, the change in cortisol from pre- to post-exercise was significantly greater in placebo versus PB-H ( p =0.039). Conclusion : These findings show that chronic consumption of PB improved antioxidant status, reduced markers of muscle stress, and promoted strength recovery post-exercise. Keywords: strength; catechins; theaflavins; cortisol; creatine phosphokinase; antioxidant; delayed onset muscle soreness (Published: 18 December 2015) Citation: Food & Nutrition Research 2015, 59: 30034 - http://dx.doi.org/10.3402/fnr.v59.30034