Differences in physiological responses between short- vs. long-graded laboratory tests in road cyclists

Area of Science:

• Exercise Physiology
• Sports Science
• Cycling Performance Analysis

Background:

• Laboratory tests are crucial for evaluating athlete physiological responses.
• Graded exercise protocols are commonly used to assess maximal and submaximal exercise parameters.
• The specificity of laboratory test protocols to real-world performance demands is a key consideration in exercise science.

Purpose of the Study:

• To compare the physiological responses of road cyclists to short-graded versus long-graded laboratory tests.
• To determine which graded protocol is more specific for assessing road cyclists' physiological responses.
• To investigate the effects of different graded protocols on substrate oxidation and metabolic thresholds.

Main Methods:

• Twenty well-trained road cyclists completed randomized, crossover short- and long-graded laboratory tests.
• Measurements included blood lactate concentration, heart rate, oxygen consumption, and carbon dioxide production.
• Fat and carbohydrate oxidation rates, lactate threshold, and individual anaerobic threshold were calculated.

Main Results:

• Maximal fat oxidation and test duration were higher in the long-graded protocol.
• Peak power output, peak heart rate, and maximal lactate concentration were higher in the short-graded protocol.
• The crossover concept shifted to higher intensities in the long-graded protocol, indicating a greater reliance on fat metabolism.

Conclusions:

• The long-graded protocol is more specific for assessing the physiological responses of road cyclists, particularly concerning relative power output.
• Differences in metabolic demands (glycolytic vs. lipolytic) were observed between the protocols at submaximal intensities.
• Both lactate threshold and individual anaerobic threshold were reached at similar relative intensities, but at significantly different absolute power outputs.