Sympathetic response to maximal bicycle exercise before and after leg strength training

Area of Science:

• Exercise Physiology
• Sports Science
• Human Physiology

Background:

• Leg strength training enhances physical performance and body composition.
• Sympathetic nervous system activity during exercise is influenced by various factors.
• Understanding the regulation of sympathetic response is crucial for exercise science.

Purpose of the Study:

• To investigate the effects of leg strength training on plasma catecholamine concentrations.
• To examine the relationship between strength training, exercise performance, and sympathetic response.
• To test the hypothesis that muscle chemoreceptors, rather than central command, primarily regulate sympathetic response to exercise.

Main Methods:

• Seven young active males underwent an 8-week leg strength training program.
• Maximal exercise tests on a cycle ergometer were performed before and after training.
• Plasma concentrations of norepinephrine, epinephrine, and lactate were measured at rest and during exercise/recovery.

Main Results:

• Strength training significantly increased squat and leg press performance and lean body mass.
• Maximal oxygen consumption and plasma lactate concentrations remained unchanged.
• No significant differences were observed in resting or exercise-induced plasma catecholamine levels before and after training.

Conclusions:

• Leg strength training improves performance without altering sympathetic neurochemical response to a given absolute workload.
• These findings support the hypothesis that muscle chemoreceptor afferents play a significant role in modulating sympathetic outflow during exercise.
• The study suggests that reduced central command at a fixed workload, rather than changes in catecholamine levels, influences the sympathetic response post-training.