Repeated Sprint Ability in Young Basketball Players (Part 2): The Chronic Effects of Multidirection and of One Change of Direction Are Comparable in Terms of Physiological and Performance Responses.

The aim of this study was to examine the effects of a 5-week training program, consisting of repeated 30-m sprints, on two repeated sprint ability (RSA) test formats: one with one change of direction (RSA) and the other with multiple changes of direction (RSM). Thirty-six young male and female basketball players (age 16.1 ± 0.9 years), divided into two experimental groups, were tested for RSA, RSM, squat jump, counter-movement jump, and the Yo-Yo Intermittent Recovery-Level-1 (Yo-Yo IR1) test, before and after a 4-week training program and 1 week of tapering. One group performed 30-m sprints with one change of direction (RSA group, RSAG), whereas the other group performed multidirectional 30-m sprints (RSM group, RSMG). Both groups improved in all scores in the post-intervention measurements (P < 0.05), except for the fatigue index in the RSM test. However, when comparing the two groups, similar effects were found for almost all parameters of the tests applied, except for RPE in the RSA test, which had a greater decrease in the RSAG (from 8.7 to 5.9) than in the RSMG (from 8.5 to 6.6, P = 0.021). We can conclude that repeated 30-m sprints, either with one change of direction or multidirectional, induce similar physiological and performance responses in young basketball players, but have a different psycho-physiological impact.

Lower Arm Muscle Activation during Indirect-Localized Vibration: The Influence of Skill Levels When Applying Different Acceleration Loads.

We investigated the electromyographic response to synchronous indirect-localized vibration interventions in international and national table tennis players. Twenty-six male table tennis players, in a standing position, underwent firstly an upper arms maximal voluntary contraction and thereafter two different 30-s vibration interventions in random order: high acceleration load (peak acceleration = 12.8 g, frequency = 40 Hz; peak-to-peak displacement = 4.0 mm), and low acceleration load (peak acceleration = 7.2 g, frequency = 30 Hz, peak-to-peak displacement = 4.0 mm). Surface electromyography root mean square from brachioradialis, extensor digitorum, flexor carpi radialis, and flexor digitorum superficialis recorded during the two vibration interventions was normalized to the maximal voluntary contraction recording. Normalized surface electromyography root mean square was higher in international table tennis players with respect to national ones in all the interactions between muscles and vibration conditions (P < 0.05), with the exception of flexor carpi radialis (at low acceleration load, P > 0.05). The difference in normalized surface electromyography root mean square between international table tennis players and national ones increased in all the muscles with high acceleration load (P < 0.05), with the exception of flexor digitorum superficialis (P > 0.05). The muscle activation during indirect-localized vibration seems to be both skill level and muscle dependent. These results can optimize the training intervention in table tennis players when applying indirect-localized vibration to lower arm muscles. Future investigations should discriminate between middle- and long-term adaptations in response to specific vibration loads.

Repeated Sprint Ability in Young Basketball Players: Multi-direction vs. One-Change of Direction (Part 1).

The aim of the present study was to examine the reliability of a novel multi-direction repeated sprint ability (RSA) test [RSM; 10 × (6 × 5-m)] compared with a RSA with one change of direction [10 × (2 × 15-m)], and the relationship of the RSM and RSA with Yo-Yo intermittent recovery test level 1 (Yo-Yo IR1) and jump performances [squat jump (SJ) and counter-movement-jump (CMJ)]. Thirty-six (male, n = 14, female n = 22) young basketball players (age 16.0 ± 0.9 yrs) performed the RSM, RSA, Yo-Yo IR1, SJ, and CMJ, and were re-tested only for RSM and RSA after 1 week. The absolute error of reliability (standard error of the measurement) was lower than 0.212 and 0.617-s for the time variables of the RSA and RSM test, respectively. Performance in the RSA and RSM test significantly correlated with CMJ and SJ. The best time, worst time, and total time of the RSA and RSM test were negatively correlated with Yo-Yo IR1 distance. Based on these findings, consistent with previously published studies, it was concluded that the novel RSM test was valid and reliable.

