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Objective: To determine the effects of exercise amount (kilocalories per session) and intensity (percent of maximal oxygen consumption [% VO 2 peak]) on adipose tissue (AT) and skeletal muscle (SM) in adults with abdominal obesity., Methods: Participants (n = 103; 52.7 ± 7.6 years) were randomized to the following groups: control; low-amount, low-intensity exercise (180 kcal/session [women] and 300 kcal/session [men] at 50% VO 2 peak); high-amount, low-intensity exercise (HALI; 360 kcal/session [women] and 600 kcal/session [men] at 50% VO 2 peak); or high-amount, high-intensity exercise (HAHI; 360 kcal/session [women] and 600 kcal/session [men] at 75% VO 2 peak) for 24 weeks. Activities of daily living were measured by accelerometry. Magnetic resonance imaging was used to measure tissue mass., Results: Reduction in all AT depots was greater in the exercise groups compared with control (P < 0.002); however, there were no differences between exercise groups (P > 0.05). Visceral and abdominal subcutaneous AT reduction was uniform across the abdomen. Total SM mass did not change with exercise compared with control (P = 0.32). However, while lower-body SM mass was maintained (P = 0.32), upper-body SM mass in the high-amount, high-intensity and the high-amount, low-intensity groups was reduced compared with controls (P < 0.008)., Conclusions: In adults with abdominal obesity, substantial reductions in total, abdominal subcutaneous, and visceral AT with a preservation of total SM mass were observed independent of exercise amount or intensity., (© 2018 The Obesity Society.)

The purpose of this study was to revisit the question of recruitment of motor units during lengthening contractions because of conflicting views in the literature on this subject. Motor unit activity was recorded from the flexor carpi radialis muscle of four human subjects to compare the patterns of recruitment during lengthening and isometric contractions. Lengthening contractions were produced either when the subject voluntarily stopped opposing a background load or when an additional load was imposed on the already contracting muscle. In both cases, lengthening of the active muscle was produced at a variety of speeds, from quite slow to "as fast as possible." No differences in recruitment order were observed between isometric and lengthening contractions at any speed of lengthening contraction. It is concluded that all contractions in normal humans recruit motor units in an orderly fashion from small to large, according to the size principle of motor unit recruitment., (Copyright 2001 John Wiley & Sons, Inc.)