Genetic associations with athlete performance and injury susceptibility in elite Australian football

Australian Football is a dynamic team sport involving a combination of physical capabilities such as endurance, strength and power. Similar to other football codes, selection into elite Australian Football teams is predominantly associated with a player’s performance in physical and technical skill assessments, as well as their performance during matches. In contrast to other sporting codes, there are no studies exploring a potential genetic association towards success in Australian Football. Moreover, no studies have explored genetic associations of skill-based performance, injury risk, and athletic performance in Australian Football players. Recently, there has been an increased focus on the genetic contribution to athleticism, which has focused on understanding the causes of player variability. To investigate this concept in Australian Football further, the aims of this thesis were to 1) examine the genetic profile of elite Australian Football players using a group of selected candidate genes; 2) investigate the relationship between cardiovascular performance and genotypes of selected genes; 3) explore the occurrence and severity of injuries in Australian Football and their possible relationship to injury-related genes and their genotypes; and 4) examine if there is a relationship between time to injury, genetic polymorphisms and strength. Study one found that the ACTN3 rs1815739-XX genotype was significantly underrepresented, and the R allele was significantly overrepresentation in elite Australian Footballers compared to healthy controls. Study two found that the ADRB1 (rs18011253) and PPARGC1a (rs8192678) genes showed significant results, in particular the Arg389Gly CC and Gly482Ser GG genotypes of their respective genes, with both genotypes associated with faster two-kilometre time trial results in the studied population. Study three found that the NOGGIN rs1372857-GG and COL5A1 rs1372857-TT genotypes were significantly associated with a higher number of estimated muscle related injuries, with the NOGGIN rs1372857-GG having an association to higher severity (moderate and high rated) of injuries. In addition, the COL5A1 rs1372857-TT genotype was also associated with bone related injuries, with an association to moderate severity rated injuries. The CC genotype of the IGF2 (rs3213221) polymorphism had a higher number of tendon related injuries, with a further association towards low severity (low rated) injuries. The COL1A1 rs-1800012-TT genotype was related to a higher estimated number of ligament related injuries with a significant association to lower severity injuries. Significant results were found in study four regarding significant association between the COL12A1 rs970547-TC genotype and an increased risk to first upper body injury compared to the TT genotype of 167.2%. The IMTP had significant results with all its variables (peak force, and relative peak force (N.kg-1 and N)) for any musculoskeletal injuries, upper body musculoskeletal injuries and non-contact upper body musculoskeletal injuries. No associations were discovered for the NordBord eccentric hamstring strength test or the 2-kilometre time trial. This scientific approach could be replicated in a larger population, i.e., the entire Australian Football League, to establish if certain genotypes or alleles are related to an earlier occurrence of injuries. This doctoral thesis provides preliminary research into understanding the links between genes and athlete’s performance and injury of elite Australian Football players. This may lead to further research to develop this knowledge, which may in the long term assist in developing targeted training programs to achieve better outcomes for both the individual athletes and their sporting organisation. Future research could be expanded to all Australian Football League teams providing a greater sample size to determine the genetic variants that predict an elite Australian Footballer player and team. Tactical and High-Performance Coaches could use this information to understand training effects on players to hone in on individual strengths and weaknesses to ideally produce a more cohesive teams without many injuries or changes throughout a season