Showing papers in "Kinesiology: international journal of fundamental and applied kinesiology in 2016"

Vertical jump performance and isokinetic torque discriminate advanced and novice judo athletes

Abstract: This study aimed to analyze neuromuscular variables (vertical jump and torque in external/internal shoulder rotation) in advanced and novice judo athletes, and to identify which neuromuscular variables allow for discrimination between them. Thirty male judo athletes participated in this study: 19 novice and 11 advanced athletes. The judo athletes performed the external/internal shoulder rotation in an isokinetic dynamometer and the countermovement jump on a force platform. Student’s t-test and the discriminant analysis were used, with the level of significance set at 5%. The main results showed that the advanced judo athletes presented higher jump height (p=.03) and power output (p=.02) compared to the novice athletes. In addition, internal shoulder rotation peak torque was higher in the advanced judokas compared to the novice judokas (p=.04), and the ratio between external rotation torque and internal rotation torque was higher in the novice judokas compared to the advanced judokas (p=.006). In this discriminant function, the variables with higher discriminatory power were (in descending order): jump height, internal shoulder peak torque, and ratio between peak torques. The results of the present study demonstrated that advanced judo athletes presented better performance in vertical jump, internal shoulder isokinetic torque, and ratio between external/ internal isokinetic torques than novice athletes. The variables used to discriminate between advanced and novice judokas may provide coaches with a guide for sport-specific training needs.

Mood aspects of rapid weight loss in adolescent wrestlers

Abstract: The aims of this paper were: a) to present weight reduction habits of adolescent wrestlers; b) to establish differences in mood states between weight groups; and c) to determine relations between weight loss and indicators of hydration with mood states. Adolescent wrestlers do resort to rapid weight loss (RWL) regimens in their training process and competition – 70.1% of the subjects reduced their body mass and the reduction regime usually lasted one week. Similar habits have been reported in other studies despite the well evidenced detrimental effects of RWL. Urine specific gravity (USG) values suggest that all the subjects were in the state of dehydration ranging from a mild to a high one. The groups of low weight (LW) and middle weight (MW) wrestlers reduced their body mass significantly more than others (BM; p<.05) and their sensation of fatigue was significantly higher (p<.05). The variables body mass reduction and %BM reduction were correlated with negative mood states, whereas the indicators of hydration in one of the groups (MW) established ambiguous relations with dehydration and positive mood states.

Practicing with gradual increases in contextual interference enhances visuomotor learning

Abstract: The purpose of this study was to determine if practicing with gradual increases in contextual interference (CI) facilitated the learning of a continuous motor skill that required visuomotor tracking. We hypothesized the group that practiced with increasing amounts of CI would perform significantly better on a retention and transfer test compared to participants that practiced with blocked and random scheduling. A total of 78 participants were randomly assigned to one of three groups (i.e. Blocked, Increasing, Random). The level of CI was modified by varying the number of revolutions per minute (RPM) on a rotary pursuit tracker. Following the acquisition phase, participants returned after a 24-hour period and completed the 12-trial retention and transfer test. The results of statistical analysis indicated that all three groups improved their performance during practice. The posttest analysis indicated the Increasing group was better than the Blocked and Random groups on the retention and transfer test.

Analysis of load and players’ effort in 4 vs 4 small-sided handball games in relation to court dimensions

Abstract: The aim of the present study was to analyse load to which players were exposed to and effort they invested in 4vs4 small-sided handball games in relation to various court dimensions. Eight male amateur handball players participated in three eight-minute 4vs4 (plus goalkeepers) small-sided handball games. The three court dimensions were 12×24 m, 30×15 m and 32×16 m. Using Global Positioning System devices (SPI pro elite 15hz, GPSports), time-motion video analysis, and Borg’s scale for rating of perceived exertion (RPE), the following performance, physiological and psychological parameters were recorded: cyclic movements for distance covered, acyclic movements for the number of technical actions executed, heart rate, and RPE. Total distance travelled increased with the increase in court size (948.1±64.5, 1087.2±92.0 and 1079.8±90.6 on the 24×12 m, 30×15 m and 32×16 m court, respectively ; p<.05). Distance covered by the players in four speed zones revealed the substantial difference between the games played on the 24×12 and 30×15m court in the first and third (p<.05 ; moderate ES) speed zone. On the 24×12 m court players covered more distance while moving in the first speed zone, but less distance when moving in the third speed zone (p<.05 ; moderate ES). On the 32×16 m court the players covered less distance while moving in the first speed zone, but they covered more distance by moving in the third speed zone (p<.05 ; moderate ES). There were no substantial differences found for the second and fourth speed zone cyclic movements and distances covered on all the three experimental court sizes. No statistical differences between the games played on various court dimensions were found in acyclic movements. No statistical differences were found in the analysis of heart rate. Further analysis of players’ self-evaluated effort confirmed the trend of heart rate values, showing no statistical differences in the RPE values among the three different court dimensions. Our findings indicate that changing court dimensions during 4vs4 small-sided handball games could influence load imposed on the players and their exertion.

Oxidative dna damage and lipid peroxidation to cluster vs. traditional sets resistance exercise in professional volleyball players

Abstract: Cells continuously produce free radicals and reactive oxygen species (ROS) as part of metabolic processes. Exercise can induce an imbalance between ROS and antioxidants, which is referred to as oxidative stress. Acute bout of resistance exercise (RE) induces activation of several distinct systems of radicals generation, but the effects of different RE loading on oxidative stress response is not clear. Therefore, the purpose of this study was to examine the influence of cluster vs. traditional sets of RE on oxidative DNA damage, lipid peroxidation and uric acid response in athletes. To elicit blood oxidative stress, 12 professional young male volleyball players undertook two different RE loading patterns: 1) cluster loading pattern, 2) traditional loading pattern which was standardized for total volume and completed in a randomized crossover fashion with a four-day interval between trials. Blood samples were collected before and after RE for markers of oxidative stress and damage. In response to both the cluster and traditional sets, 8-hydroxy-2-deoxyguanosine (8-OHdG), 4-hydroxy-2-nonenal (4-HNE), and uric acid were significantly elevated post exercise (p<.05). Although no statistically significant differences between loading patterns were observed, the rate of elevations in 8-OHdG (effect size [ES]: 1.4 vs. 1.3) and 4-HNE (ES: 8.1 vs. 7.9) was greater for the traditional sets; likewise, the rate of uric acid excretion was greater for the cluster RE (ES: 1.6 vs. 1.4). These data suggests that RE induced DNA damage, and lipid peroxidation, but they were greater for the traditional RE. Therefore, strength and conditioning professionals in the field of volleyball must keep in their mind that RE induces oxidative stress and should use proper RE loading patterns in their training schedule.

Metric characteristics of a new test for the evaluation of dynamic balance

Abstract: The aim of the study was to determine psychometric characteristics of a new test for the evaluation of dynamic balance in healthy individuals. The research was conducted on a sample of 60 female students (21.18±.86 years). The participants performed three trials of the new test for each of the two different ways of walking. The results of reliability have shown high values of factor loadings (.91-.97) and standardized Cronbach’s alpha values (.87-.98), as well as the average inter-item correlation values (full feet walking, tip toe walking and the number of steps) (.78-.94). High values of factor loadings (.88-.97) and the fact that the total explained variance was very high (93.3%), with a relatively small variability between the attempts, suggests that all the rules for consistency of testing have been satisfied and that the new test is reliable enough for its application in practice.