Attack and Defense Performance in Goalball: A Proposal for Throwing, Balance and Acoustic Reaction Evaluation.

Goalball is a sport for visually impaired athletes, where the roles of attack and defense change continuously during the game. Performance evaluation should consider the variables that determine the throwing and the stop and clearance of the ball. The aim of this study is to evaluate the precision and velocity of the ball throwing in goalball, besides core stability and balance as variables that determine an optimal throwing. Moreover, a novel acoustic reaction time is applied to analyze the defense performance. Eight goalball players (33 ± 9 years old; 77.8 ± 22.7 kg; 174 ± 13 cm; 10 ± 5 years of experience) were recruited to assess ball velocity, with a radar gun, and throwing accuracy. Anthropometry, static balance, and core stability were assessed using a computerized pressure platform. Acoustic reaction time was measured with a photoelectric system. A significant positive correlation was found between throwing speed and the years of experience (Ç· = 0.714, p = 0.047), height (Ç· = 0.786, p = 0.021), dominant leg surface area of the stabilogram (Ç· = 0.738, p = 0.037), and non-dominant leg center of pressure mean velocity (Ç· = 0.714, p = 0.017). In the present pilot study, height and years of experience are correlated to throwing velocity. This is also the first test proposal to assess throwing precision and complex acoustic reaction in goalball players, which could be used to assess the level of performance in future studies.

Effect of a Long Exercise Program in the Reduction of Musculoskeletal Discomfort in Office Workers.

The purpose of this study was to assess the effect of a six week exercise program to reduce the muscle tone of the trapezius and musculoskeletal discomfort (MED) of office workers. Twenty-six workers performed an exercise program based on: (1) stretching of cervical and/or dorsal region; (2) joint mobility of shoulders and rachis; (3) strengthening deep stabilizer and core muscles; and (4) scapula stabilizing exercises. A Myoton device was used to evaluate trapezius tone and the Cornell Musculoskeletal Discomfort Questionnaire was used to assess changes in MED at three points of evaluation: at the beginning (Pre_1) and at the end of the workday (Post_1), and after the training program (Pre_2). The Wilcoxon test and Cohen's d were performed to examine differences and effect sizes between evaluations. Main results show that trapezius tone remained constant during the workday, but decreased in the dominant upper trapezius (p = 0.003, ES = -0.60) and increased in the non-dominant middle trapezius (p = 0.016, ES = 0.45) after the exercise program, which eliminated significant muscle asymmetries. MED significantly decreased in the neck (p = 0.027, ES = -0.60) and upper back (p = 0.046, ES = -0.67). In conclusion, MED appears to improve in office workers after a six week training program, which may be explained by a decrease in trapezius tone and increase in the left middle trapezius tone.

Validity and Reliability of a 10 Hz GPS for Assessing Variable and Mean Running Speed.

Our purpose was to assess the 10 Hz Viper GPS devices' validity and reliability (STATSport) in both instantaneous and mean speed measuring in accelerations and decelerations in straight-line running conditions. Eight amateur team sport players participated in the study, performing firstly 21 x 40 m sprints at submaximal incremental speed, and secondly 21 x 40 m sprints, with the first stage consisting of submaximal incremental speed, and the second stage of subsequent submaximal decreasing speed. Criteria systems used to evaluate the GPS validity were a radar gun for instantaneous speed, and timing-gates for mean speed. Reliability was measured with two GPS devices carried by the same athlete, running 10 x (20 m + 20 m) sprints with a 180º change of direction and a 10 s inter-set rest interval. Results showed an agreement between GPS devices and the criteria systems measuring instantaneous speed (r = 0.98; standardized mean bias (SMB) = -0.07; standard typical error (STE) = 0.22) and mean speed (r = 0.99; SMB = 0.38; STE = 0.17). The reliability study presented a nearly perfect correlation between devices, a trivial SMB and a small STE (r = 0.97; SMB = 0.04; STE = 0.23). 10 Hz GPS devices are an adequate solution to monitor straight-line running speed in acceleration and deceleration conditions, but we would like to draw attention to the small errors and bias detected, such as the speed overestimation compared with timing gates.