Cardiac structure and function in resistance-trained and untrained adults: a systematic review and meta-analysis

Variations in the haemodynamic demands of specific training modalities may explain characteristic differences in cardiac structure and function amongst athletes. However, current consensus regarding these adaptations in highly resistance-trained athletes is yet to be established. The current invetsigation aimed to collate research investigating cardiac structure and function in resistance-trained athletes, exploring the defining characteristics of Athlete’s Heart within these individuals. Seven electronic databases were searched. Studies which examined at least one measure of cardiac structure or function, included healthy, normotensive male or females (>18 years) and compared athletes engaged in a resistance training programme (>12 months) to an untrained group engaged in no structured training programme were included. Systematic selection and quality appraisal of articles was performed by two reviewers, with a random effects meta-analysis model applied to suitable studies. Studies were limited to orginal peer-reviewed articles published in English. Resistance-trained athletes (n = 949) demonstrated greater cardiac dimensions compared to their untrained counterparts (n = 1053). No clear impairments to systolic or diastolic cardiac function were observed in athletic population studied here. Resistance-trained athletes display some characteristics of the Athlete's Heart phenomenon, including greater wall thickening and chamber dilation compared to their untrained counterparts.