Predicting the individual lactate minimum speed by T10 and T30 in swimming.

BACKGROUND: This study investigated the relationship between the lactate minimum (LACmin) and the 10- (T10) and 30-min (T30) continuous tests in swimmers. METHODS: Twelve swimmers (78.1±3.1% of the world record) performed the LACmin (hyperlactatemia: 2×50 m all-out 8-min apart, incremental part: N.×300 m 30-s apart), T30 and T10 using the front-crawl stroke. Blood samples were collected after each stage of LACmin for lactate analysis. Swimmers were oriented to swim as fast and as constant as possible in T10 and T30. RESULTS: Speeds in T10 (1.28±0.10 m/s) and T30 (1.21±0.09 m/s) were different from LACmin (1.24±0.09 m/s). T10 and T30 speeds presented a nearly perfect relationship with LACmin and acceptable prediction errors (T10: r=0.938, P<0.001, 0.033 m/s; T30: r=0.927, P<0.001, 0.036 m/s, respectively). CONCLUSIONS: T10 and T30 can be used as indirect tests for evaluating LACmin in swimming.

Acute responses of biomechanical parameters to different sizes of hand paddles in front-crawl stroke.

This study investigated the acute effects of different sizes of paddles on the force-time curve during tethered swimming and swimming velocity in front-crawl stroke. Fourteen male swimmers (20.0 ± 3.7 years; 100-m best time: 53.70 ± 0.87 s) performed two 10-s maximal efforts in tethered swimming to obtain peak force, average force, impulse, rate of force development, stroke duration and time to peak force. Swimming velocity, stroke rate and stroke length were obtained from two 25-m maximal swims. Both tests were repeated in five conditions: free swimming, wearing small (280 cm (2) ), medium (352 cm (2) ), large (462 cm (2) ) and extra-large (552 cm (2) ) hand paddles. Compared to free swimming, paddles provided significant increases of peak force (medium: 11.5%, large: 16.7%, extra-large: 21.7%), impulse (medium: 15.2%, large: 22.4%, extra-large: 30.9%), average force (medium: 5.1%, large: 7.5%), rate of force development (extra-large: 11.3%), stroke duration (medium: 9.3%, large: 11.8%, extra-large: 18.5%), time to peak force (medium: 11.1%, large: 15.9%, extra-large: 22.1%), swimming velocity (medium: 2.2%, large: 3.2%, extra-large: 3.7%) and stroke length (medium: 9.0%, large: 9.0%, extra-large: 14.8%), while stroke rate decreased (medium: -6.2%, large: -5.5%, extra-large: -9.5%). It is concluded that medium, large and extra-large paddles influence the force-time curve and change swimming velocity, suggesting these sizes may be useful for force development in water.