Serum creatine is not a reliable marker of muscular fitness in young adults

Abstract

Purpose: Elevated serum creatine and higher handgrip strength are individually associated with better health profiles yet the link between two variables remains unknown. In this cross-sectional study, we evaluated serum creatine levels in relation to handgrip strength in a cohort of 130 young healthy adults (61 women and 69 men; age 23.3 ± 2.6 years), while controlling for age, gender, fat-free mass and biomarkers of creatine metabolism as effect modifiers.

Materials and methods: Serum creatine, creatinine and guanidinoacetic acid (GAA) levels were measured with liquid chromatography-tandem mass spectroscopy, while handgrip strength was assessed with a hydraulic hand dynamometer.

Results: Hierarchical multiple regression revealed that our model as a whole explained 79.9% of the variance in handgrip strength (p < 0.001). However, the evaluation of the contribution of each independent variable revealed that gender and free-fat mass make significant contributions (45.4 and 31.8%, respectively) to our model (p < 0.05), while neither age (0.9%) nor serum creatine (4.5%) or any other lab markers made significant contributions to the model (p > 0.05).

Conclusions: Having higher blood creatine appears to be unrelated with better physical performance in young healthy adults. Serum creatine was not a reliable marker of muscular fitness in this population.

Keywords:

• Creatine
• guanidinoacetic acid
• hierarchical multiple regression
• muscular fitness
• fat-free mass

Disclosure statement

The authors report no conflicts of interest.

Additional information

Funding

This study was supported by the Serbian Ministry of Education, Science and Technological Development (175037), the Provincial Secretariat for Higher Education and Scientific Research (114-451-710), the Faculty of Sport and Physical Education and the Center for Health, Exercise and Sport Sciences. The funders had no role in study design, data collection, analysis and interpretation, decision to publish or preparation of the manuscript.