Many individuals engage in short-term fasting in combination with early morning physical activity, for the perceived health benefits such as weight management and improvements in body composition. Evidence for performance implications has been found in strength- and endurance-based training following short-term fasting; however, few studies have utilised the isokinetic dynamometer as a measurement of strength performance outcomes. Therefore, this study aimed to investigate the effects of a short-term fast on isokinetic muscular performance in recreationally active individuals. Eleven participants (male = 2, female = 9) completed two trials in fasted and non-fasted states. Participants completed a ten-hour overnight fast before both trials. In the fasted condition, they continued fasting for an additional two hours before testing. In the non-fasted condition, breakfast was consumed after the ten-hour overnight fast, and testing took place two hours later.
Maximal effort knee extension contractions were carried out at four different angular velocities (0, 45, 90, 180°/s) on an isokinetic dynamometer. Fasting state did not have any significant impact on muscular performance parameters, including peak power, peak power relative to bodyweight, the angle of peak torque, degrees to peak torque, and functional range (each p >0.07, d <0.44). Significant differences were found for peak torque, peak torque relative to bodyweight, time to peak torque, work and work relative to bodyweight (each p <0.03, d <0.45), however, effect sizes were small, and significance did not extend to speeds other than 45°/s. The findings of this study suggest that a short-term overnight fast does not alter isokinetic knee extensor performance in this population. Individuals who prefer to carry out exercise in a fasted state can do so without experiencing significant deficits in their muscular performance, which in turn may lead to greater adherence to regular exercise.
PLEASE NOTE: You must be a member of the University of Lincoln to be able to view this dissertation. Please log in here.