No abstract

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.

Purpose This study assessed the effects of 12-week supervised resistance training combined with home-based physical activity on physical fitness, cancer-related fatigue, depressive symptoms, health-related quality of life (HRQoL), and life satisfaction in female breast cancer survivors. Methods A parallel-group, outcome assessor-blinded, randomized controlled trial included 60 female breast cancer survivors who had completed their core treatments within the previous 10 years. Through computer-generated simple randomization, participants were assigned to resistance training (RTG; two sessions/week for 12 weeks plus instructions to undertake ≥ 10,000 steps/d) or control (CG; ≥ 10,000 steps/d only). Outcomes were evaluated at baseline and week 12. Muscular strength was assessed with electromechanical dynamometry. A standardized full-body muscular strength score was the primary outcome. Secondary outcomes included cardiorespiratory fitness, shoulder mobility, cancer-related fatigue, depressive symptoms, HRQoL, and life satisfaction. Results Thirty-two participants were assigned to RTG (29 achieved ≥ 75% attendance) and 28 to CG (all completed the trial). Intention-to-treat analyses revealed that the standardized full-body muscular strength score increased significantly in the RTG compared to the CG (0.718; 95% CI 0.361–1.074, P < 0.001, Cohen's d = 1.04). This increase was consistent for the standardized scores of upper-body (0.727; 95% CI 0.294–1.160, P = 0.001, d = 0.87) and lower-body (0.709; 95% CI 0.324–1.094, P = 0.001, d = 0.96) strength. There was no effect on cardiorespiratory fitness, shoulder flexion, cancer-related fatigue, depressive symptoms, HRQoL, or life satisfaction. The sensitivity analyses confirmed these results. Conclusion and implication for cancer survivors. In female breast cancer survivors who had completed their core treatments within the past 10 years, adding two weekly sessions of supervised resistance training to a prescription of home-based physical activity for 12 weeks produced a large increase in upper-, lower-, and full-body muscular strength, while other fitness components and patient-reported outcomes did not improve. Trial registration number. ISRCTN14601208.

Baena-Raya, A, Díez-Fern ández, DM, L ópez-Sagarra, A, Martínez-Rubio, C, Soriano-Maldonado, A, and Rodríguez-P érez, MA. Novel curvilinear sprint test in basketball: reliability and comparison with linear sprint. J Strength Cond Res 37(9): e535-e540, 2023-This study (a) evaluated the reliability of a curvilinear sprint (CS) test to assess kinetic and kinematic outcomes in basketball players, (b) compared the kinetic and kinematic outcomes derived from curvilinear vs. linear sprints (LS), and (c) examined the association of both the CS and LS with change of direction (COD) performance. Thirty young basketball players (17 men and 13 women) competing at the national level (i.e., Spanish Basketball National League) performed a novel CS test around the 3-point line (the 3-point line CS test) to the right and left sides. The maximum and average values of acceleration (ACC), velocity (VEL), and centripetal force (CentF) were measured using Local Positioning System technology (WIMU PRO, Realtrack Systems S.L., Almería, Spain). All outcomes showed a high relative (intraclass correlations coefficient $ 0.90) and absolute (coefficient of variation [CV] , 5%) reliability, except the maximal CentF to the right (CV 5 5.41%) and left sides (CV 5 7.72%). Linear sprints displayed higher ACC and VEL outputs compared with the 3-point line CS test (all p , 0.001). Both sprinting tests were very large to nearly perfect associated with COD performance (LS r range from 20.71 to 20.86; CS r range from 20.68 to 20.94; p , 0.001), and the curvilinear ACC max was the kinematic outcome most strongly associated with COD performance (r range from 20.73 to 20.94). In conclusion, the 3-point line CS test is reliable to measure CS performance in basketball and presents different kinetic and kinematic features than LS.

The aim of this study was to examine the concurrent validity and reliability of a functional electromechanical dynamometer (FEMD) to assess the isometric mid-thigh pull (IMTP) kinetic variables: peak force (PF), rate of force development (RFD), and time-specific force values (50-, 100-, 150-, and 200-ms). Twenty-seven male collegiate athletes (age: 22.9 ± 1.9 years; stature: 184.8 ± 10.4 cm; body mass: 84.2 ± 11.8 kg) performed four IMTP trials simultaneously on a force platform and the FEMD. The PF variables calculated from performance of the IMTP on both devices were reliable (CV < 3%; ICC > 0.90) and valid (bias < 13.9 N; random error < 52.1 N; r = 1.00), but they showed heteroscedasticity of the errors ( R2 > 0.23). The RFD (CV > 10.88%; ICC < 0.76) and initial force (CV > 8.81%; ICC < 0.76) variables did not reach an acceptable reliability for any device, but they showed strong associations between them ( r range = 0.53–0.69). These results indicate that the FEMD is an acceptable alternative to assess athlete’s maximal force production (i.e. PF), but the data collected with FEMD and force plates should not be used interchangeably.

Background: Although breast cancer (BC) is the most prevalent type of cancer in the world, its high survival rate implies that many people live long after the treatments and face their side effects. The physical function (PF) and health-related quality of life (HRQoL) of people surviving BC decreases significantly, which makes important to identify markers that may be associated with a better health status and prognosis. Previous studies suggest that handgrip strength (HGS) and HGS relative to the body mass index (rHGS) are good indicators of PF and HRQoL in different populations. However, it is unknown whether this applies to BC survivors. This study aimed to evaluate the association of HGS and rHGS with PF and HRQoL in this population. Methods: Sixty female BC survivors participated. Handgrip strength was assessed with a dynamometer. Arm volume was estimated and upper limb impairments, as well as cancer-related fatigue, depression, life satisfaction and HRQoL, were assessed using standardized questionnaires. Results: Higher levels of HGS and rHGS were associated with higher levels of HRQoL, lower cancer-related fatigue, and fewer problems with the affected arm. Conclusions: These results suggest that HGS may be a good indicator of self-reported PF and HRQoL in female BC survivors.

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.