None listed
Conditions
Brief summary
Background: Sodium bicarbonate is a compound often used in food and baking, and has been associated with improvements in high intensity exercise of different modalities, including running, swimming and cycling (Burke and Pyne, 2007). Ingestion of sodium bicarbonate results in an increased blood alkalosis (measured via blood pH and blood bicarbonate concentration), which can aid in buffering hydrogen ions, and act to delay the onset of fatigue in high-intensity exercise (Carr et al., 2011). Sodium bicarbonate is most often ingested at a dose of 0.3 grams per kilogram of participants’ body mass, a dose that has been found to have the greatest effect on performance (McNaughton et al., 1992). Phosphate is an essential mineral that is obtained in the diet, and is a component of phosphocreatine and adenosine triphosphate, important components in oxygen transport within the red blood cell (Brewer et al., 2013). Phosphate can be ingested in the form of sodium phosphate, which has been associated with enhancements in endurance exercise performance (Cade et al., 1984) and peak aerobic capacity (Folland et al., 2008). The recommended dose of sodium phosphate is 50 mg per kg of participants’ fat free mass. Mechanisms associated with sodium phosphate supplementation include an increase in 2,3-diphosphoglycerate content in the blood, which can aid with the release of oxygen to the muscle, as well as an increased buffering capacity (Brewer et al., 2014). Participants: One hundred and twenty well-trained, male and female cyclists will be recruited to complete this study. Experimental Design: Experimental Testing Overview: Participants will visit the laboratory on three occasions. The first visit to the laboratory will require participants to complete a DEXA scan and simple anthropometric measures (height, mass and sum of 7 skin folds) to assess body composition, as well as a graded exercise test to determine maximal oxygen consumption (VO2max), and a familiarisation with the cycling performance test. The remaining two visits will require participants to complete cycling performance trials. For the second laboratory visit, participants will complete a baseline cycling performance test. The third laboratory visit will require participants to complete the same cycling performance test, under one of four supplementation conditions, assigned in a parallel groups design. The four experimental conditions are: 1) sodium phosphate and placebo, 2) sodium phosphate and sodium bicarbonate, 3) sodium bicarbonate and placebo, 4) placebo and placebo. Capillary and venous blood samples will also be taken during the second and third laboratory visits.
Interventions
Two safe and legal supplements (sodium phosphate and sodium bicarbonate) will be administered to well-trained cyclists, prior to performing a cycling-based performance test in the laboratory.
Participants' performance will be compared to their own baseline performance, and also to the placebo condition. There will be four treatment groups:
1) Sodium phosphate supplementation - requiring participants to ingest sodium phosphate for the six days prior to the second cycling performance test, and a
Two safe and legal supplements (sodium phosphate and sodium bicarbonate) will be administered to well-trained cyclists, prior to performing a cycling-based performance test in the laboratory. Participants' performance will be compared to their own baseline performance, and also to the placebo condition. There will be four treatment groups: 1) Sodium phosphate supplementation - requiring participants to ingest sodium phosphate for the six days prior to the second cycling performance test, and a placebo on the day of the second performance test. 2) Sodium phosphate and sodium bicarbonate supplementation - requiring participants to ingest sodium phosphate for the six days prior to the second performance test, and sodium bicarbonate on the day of the second performance test. 3) Sodium bicarbonate supplementation - requiring participants to ingest a placebo for the six days prior to the second performance test, and sodium bicarbonate on the day of the second performance test. 4) Placebo - requiring participants to ingest a placebo for the six days prior to the second performance test, and also ingest a placebo on the day of the second performance test. The sodium bicarbonate will be administered at a dose of 300 mg per kg of the participants' body mass, and will be ingested in capsule form, 90 min prior to the start of the second cycling performance test. The sodium bicarbonate will be ingested in the laboratory, on the day of the second cycling performance test, under the supervision of staff. The sodium phosphate will be administered at a dose of 50 mg per kg of participants' fat free mass (as determined by a DEXA scan), and will be ingested as a solution (sodium phosphate powder mixed with sports drink powder, and then dissolved in water). The sodium phosphate dosage will be provided to participants after they perform their baseline test, and they will be instructed to ingest the sodium phosphate daily for the six days prior to the second cycling performance test. Participants will be asked to verbally confirm that they have ingested the sodium phosphate as instructed. There will be one week between the baseline and post-intervention cycling tests. The cycling test comprises six sets of repeated sprints and time trials, and is 43 min in total duration. The performance test has previously been used in a previous study (Brewer et al., 2015). This reference has now been attached to the application. To summarise the performance test, the first set comprises 6 x 15 second sprints, with 45 seconds active recovery between each sprint. The second set comprises 6 x 15 second sprints, with 15 seconds of active recovery between each sprint. The third set comprises a continuous, 5 min time trial. The fourth set again comprises 6 x 15 second sprints with 45 seconds active recovery, the fifth set is 6 x 15 second sprints with 15 seconds active recovery, and the sixth set is a continuous, 5 min time trial. A 3 minute active recovery at a minimum power output of 100 watts is performed after the first 5 sets, and the test concludes at the end of the sixth set. Performance will be measured in comparison to baseline performance on the same cycling performance test.
Sponsors
Dr Amelia Carr
Study design
Allocation
Non-randomised trial
Intervention model
Parallel
Primary purpose
Educational / counselling / training
Masking
Blinded (masking used) (Subject)
Eligibility
Sex/Gender
All
Age
18 Years to 40 Years
Healthy volunteers
Yes
Inclusion criteria
Male and female, well trained cyclists. Cyclists will need to demonstrate evidence of participation in a recent Criterium (short road race).
Exclusion criteria
Children under 18 years of age, as well as pregnant women.
Outcome results
None listed