Prediction of Drafted-Triathlon Race Time From Submaximal Laboratory Testing in Elite Triathletes

Purpose and methods: To determine which physiological variables accurately predict the race time of an Olympic-distance International Triathlon undertaken in drafted conditions, 8 elite triathletes underwent both maximal and submaximal laboratory and field physiological testing: a 400-m maximal swim test; an incremental treadmill test; an incremental cycling test; 30 min of cycling followed by 20 min of running (C-R); and 20 min of control running (R) at the exact same speed variations as in running in C-R. Blood samples were drawn to measure venous lactate concentration after the 400-m swim and the cycle and run segments of C-R. During the maximal cycling and running exercises, data were collected using an automated breath-by-breath system. Results: The only parameters correlated with the overall drafted-triathlon time were lactate concentration noted at the end of the cycle segment (r = 0.83, p < 0. 05) and the distance covered during the running part of the submaximal C-R test (r = -0.92, p < 0.01). Stepwise multiple regression analysis revealed a highly significant (r = 0.96, p < 0.02) relationship between predicted race time (from laboratory measures) and actual race time, using the following calculation: Predicted Triathlon Time (s) = -1.128 (distance covered during R of C-R [m]) + 38.8 ([lactate] at the end of C in C-R) + 13,338. The high R2 value of 0.93 indicated that, taken together, these two laboratory measures could account for 93% of the variance in race times during a drafted triathlon. Conclusion: Complementing previous studies, this study demonstrates that different parameters seem to be reliable for predicting performance in drafted vs. nondrafted Olympic-triathlon races. It also demonstrates that, for elite triathletes competing in a drafted Olympic-distance triathlon, performance is accurately predicted from the results of submaximal laboratory measures. Key words: swimming, cycling, running, lactate, oxygen uptake

Temperature and Water Velocity Effects on the Swimming Performances of Young-of-the-Year Striped Mullet (Mugil cephalus), Spot (Leiostomus xanthurus), and Pinfish (Lagodon rhomboides)

Swimming performances of young-of-the-year striped mullet (Mugil cephalus), spot (Leiostomus xanthurus), and pinfish (Lagodon rhomboides) were tested by examining the combination of physical endurance and swimming behavior to provide information on potential fish entrainment and impingement problems at industrial intakes. Tests were conducted at three temperatures (15–25 °C) and six water velocities (12–48 cm/s). Fish lengths ranged from 1.4 to 7.0 cm TL. Fish tested at higher temperatures exhibited increased time for steady swimming and for impingement avoidance. Temperature was also positively correlated with maximum swimming speeds and with the number of bursts performed during drift–burst activity (drifting with the current and returning upstream with a burst of swimming). Increased water velocities resulted in decreased times of steady swimming and impingement avoidance, and reduced drift–burst activity. Larger fish avoided impingement longer and had faster maximum swimming speeds; however, smaller fish showed stronger rheotaxis and swam steadily for longer periods at equal water velocities. Abnormally heavy mullet and spot had reduced capabilities for position maintenance (steady swimming) which may decrease their ability to avoid impingement. Key words: swimming speeds, temperature, water current, impingement, behavior, mullet, spot, pinfish