Time course of adaptation to low intensity training in sedentary men: dissociation of central and local effects.

The oxygen transporting capacity and the metabolic capacity of the vastus lateralis muscle were followed in parallel in 9 sedentary, overweighted men during a low intensity training program. Measurements were made at 0, 3, 6, 9, 12 and 30 weeks. Maximal oxygen uptake increased in an approximately linear fashion during the first 12 weeks (11%), but decreased a little (3%) during the following 18 weeks. Mean body weight decreased 8% (7.4 kg) during the training. The distribution of muscle fibre types, including the subgroups of type II fibres, did not change. Muscle enzyme activities remained essentially unchanged during the training. It was concluded that "central" och "local" adaptation need not occur in parallel, and that the leg oxygen utilization capacity probably does not limit the whole body's maximal oxygen uptake.