The article examines how to estimate the total energy expenditure of intermittent, high‑intensity exercise—particularly resistance training—by integrating both aerobic (oxygen uptake, excess post‑exercise oxygen consumption) and anaerobic (blood lactate) components. The authors challenge the prevailing reliance on steady‑state models, which assume a linear relationship between work rate and oxygen uptake, and argue that such models inadequately capture the metabolic dynamics of brief, intense bouts. They hypothesize that, despite inherent metabolic variability, the combined aerobic and anaerobic energy costs of intermittent exercise rise proportionally with work volume, mirroring steady‑state exercise. Using resistance‑training protocols, they demonstrate that (1) lifting time is brief, yielding minimal oxygen uptake during the set; (2) anaerobic contributions are substantial; (3) post‑set oxygen uptake (EPOC) often dominates total cost; and (4) variability in aerobic and anaerobic estimates is high when considered separately but is reduced when summed. The paper presents empirical data on oxygen uptake kinetics in steady, non‑steady, and intermittent conditions, discusses the variability observed across subjects and protocols, and proposes an “energy cost vector” that aligns intermittent exercise energetics with steady‑state extrapolations. The authors conclude that estimating total energy cost via combined aerobic‑anaerobic measures and repeated trials provides a more reliable, less variable assessment for intermittent exercise, supporting the use of steady‑state models as a reasonable approximation when variability is accounted for.
Topics
Hypothesis Linking Steady‑State and Intermittent Energetics
The central claim that total aerobic and anaerobic energy costs of intermittent exercise increase proportionally with work volume, just as in steady‑state exercise, and that the converse of steady‑state modeling applies to intermittent work.
Contrasting Metabolic Profiles: Steady vs. Intermittent Exercise
Comparison of physiological responses—brief lifting time, minimal in‑set oxygen uptake, significant anaerobic contribution, and dominant post‑set EPOC—in resistance training versus continuous aerobic modalities.
Variability in Aerobic and Anaerobic Measurements
Evidence showing high coefficients of variation (up to 47%) for separate aerobic and anaerobic components, and how combining them reduces overall variability to ~15%.
Methodological Approach: Resistance‑Training Model and Energy Component Estimation
Description of experimental protocols (bench press at %1‑RM, measurement of oxygen uptake during exercise and recovery, blood lactate for anaerobic cost) and how these data support the hypothesis.
Energy Cost Vector Concept
Proposed graphical model that aligns intermittent exercise energetics with steady‑state extrapolations, illustrating linear central tendency of combined aerobic‑anaerobic costs across work volumes.
Implications for Energy Expenditure Modeling
Discussion of how integrating both metabolic systems and using repeated measures can improve the validity of energy cost estimates for intermittent exercise, informing training prescription and research methodology.