Vegetarian Advantage in Muscle Performance: Novel Evidence from Controlled Isokinetic Assessments

• Three groups with varying levels of animal-derived food in their diets are evaluated. • 17 isokinetic parameters are analysed to comprehend total muscle performance. • A robust statistical methodology using adjusted linear regression models was applied. • No significant differences were found between groups in only four parameters. • Vegetarian diets are linked to improved isokinetic muscle performance. A variety of factors can contribute to muscular performance, including diet. Vegetarian diets are characterized by higher intakes of carbohydrates, micronutrients, and bioactive compounds, which are known to act as antioxidants and have vasodilatory effects, potentially positively impacting muscle performance. This study aims to evaluate muscle performance across dietary patterns with varying levels of exclusion of animal-based foods. Thirty-six trained men were divided into three groups based on their responses to the Food Frequency Questionnaire: 13 omnivores, 10 lacto-ovo-vegetarians, and 13 strict vegetarians. An exhaustive exercise protocol was performed on an isokinetic dynamometer, involving the quadriceps of the dominant leg, and the performance outcomes were recorded. A covariance analysis was performed to describe the independent effect of dietary patterns on isokinetic muscle performance, using 17 isokinetic parameters as dependent variables, dietary patterns as independent factors, and age, body composition, and training level as covariates. Most parameters showed statistically significant differences, with p < 0.01. No significant differences were observed in the parameters deceleration time (msec) (p=0.138) and repetition number that requires more work (#) (p= 0.496). The peak torque at 30 degrees showed a large effect size, and the other parameters showed medium or small effect sizes. The results of this study indicate that vegetarian dietary patterns are associated with greater isokinetic muscle strength and faster movement speed. Omnivorous individuals showed better muscle power. Muscle resistance demonstrated homogeneous results among dietary patterns. Although the effects observed were of small to moderate magnitude, vegetarian individuals showed an advantage in parameters related to strength and movement speed compared with omnivores.