Phosphate Loading Does not Improve 30-km Cycling Time-Trial Performance in Trained Cyclists.

Area of Science:

• Exercise Physiology
• Nutritional Biochemistry

Background:

• Phosphate is crucial for metabolic processes influencing exercise performance, including cardiac function and oxidative metabolism.
• Previous research on phosphate loading for performance enhancement is limited and yields conflicting results, partly due to varied supplement formulations.
• Standardizing phosphate dosage is essential for reliable ergogenic effect studies.

Purpose of the Study:

• To investigate the ergogenic potential of phosphate loading in well-trained cyclists.
• To determine if high-dose dibasic sodium phosphate supplementation improves 30-km time trial performance.
• To assess the impact of phosphate loading on physiological markers of performance.

Main Methods:

• A randomized, single-blind, cross-over design was employed with 16 trained cyclists.
• Participants ingested either 3.5 g/day of dibasic sodium phosphate (24.7 mmol phosphate/day) or a sodium chloride placebo for 4 days.
• Performance was assessed via two 30-km time trials, separated by a 14-day washout period.

Main Results:

• No significant differences were observed in time to complete the 30-km time trial between phosphate loading and placebo conditions.
• Absolute and relative mean power outputs did not differ meaningfully between the two groups.
• Cardiovascular strain (heart rate) and perceived exertion levels were closely matched across treatments.

Conclusions:

• Supplementing with high absolute doses of phosphate (>10 mmol daily for 4 days) does not provide ergogenic effects for trained cyclists in 30-km time trials.
• The study suggests that phosphate loading, under these conditions, does not enhance endurance performance.
• Further research may be needed to explore potential benefits in different populations or under varied exercise protocols.