Impact of 8 weeks of supplementation with Withania somnifera on strength in trained individuals

Abstract

Withania somnifera (WS) is a traditional Ayurvedic herb. In addition to Ayurveda texts, the modern medical literature reports many potential health benefits of WS, including its possible use as a supplement as an ergogenic aid. Only recently, the efficacy of WS as an adjuvant to resistance training programmes was assessed. Most of the studies investigating this research area have mainly considered untrained subjects. In this regard, the aim of this study was to evaluate the impact of eight weeks of WS supplementation on strength training adaptations in trained individuals. Sixteen trained male individuals (25.7 ± 3.0 years; 74.7 ± 6.9 kg; 178.9 ± 4.5 cm; 23.3 ± 1.1 BMI), with at least four years of resistance training experience, participated in the study. Individuals continued with their resistance–strength training programmes, while diets and supplementation strategies remained unchanged. Eight of the 16 subjects (treated group) were supplemented with WS (500 mg/d WS powder extract, withanolides 2.5%) for a period of eight weeks, while the other eight subjects (control group) were not supplemented. To evaluate strength, one-repetition maximum tests (1RMs) were performed in four selected exercises at the beginning (T1), in the middle (T2) and at the end (T3) of the study. Compared to the untreated group, treated individuals showed a significant increase in total maximal strength (the sum of 1RM results) (p=0.05); however, no significant differences emerged from any single exercise maximal strength comparisons. These preliminary data suggest that, in these experimental conditions, eight weeks of supplementation with WS does not appear to contribute significantly to the induction of strength training adaptations in trained individuals.