## 6 The Roles of Antioxidants and Strength Training in Muscular Performance
\begin{tabular}{c} **Sports Activity/Number** \\ **of Subjects** \\ \end{tabular}  & **Treatments** & **Effects of Polyphenol Supplementation** & **References** \\ \hline \hline \multirow{8}{*}{New Zealand blackcurrant power} & \multirow{8}{*}{13 trained triathletes (8 males)} & \multirow{8}{*}{13 trained triathletes (8 males)} & \multirow{8}{*}{140 mL of water before completing an incremental cycle ergometer test} & \multirow{8}{*}{*} & Caused a downward shift of the lactate curve during incremental intensity cycling & \multirow{8}{*}{No difference in heart rate or oxygen uptake at pre-defined reference points during the incremental exercise} & \\  & & 7 days/6 g-day\({}^{-1}\) (-139 mg & & & \\  & & anthocyanin/day-1) dissolved & & & \\  & & in 140 mL of water before completing an incremental cycle & & & \\  & & & ergometer test & & \\  & & & & \\  & & & & \\  & & & & \\  & & & & \\ \hline \hline \multirow{2}{*}{Blackcurrant anthocyanins} & \multirow{2}{*}{14 trained male cyclists/16.1 km cycling ergometer time trial} & 7-day intake of blackcurrant extract capsules (105 mg & \multirow{2}{*}{*} & \multirow{2}{*}{2.4\% faster 16.1 km time compared with placebo group} & \multirow{2}{*}{[184]} \\  & & & anthocyanin-day-1) & & \\ \hline \multirow{2}{*}{Cherry anthocyanins} & \multirow{2}{*}{20 km cycle ergometer time-trial performance in nine moderately trained triathletes and cyclists} & \multirow{2}{*}{2 days before and on the day of the time trial} & \multirow{2}{*}{*} & \multirow{2}{*}{Inconclusive findings} & \multirow{2}{*}{[186]} \\  & & & the marathon & & \\ \hline \multirow{2}{*}{Cherry juice (\(-40\) mg-day-1 anthocyanins)} & \multirow{2}{*}{Recreational marathon runners} & \multirow{2}{*}{A short intake (5 days) before the marathon} & \multirow{2}{*}{*} & No difference in marathon finishing time compared with placebo group & \multirow{2}{*}{[187]} \\  & & & & \\  
It is generally accepted that flavonoids possess strong antioxidant effects, and the mechanisms are not necessarily related to the direct scavenging of ROS but rather to the indirect modulation of multiple cell signaling pathways [190; 193]. The reported results may also be related to a positive adaptation of the endogenous antioxidant system in response to strength training. The authors acknowledge the variation in polyphenol types, so not all antioxidants possess similar physiological effects. However, opinions are still divided, with some authors arguing that antioxidant supplements would not be beneficial in terms of athletes' performance. However, the strongest argument in favor of antioxidant supplementation (especially natural ones) remains the fact that antioxidant supplementation can delay fatigue and improve endurance performance [194]. There is no doubt that the physical activity of elite combat sports athletes generates oxidative stress that exceeds the endogenous antioxidant capacity to neutralize it, although a study performed on 10 judokas and another one on 12 karate athletes demonstrated that they had stronger intrinsic antioxidant activity [195; 196]. Antioxidant and prooxidant activities were also demonstrated to be altered by rapid weight loss in judo athletes [197]. Supplementation with grape juice for 14 days was proven to increase antioxidant capacity, reduce lipid and DNA damage and increase upper limb strength in a double-blind study including 20 judokas [198]. Kendo athletes benefitted from reduced muscle injury after Q10 coenzyme supplementation in a double-blind 18-participant study [199]. Improved immune function and antioxidant capacity were observed after _Lycium barbarum_ extract supplementation in taekwondo athletes [200]. Regarding strength training and muscle hypertrophy, the addition of extrinsic antioxidants may interfere with the cell signaling system and limit anabolic signals, resulting in