20 healthy trained males will volunteer to participate in this study. there will be 2 treatments: Carbohydrate- ketone supplementation and carbohydrate alone. The purpose of this study is to evaluate the effect of glucose-ketone supplementation on a 20 km cycling time trial with a 2-hour feeding during a 4-hour recovery period following glycogen depleting exercise.
Carbohydrates (starches \& sugars) are important muscle fuel for exercise at moderate to high intensities. Low glycogen content (stored form of carbohydrates in the body) is associated with fatigue. Thus, greater initial glycogen content has been associated with better performance not only in high intensity intermittent sports, but also in prolonged endurance sports. Dose-response studies have determined that ingestion of 1.2 g·kg-1·h-1 of CHO is the appropriate acute recovery dose to optimize glycogen repletion, with no apparent benefit at higher doses. Protein in combination with CHO has also been proposed to enhance glycogen resynthesis when 1 part protein is provided with \~4 parts CHO. Both strategies, optimal CHO intake and CHO in combination with protein for glycogen resynthesis, have resulted in better exercise performance a few hours after a depleting exercise bout. A recent study provided athletes with ketone esters in a drink after glycogen depleting exercise and found that in the presence of high glucose availability, ketone esters increased glycogen stores by 50% compared to a no ketone, high carbohydrate treatment. However, the authors of this study provided a large quantity of carbohydrates intravenously to maintain blood glucose at 10Mm/L. Consequently, it is unknown whether or not ingesting glucose at the optimal dosage would have the same effect. Furthermore, it is unclear whether or not this difference would translate into improved performance in efforts of more moderate duration. Therefore, the purpose of this study is to assess the effect of glucose-ketone supplementation on a 20 km cycling time trial with a 2-hour feeding during a 4-hour recovery period following glycogen depleting exercise.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
OTHER
Masking
DOUBLE
Enrollment
20
20 km time trial cycling test will be conducted to measure the effect of different drinks on performance time
Glycogen will be lowered using a 10-min warm-up period at a workload of 50% max wattage power output (Wmax). Thereafter, participants will be instructed to cycle 2-min block periods at alternating workloads of 90% and 50% of Wmax, respectively. This will be continued until the participants are no longer able to complete the 2 min at 90% Wmax. That moment will be defined as the time at which the individual is unable to maintain cycling speed at 60 revolutions/min. At that moment the high-intensity block will be reduced to 80% Wmax. Again, athletes will cycle until they are unable to complete a 2-min block at 80% Wmax, after which the high-intensity block will be reduced to 70% Wmax. Finally, participants will be allowed to stop when pedalling speed could not be maintained at 70% Wmax.
Exercise Nutrition Laboratory (Western University)
London, Ontario, Canada
RECRUITING20 km cycling time trial
participants will ride for 20 km on a stationary bike and time to finish will be measured
Time frame: 40 minutes
Blood insulin
insulin in blood will be measured using ELISA kits
Time frame: 2 hours
Blood Lactate
blood lactate will be measured using lactate meter
Time frame: 45 minutes
Blood Ketones
Ketones in blood will be measured using ketone meter
Time frame: 2 hours
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