Resistance Training-Induced Gains in Muscle Strength and Power Mediate the Improvement in Walking Speed in Middle-Aged Women Who Are Breast Cancer Survivors.

ABSTRACT: Santagnello, SB, Martins, FM, de Oliveira Junior, GN, de Sousa, JdeFR, Nomelini, RS, Murta, EFC, and Orsatti, FL. Resistance training-induced gains in muscle strength and power mediate the improvement in walking speed in middle-aged women who are breast cancer survivors. J Strength Cond Res 38(4): 773-782, 2024-(a) Ascertain whether lower muscle mass, strength (1 repetition maximum [1RM]), and power (Pmax) in middle-aged women who are breast cancer survivors (BCS), when compared with women of a similar age never diagnosed with cancer (WNC), are related with lower walking speed (WS). (b) Ascertain whether changes in WS are associated with changes in muscle mass, 1RM, and (or) Pmax after resistance training (RT) in middle-aged BCS. A cross-section study was performed. Twenty WNC and 21 BCS were evaluated for lean mass of legs (LLM), 1RM (knee extension), muscle quality index (MQI = 1RM/LLM), Pmax (maximum muscle power-knee extension), and fast WS (10 and 400-meters). Randomized clinical trial was performed. The BCS were randomly divided into the control group ( n = 9) and the RT group ( n = 11). Breast cancer survivors exhibited lower 1RM (24.2%, p ˂ 0.001), Pmax (30.6%, p ˂ 0.001), MQI (22.2%, p = 0.001), and WS (10-m = 17.0%, p ˂ 0.001 and 400-m = 10.5%, p = 0.002) than WNC. Resistance training increased 1RM (31.6%, p = 0.001), MP (29.0%, p = 0.012), MQI (28.5%, p = 0.008), and WS (10-m = 9.4%, p = 0.009 and 400-m = 6.2%, p = 0.006) in BCS. The changes in WS were positively associated with 1RM (10-m = 68%, p = 0.001 and 400-m = 37%, p = 0.036) and Pmax (10-m = 56%, p = 0.005 and 400-m = 40%, p = 0.027) and MQI (10-m = 63%, p = 0.043 and 400-m = 37%, p = 0.035). Resistance training-induced gains in muscle strength and power mediate the improvement in WS in middle-aged BCS. Resistance training is an effective strategy to improve WS in middle-aged BCS.

Impact of Resistance Training Volume on Physical and Perceptual Outcomes of Breast Cancer Survivors Submitted to a Combined Training Program: A Randomized, Single-Blinded Study.

BACKGROUND: To determine the effect of resistance training volume on physical and perceptual outcomes of breast cancer survivors submitted to a combined training program. DESIGN: Randomized single-blinded study. METHODS: Nineteen breast cancer survivor women were randomized to a single-set (SS) or a multiple-set (MS) group. Both groups completed an 8-week combined training intervention in which the SS and MS groups performed 1 and 3 sets per resistance exercise, respectively. The following outcomes were assessed preintervention and postintervention: maximal knee extension dynamic strength (1-repetition maximum), quadriceps muscle thickness, peak oxygen uptake, time to exhaustion, cancer-related fatigue, and quality of life. RESULTS: Both interventions increased knee extension 1-repetition maximum (SS: 29.8% [37.5%]; MS: 19.3% [11.8%]), quadriceps muscle thickness (9.4% [4.1%]; 8.9% [5.9%]), and quality of life (4.3% [6.3%]; 7.9% [9.0%]), with no difference between the groups. However, only MS improved cancer-related fatigue (-2.1% [1.7%]) and time to exhaustion (21.3% [14.9%]), whereas peak oxygen uptake remained unchanged in both groups. CONCLUSIONS: Cancer-related fatigue and time to exhaustion, improved only in the MS group after the intervention. On the other hand, similar knee extension 1-repetition maximum, quadriceps muscle thickness, and quality of life improvements were observed in breast cancer survivors irrespective of the resistance training volume performed.

Lower-Body Resistance Training Reduces Interleukin-1ß and Transforming Growth Factor-ß1 Levels and Fatigue and Increases Physical Performance in Breast Cancer Survivors.

