SIMULATED FRONT CRAWL SWIMMING PERFORMANCE RELATED TO CRITICAL SPEED AND CRITICAL POWER

Purpose: Competitive pool swimming events range in distance from 50 to 1500 m. Given the difference in performance times (+/-23-1000 s), the contribution of the aerobic and anaerobic energy systems changes cons iderably with race distance. In training practice the regression line between swimming distance and time (Distance = critical velocity X tim e + anaerobic swimming capacity) is used to determine the individual c apacity of the aerobic and anaerobic metabolic pathways. Although ther e is confidence that critical velocity and anaerobic swimming capacity are fitness measures that separate aerobic and anaerobic components, a firm theoretical basis for the interpretation of these results does not exist. The purpose of this study was to evaluate the critical powe r concept and anaerobic swimming capacity as measures of the aerobic a nd anaerobic capacity using a modeling approach, Methods: A systems mo del was developed that relates the mechanics and energetics involved i n front crawl swimming performance. From actual swimming flume measure ments, the time dependent aerobic and anaerobic energy release was mod eled. Data derived from the literature were used to relate the energy cost of front crawl swimming to swimming velocity. A balance should ex ist between the energy cost to swim a distance in a certain time and t he concomitant aerobic and anaerobic energy release. The ensuing model was used to predict performance times over a range of distances (50-1 500 m) and to calculate the regression line between swimming distance and time. Results and Conclusions: Using a sensitivity analysis, it wa s demonstrated that the critical velocity is indicative for the capaci ty of the aerobic energy system. Estimates of the anaerobic swimming c apacity, however were influenced by variations in both anaerobic and a erobic energy release. Therefore, it was concluded that the anaerobic swimming capacity does not provide a reliable estimate of the anaerobi c capacity.