The purpose of this study was to determine the relationship between oxygen demand, stroke rate and swimming velocity in competitive swimmers. The subjects who volunteered for this study were ten trained male swimmers (age, 16.7 +/- 0.4 yrs). VO2peak, swimming velocities at 80% (V80% VO2peak) and 100% (V100% VO2peak) of VO2peak and swimming velocity at the onset of blood lactate accumulation (VOBLA) were determined during a swimming economy profile test in a swimming flume. In the swimming economy test, determined by studying the relationship between oxygen uptake and swimming velocity cubed, the subjects were instructed to swim for six minutes at five or six submaximal swimming velocities. Steady-state oxygen uptake and stroke rate were calculated during the final two minutes of swimming. Results indicated that there were significant correlations between oxygen uptake and swimming velocity cubed (r = 0.963 to 0.998, p < 0.01), between oxygen uptake and stroke rate (r = 0.925 to 0.998, p < 0.01) and between stroke rate and swimming velocity cubed (r = 0.897, p < 0.05; to 0.994, p < 0.01) for all subjects. Furthermore, it was found that the slopes of the regression lines between oxygen uptake and swimming velocity cubed and between oxygen demand and stroke rate were significantly correlated to swimming performance indices (V80% VO2peak, V100% VO2peak and VOBLA). The results of this study suggest that the slope of the regression line between oxygen uptake and stroke rate can be utilized as an effective index of evaluating swimming performance.

The purpose of this study was to examine the effects of lifelong aerobic exercise (LLE) on VOmax and skeletal muscle metabolic fitness in trained females (n=7, 72±2y) and males (n=21, 74±1y), and compare them to old healthy non-exercisers (OH; females: n=10, 75±1y; males: n=10, 75±1y), and young exercisers (YE; females: n=10, 25±1y; males: n=10, 25±1y). LLE males were further subdivided based on intensity of lifelong exercise and competitive status into performance (LLE-P, n=14) and fitness (LLE-F, n=7). On average, LLE exercised 5d/wk for 7h/wk over the past 52±1y. Each subject performed a maximal cycle test to assess VOmax and had a vastus lateralis muscle biopsy to examine capillarization and metabolic enzymes (citrate synthase, β-HAD, and glycogen phosphorylase). VOmax had a hierarchical pattern (YE>LLE>OH, P<0.05) for females (44±2>26±2>18±1 ml•kg•min) and males (53±3>34±1>22±1 ml•kg•min), and was greater (P<0.05) in LLE-P (38±1 ml•kg•min) than LLE-F (27±2 ml•kg•min). LLE males, regardless of intensity, and females had similar capillarization and aerobic enzyme activity (citrate synthase and β-HAD) as YE, which were 20-90% greater (P<0.05) than OH. In summary, these data show a substantial VOmax benefit with LLE that tracked similarly between the sexes, with further enhancement in performance trained males. For skeletal muscle, 50+ years of aerobic exercise fully preserved capillarization and aerobic enzymes, regardless of intensity. These data suggest that skeletal muscle metabolic fitness may easier to maintain with lifelong aerobic exercise than more central aspects of the cardiovascular system.

SWE elicited metabolic and cardiovascular responses that met ACSM's guidelines for establishing health benefits. Furthermore, older females may self-select a greater relative exercise intensity during SWE compared with younger counterparts when provided with the same verbal instructions and encouragement.

Despite similar rates of energy expenditure during training, it has been suggested that swimmers store greater amounts of body fat than runners. To investigate these discrepancies, eight male swimmers (S) and runners (R) were monitored during 45 min of swimming or running (75% VO2max), respectively, and six triathletes were monitored during swimming (ST) and running (RT). Each group was also monitored during two hours of recovery. Venous blood samples were obtained before exercise, immediately after exercise (0 min) and at 15, 30, 60 and 120 min of recovery. These samples were analyzed for glucose, lactate, glycerol, free fatty acids (FFA), insulin, glucagon, norepinephrine (NE) and epinephrine (E). Expired gases and heart rates (HR) were obtained during exercise and also during recovery. The caloric cost of recovery was similar, but the RER results suggested increased fat oxidation during recovery for the S and the ST. Serum glucose was greater (P less than 0.05) immediately after exercise for R (6.71 +/- 0.29 mmol/l) and RT (6.40 +/- 0.26) compared to the S (4.97 +/- 0.19) and ST (4.87 +/- 0.18), and was significantly elevated for the initial 30 min of recovery. FFA were similar throughout the recovery period; however, blood glycerol was greater immediately after exercise (0 min) for R compared to S (NS) and was significantly elevated after exercise (0 min) for RT compared to ST. Differences in blood glucose or fat release were not explained by differences in NE or E; however, the glucacon-to-insulin ratio was significantly greater after exercise in the S and ST compared to the R and RT.(ABSTRACT TRUNCATED AT 250 WORDS)

No abstract