Nakamura, FY, Antunes, P, Nunes, C, Costa, JA, Esco, MR, and Travassos, B. Heart rate variability changes from traditional vs. ultra–short-term recordings in relation to preseason training load and performance in futsal players. J Strength Cond Res 34(10): 2974–2981, 2020—The aims of this study were to analyze heart rate variability (HRV) changes in futsal players during preseason training using both “criterion” (10-minute) and ultra-shortened (2-minute) measures, and to determine whether they were related to changes in the Yo-Yo Intermittent Recovery Test, level 1 (Yo-Yo IR1) performance and accumulated training load (TL). Eleven male competitive futsal players (age = 25.19 ± 4.70 years; body mass = 73.15 ± 11.70 kg; and height = 176.90 ± 5.01 cm) volunteered for the study. Data collection took place during the first to the fourth weeks of preseason training. Training load was monitored with session ratings of perceived exertion. The total distance (TD) covered during the Yo-Yo IR1 was recorded during week 1 and week 4. Heart rate variability was measured through the log-transformed root mean square of successive normal-to-normal interval differences using the ultra-short analysis, with its weekly mean (lnRMSSD_M) and coefficient of variation (lnRMSSD_CV) recorded, and by means of the criterion method (weeks 1 and 4). lnRMSSD_M was likely higher at week 4 compared with week 1 using both criterion and ultra-short recordings. Moderate-to-large correlations were found between changes in the lnRMSSD_M and lnRMSSD_CV values and changes in TL and TD (r values ranged from −0.48 to 0.65). Changes in ultra-short HRV measures (i.e., increase in lnRMSSD_M and decrease in lnRMSSD_CV) during futsal preseason were associated with increased performance. The players who accumulated higher perceived TLs displayed smaller improvements in the Yo-Yo IR1 performance and HRV.

Gonçalves, CA, Lopes, TJD, Nunes, C, Marinho, DA, and Neiva, HP. Neuromuscular jumping performance and upper-body horizontal power of volleyball players. J Strength Cond Res 35(8): 2236–2241, 2021—The aim of the current study was to characterize the neuromuscular jumping performance and upper-body horizontal power of elite and subelite volleyball players. In addition, those neuromuscular performances were compared between field positions. One hundred twenty-two male volleyball players participated in the study: 83 elite players (mean ± SD : 24.11 ± 5.57 years) and 39 subelite players (25.38 ± 6.19 years). They were divided according to their playing position: setters ( n = 22), opposite hitters ( n = 16), middle hitters ( n = 30), right-side hitters ( n = 38), and liberos ( n = 16). Each subject randomly performed 3 repetitions of medicine ball throwing (MBT), countermovement jump (CMJ), CMJ with free arms (CMJFA), and spike jump (SPJ). The results showed no significant differences between positions in the analyzed variables. However, there were differences between elite and subelite in the CMJ ( p = 0.000, = 0.12), the CMJFA ( p = 0.000, = 0.15), the SPJ ( p = 0.000, = 0.21), and MBT ( p = 0.001, = 0.09), showing a tendency for increased jumping performance and upper-body horizontal power for elite players. The elite opposite hitters and right-side hitters recorded greater CMJ performances ( d = 1.20 and d = 1.62, respectively). The right-side hitters were the only group that showed greater horizontal upper-body muscular power ( p = 0.000, d = 1.50). It is suggested that jumping performance is a determining factor for higher-level players, which was more relevant for the opposite hitters and right-side hitters. Nevertheless, the movement pattern of MBT seems to be relevant for the right-side hitters. Coaches should seek to develop jumping ability for the improvement of volleyball performances, without disregarding upper-body performances, depending on the position-specific demands.

Anthracyclines are chemotherapeutic agents frequently used in breast cancer (BC) treatment. Although it improves disease-free and overall survival, the use of anthracyclines is associated with a cumulative risk of cardiac toxicity. Preventive strategies to optimize cardiac health are needed and exercise is proposed as a potential non-pharmacological approach for counteracting anthracycline-related cardiotoxicity (ARC). Most of the data on the effects of exercise to reduce ACT are from animal studies, with only a few studies in a limited number of patients indicating beneficial effects. To better understand the effectiveness of exercise in the mitigation of ARC, clinical, real-world trials claim require a larger sample size and more accurate and valuable clinical biomarkers. In this study, we intend to include a large sample and investigate cardiac function through serial measures of biomarkers and imaging techniques. This protocol describes a two-arm, prospective, randomized controlled trial that will explore the cardioprotective effect of a structured exercise program in women with BC undergoing anthracycline-containing chemotherapy (ACT). Ninety adult women with early BC and recommended to receive ACT will be randomly assigned (1:1) to an intervention group or a control group. Patients allocated to the intervention group will perform a supervised exercise program three times per week, consisting of a combination of aerobic and resistance training with progressive intensity and volume, during the time period they receive ACT. The control group will receive standard BC care. Primary outcomes related to cardiac (dys)function will be circulating N-terminal pro-brain natriuretic peptide (NT-proBNP) levels, resting left ventricular (LV) longitudinal strain, and resting LV ejection fraction. Secondary outcomes will include the assessment of resting blood pressure, resting heart rate (HR), resting HR variability (HRV), recovery HR, physical function outcomes, self-reported physical activity level, health-related quality of life, and fatigue. Data will be obtained at baseline (t0), after the end of anthracycline-treatment (t2), and 3 months after t2 (t3). Additionally, NT-proBNP will be measured 1–24 h prior to each anthracycline-treatment cycle (t1). The implementation of the present study design, using novel clinical biomarkers, will determine the effect of structured exercise interventions at mitigating ARC, with the overall aim of finding means to further improve BC care. ISRCTN, ISRCTN32617901 . Registered on 24 October 2018. Last updated on 11 January 2019.