Contents lists available at ScienceDirect Experimental Gerontology journal homepage: www.elsevier.com/locate/expgero High-speed resistance training in elderly women: Effects of cluster training sets on functional performance and quality of life Rodrigo Ramirez-Campillo a , Cristian Alvarez a , Antonio Garcìa-Hermoso b , Carlos Celis-Morales c , Robinson Ramirez-Velez d , Paulo Gentil e , Mikel Izquierdo f, ⁎ a Universidad de Los Lagos, Department of Physical Activity Sciences, Research Nucleus in Health, Physical Activity and Sport, Laboratory of Measurement and Assessment in Sport, Osorno, Chile b Laboratorio de Ciencias de la Actividad Física, el Deporte y la Salud, Facultad de Ciencias Médicas, Universidad de Santiago de Chile, USACH, Chile c Human Nutrition Research Center, Institute of Cellular Medicine, Newcastle University, Newcastle Upon Tyne, United Kingdom d Centro de Estudios para la Medición de la Actividad Física “CEMA”, Escuela de Medicina y Ciencias de la Salud, Universidad del Rosario, Bogotá, D.C. 111221, Colombia e Faculdade de Educação Física e Dança, Universidade Federal de Goias, Goiânia, Brazil f Department of Health Sciences, Public University of Navarre, CIBER of Frailty and Healthy Aging (CIBERFES), Navarrabiomed, Pamplona, Navarre, Spain ARTICLE INFO Section Editor: Christiaan Leeuwenburgh Keywords: Strength training Resistance training Aging Women Power output Older adult ABSTRACT Objective: To compare the effects of 12 weeks of high-speed resistance training on functional performance and quality of life in elderly women when using either a traditional-set (TS) or a cluster-set (CS) configuration for inter-set rest. Methods: Three groups of subjects were formed by block-design randomization as follows: (i) control group (CG, n = 17; age, 66.5 ± 5.4 years); (ii) 12-week high-speed resistance training group under a CS configuration (CSG, n = 15; age, 67.6 ± 5.4 years); and (iii) 12-week high-speed resistance training group under a TS con- figuration (TSG, n = 20; age, 68.0 ± 5.3 years). Training was undertaken three times per week, including high- speed resistance training exercises. The main difference between the training groups was the recovery set structure. In the TSG, women rested for 150 s after each set of eight repetitions, whereas the CSG used an interest rest redistribution, such that after two consecutive repetitions, a 30-s rest was allowed. Results: Group × test interactions were observed for a 10-m walking speed test, an 8-foot up-and-go test, a sit-to- stand test, and physical quality of life (p < 0.05; d = 0.12–0.81). The main results suggest that both training methods improve functional performance and quality of life, however, the CS configuration induced significantly greater improvements in functional performance and quality of life than the TS configuration. Conclusion: These results should be considered when designing appropriate and better resistance training pro- grams for older adults. 1. Introduction Functional capacity shows a progressive decline with aging, reaching a reduction of as much as 40% between 60 and 90 years (Rikli and Jones, 2013); this decline might be associated with many factors, such as decreases in muscle mass, strength and power (Byrne et al., 2016). The ability to exert high force at higher velocities show a pro- nounced and particularly sharp decline with age, with an even more pronounced decline than that in muscle mass and strength (Edwen et al., 2014). This loss of muscle power has been associated with an increased risk of falling and with impairments in quality of life, cog- nitive function and functional performance (Alcazar et al., 2018; Bean et al., 2002; Martinikorena et al., 2016). Therefore, adopting strategies that aim to preserve or increase muscle power might be of great im- portance to older people. One common strategy to attain this goal is through high-velocity resistance training (HVRT). In agreement with this suggestion, previous studies have shown that HVRT is able to in- crease muscle functionality largely than traditional resistance training in older people (Ramirez-Campillo et al., 2014, 2016, 2017). Notwithstanding its potential benefits, a discussion about the fea- sibility of HVRT has emerged (Cadore and Izquierdo, 2018; Cadore et al., 2018), and more information is needed on how to implement this type of activity. One possible strategy to perform HVRT in the elderly might be using cluster sets (CS), which involves performing resistance https://doi.org/10.1016/j.exger.2018.06.014 Received 21 April 2018; Received in revised form 9 May 2018; Accepted 12 June 2018 ⁎ Corresponding author. E-mail address: mikel.izquierdo@gmail.com (M. Izquierdo). Experimental Gerontology 110 (2018) 216–222 Available online 15 June 2018 0531-5565/ © 2018 Elsevier Inc. All rights reserved. T