Oxygen Uptake On-Kinetics during Low-Intensity Resistance Exercise: Effect of Exercise Mode and Load.

Eduardo B Neves,André L Carneiro,Carlo Baldari,Nuno Garrido,Ana Sousa,Victor M Reis,Tiago Barbosa

doi:10.3390/ijerph16142524

Abstract

Oxygen uptake (VO2) kinetics has been analyzed through mathematical modeling of constant work-rate exercise, however, the exponential nature of the VO2 response in resistance exercise is currently unknown. The present work assessed the VO2 on-kinetics during two different sub maximal intensities in the inclined bench press and in the seated leg extension exercise. Twelve males (age: 27.2 ± 4.3 years, height: 177 ± 5 cm, body mass: 79.0 ± 10.6 kg and estimated body fat: 11.4 ± 4.1%) involved in recreational resistance exercise randomly performed 4-min transitions from rest to 12% and 24% of 1 repetition maximum each, of inclined bench press (45°) and leg extension exercises. During all testing, expired gases were collected breath-by-breath with a portable gas analyzer (K4b2, Cosmed, Italy) and VO2 on-kinetics were identified using a multi-exponential mathematical model. Leg extension exercise exhibited a higher R-square, compared with inclined bench press, but no differences were found in-between exercises for the VO2 kinetics parameters. VO2 on-kinetics seems to be more sensitive to muscle related parameters (upper vs. lower body exercise) and less to small load variations in the resistance exercise. The absence of a true slow component indicates that is possible to calculate low-intensity resistance exercise energy cost based solely on VO2 measurements.

Highlights

The oxygen uptake (VO2 ) on-kinetics has been shown to respond according to different workloads and types of exercise [1,2] as well as to aerobic fitness [3]
This did not confirm the first hypothesis that leg extension exercise VO2 kinetics would be different compared with inclined bench press VO2 kinetics
The present study demonstrated that resistance exercise (RE) for upper body or lower body exercise with a load variation (12% and 24% of 1-RM) did not modify VO2 kinetics

Summary

Introduction

The oxygen uptake (VO2 ) on-kinetics has been shown to respond according to different workloads and types of exercise [1,2] as well as to aerobic fitness [3]. In 1982, Whipp and co-workers [4] presented a VO2 on-kinetics three-phase model, in which: (i) the cardio-dynamic phase (lasting ≈ 15–20 s) is due to the fast increase in alveolar O2, (ii) the second phase (primary component lasting ≈ 2–3 min) is characterized by an exponential increase of VO2 due to muscle oxygen demand, and (iii) the third phase is described either by an additional slow rise on VO2 (slow component, SC), superimposing the primary component initiated at exercise, or by the stabilization in VO2 at the moderate exercise intensity domain [5]. The mathematical analysis of VO2 on-kinetics with multi exponential models enables assessment of the intensity at which the individual adjusts to the energy demand (through time constant parameter). Public Health 2019, 16, 2524; doi:10.3390/ijerph16142524 www.mdpi.com/journal/ijerph

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