The article provides a critical review of how the energy cost (EC) of resistance exercises (RE) is quantified, distinguishing EC from the broader concept of energy expenditure (EE). It highlights the large variability in reported EC values (≈3–30 kcal·min⁻¹, up to ~40 kcal·min⁻¹ for large‑muscle exercises) and attributes this to methodological inconsistencies and the multitude of exercise variables (load, speed, range of motion, etc.). The authors examine aerobic EC measurement via expired‑gas VO₂ and respiratory exchange ratio (R), emphasizing the need for steady‑state conditions and the difficulty of applying VO₂ kinetics to RE. For anaerobic EC, they discuss two indirect approaches: the blood‑lactate energy equivalent and the accumulated oxygen deficit (AOD), outlining their assumptions, limitations, and the lack of validation for RE. Empirical data from the literature and the authors’ unpublished work are summarized for bench press, half‑squat, and other exercises, showing that aerobic contribution dominates at low intensities (<30 % 1‑RM) while anaerobic contribution becomes predominant at higher loads, with half‑squat reaching up to 40 kcal·min⁻¹ and anaerobic fractions of 80 %+. The paper concludes that knowledge of RE EC is still nascent, calling for isolated‑exercise studies, detailed VO₂ on‑kinetics analyses, comparative validation of lactate‑equivalent vs. AOD methods, and precise quantification of active muscle mass. These steps are deemed essential for designing strength‑training programs aimed at body‑mass or fat‑mass control.
Topics
Distinguishing Energy Cost (EC) from Energy Expenditure (EE) in Resistance Training
Conceptual clarification that EC includes both aerobic and anaerobic components, whereas EE is only appropriate when aerobic VO₂ can be measured without significant anaerobic contribution.