Distribution of concurrent training sessions does not impact endurance adaptation

Area of Science:

• Exercise Physiology
• Military Training Science
• Sports Science

Background:

• Optimized concurrent training is crucial for military, law enforcement, and rescue personnel.
• Understanding the impact of training frequency and duration on physical capacity is essential for these demanding professions.

Purpose of the Study:

• To compare the effectiveness of four 15-minute endurance training sessions versus one 60-minute session weekly.
• To evaluate improvements in aerobic capacity and performance during the initial phase of Basic Military Training.

Main Methods:

• A randomized intervention study involving 290 military conscripts over 9 weeks.
• Three groups: Micro-training (MIC) with 4x15min sessions, Classical-training (CLA) with 1x60min session, and Control-training (CON).
• Functional and physiological tests were conducted before and after the intervention.

Main Results:

• Running performance (12-min and shuttle run) and functional exercise capacity (lunges, push-ups, abdominal flexions) improved similarly across all groups.
• Peak oxygen uptake increased significantly in the MIC and CON groups, but not in the CLA group.
• Muscle enzyme activity (CS and HAD) decreased in the MIC and CLA groups, indicating reduced oxidative capacity.

Conclusions:

• Shorter, more frequent endurance training sessions (MIC) are as effective as longer, less frequent sessions (CLA) for improving running and strength-endurance.
• Increased aerobic capacity (peak oxygen uptake) requires more than one endurance session per week.
• Basic Military Training may lead to a reduction in leg muscle oxidative capacity, particularly with less frequent endurance training.