Comparative effects of exercise, dietary supplements, and effective food interventions on endurance and agility performance among runners

Abstract

Endurance and agility jointly determine competitive success in middle-distance and distance running, yet the relative contributions of training and nutrition interventions remain unresolved. This randomized controlled, pre-test/post-test study examined whether Regular Exercise, Dietary Supplements, Effective Food (whole-food nutrition), and a no-intervention Control produced different changes in 800-m endurance and agility (Agility T-Test) among 65 recreational and competitive runners (Exercise, n = 16; Supplements, n = 17; Food, n = 16; Control, n = 16). Participants were tested at baseline, randomly allocated, followed their assigned protocol, and were re-tested. 2 (Time) × 4 (Group) mixed-design ANOVAs were conducted, with Tukey-adjusted pairwise comparisons and partial eta-squared (ηp²) effect sizes. Groups did not differ at baseline. For 800-m endurance, the Group × Time interaction was significant, F (3, 61) = 5.76, p = .002, ηp² = .22, as was the post-intervention between-group effect, F (3, 61) = 4.20, p = .009, ηp² = .17, with the Regular Exercise group showing the greatest improvement. For agility, the Group × Time interaction was marginal, F (3, 61) = 2.68, p = .055, ηp² = .12, and the post-intervention between-group effect approached significance, F (3, 61) = 2.55, p = .06, ηp² = .11; however, the Regular Exercise group significantly outperformed the Dietary Supplements group at post-test (p = .045). Structured exercise training yielded the most consistent benefit across both outcomes, whereas nutritional interventions alone, whether supplements or whole food, appeared insufficient to produce comparable gains, particularly for agility. Implications for coaching, nutrition programming, and future trials are discussed.