Severe obesity reduces muscle contractile function, which manifests as a diminished ability to perform activities of daily living. These functional impairments often lead to pain during movement and a decreased motivation to exercise.
In the United Kingdom (UK), specialist Tier 3 weight management services are provisioned for adults with severe obesity. Tier 3 services comprise a multidisciplinary team (MDT) of specialists and mainly adopt an educational approach, focusing on psychological therapy, dietary modification, pharmacotherapy and physical activity advice. However, current Tier 3 programmes do not specifically address the functional impairments imposed by obesity, which predisposes adults with severe obesity to musculoskeletal pain and pathology.
Adding supervised resistance training to MDT weight management programmes has been shown to improve functional capacity in adults with severe obesity. However, supervised interventions place considerable time and resource burdens on the service provider and patient, which may not be conducive to sustained participation. Obese individuals often report feeling too embarrassed to exercise in front of others and feel uncomfortable appearing in public wearing exercise clothing. Home-based exercise is a convenient alternative to supervised interventions and may promote similar functional adaptations.
Traditional resistance training typically involves sustained contractions at low to moderate velocities. While this method of training is effective for augmenting maximal strength production, which is executed at slow velocities, it may neglect the development of muscle power. This is problematic because lower-limb power has recently emerged as a critical determinant of function in adults with severe obesity.
Power training integrates a high-speed component into conventional resistance training exercises. Research in older adults has consistently shown that power training is superior to conventional slow-speed strength training for improving functionality. Preliminary evidence also exists supporting the superiority of power training in sarcopenic obese adults. Nevertheless, it is unknown whether home-based power training is feasible or effective when added to an MDT weight management programme.
The investigators recruited participants from a UK Tier 3 specialist weight management service. In a prospective, parallel groups, randomised design, participants were randomly allocated to a slow-speed strength training group or a high-speed power training group. Both groups completed a 12-week, individualised, home-based resistance training intervention (2x/week) with behavioural support. The high-speed power training group performed resistance exercises with maximal intended concentric velocity whereas the slow-speed strength training group maintained a slow (2-s) lifting speed. Outcomes were assessed at baseline, 3-month (post-intervention), and 6-month (follow-up) endpoints.
