Background: The number of people living with the side effects of breast cancer treatment (eg, loss of muscular mass and muscular strength, upper-limb mobility and disability, lymphedema, cardiac toxicity, and reduced quality of life) is increasing yearly. These consequences can be improved through exercise, specially combining resistance and aerobic training. Previous exercise trials have not been consistent in applying training principles and standardized reporting, and this partly explains the variability in obtained results. The aim of this study is to assess the effect of a 12-week supervised resistance exercise program combined with home-based aerobic exercise, compared with home-based aerobic exercise only, on muscular strength and several aspects of health-related quality of life in breast cancer survivors. To maximize transparency, replicability, and clinical applicability, the intervention is described following the consensus on exercise reporting template. Methods: This study is a parallel-group randomized controlled trial in which 60 female breast cancer survivors, who have completed central treatments of the disease in the last 5 years, will be randomly assigned to either an experimental group that will perform a total of 24 progressive resistance training sessions for 12 weeks (ie, 2 weeks of individual training and 10 weeks of micro-group training) and will be requested to undertake 10,000 steps/d, or a control group that will be requested to undertake 10,000 steps/d, only. Outcomes will be evaluated at baseline and at week 12. Primary outcome measure is peak isometric muscular strength of the lower- and upper-body, assessed with several exercises through an electromechanical dynamometer. Secondary outcomes include cardiorespiratory fitness, upper-joint mobility and disability, health-related quality of life, cancer-related fatigue, depression, life satisfaction, and presence of lymphedema. Discussion: This study aims to investigate the extent to which a 12-week supervised and progressive resistance exercise program, in addition to home-based aerobic physical activity, might improve muscular strength and health-related quality of life in breast cancer survivors. The comprehensive description of the intervention will likely contribute to enhancing exercise prescription in this population. Trial registration number: ISRCTN14601208.

The aims of this study were: (i) to analyse the load-velocity relationship in the bilateral leg-press exercise in female breast cancer survivors, (ii) to assess whether mean velocity (MV) or peak velocity (PV) show stronger relationship with the relative load, and (iii) to examine whether linear (LA) or polynomic (PA) adjustment predict the velocities associated with each %1RM with greater precision. Twenty-two female breast cancer survivors (age: 50.2 ± 10.8 years, weight: 69.6 ± 15.2 kg, height: 160.51 ± 5.25 cm) completed an incremental load test until 1RM in the bilateral leg-press exercise. The MV and the PV of the concentric phase were measured in each repetition using a linear velocity transducer, and were analysed by regression models using LA and PA. A very close relationship of MV (R 2 = 0.924; p < 0.0001; SEE = 0.08m . s −1 by LA, and R² = 0.952; p < 0.0001; SEE = 0.063 m . s −1 by PA) and PV (R² = 0.928; p < 0.0001; SEE = 0.119 m . s −1 by LA and R² = 0.941; p < 0.0001; SEE = 0.108 m . s −1 by PA) with %1RM were observed. The MV of 1RM was 0.24 ± 0.03 m•s −1 , whereas the PV at 1RM was 0.60 ± 0.10 m . s −1 . A comprehensive analysis of the bilateral leg-press load-velocity relationship in breast cancer survivors is presented. The results suggest that MV is the most recommendable velocity variable to prescribe the relative load during resistance training, and that the PA presents better accuracy to predict velocities associated with each %1RM, although LA is sufficiently valid to use this model as an alternative to the quadratic model. The implications for resistance training in breast cancer are discussed.

Objetivo: Evaluar la asociación entre la fuerza de prensión manual (FPM) y diversos parámetros de condición física y composición corporal en mujeres supervivientes de cáncer de mama. Método: Se realizó un estudio transversal con los datos basales del ensayo clínico EFICAN (Ejercicio FÍsico para supervivientes de CÁNcer de mama). Participaron 60 mujeres supervivientes de cáncer de mama que habían terminado los tratamientos centrales de la enfermedad en los 10 años previos al comienzo del estudio, que no presentaban enfermedad pulmonar o cardiovascular, cáncer de mama metastásico, ni tenían prevista una intervención para reconstrucción mamaria en un plazo de 3 meses desde el comienzo del estudio. Se evaluó la fuerza de prensión manual mediante dinamometría manual, la fuerza muscular isométrica pico mediante dinamometría electromecánica funcional, el fitness cardiorrespiratorio (VO2máx) se estimó a través del Siconolfi step test, la amplitud de movimiento (ADM) en flexión de hombro mediante goniometría digital, y la composición corporal mediante bioimpedancia. Resultados: Se observó una asociación positiva de la FPM con la masa muscular (r=0.423), y con la fuerza isométrica de miembro superior (r=0.523) e inferior (r=0.335), y una asociación negativa de la FPM con el porcentaje de grasa corporal (r=-0.405). Sin embargo, no se encontró asociación entre FPM y VO2máx ni ADM del hombro (P>0.05). Conclusiones: Estos resultados sugieren que la FPM puede ser un buen indicador de fuerza muscular, así como de composición corporal en mujeres supervivientes de cáncer de mama. Futuros estudios prospectivos deberán evaluar el valor predictivo de la FPM en esta población.