Anabolic Androgenic Steroid (AAS) doping pervasiveness, identified retrospectively through International Olympic Committee (IOC) re-tests of the 2004-2012 summer Olympic Games (OG) threatened weightlifting’s place at the 2024 OG. Despite this, analysing doping practices in weightlifting and an investigation of IOC re-test efficacy, across all summer OG sports, is outstanding. AAS induce human hypertrophy via increasing myonuclei, and mice data suggests myonuclei permanency causing a “memory” of exposure and long-term advantage. However, limited human data exists on past AAS users and there is no longitudinal data post AAS exposure. Furthermore, RNA-Seq has yet to be conducted on human samples exposed to AAS. Chapter 1 outlines an introduction and Chapter 2 methodologies. Chapter 3 provides results of analysing weightlifting doping practices from 2008-2019 and identified continental differences in detected substances. Chapter 4 analysed doping that impacted medal results for the 1968-2012 summer OG and showed most doping (74% of medals impacted by doping) was identified retrospectively, either from events prior to OG (17%) or IOC re-tests of 2004-2012 (57%). Chapter 5 describes the males recruited for cross-sectional observational research on AAS and myonuclear permanency and Chapter 6 their transcriptome data. Fifty-six men aged 20-42 years were recruited: Non–resistance trained (C), resistance-trained (RT), RT currently using AAS (RT-AS), of which if AAS usage ceased for ≥18 weeks resampled as Returning Participants (RP) or RT previously using AAS (PREV). There were no significant differences between C (n = 5), RT (n = 15), RT-AS (n = 17), and PREV (n = 6) for trapezius myonuclei per fibre data. Three of 5 returning participants (RP1-3) were sampled longitudinally. Fibre cross-sectional area decreased for RP1 and RP2 between visits, whilst myonuclei per fibre remained similar, congruent with the memory mechanism. However, these values increased for RP3 and self-declared AAS regimens varied. For RNA-Seq, RT-AS was divided to participants who ceased exposure ≤2 or ≥10 weeks prior to sampling. For validation, RNA-Seq was conducted twice but cross comparison of whole blood datasets showed no differential expression between RP time points or comparisons of RT-AS≤2 to other groups. In both muscle datasets, nine differentially expressed genes overlapped with RT-AS≤2 vs RT and RT-AS≤2 vs C, but were not differentially expressed with RT vs C, possibly suggesting they are from acute doping alone, but differential training routines is a confounder. This thesis identified geographical differences in weightlifting doping, demonstrated retrospective doping testing efficacy and contributed data on AAS regarding muscle memory and the human transcriptome.
|Date of Award||Jun 2023|
|Supervisor||Fergus Guppy (Supervisor), Guan Wang (Supervisor) & Yannis Pitsiladis (Supervisor)|