title: Structural and Functional Adaptation of the Heart to Resistance Training in Combination with Anabolic Androgenic Steroid Use – Insights from Echocardiography and the 12 Lead Electrocardiogram
Creators: name: Carpenter, H
Publisher: name: Liverpool John Moores University
Year: 2025

description: The ‘Athlete’s Heart’ (AH) is a complex phenomenon that has been extensively researched in the modern era. It has been described as the chronic process of cardiac structural and functional remodelling that occurs as a result of regular exercise (Prior and La Gerche, 2012). The type and magnitude of adaptation that occurs is subject to various factors including age, gender, ethnicity, and type of exercise. Adaptations to both endurance (ET) and resistance training (RT) have been well documented (Spence et al., 2013a; Dores et al., 2015; Utomi et al., 2015). However, recent literature has refuted historic work that previously stated a dichotomy of adaptation between ET and RT athletes (Morganroth et al., 1975). Rendering the Morganroth hypothesis obsolete in the present day, illustrating a more complex relationship between the two disciplines, rather than a simple dichotomous one. 
The use of anabolic-androgenic steroids (AAS) has increased significantly over the past decade, with their prevalence spreading across the world (McVeigh et al., 2021) (Baggish et al., 2017). This is due to their increased popularity as Image and Performance Enhancing Drugs (IPED’s) (McVeigh et al., 2021). The use of IPED’s has become widespread, from the recreational gym user to high profile and professional athletes.
Echocardiography has been used in previous work to assess the impact of RT in combination with AAS use (Angell et al., 2014; Baggish et al., 2017). Illustrating a significantly larger cardiac geometry in AAS users, with a concomitant decrease in ventricular function. Although research on this topic has become more prevalent in recent years, the difficulty still remains in standardising these adaptations in such a wide and diverse population. This thesis explores structural and functional adaptation within non-using or ‘pure’ RT athletes. Additionally, this will be assessed in RT athletes that are both past and current users of AAS. The thesis will seek to highlight any differences in structural and functional adaptation between the three groups. 
The first empirical study focuses on echocardiographic assessment of the heart, where that all mean values of both left ventricular (LV) and right ventricular (RV) parameters for non-using RT athletes, were within normal ranges for non-athletic individuals (Harkness et al., 2020b). Current users of AAS experienced significantly larger absolute and indexed values of LV mass (LVM) and mean wall thickness (MWT) compared to both past and non-users. Current users also demonstrated higher absolute values of LV dimension (LVIDd) and LV end diastolic volume (LVEDV) compared to non-users albeit these differences disappeared for indexed values to body surface area (BSA). There were no significant differences between past and non-users for any LV structural parameter. LV ejection fraction (EF) was significantly lower in current users compared to non-users and they also demonstrated significantly lower peak global longitudinal strain (GLS) and global circumferential strain (GCS) compared to both non-users and past users. Peak GLS was significantly lower in past users compared to non-users. 
Current users had significantly larger absolute values of the proximal RV outflow tract (RVOT1) than both non and past users and had significantly greater absolute values for RVOTplax, RVOT2, RV dimensions (RVD1, RVD2, and RVD3) than non-users. These differences disappeared when RV chamber dimensions were indexed to BSA. There were no significant differences between past and non-users for any RV structural measurements. Peak RV free wall strain was also significantly lower in current users compared to both past and non-users. 
The second empirical study focused on the electrocardiogram (12-lead ECG) and demonstrated that non-users displayed a greater prevalence of 2 or more training related ECG changes (55%). Only current users (n=57) demonstrated borderline (n=4) and abnormal (n=2) findings. T wave axis was significantly lower in current users compared to both past and non-users. QRS duration and voltages for RVH were also significantly higher in current users compared to non-users. 
To summarise, the main findings from the thesis are 1) non-using RT athletes display minimal adaptation to RT; with echocardiographic parameters within normal ranges for non-athletic individuals (Harkness et al., 2020b), 2) current users exhibit significantly larger hearts than their non-using counterparts, with a concomitant decrease in function, particularly systolic and 3) past users exhibit significantly smaller LV and RV size compared to current users. Additionally, they displayed non-significant differences between themselves and non-users. Suggesting that certain adaptations to AAS may be reversed with abstinence. 
This thesis highlights some significant implications. First, these findings further refute the Morganroth hypothesis, highlighting minimal adaptation to RT alone, with no concentric hypertrophy amongst non-using RT athletes. Second, current users demonstrate a potential pathological pathway of adaptation, with significantly increased structural measurements, combined with a global reduction in systolic function. Third, current users exhibit potential abnormal ECG changes, shown through a significantly reduced T axis, a novel finding. Finally, past users seem to exhibit a reverse in structural adaptation with abstinence. However, some functional parameters still remain significantly different to that of non-users. Suggesting a more permanent form of adaptation, shown through reduced function.