Task complexity reveals expertise of table tennis players.

BACKGROUND: The purpose of this study was to examine the effect of intensive practice in table tennis on perceptual, decision-making and motor-systems. Groups of elite (HL, N.=11), intermediate (LL, N.=6) and control players (CC, N.=11) performed tasks of different levels. METHODS: All subjects underwent to reaction time test and response time test consisting of a pointing task to targets placed at distinct distances (15 and 25 cm away) on the right and left sides. Only the HL and LL groups were requested to perform the ball speed test in forehand and backhand condition. RESULTS: In the CC group reaction time was higher compared to the HL (P<0.05) group. In the response time test, there was a significant main effect of distance (P<0.0001) and the tennis table expertise (P=0.011). In the ball speed test HL players were consistently faster compared to LL players in both forehand stroke (P<0.0001) and backhand stroke (P<0.0001). Overall, the forehand stroke was significantly faster than the backhand stroke. CONCLUSIONS: We can conclude that table tennis players have shorter response times than non-athletes and the tasks of reaction time and response time are incapable to distinguish between the performance of well-trained table tennis players and that of intermediate players, but the ball speed test seems to be able to do it.

Quality of life, cortisol blood levels and exercise in older adults: results of a randomized controlled trial.

INTRODUCTION: Cortisol plays a central role in the stress response; while high stress can determine physical and psychological impairment, moderate stress, with a mild increase in cortisol level, may have a positive effect on coping and physical performance. This trial attempted to determine whether cortisol levels were associated with Quality of Life (QoL) in a sample of elderly subjects undertaking an exercise program. METHODS: 42 subjects aged ≥65 years were randomlyassigned in a 1:1 fashion either to a vigorous physical activity (VAG: N=21) or to a postural gimnastic group (PGG: N=21). Differences between the two groups in QoL (on SF-12), and blood cortisol levels were assessed by ANOVA at different times. RESULTS: In both the VAG and PGG, cortisol levels rose at the end of the trial, with statistically significant differences as compared to the baseline. QoL at the end of the trial was higher than in the national normative sample. Cortisol and QoL in both groups decreased slightly 12 weeks after the end of the trial (T2); however, only in the VAG did the difference from the initial level remain statistically significant. At T1 and T2, subjects with higher SF-12 scores were found in subsamples in both groups with cortisol levels moderately increased (between 200 and 300 mg/ml). CONCLUSION: In a sample of elderly subjects undergoing two different kinds of exercise, a better perception of Quality of Life was associated with a moderate, non-pathological increase in cortisol. The results need to be confirmed by trials on larger samples.

Kinematics of running at different slopes and speeds.

The aim of this study was to verify the influence of the combination of different running speeds and slopes based on main kinematic parameters in both groups of elite (RE) and amateur (RA) marathon runners. All subjects performed various tests on a treadmill at 0, 2, and 7% slopes at different speeds: 3.89, 4.17, 4.44, 4.72, and 5.00 m·s. A high speed digital camera, 210 Hz, has been used to record; Dartfish 5.5Pro has been used to perform a 2D video analysis. Step length (SL), step frequency (SF), flight time (FT), and contact time (CT) were determined and used for comparison. SL, SF, and FT parameters increased, and CT parameter decreased as speed increased. As slopes increased, SL and FT decreased and SF increased in both groups and only CT decreased in RE, whereas in RA, it increased. Data were fitted to the linear regression line (R > 0.95). The 2 groups were significantly different (p < 0.05) in FT, SL, and SF at all speeds in level running. A significant difference between the 2 groups was found in FT at 2 and 7% slopes at all speeds (p < 0.05). Percentage alterations in all variables were greater in the RA group. In conclusion, the choice of optimum SL and SF, through efficient running can be maintained, is influenced not only by speed but also by slopes. Elite runners perform more efficiently than amateur runners who have less experience.