Effects of different training strategies with a weight vest on countermovement vertical jump and change-of-direction ability in male volleyball athletes.

BACKGROUND: Weight vest training (WVT) is a strategy used to improve the physical performance of athletes. The objective of this study was to determine the effects of different training strategies with weight vests on vertical jump and change-of-direction ability (CODA) in male volleyball athletes. METHODS: Fifteen volleyball athletes (22.87±3.04 years, 83.22±10.84 kg, 1.86±0.69 m) participated in a six-week training programme and were randomized into three groups: weight vest plyometric training (WPG), weight vest technical-tactical training (WTG) and a control group (CG). The additional weight of 7.5% of individual body mass was employed in the experimental groups. Before and after the WVT, athletes performed countermovement vertical jump (CMJ) and CODA (t-test) tests. RESULTS: Two-way ANOVA with repeated measures showed that CMJ height increased in all training groups (P<0.05), with the WTG inducing greater CMJ height gains in comparison to the CG (P<0.05). According to magnitude-based inference, the effects of the WTG strategy were "very likely" beneficial for the CMJ compared to the CG. In addition, t-test time decreased similarly among the three training groups (P<0.05). CONCLUSIONS: The results suggested that WVT may be incorporated in a volleyball training routine as an effective strategy for improving the CMJ performance in male volleyball athletes.

Influence of Competitive-Anxiety on Heart Rate Variability in Swimmers.

The aim of this study was to analyze the relationship between competitive anxiety and heart rate variability (HRV) in swimming athletes. A total of 66 volunteers (41 male and 27 female) who swam the 400-m freestyle in the Brazilian Swimming Championships participated. Thirty minutes before the 400-m freestyle event, the athletes answered the Competitive Anxiety Inventory (CSAI-2R) questionnaire, then underwent anthropometric (body weight, height, and skinfold thickness) and HRV measurements. Then, at a second meeting, held 3 h after the 400-m freestyle event, the athletes returned to the evaluation room for HRV measurement (Polar® RS800cx, Kempele, Finland). Multiple linear regression was used to evaluate the relationship between competitive anxiety and HRV. The multiple linear regression was performed in three blocks (block 1: cognitive anxiety, block 2: somatic anxiety, and block 3: self-confidence), adopting the forward model. The results indicated a significant association between cognitive anxiety (p = 0.001) and HRV. An increased magnitude of the association was observed when somatic anxiety was inserted in the model (p = 0.001). In contrast, self-confidence showed, which was inserted in block 3, no relationship with HRV (p = 0.27). It was concluded that cognitive and somatic anxieties were associated with the HRV of swimmers. Athletes with a high magnitude of cognitive and/or somatic anxiety demonstrated more significant autonomic nervous system disturbance. Practically, psychological interventions are needed to improve anxiety states that are specific to perform well, and to improve HRV.

Impact of Strength Training on Bone Mineral Density in Patients Infected With HIV Exhibiting Lipodystrophy.

This study aimed to evaluate the impact of strength training on bone mineral density (BMD) in individuals harboring HIV exhibiting lipodystrophy. The study included 20 subjects (16 men) aged 50.60 ± 6.40 years with reduced BMD, presenting positive serology for HIV, using highly active antiretroviral therapy, and performing no regular practice of physical exercise before being enrolled in the study. Bone mineral density levels were evaluated by dual-energy x-ray absorptiometry in the lumbar spine, femoral neck, and 1/3 radius, before and after 36 sessions (12 weeks) of strength training. Compared with pre-exercise period, the results showed increased BMD in lumbar spine (3.28%; p = 0.012), femoral neck (8.45%; p = 0.044), and 1/3 radius (5.41%; p = 0.035). This is the first study evaluating the impact of strength training in patients living with HIV and exhibiting lipodystrophy, showing an increased BMD in all the regions measured (lumbar spine, femoral neck, and 1/3 radius). This study showed the beneficial impact of the strength training on BMD increase in patients living with HIV as an effective and available approach to improve bone health.