King Grub
2016-06-02, 11:48
PURPOSE:
To examine the effects of 3 days of intermittent fasting (3d-IF: abstaining from eating/drinking from dawn to sunset) on physical performance and metabolic responses to repeated-sprints (RS).
METHODS:
Twenty-one active males performed an RS-test [2 sets: 5×5-second maximal-sprints with 25 seconds of recovery between sprints and 3 minutes of recovery between sets on an instrumented treadmill] in two conditions: counter-balanced fed/control session (CS) and fasting session (FS assessed on the 3rd day of IF; sessions: 4pm to 6pm, 7 days in-between). Biomechanical and biochemical markers were assessed pre- and post-exercise.
RESULTS:
Significant main effects of IF were observed for sprints: maximal-speed (P=0.016), mean-speed (P=0.015), maximal-power (P=0.035), mean-power (P=0.049), vertical stiffness (P=0.032), and vertical center of mass displacement (P=0.047). Sprint speed and vertical stiffness decreased during the first and second sprints of set-2 (P=0.030). Post-exercise insulin decreased in CS (P=0.023) but not in FS (P=0.230). Free-fatty acid levels were higher in FS than that of CS at pre- (P<0.001) and at post-exercise (P=0.009). HDL-cholesterol was higher at post-exercise in FS (1.32±0.22-mmol.l-1) compared with that of CS (1.26±0.21-mmol.l-1, P=0.039). The triglyceride concentration was decreased in FS (P<0.05) compared with that of CS.
CONCLUSION:
The findings were that 3d-IF impaired speed and power through a decrease in vertical stiffness during the initial runs of the second set. The findings of the present study confirmed the benefits of 3d-IF: improved HDL-C and TG profiles while maintaining TC and LDL-C levels. Moreover, improving muscle power might be a key factor to retain a higher vertical stiffness and to partly counteract the negative effects of intermittent fasting. FS showed beneficial changes in biochemical marker levels from an overall health point of view.
Int J Sports Physiol Perform. 2016 Jun 1. Three Days of Intermittent Fasting: Repeated-Sprint Performance Decreased by Vertical Stiffness Impairment.
To examine the effects of 3 days of intermittent fasting (3d-IF: abstaining from eating/drinking from dawn to sunset) on physical performance and metabolic responses to repeated-sprints (RS).
METHODS:
Twenty-one active males performed an RS-test [2 sets: 5×5-second maximal-sprints with 25 seconds of recovery between sprints and 3 minutes of recovery between sets on an instrumented treadmill] in two conditions: counter-balanced fed/control session (CS) and fasting session (FS assessed on the 3rd day of IF; sessions: 4pm to 6pm, 7 days in-between). Biomechanical and biochemical markers were assessed pre- and post-exercise.
RESULTS:
Significant main effects of IF were observed for sprints: maximal-speed (P=0.016), mean-speed (P=0.015), maximal-power (P=0.035), mean-power (P=0.049), vertical stiffness (P=0.032), and vertical center of mass displacement (P=0.047). Sprint speed and vertical stiffness decreased during the first and second sprints of set-2 (P=0.030). Post-exercise insulin decreased in CS (P=0.023) but not in FS (P=0.230). Free-fatty acid levels were higher in FS than that of CS at pre- (P<0.001) and at post-exercise (P=0.009). HDL-cholesterol was higher at post-exercise in FS (1.32±0.22-mmol.l-1) compared with that of CS (1.26±0.21-mmol.l-1, P=0.039). The triglyceride concentration was decreased in FS (P<0.05) compared with that of CS.
CONCLUSION:
The findings were that 3d-IF impaired speed and power through a decrease in vertical stiffness during the initial runs of the second set. The findings of the present study confirmed the benefits of 3d-IF: improved HDL-C and TG profiles while maintaining TC and LDL-C levels. Moreover, improving muscle power might be a key factor to retain a higher vertical stiffness and to partly counteract the negative effects of intermittent fasting. FS showed beneficial changes in biochemical marker levels from an overall health point of view.
Int J Sports Physiol Perform. 2016 Jun 1. Three Days of Intermittent Fasting: Repeated-Sprint Performance Decreased by Vertical Stiffness Impairment.