Association of Gene Variants for Mechanical and Metabolic Muscle Quality with Cardiorespiratory and Muscular Variables Related to Performance in Skiing Athletes

Abstract

Background: Skiing is a popular outdoor sport posing different requirements on musculoskeletal and cardiorespiratory function to excel in competition. The extent to which genotypic features contribute to the development of performance with years of ski-specific training remains to be elucidated. We therefore tested whether prominent polymorphisms in genes for angiotensin converting enzyme (ACE-I/D, rs1799752), tenascin-C (TNC, rs2104772), actinin-3 (ACTN3, rs1815739) and PTK2 (rs7460 and rs7843014) are associated with the differentiation of cellular hallmarks of muscle metabolism and contraction in high level skiers. Material & Methods: Forty-three skiers of a world-leading national ski team performed exhaustive cardiopulmonary exercise testing as well as isokinetic strength testing for single contractions, whereby 230 cardiopulmonary measurements were performed in the period from 2015–2018. A total of 168 and 62 data measurements were from the Alpine and Nordic skiing squads, respectively. Ninety-five and one hundred thirty-five measurements, respectively, were from male and female athletes. The average (± SD) age was 21.5 ± 3.0 years, height 174.0 ± 8.7 cm, and weight 71.0 ± 10.9 kg for the analysed skiers. Furthermore, all skiers were analysed concerning their genotype ACE-I/D, Tenascin C, ACTN3, PTK2. Results: The genotype distribution deviated from Hardy–Weinberg equilibrium for the ACTN3 genotype, where rs1815739-TT genotypes (corresponding to the nonsense mutation) were overrepresented in world-class skiers, indicating a slow muscle fibre phenotype. Furthermore, the heterozygous rs2104772-AT genotypes of TNC also demonstrated the best scaled peak power output values during ramp exercise to exhaustion. The highest values under maximum performance for heart rate were associated with the rs1799752-II and rs1815739-CC genotypes. The lowest values for peak power of single contractions were achieved for rs1815739-CC, rs1799752-II and rs7843014-CT genotypes. The skiing discipline demonstrated a main influence on cardiorespiratory parameters but did not further interact with genotype-associated variability in performance. Discussion: Classically, it is pointed out that muscles of, for example, alpine skiers do not possess a distinct fibre type composition, but that skiers tend to have a preponderance of slow-twitch fibres. Consequently, our findings of an overrepresentation of ACTN3-TT genotypes in a highly selective sample of elite world class skiers support the potential superiority of a slow fibre type distribution. Conclusion: We suggest that one competitive advantage that results from a slow, typically fatigue-resistant fibre type distribution might be that performance during intense training days is better preserved, whereby simply a higher technical training volume can be performed, yielding to a competitive advantage.

Association of Gene Variants with Seasonal Variation in Muscle Strength and Aerobic Capacity in Elite Skiers

“…Genotyping : Gene polymorphisms of interest (ACE-I/D, rs1799752; ACTN3, rs1815739; TNC, rs2104772; PTK2, rs7460, and rs7843014) were determined from drawn blood with polymerase chain reactions (PCR) essentially as described [ 26 ]. In brief, blood was drawn from the cubital vein, and genomic DNA was extracted by the DNeasy Blood and Tissue Kit (Cat No.…”

“…Where indicated, the genotype was confirmed by Sanger sequencing (Microsynth, Balgach, Switzerland) and gel electrophoresis. The following primer pairs were used as described [ 26 , 27 ]: rs1799752 (I-allele: 5′-tgggattacaggcgtgatacag-3′ and 5′ atttcagagctggaataaaatt-3′; D-allele: 5′-catcctttctcccatttctc-3′ and 5′-atttcagagctggaataaaatt-3′), rs2104772 (5′-caaaaagcagtctgagccac-3′ and 5′-ttcagtagcctctctctgagac-3′), rs1815739 (5′-ctgtttgcctgtgtgtaagtggggggg-3, 5′-tgtcacagtatgcaggagggg-3′), rs7460 (5′-tgggtcgggaactagctgta-3′, 5′-atggaaaaaggggatggtcc-3′), and rs7843014 (5′-tgatgggacctaaacccatt-3′, 5′-tttcccatcagctgcttgtt-3′). For further details, see Supplemental Table S1 and Supplemental Figure S4 [ 26 , 27 ].…”

“…Combinations of gene variants plausibly affect skill levels in athletes beyond what is known for the “general” population and are differentially expressed over the season [ 10 , 17 , 21 , 22 , 23 , 24 , 25 , 26 , 27 ]. In this respect, frequent natural polymorphisms in genes affect the specialization of the metabolic and contractile phenotypes in healthy subjects and athletes with endurance- and strength-type training [ 10 ].…”

“…In this respect, frequent natural polymorphisms in genes affect the specialization of the metabolic and contractile phenotypes in healthy subjects and athletes with endurance- and strength-type training [ 10 ]. Namely, this concerns gene polymorphisms of angiotensin converting enzyme (ACE, insertion/deletion, rs1799752), tenascin-C (TNC, rs2104772, (A/T), actinin-3 (ACTN3, rs1815739, C/T), and protein tyrosine kinase 2 (PTK2, rs7460, rs7843014) that affect the fibre type composition, cross-sectional area, specific force, and capillary and mitochondria-related energy supply of the skeletal muscle and the myocard contractile performance [ 10 , 26 , 28 , 29 , 30 , 31 ]. Recently, the association of cardiopulmonary and muscle performance in elite skiers was reported with the aforementioned genotypes [ 26 ], but whether these differences are explained by exercise conditioning or progression through years of training has not yet been explored.…”

“…Namely, this concerns gene polymorphisms of angiotensin converting enzyme (ACE, insertion/deletion, rs1799752), tenascin-C (TNC, rs2104772, (A/T), actinin-3 (ACTN3, rs1815739, C/T), and protein tyrosine kinase 2 (PTK2, rs7460, rs7843014) that affect the fibre type composition, cross-sectional area, specific force, and capillary and mitochondria-related energy supply of the skeletal muscle and the myocard contractile performance [ 10 , 26 , 28 , 29 , 30 , 31 ]. Recently, the association of cardiopulmonary and muscle performance in elite skiers was reported with the aforementioned genotypes [ 26 ], but whether these differences are explained by exercise conditioning or progression through years of training has not yet been explored. The chosen genotypes were based on research on molecular and cellular mechanisms underpinning the associations of these genotypes with variability in performance in human investigations and transgenic experiments [ 32 , 33 , 34 ].…”