The Association of Serum Calprotectin with Fitness Indicators and Biochemical Markers in High-Level Athletes: A Continuous Dynamic Monitoring during One Competitive Season

Abstract

The objective was to determine the associations between several biochemical indicators and the dynamics of concentration change across four physical fitness phases over the period of a competitive season. Furthermore, associations between serum calprotectin and biomarkers of inflammation or muscle injury and physical indicators were examined.

Subjects and methods: Twenty professional male water polo players (median age: 28 (22-42)) were included in this study. Serum creatine kinase activity was determined by the automated photometric UV method. The concentrations of calprotectin, C-reactive protein, and myoglobin were measured using an automated immunoturbidimetric method, while an automated immunochemistry method was employed for interleukin-6, troponin I, and cortisol determination. Tests of repeated strength, maximal strength, and static strength were used to evaluate physical activity.

Results: Serum calprotectin concentrations expressed in median and IQR were significantly different: T1: 2.92 g/mL (2.47; 3.86); T2: 2.35 g/mL (1.26; 2.87); T3: 2.27 g/mL (1.60; 3.27); and T4: 1.47 g/mL (1.04; 2.85) (p = 0.004). Cortisol concentration and CK activity showed significant changes among phases (p = 0.049 and p = 0.014, respectively). Each physical activity examined showed a significant seasonal decrease (all p values were 0.001). Calprotectin serum concentration and indicators of muscular injury, inflammation, and physical activity were found to be correlated during particular stages of the seasonal examination.

Conclusions: Calprotectin values determined throughout one competitive season decreased as training intensity among water polo players increased. Serum calprotectin concentrations and indicators were related to biochemical markers of inflammation and muscle damage.

Keywords: biochemical markers; calprotectin; dynamic monitoring; physical fitness; water polo players.

Figure 1

Calprotectin values over the study period at the beginning of the season (T1), at the time of low-intensity training (T2), at the time of high-intensity training (T3), and at the end of the season (T4). The period between every time point was 10–12 weeks. All data are expressed as median and interquartile ranges. Significant (p < 0.05) from the corresponding T2 vs. T1 and T4 vs. T1.

Figure 2

Cortisol values over the study period at the beginning of the season (T1), at the time of low-intensity training (T2), at the time of high-intensity training (T3), and at the end of the season (T4). The period between every time point was 10–12 weeks. All data are expressed as median and interquartile ranges. Significant (p < 0.05) from the corresponding T2 vs. T1.

Figure 3

Creatine kinase values over the study period at the beginning of the season (T1), at the time of low-intensity training (T2), at the time of high-intensity training (T3), and at the end of the season (T4). The period between every time point was 10–12 weeks. All data are expressed as median and interquartile ranges. Significant (p < 0.05) from the corresponding T2 vs. T1, T3 vs. T1, and T4 vs. T1.