The purpose of this study was to investigate the characteristrics of anaerobic capacity from pre-puberty to adlescence. Twenty eight well trained swimmers were divided into five groups following age of 9 to 10 yrs (AG1), 11 to 12 yrs (AG2), 13 to 14 yrs (AG3), 15 to 16 yrs (AG4) and 17 to 18 (AG5). All swimmers first completed a series of four submaximal and one maximal effort swims for determination of swimming economy profile. The linear relationship (VO2 vs. velocity^3) was extrapolated to 140% of max VO2 for each swimmer and a corresponding velocity selected. The following day, swimmers completed a freestyle swim at the pace selected from the economy profile. During this test, accumulated 02 uptake was mearured continuously and the accumulated 02 deficit calculated following the swim (Hermansen, 1984). A two minute post swim blood sample was taken for analysis of lactate. Girth measurements of the upper arm were taken for determination of muscle area. A swim bench test was also administered for deterninetion of peak muscle power and total muscular work. The results were as follows ; 1) The values of O_2 deficit, % anaerobic contribution, and lactate acid showed increases with age. 2) Power/muscle and total muscular work displayed higher values with age. 3) A significant increase was found from AG2 to AG3 in all the items
