Evaluation of swimmers by coaches in relation to IL-6 G/C rs56588968 Polymorphism: an Exploratory Study

Interleukin-6 (IL-6) is a multi-functional cytokine which plays a pivotal role in muscle hypertrophy and repair following exercise-related muscle damage. IL-6-174G/C (rs1800795) single nucleotide polymorphism (SNP) affects IL-6 promoter activity, and C allele associated with eccentric exercise-induced muscle damage. C-allele is highly prevalent among long-distance swimmers, whilst exercise-associated rhabdomyolysis is rare, probably due to water-related protective mechanisms. The aim of the current study is to explore whether elite swimming coaches can identify C allele carriers by evaluation of swimmer's performance dimensions. Ninety-five (95) long and short distance swimmers (70 males, 25 females, aged 14-29) and six coaches participated in the current study. All swimmers were ranked among the top Israeli results in their event/age group. All coaches graduated from the same College, and were experienced senior-level coaches with experience working in an elite competitive setting Swimmer were rated by his/her coach on 3 performance dimensions: training recovery, performance, and physiological abilities. Genomic DNA was extracted from peripheral blood following a standard protocol. IL-6-174G/C Genotyping was performed using polymerase chain reaction (PCR). Both in-water and land training recovery were categorized by the coaches as significantly better in non C-allele carriers compared to C-allele carriers. Swimmers' aerobic performance evaluation by the coaches was significantly higher among C-allele non-carriers. The results suggest that experienced coaches can adequately classify swimmers according to their genetically determined recovery capabilities. Thus, knowing the swimmer's genetic background may possibly encourage coaches to perform individualized training adaptations in an effort to optimize their swimmers’ performance.