Synergetic Effect of NO Precursor Supplementation and Exercise Training.

Area of Science:

• Exercise Physiology
• Nutritional Biochemistry
• Sports Science

Background:

• Nitric oxide (NO) precursor supplementation may enhance vascular function and exercise capacity.
• The synergistic effects of combining NO precursor supplementation with exercise training on performance adaptations remain unclear.

Purpose of the Study:

• To investigate the impact of chronic nitrate and citrulline supplementation on exercise training adaptations in healthy young individuals.
• To assess potential synergistic effects on vascular function, muscle oxygenation, and exercise performance.

Main Methods:

• A 2-month randomized, double-blind trial involving 24 healthy young subjects.
• Daily intake of a placebo or a nitrate-rich (520 mg) and citrulline (6 g) drink during an exercise training program.
• Assessment of vascular function, muscle and cerebral oxygenation (near-infrared spectroscopy), and local (knee extension) and whole-body (cycling) exercise tests.

Main Results:

• Nitrate and citrulline supplementation did not alter vascular function or muscle and cerebral oxygenation during exercise.
• Significant improvements in maximal knee extensor strength (+5.1 kg) and a trend towards increased endurance were observed with supplementation compared to placebo.
• No significant effect on exercise training-induced improvements in maximal aerobic performance.

Conclusions:

• Chronic nitrate and citrulline supplementation amplifies exercise training adaptations in quadriceps muscle function.
• These ergogenic effects on muscle strength and endurance do not extend to improvements in maximal aerobic capacity.