Carbohydrate Ingestion During Resistance Exercise Elevates Blood Glucose and May Improve Muscular Endurance but Not Maximal Strength or Power: A Randomised, Placebo-Controlled, Workload-Matched Crossover Trial
Engeroff T, Niederer D, Groneberg D. · Research Square · 2026
Abstract
Background: Carbohydrates are among the most frequently used nutritional supplements to enhance exercise performance and recovery, yet their acute effects during resistance training remain less clear.
Methods: In a randomized, placebo-controlled crossover trial, 15 resistance-trained participants performed two workload-matched full-body resistance sessions (leg press, knee extension, cable crunches, lat pulldown, bench press; 80% 1RM) 3 hours after a standardized breakfast ingesting 60 g carbohydrate or placebo. Participants rated their perceived exertion, affective state and gastrointestinal distress during exercise. Drop jumps, isometric handgrip strength, muscular endurance (knee extension to failure), blood glucose and lactate were assessed post-exercise.
Results: Sixteen participants were randomised and 15 analysed. Carbohydrate ingestion elevated blood glucose (+ 19.0 mg/dL; 95% CI 8.12–29.88; p = .002) without increasing lactate, while subjective and strength outcomes were unaffected. Knee extension repetitions were higher after carbohydrate ingestion for the dominant leg (+ 2.7 repetitions; 95% CI 0.07–5.33; p = .046) but not for the non-dominant leg (+ 2.4 repetitions; 95% CI − 0.45–5.25; p = .089). The difference in glucose between intervention and placebo was associated with body height but not pre-exercise caloric intake.
Conclusions: Intra-workout carbohydrate ingestion raises blood glucose without increasing lactate at a matched workload. A benefit for muscular endurance was observed for the dominant leg only and was not statistically significant for the non-dominant leg; maximal strength and power were unaffected. These exploratory
Findings: require confirmation in an adequately powered trial. Study Registration: German Clinical Trials Register (registration date: 27.04.2026; DRKS-ID: DRKS00038810)