Maximal-Intentional Velocity Resistance Training Interventions for Older Adults: design and implementation

Older age is associated with significant declines in muscle mass and function which affect the ability to perform activities of daily living (ADLs), independence, quality of life (QoL), risk of mortality, and healthcare costs, implicating these changes in muscle as a major health issue for individuals and society (Lanza et al., 2003; Maden-Wilkinson et al., 2015; Beaudart et al., 2017; Kim et al., 2018). It has been strongly suggested that maximal-intentional velocity resistance training (MIV-RT), otherwise known as power training, explosive, high-speed or high-velocity resistance training (RT) (de Vos et al., 2005, Richardson et al., 2019, Sayers and Gibson, 2010, Pearson et al., 2022) is an optimal method for improvements in functional ability, improves muscle mass and function and thus, should be prioritised for older adults (OAs) (Cadore et al., 2018; Orssatto et al., 2019). However, despite existing evidence to support MIV-RT as an effective method to improve muscle mass and function in OAs (Blazevich et al., 2020a; Rodriguez-Lopez et al., 2022; Morrison et al., 2023), methodological issues in research studies preclude the ability to draw definitive conclusions about the efficacy and safety of MIV-RT. This includes heterogeneity in study designs, inconsistencies in terminology and programme design and the use of suboptimal methods to understand the risks associated with this training type. Therefore, this thesis has taken a critical lens to understand and advance MIV-RT interventions for OAs. By examining and clarifying the terminology and methods used to describe and measure the ability to produce force rapidly, chapter 3 aims to improve understanding and consistency in the application of terminology and outcome measurements, facilitating effective communication of research findings, and the development of effective RT interventions. A systematic review of MIV-RT interventions for OAs (Chapter 4) highlights gaps in intervention design and reporting practices, hindering the literature and our understanding of MIV-RT for OAs. Chapter 5 explores in detail the implementation of MIV-RT in real-world settings, comparing practitioner insights with research evidence, and highlighting disparities between research and applied practice, including the utilisation of different equipment and exercises. Moreover, practitioners’ reasons for not prescribing MIV-RT for OAs are identified, including a perceived lack of safety or risk of injury and fear from OAs, providing recommendations for future research studies tailored to the needs of all stakeholders. Indeed, this thesis highlights that the safety of MIVRT for OAs remains uncertain (Chapter 2) and that identification of practical and sensitive measurement tools is necessary to better assess the safety of MIV-RT for OAs. Therefore, Chapter 6 investigates the validity and reliability of novel measurement tools to measure postural stability, a potential indicator of the safety of MIV-RT, demonstrating that pressure insoles may provide a valid and reliable tool. Overall, this thesis advances our understanding of MIV-RT for OAs and offers specific and practical recommendations for future MIV-RT interventions. By addressing critical underpinning factors and providing evidence-based insights, this work aims to promote the design of interventions that target the desired and most relevant physiological adaptations, reduce barriers to real-world implementation and effectively communicate findings through accurate and thorough reporting.