The aim of the study was to investigate the relationship between local tissue temperature, peak torque and time to fatigue during isometric knee extensions. Nine males performed maximum voluntary contractions (MVCs) and isometric knee extensions at 70% MVC to exhaustion after 30 min of hot [H, 47.7 (1.3) degrees C; mean (SD)], warm [W, 34.6 (0.4) degrees C], temperate [T, 24.5 (1.3) degrees C], and cold [C, -11.9 (1.8) degrees C] localized temperature applications. Isometric peak torque was not significantly affected by temperature. Time to fatigue was strongly and negatively correlated ( r=-0.98) to temperature, with endurance after H [46.99 (4.98) s] and W [54.36 (9.18) s] significantly shorter than after C [73.27 (13.43) s]. We conclude that local tissue temperature does not impair peak force production but may change muscular endurance through local factors.

Purpose: To determine the reliability and validity of a novel trunk maximal isometric force assessment involving 7 different tasks with 200-m times for elite sprint flat-water kayakers. Methods: Ten elite sprint flat-water kayakers performed a series of maximal isometric voluntary contractions (MVCs) on 2 separate days to assess reliability. MVC force was assessed as the participants sat on a modified kayak ergometer and applied their maximal isometric force to a uniaxial load cell during 7 different tasks. The 7 tasks of interest were a seated trunk-forward flexion, bilateral (left and right) rotational pulls, bilateral rotational pushes, and a sport-specific bilateral kayak-stroke simulation. Twenty elite flat-water kayak athletes (10 male and 10 female) participated in the validity portion by completing the series of tasks in conjunction with a 200-m race. Results: MVC force values ranged from 84 to 800 N across all participants and all tasks. The average coefficient of variation of the 7 tasks ranged from 2.4% to 7.7%. Regression analysis showed Pearson correlations ranging from −.84 to −.22 for both absolute and relative values with 200-m performance times. Conclusions: MVC force measured in each task was considered reliable as a small degree of variance between trials was found. The summation of the 7 trunk scores showed very strong correlations with on-water performance, indicating that this assessment is valid for elite sprint kayakers.