ABSTRACT: Martins, FM, Santagnello, SB, de Oliveira Junior, GN, de Sousa, JdFR, Michelin, MA, Nomelini, RS, Murta, EFC, and Orsatti, FL. Lower-body resistance training reduces interleukin-1ß and transforming growth factor-ß1 levels and fatigue and increases physical performance in breast cancer survivors. J Strength Cond Res 37(2): 439-451, 2023-This article ascertains whether resistance training (RT) improves inflammatory markers, fatigue (sensations and fatigability), and physical performance in breast cancer survivors (BCS) and investigates whether the changes in the inflammatory markers, fatigue, and physical performance are associated with each other. Volunteers were randomly divided into 2 groups: control group (n = 11) and RT group (n = 11). Resistance training (3 sets of 8-12 repetitions with 80% 1 repetition maximum (1RM) on 4 exercises-leg extension, leg curl, 45° leg press, and calf raise) was performed 3 times a week for 12 weeks. Self-reported fatigue (SRF), fatigability (critical torque [CT] and W prime [W']), muscle strength, and circulating inflammatory markers were assessed using the Brief Fatigue Inventory, iDXA, 1RM test, protocol of 60 maximal voluntary isometric contractions, and enzyme-linked immunosorbent assay, respectively. Resistance training reduced interleukin (IL)-1ß, transforming growth factor (TGF)-ß1, and SRF score and increased muscle strength, 6-minute walk test (6MWT), CT, and W'. In the RT group, the changes in SRF were positively associated with the changes in IL-1ß. The changes in muscle strength were associated with the changes in CT and W', and the changes in the 6MWT were associated with the changes in CT, W', muscle strength, and SRF. Resistance training improved fatigue and physical performance and reduced IL-1ß, and TGF-ß1 in BCS. Although improvement in fatigability seems to be dependent on the increase in muscle strength, improvement in the sensation of fatigue seems to be dependent on the reduction in IL-1ß after RT. Increase in physical performance seems to be dependent on improvement in muscle strength and fatigue.

Resistance Training Volume Enhances Muscle Hypertrophy, but Not Strength in Postmenopausal Women: A Randomized Controlled Trial.

ABSTRACT: Nascimento de Oliveira Júnior, G, de Freitas Rodrigues de Sousa, J, Augusto da Silva Carneiro, M, Martins, FM, Santagnello, SB, Campos Souza, MV, and Orsatti, FL. Resistance training volume enhances muscle hypertrophy, but not strength in postmenopausal women: a randomized controlled trial. J Strength Cond Res 36(5): 1216-1221, 2022-Among several possible resistance training (RT) variables to be manipulated, the training volume has been considered as a critical variable to maximize RT-induced hypertrophy. Many of the studies that compared one set of RT with 3 sets have failed to show a difference in muscle hypertrophy in older adults. However, it is not clear whether further increases in RT volume (i.e., 6 sets) would result in even greater RT-related hypertrophy than 3 sets in older adults. This study aimed to investigate whether higher-volume RT (HV-RT) maximizes gains in lean body mass and muscle strength (MS) when compared with lower-volume RT (LV-RT) in postmenopausal women (PW). Fifty-eight PW were randomized into 1 of the 3 groups: control group (CT, no exercise), HV-RT (6 sets per exercise), and LV-RT (3 sets per exercise). Volunteers took part in a supervised training program (leg press 45°, leg extension, leg curl and standing calf raises) and were assessed for leg lean mass (LLM; dual X-ray absorptiometry) and lower limb MS (leg press and leg extension; 1 repetition maximum [1RM]) before and after 12 weeks of RT. Both HV-RT and LV-RT groups increased (p < 0.05) LLM and MS when compared with the CT group. Higher increases in LLM gains were observed for the HV-RT group when compared with the LV-RT group (6.1 and 2.3%, p < 0.001). Both HV-RT and LV-RT groups similarly increased 1RM in the leg press and leg extension. Thus, there seems to be a dose-response relationship between RT volume and muscle hypertrophy, but not for MS gains in PW.

Different cutoff points to diagnose low muscle mass and prediction of osteoporosis in postmenopausal women.

