Progressive Metabolic Adaptations to Low Intensity Exercise Training and Weight Loss

the investigators first aim is to determine the effect of low intensity exercise (without
weight loss) on insulin sensitivity, muscle lipid metabolism, and factors regulating these
processes in skeletal muscle after 1 day, 2 wks, 12 wks of training, and again after 3 days
without exercise in obese adults. the investigators second aim is to determine the effect of
combining low intensity exercise training with 10% weight loss on insulin sensitivity, muscle
lipid metabolism, and factors regulating these processes in skeletal muscle.

Although a single 40 minute session of exercise at a low exercise intensity will not improve
insulin sensitivity, the investigators anticipate adaptations after two weeks of exercise
training (6 session/wk; 12 session total) will improve insulin sensitivity and be accompanied
by a reduction in fatty acid intermediates and a reduction in markers for pro-inflammatory
activation in muscle. the investigators anticipate changes in insulin sensitivity, fatty acid
partitioning, and pro-inflammatory markers the day after the last session of a 12 wk training
program (without weight-loss) will be similar to that measured after 2 weeks of training. the
investigators anticipate insulin sensitivity, accumulation of fatty acid intermediates, and
pro-inflammatory activation will be markedly improved after 10% weight loss when measured the
day after exercise. the investigators would expect the improvements in Insulin sensitivity,
accumulation of fatty acid intermediates, and markers of inflammatory stress will be
significantly attenuated when measured 3 days after the most recent exercise session, but
beneficial effects of 10% weight loss on these metabolic endpoints will persist when compared
with before weight loss.