An investigation into minimal-dose resistance training and its effects on quality-of-life, functional capacity, and strength in older adults: how much is just enough?

Abstract

The unprecedented demographic shift towards an ageing population represents one of the most significant public health challenges of the 21st century, with the global population aged over 60 years projected to reach 2.1 billion by 2050, doubling current figures. Age-related decline in muscle strength and functional capacity significantly impacts quality of life (QoL) and healthcare costs. While resistance training (RT) effectively combats these declines, traditional protocols face poor adherence due to time constraints and perceived complexity. However, the minimum effective dose of RT required to achieve meaningful benefits in older adults remains unclear, necessitating the investigation of minimal-dose approaches.

This mixed-methods thesis employed a sequential two-phase design utilising randomised comparative effectiveness trials: initially validating methodology with younger adults (n = 24) through a 9-week intervention and qualitative focus groups, followed by application to older adults (n = 48) over six months. The intervention comprised a 9-week training intervention with six training sessions and a three-month follow-up period. Participants were randomised to either maximal-intent (MI) or controlled-tempo (CT) RT protocols, performing weekly sessions of three sets of five repetitions at 60% of one-repetition maximum (1RM). Quantitative measures were collected at four time points (familiarisation, pre-testing, mid-testing, and post-testing) using the Short Form-36 (SF-36) questionnaire, functional tests (six-minute walk test, timed up-and-go, 30-second sit-to-stand), and strength measurements.. Qualitative data were obtained through focus groups and a three-month follow-up survey. Primary outcomes were QoL, functional capacity, and strength, assessed using the Short Form-36 (SF-36) questionnaire and functional tests. Minimal-dose RT led to statistically significantly improved QoL (p < 0.001, d = 0.82), functional capacity (p < 0.001, d = 0.75), and strength (p < 0.001, d = 0.89) across both training modalities in older adults. Cohen's d values indicate a large effect on QoL and strength, and a moderate to large effect on functional capacity, suggesting meaningful practical benefits from this intervention. Improvements were observed within three weeks and maintained at the three-month follow-up despite reducing the relative training load from 60% to 47% 1RM. The intervention achieved 86% adherence.

These findings demonstrate that minimal-dose RT effectively attenuates age-related functional decline whilst addressing common barriers to exercise participation. This research provides evidence-based recommendations for exercise prescription in older adults, suggesting healthcare providers could achieve meaningful outcomes with substantially reduced training volumes. The high adherence and significant improvements support the feasibility of widespread implementation, offering a sustainable solution to maintaining independence in our ageing population.

Date of Award	22 May 2025
Original language	English
Awarding Institution	Northumbria University
Supervisor	Gill Barry (Supervisor), Sam Stuart (Supervisor) & Stuart Goodall (Supervisor)