A Multi-Center Comparison of O2peak Trainability Between Interval Training and Moderate Intensity Continuous Training

Abstract

There is heterogeneity in the observed O2peak response to similar exercise training, and different exercise approaches produce variable degrees of exercise response (trainability). The aim of this study was to combine data from different laboratories to compare O2peak trainability between various volumes of interval training and Moderate Intensity Continuous Training (MICT). For interval training, volumes were classified by the duration of total interval time. High-volume High Intensity Interval Training (HIIT) included studies that had participants complete more than 15 min of high intensity efforts per session. Low-volume HIIT/Sprint Interval Training (SIT) included studies using less than 15 min of high intensity efforts per session. In total, 677 participants across 18 aerobic exercise training interventions from eight different universities in five countries were included in the analysis. Participants had completed 3 weeks or more of either high-volume HIIT (n = 299), low-volume HIIT/SIT (n = 116), or MICT (n = 262) and were predominately men (n = 495) with a mix of healthy, elderly and clinical populations. Each training intervention improved mean O2peak at the group level (P < 0.001). After adjusting for covariates, high-volume HIIT had a significantly greater (P < 0.05) absolute O2peak increase (0.29 L/min) compared to MICT (0.20 L/min) and low-volume HIIT/SIT (0.18 L/min). Adjusted relative O2peak increase was also significantly greater (P < 0.01) in high-volume HIIT (3.3 ml/kg/min) than MICT (2.4 ml/kg/min) and insignificantly greater (P = 0.09) than low-volume HIIT/SIT (2.5 mL/kg/min). Based on a high threshold for a likely response (technical error of measurement plus the minimal clinically important difference), high-volume HIIT had significantly more (P < 0.01) likely responders (31%) compared to low-volume HIIT/SIT (16%) and MICT (21%). Covariates such as age, sex, the individual study, population group, sessions per week, study duration and the average between pre and post O2peak explained only 17.3% of the variance in O2peak trainability. In conclusion, high-volume HIIT had more likely responders to improvements in O2peak compared to low-volume HIIT/SIT and MICT.

Issues in the determination of ‘responders’ and ‘non‐responders’ in physiological research

“…This design and context are similar to those reported recently byWilliams et al (2019). This design and context are similar to those reported recently byWilliams et al (2019).…”

“…, we present the results of the data simulation for a three-group parallel arm intervention study designed to quantify the effects of two exercise interventions versus a control group on maximal oxygen uptake (V O 2 max ). This design and context are similar to those reported recently byWilliams et al (2019). The three study groups are as follows: control (zero change in trueV O 2 max for all participants), Intervention 1 (a 3.6 ml kg −1 min −1 increase in trueV O 2 max for all participants) and Intervention 2 (a 2.0 ml kg −1 min −1 increase in trueV O 2 max for all participants).…”

“…Note in Table 1 and Figure 1 how the group differences in the observed mean response lead to group differences in the observed numbers of responders, adverse responders and trivial responders (according to a response threshold of 5 ml kg −1 min −1 and an adverse response threshold of −5 ml kg −1 min −1 ). Therefore, although researchers have made inferences relating to response heterogeneity or 'trainability' on the basis of such 'responder counts' (Bonafiglia, Ross, & Gurd, 2019;Hammond et al, 2019;Ross, de Lannoy, & Stotz, 2015;Williams et al, 2019), it is in fact the group differences in mean treatment response that explain the differences in responder counts between our groups (Figure 1), besides the fact that the responder counts cannot be correct in the first place. Therefore, such group comparisons of responder counts do not provide much information about response heterogeneity, as defined in the context of precision medicine (Section 2).…”

“…The number of 'responders' was found to increase as the group mean response increased. This approach to responder counting has also been adopted by researchers who defined their study topic as 'trainability' (Williams et al, 2019). Most definitions of this term encompass the notion that individuals differ in their response to the same or similar interventions.…”

Cardiovascular Remodeling Experienced by Real-World, Unsupervised, Young Novice Marathon Runners

“…To fully characterize exercise ability and potential using the semi-recumbent ergometer, both maximal (maximal VO 2 and percentage predicted maximal VO 2 ) and submaximal indices [oxygen uptake efficiency slope (OUES)] were assessed. In order to appropriately classify cardiorespiratory trainability by accounting for the random within-individual variation and measurement error, a combination of the technical error of measurement (TEM) and the minimal clinically important difference (MCID) were incorporated, as previously described (Williams et al, 2019). Studies were performed by four experienced cardiac physiologists working a rotational day schedule and analyzed by a single investigator (AD).…”