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Introduction: People with chronic low back pain have functional disability associated with a decrease in productivity with major socioeconomic consequences. Resistance training is a form of exercise treatment that has been proposed to mitigate the problems caused by low back pain. It is recommended that the resistance training exercises focus on the posterior chain muscles and that the fragile condition of this population be considered. To the best of our knowledge, no study has yet investigated the effects of an acute resistance training session on pain and functional disability, considering such recommendations for people with non-specific chronic low back pain. Objective: Our aim was to assess the effects of a single resistance training session on pain and functional disability in people with non-specific chronic low back pain. Methods: 31 subjects of both genders with non-specific chronic low back pain took part in the study. Participants were randomized into two groups: the resistance training group (RTG) and the control group (CG). The RTG underwent a single exercise session. Results: The RTG showed a significant (p=0.001) decrease in perceived pain (5.9±1.6 versus 4.9±1.8) and a significant (p=0.016) decrease in functional disability (25.6±6.3 versus 20.5±4.1), after the resistance training session. The CG did not show significant differences (p=0.190) in perceived pain (6.9±1.7 versus 7.4±1.9)and in functional disability (26.8±7.8 versus 27.8 ±9.2), after the final assessment. The RTG showed a significant (p=0.001) increase in strength between the initial and final assessments (47.7 ±26.6kgf versus 60.2 ±31.4kgf) while the CG did not show any differences. Conclusion: A single resistance training session reduces pain and functional disability in people with chronic non-specific low back pain. [ABSTRACT FROM AUTHOR]

Copyright of Revista Portuguesa de Ciências do Desporto is the property of Universidade do Porto, Faculdade de Desporto and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The popularization of whole-body mechanical vibration training has made necessary to consider safety aspects of whole-body vibration training. In order to understand how vibration affects the human body, two important indices are calculated from acceleration data: transmissibility and estimated Vibration Dose Value (eVDV). This study aims to compare the acceleration and transmissibility to the head (TH) between different frequencies of WBV in the isometric semi-squat exercise as well as to classify the acceleration and eVDV from normative values established in literature. Twenty-four individuals (25.65 ± 5.22 years; 84.44 ± 21.91 kg; 1.73.80 ± 0.21 m; 14.28 ± 6.27% fat) who exercise regularly participated in the study. There were four, 30-second repetitions of semi-squatting in the frequencies of 5 Hz, 15 Hz, and 22 Hz, with a 30-second rest between the repetitions. One frequency per day was applied over the course of three days. The acceleration was previously measured at the base of the platform at each frequency and then measured in the head. A one-way ANOVA parametric test with repeated measures was performed to compare the acceleration and transmissibility to the head between frequencies, considering a significance equal to p<0.05. The 5 Hz frequency presented lower values of acceleration and higher transmissibility to the head in relation to the other frequencies. The training protocol adopted in this study can be considered safe regarding transmissibility to the head. On the other hand, considering the ISO-2631 normative values, the protocol can be considered uncomfortable regarding estimated Vibration Dose Value. As to the frequencies used, 5 Hz is more applicable considering acceleration and estimated Vibration Dose Value; however, it presents higher transmissibility to the head. [ABSTRACT FROM AUTHOR]

Copyright of Revista Portuguesa de Ciências do Desporto is the property of Universidade do Porto, Faculdade de Desporto and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The purpose of this study was to verify the acute effect of different vibration frequencies on countermovement jump (CMJ) performance after Whole Body Vibration (WBV) training. The sample consisted of 24 men who attended the laboratory to perform a WBV protocol, each day with a different vibration frequency (5, 15, 22, or 30 Hz). The sessions consisted of a warm-up, 3 CMJ attempts, followed by WBV training that consisted of 4 x 30 sec with a 30-sec interval between sets. The CMJ was again performed (3 attempts 1 min and 3 attempts 5 min post WBV). Analyzing the performance delta values for Δ5CMJ (height 5 min after WBV - height pre WBV), the frequency of 22 Hz presented higher delta than 30 Hz (1.11 ± 2.61 vs. -0.71 ± 2.61 cm; P=0.03). When comparing the highest performance with baseline, regardless of the vibration frequency, there was a difference for both 1 min (36.8 ± 4.69 vs. 34.92 ± 5.04 cm; P=0.01) as for 5 min (36.84 ± 5.19 vs. 34.92 ± 5.04 cm; P=0.01). Despite the better performance at 22 Hz compared to 30 Hz, analysis between the highest and baseline performance suggests that each individual may have a specific frequency to which the neuromuscular system is more responsive. [ABSTRACT FROM AUTHOR]

The aim of this study was to verify if the mechanical vibration in the exercise of isometric push-up affects the electrical activity of muscles of the upper limbs and the time until the exhaustion. The subjects were 13 experienced strength-training volunteers (25.52 ± 4.44 yrs). The push-up exercise with vibration of 20 Hz (V20) was accomplished until the exhaustion in one day and on another day without vibration (V00). The electromyographic activity (EMG) of the triceps brachii (TRB) and pectoralis (PT) was measured. There was no difference in the exercise duration between V20 and V00 (P = 0.954), but in the analysis of the complete signal, the Root Mean Square (RMS) of the TRB and PT was higher in V20 compared to V00 (P = 0.015, P = 0.018, respectively) and the Median Frequency (FMA) of the EMG was not different between the situations. The partial analysis of the EMG signal showed that in both muscles RMS was bigger in the 10 last sec (10f) and the FMA significantly lower in 10f compared to initial 10 sec. The findings indicate that the frequency vibration of 20 Hz increased the electrical activity of the upper limb muscles, but did not change the performance of strength resistance. [ABSTRACT FROM AUTHOR]

