Written by Joyce Smith, BS. Twelve weeks of resistance training and 500 mg daily of Sensoril® (Withania somnifera) improved body composition and muscle strength in healthy male participants.
The S.T.A.R. (Strength Training Adaptations and Recovery) trial, a 12-week, randomized, parallel-group, placebo-controlled study, was conducted to examine the impact of supplementation with Sensoril® on strength training adaptations. Sensoril®, a standardized aqueous extract of the roots and leaves of Withania somnifera (Ashwagandha), is an Ayurvedic herb known to have “rasayana” (rejuvenator), longevity, and revitalizing properties1-3. Previous studies have credited its bioactive compounds with cognitive, mood, psychomotor, and joint health 2, antioxidant 3, and anti-inflammatory properties while its adaptogenic properties may support the physical and mental stress of high –intensity exercise 1. Doses of 250 – 1000 mg per day suggest ergogenic benefits such as anxiolytic 4, analgesic 5, anti-inflammatory, anabolic, cardiopulmonary, and antioxidant effects 6. Despite emerging studies highlighting Ashwagandha’s ergogenic benefits, research utilizing a longer training protocol as well as the bioactive components of both the leaves and roots of the plant is needed.
Sensoril® is a standardized aqueous extract of the roots and leaves of Withania somnifera, and contains glycosides, Withering-A, and oligosaccharides as major bioactive components. Lopez and colleagues 7 in a randomized, double-blind, placebo controlled study, tested the hypothesis that ashwagandha supplementation would significantly improve muscular and aerobic performance in a 12-week resistance training and supplementation protocol. They assigned thirty-eight healthy males between the ages of 18 and 45 to supplement with either 500 mg/day of Sensoril® (S500) or a placebo. Participants were trained recreationally and had no more than 2-3 days/week of exercise. Primary outcomes were changes in muscle strength: secondary measures were changes in body composition, visual analog scales for recovery and affect, muscle endurance, and power.
The following measures of body composition [lean mass, fat mass, percentage of fat, and android/gynoid ratio were determined by dual-energy x-ray absorptiometry (DEXA)], muscular strength [using standard NSCA (National Strength and Conditioning Association) protocols] 8, power, and endurance were taken at baseline and after 12 weeks of supplementation and training. The 12-week training program consisted of a weekly exercise program, performed 4 days/week, during which all participants exercised with gradually increasing volume and intensity. Workouts included bench press, let pulldown, shoulder press, seated row, shoulder shrug, dip, bicep curl, triceps pushdown, leg press, squat deadlift, lunge, leg curl, leg extension, and calf raise. Daily workouts were not supervised; however, subjects were required to complete training logs that were signed by a training partner or fitness staff and were monitored via weekly phone calls.
Compared to placebo, the Sensoril® group made significantly greater improvements in 1-RM squat (p=0.009), bench press (p=0.048), and DEXA-derived android/ganoid ratio (p=0.03). No other between group differences were found for body composition, body fat percentage, fat-free mass, or fat mass, visual analog scales for recovery and affect, or systemic hemodynamics. Only the Sensoril® group experienced statistically significant improvements in average squat power, peak bench press power, 7.5 km time trial performance, and perceived recovery scores.
A notable study strength was the 12-week long exercise regime; limitations included a lower than recommended protein intake requirement which may have undermined the ability of participants to achieve optimal muscle mass 9, and the lack of closely supervised workouts. Future studies that empathize a controlled diet and utilize appetite measurements along with biomarkers of cardiovascular and metabolic disease markers are recommended.
Source: Ziegenfuss, Tim, Anurag Kedia, Jennifer Sandrock, Betsy Raub, Chad Kerksick, and Hector Lopez. “Effects of an Aqueous Extract of Withania somnifera on Strength Training Adaptations and Recovery: The STAR Trial.” Nutrients 10, no. 11 (2018): 1807
© 2018 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution(CC BY) license (http://creativecommons.org/licenses/by/4.0/).
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Posted January 6, 2020.
Joyce Smith, BS, is a degreed laboratory technologist. She received her bachelor of arts with a major in Chemistry and a minor in Biology from the University of Saskatchewan and her internship through the University of Saskatchewan College of Medicine and the Royal University Hospital in Saskatoon, Saskatchewan. She currently resides in Bloomingdale, IL.
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- Ziegenfuss T, Kedia A, Sandrock J, Raub B, Kerksick C, Lopez H. Effects of an Aqueous Extract of Withania somnifera on Strength Training Adaptations and Recovery: The STAR Trial. Nutrients. 2018;10(11):1807.
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