OBJECTIVE: This study aimed to verify which of the different cutoff points of low muscle mass (LMM) based on appendicular lean mass (ALM) is associated with osteoporosis in postmenopausal women (PMW). METHODS: Cross-sectional study. PMW (n = 355) were classified for the presence of osteoporosis (score <-2.5 standard deviations) at the femoral neck and lumbar spine and LMM (three cutoff points: ALM < 15 kg; ALM/height2 [ALM index] <5.67 kg/m2 and ratio between ALM and body mass index [ALMBMI] <0.512). RESULTS: After adjustments for confounding factors, binary logistic regression showed that ALM and ALM index were associated with osteoporosis at the lumbar spine (odds ratio [OR] = 5.3 [95% CI: 2.3-12.5] and OR = 2.5 [95% CI: 1.0-6.2], respectively) and only ALM was associated with osteoporosis at the femoral neck (OR = 16.1 [95% CI: 4.1-62.5]). When women were classified as having osteoporosis in at least one site, only ALM was associated with osteoporosis (OR = 7.7 [95% CI: 3.3-15.6]). There was no association between ALMBMI and osteoporosis. The predictive value of ALM for osteoporosis decreased after BMI or height were included as a covariate in the model. CONCLUSION: Absolute ALM (<15 kg) seems to be the most suitable for predicting osteoporosis based on LMM in PMW.

Resistance training-induced improvement in exercise tolerance is not dependent on muscle mass gain in post-menopausal women.

Menopause transition may impair muscle function, decreasing exercise tolerance. The torque-duration relationship (hyperbolic curve) forms a practical framework within which exercise tolerance may be explored. In this regard, resistance training (RT) increases the curvature constant of this relationship (W'). Muscle hypertrophy and strength gains have been suggested as possible mediators of RT-induced improvement in W', however, it is unclear what the main mediator is. Higher-volume RT (HV-RT), beyond that recommended by RT-guidelines (i.e. three sets per exercise), may promote greater hypertrophy, but not higher strength gains. Hence, this study aimed to investigate whether greater hypertrophy in HV-RT maximises W' gain when compared to LVRT in postmenopausal women (PW). Fifty-eight PW were randomised to the control group (CTRL), HV-RT (six sets per exercise) or LV-RT (three sets per exercise). They underwent a 12-week RT program and were assessed for W', thigh lean body mass (TLBM) and maximal isometric voluntary contraction (MIVC). The TLBM gain was higher (P < 0.001) in the HV-RT (9.4%) than LV-RT (3.7%). However, both HV-RT and LV-RT similarly increased MIVC (9.7% vs. 16.5%, P = 0.063) and W' (26.4% vs. 34.6% P = 0.163). Additionally, the changes in W' were associated with the changes in TLBM (31%, P = 0.003) and MIVC (52%, P= <0.001). However, when the changes in TLBM and MIVC were inserted into the predictive model, only the MIVC (33%, P = 0.002) was a predictor of W'. Thus, although HV-RT promoted greater hypertrophy than LV-RT, HV-RT does not seem to maximise W' in PW.

Improvements in muscle strength, power, and size and self-reported fatigue as mediators of the effect of resistance exercise on physical performance breast cancer survivor women: a randomized controlled trial.

PURPOSE: To gain more knowledge about the mechanism (i.e., mediators) of resistance exercise (RE)-induced improvements in physical performance (PP), we seek to investigate whether improvements in muscle strength (MS), muscle power (MP), and lean body mass (LBM) and (or) self-reported fatigue (SRF) are mediators of the effect of RE on PP in breast cancer survivor women (BCSW). METHODS: The volunteers were randomly divided into two groups: control group (CT; n = 9) and resistance exercise (RE; n = 11). The RE protocol consisted of three sets in each exercise (leg extension, leg curl, 45° leg press, and calf raise), between 8 and 12 repetitions per set, with an estimated load of 80% of one-repetition maximum (1RM), and three times a week on non-consecutive days for 12 weeks. The CT group performed only stretching exercises twice a week. SRF, maximal muscle power (Pmax), MP, LBM, and PP were assessed using the Brief Fatigue Inventory Questionnaire; 1RM test; isoinertial dynamometer; DXA; and walking speed, sit-to-stand (STS), and timed up and go (TUG) test, respectively. RESULTS: Following 12 weeks, the RE group reduced SRF and increased MP, Pmax, LBM, and performance in all tests (walking speed, STS, and TUG) when compared with the CT group. There were significant associations of the changes in LBM, MS, Pmax, and SRF with changes in physical performance tests only in the RE group. CONCLUSION: Our findings suggest that improvements in LBM, MS, MP, and self-reported fatigue mediate the effect of resistance exercise on physical performance in BCSW.