Clinical implications and limitations
muscle mass
Each full training session in the AG, combining treadmill and abdominal aerobic endurance exercise, lasted in total 84 min, almost double the duration compared to the moderate intensity treadmill intervention in the CG. The smaller muscle mass used in the abdominal endurance exercise, as compared to whole‐body treadmill exercise, necessitates longer duration to match for total energy expenditure. Although the subjects were instructed not to change their dietary habits during this study, including a measure of dietary control would have strengthened the study design, as energy balance, that is, energy intake versus expenditure, impacts whether excess energy is stored as fat or used as fuel. While we did not observe a significant difference in body composition between the training groups at baseline, we cannot fully discount the possibility that the somewhat higher body fat and lean tissue mass in the AG increased the availability of fat to be utilized during training. However, no difference in total fat mass reduction between the groups was observed. This suggests not only that the external work output, and therefore energy requirement, was adequately balanced between the interventions, but also that it is unlikely any numeric difference in body composition at baseline would have influenced the amount of local adipose tissue loss to any large extent.The fact that we did not observe a difference in the percentage energy cost of the abdominal aerobic endurance training compared to treadmill training between our pilot test (40.4%) and supplementary test subjects (41.5%), and the use of relative workloads (% of HR