We aimed to compare electromyographic activity of the external portion of the pectoralis major, latissimus dorsi and triceps brachii long head in an acute resistance training session between bench press (BP), lat pull down, pullover and triceps lying exercises. Concentric and eccentric phases electromyographic activity were compared. pectoralis major showed significantly higher activity in bench press (67.9 %) than in pullover (50.8 %), triceps lying (35.9 %) and lat pull down (14.1 %) in the concentric and eccentric phase (43.4 %, 27.5 %, 24.5 % and 7%, respectively). Latissimus dorsi showed significantly higher activity in lat pull down (59.5 %) than in pullover (22.7 %), triceps lying (10.7 %) and bench press (6.6 %) in the concentric and eccentric phase (37.4 %, 8.4 %, 7.6 % and 4.4 %, respectively). Triceps brachii long head showed significantly higher activity in triceps lying (67.7 %) than in bench press (49.2 %), pullover (34.3 %) and lat pull down (12.4 %) in the concentric and eccentric phase (37.6 %, 23.8 %, 20.5 % and 9.7 %, respectively). We found that bench press, lat pull down and triceps lying exercises are more effective to activate pectoralis major, latissimus dorsi and brachii long head muscles, respectively. Pullover exercise is more effective to activate pectoralis major (50.8 %) rather that latissimus dorsi (22.7 %). One should take into account such results while preparing a strength training periodization routine in order to avoid overtraining. [ABSTRACT FROM AUTHOR]

Copyright of Revista Brasileira de Medicina do Esporte is the property of Redprint Editora Ltda. and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

In high level championships small details are able to define the swimming medalists. Overall 0.01 s represents just a short piece of swimming final time, but between elite swimmers just 1.12% of the final time performance in 50 meters freestyle are improved annually. In this perspective greater block time differences over swimming final time differences could change the importance of block time to the swimmers classification. Thus the aim was to investigate the influence of block time in the final sprint events (50 and 100m) classification, including seven FINA World Championships (2003-2015). Thereunto, were calculated the frequency of possible Classification Changes (CC), based on differences between block times (BT) and final times (FT) in each swimming event. Public data was collected at the Omega Timing website. Totally, 112 events and 894 individual results (447 men and 447 women) were analyzed. The Chi-Square test was used to verify the Classification Changes occurrence between strokes (freestyle, backstroke, breaststroke and butterfly), event distances (50 and 100m), sex (male and female), block versions (traditional block used by FINA until 2007 - OSB9; and new block used by FINA from 2009 - OSB11), and years of championship (2003, 2005, 2007, 2009, 2011, 2013 and 2015). Between strokes and distances, the Classification Changes effect was shown more frequent in backstroke and 50m (4.97% CC and 4.24% CC; respectively). In addition, although the new block version has been shown to reduce the block times, it did not affect notably the Classification Changes. However, overall differences in block times were greater than differences in final time events (3.44% CC). These findings emphasize the importance of BT and recommend the block start technical training to achieve better swimming classifications. [ABSTRACT FROM AUTHOR]

Objectives: The primary objective of this meta-analysis was to compare countermovement jump (CMJ) performance in studies that reported the highest value as opposed to average value for the purposes of monitoring neuromuscular status (i.e., fatigue and supercompensation). The secondary aim was to determine the sensitivity of the dependent variables.Design: Systematic review with meta-analysis.Methods: The meta-analysis was conducted on the highest or average of a number of CMJ variables. Multiple literature searches were undertaken in Pubmed, Scopus, and Web of Science to identify articles utilizing CMJ to monitor training status. Effect sizes (ES) with 95% confidence interval (95% CI) were calculated using the mean and standard deviation of the pre- and post-testing data. The coefficient of variation (CV) with 95% CI was also calculated to assess the level of instability of each variable. Heterogeneity was assessed using a random-effects model.Results: 151 articles were included providing a total of 531 ESs for the meta-analyses; 85.4% of articles used highest CMJ height, 13.2% used average and 1.3% used both when reporting changes in CMJ performance. Based on the meta-analysis, average CMJ height was more sensitive than highest CMJ height in detecting CMJ fatigue and supercompensation. Furthermore, other CMJ variables such as peak power, mean power, peak velocity, peak force, mean impulse, and power were sensitive in tracking the supercompensation effects of training.Conclusions: The average CMJ height was more sensitive than highest CMJ height in monitoring neuromuscular status; however, further investigation is needed to determine the sensitivity of other CMJ performance variables. [ABSTRACT FROM AUTHOR]

Copyright of Revista Brasileira de Medicina do Esporte is the property of Redprint Editora Ltda. and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Revista Brasileira de Medicina do Esporte is the property of Redprint Editora Ltda. and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The article presents a study that proposes an individualized familiarization method for vertical jumps and to verify its effect on intra-subject variability. The study included fifty three men aged around 23 years orld who performed successive jumps to reach the proposed stability level. It also reveals that the proposed individualized familiarization method significantly decreased intra-subject variability.