Oral creatine supplementation augments the repeated bout effect

Area of Science:

• Exercise Physiology
• Sports Nutrition
• Muscle Metabolism

Background:

• Resistance exercise induces muscle damage, characterized by soreness and elevated creatine kinase (CK).
• Repeated bouts of exercise typically elicit a reduced response, known as the repeated bout effect.
• Understanding factors that augment this effect is crucial for optimizing training and recovery.

Purpose of the Study:

• To investigate the impact of creatine supplementation on the physiological response to repeated bouts of resistance exercise.
• To determine if creatine influences markers of muscle damage and recovery.

Main Methods:

• Young men were divided into creatine (CM) and placebo (PL) groups.
• Subjects performed two bouts of bicep curls to failure, separated by a period of supplementation (20g/d creatine monohydrate or placebo).
• Muscle soreness, range of motion (ROM), and serum creatine kinase (CK) activity were measured to assess muscle damage and recovery.

Main Results:

• Both groups experienced muscle damage after the first exercise bout, indicated by increased soreness, CK, and decreased ROM.
• The second exercise bout resulted in a lesser increase in damage markers compared to the first bout in both groups.
• Creatine supplementation significantly attenuated the rise in serum CK and muscle soreness, and preserved elbow ROM more effectively than placebo after the second bout.

Conclusions:

• Creatine supplementation demonstrates an additive effect in reducing muscle damage markers following repeated resistance exercise bouts.
• Creatine appears to enhance the repeated bout effect, potentially through its multifaceted physiological functions.
• These findings suggest creatine can aid recovery and adaptation to resistance training.