Serum creatine kinase activity following forearm flexion isometric exercise

Area of Science:

• Exercise Physiology
• Biochemistry
• Sports Medicine

Background:

• Serum creatine kinase (CK) is a marker of muscle damage and stress.
• Isometric exercise elicits unique physiological responses compared to dynamic exercise.
• Understanding the factors influencing CK response is crucial for training and recovery protocols.

Purpose of the Study:

• To compare serum CK activity after two isometric forearm flexion exercise regimens with different work-to-rest ratios.
• To investigate the effect of a repeated bout of isometric exercise on CK response.

Main Methods:

• Eleven males participated in two testing sessions one week apart.
• Bout 1 involved two groups: Group A (10:20 work:rest ratio) and Group B (10:5 work:rest ratio).
• Both groups repeated the 10:20 exercise one week later for Bout 2.

Main Results:

• The 10:20 exercise regimen resulted in a significantly greater serum CK increase (143%) compared to the 10:5 regimen (52%).
• Higher tension generation was observed with the 10:20 exercise.
• A substantial reduction in CK response was noted during the repeated 10:20 bout, independent of tension levels.

Conclusions:

• Greater overall tension during isometric exercise correlates with a higher serum CK response.
• A repeated bout of isometric exercise induces a significantly blunted CK response, suggesting an adaptation or protective effect.
• The reduced CK response upon re-exposure indicates muscle adaptation, irrespective of the initial exercise's tension levels.