Volume 25 (2010): Issue 2010 (September 2010)

After initial learning, a one-finger key stroke sequence, defined by a specific relative timing pattern (temporal structure) and absolute total movement time (temporal parameter), was practiced (with KR provided) either under dual-task conditions (experimental group), or under single-task conditions (control group). During dual-task practice, the key stroke sequence (i.e., the primary-task) was always executed in parallel to one of two cognitively demanding secondary tasks (subtracting numbers, or sorting marbles). Secondary tasks were alternated every 20 practice trials. Before (Pre-test) and after practice (Post-test), performance in each group was assessed under single-task and under dual-task conditions (no KR during tests). From Pre- to Post-test, primary-task performance in both groups significantly increased (relative timing in particular). Also, after practice dual-task costs found during Pre-test in both groups were still prevalent in the control group, but completely vanished in the experimental group with respect to those task combinations that were practiced before. However, when a new secondary task (repeating letters) was introduced, dual-task costs fully reappeared in the experimental group with respect to relative timing of the key stroke sequence. These results contradict the notion of readily acquiring automatic control in the course of dual-task practice by "Structural Displacement" (Blischke & Reiter, 2002), but they are well in line with the concept of developing cognitive strategies for "Integrated Task Processing" (Manzey, 1993). Thus, impact of dual-task practice on motor sequence production may be different from that on motor parameter control. In this context, implications of recent findings from neuropsychology on cortical systems engaged in the pursuit of concurrent behavioural goals (cf. Charron & Koechlin, 2010) are discussed.

Functional changes following whole body vibration (WBV) training have been attributed to adaptations in the neuromuscular system. However, these changes have mainly been observed in the lower extremity with minimal change to the upper extremity. The purpose of the study is to examine the acute effect of shoulder vibration on joint position sense and selected muscle performance characteristics (peak torque, time to peak torque, and power). Forty young individuals (19.84 ± 1.73 yrs, 171.41 ± 7.73 cm, 70.07 ± 9.32 kg) with no history of upper body injuries were randomly assigned to an experimental (Vibration) or control (No-Vibration) group. To assess shoulder proprioception, active and passive joint position senses were measured on both internal and external rotation of the shoulder. The muscle performance variables (peak torque and time to peak torque) were measured using isokinetic dynamometer with the velocity of 60°/sec. After three bouts of 1 minute vibration training, the experimental group demonstrated a significant improvement in the internal rotation peak torque, time to peak torque and external rotation time to peak torque (p<0.05). However, no-significant differences were revealed for joint position sense, external rotation peak torque, and time to peak torque between the groups. Our findings suggest that short bouts of vibration treatment have a significant effect on shoulder muscle characteristics.

The aim of the present study was to examine the rate of central and peripheral contributions in circadian rhythms and gender differences after exhausted maximal exercise. From 36 volunteers, 12 healthy male and female subjects who had H-reflex (It is elicited by electrical stimulation and it has been suggested to be one of mechanisms that could cause central fatigue) were selected (mean age of 23.5±1.37 years, height of 166.83±5.11cm, weight of 59.8±9.15 kg, VO_2max of 33.14±4.71 ml. kg^-1. min^-1in male subjects and mean age of 23±6.32 years, height of 165.17±2.48 cm, weight of 56±2.09 kg and VO_2max of 29.05±2.89 ml. kg^-1. min^-1 in female subjects) and took part in this investigation. Central (MVC, latency of H-reflex, amplitude of H-reflex and ratio of H-reflex to M-wave) and peripheral properties of fatigue (blood lactate and M-wave) were recorded before and after an exhausted maximal exercise at two different times of day: 9 am and 6 pm which is separated by a week. Significant differences were found in HR, blood lactate and latency of H-reflex before and after exercise. However differences between male and female in MVC, amplitude of H-reflex, ratio of H-reflex to M-wave and M-wave was significant. With induced -exercise, central and peripheral fatigue was higher in men in the morning and in women in the afternoon., thus our results recommended designing suitable exercise programs for men and women in the afternoon and morning, respectively. However, further studies are needed to confirm these results, especially in recommending using transcranial magnetic stimulation.

The aim of the study was to find factors which differentiate generally healthy elderly men who had fallen versus those whom had not fallen throughout the year prior to the study. The participants (66 generally healthy men aged over 70 years) were divided into two groups - those who had fallen (F) and those who had not fallen (NF) in the period of one year before the study. Their body mass index and fat mass were measured. On the basis of the value of maximum sways on a stable posturographic platform, the sway area was calculated. To study psychomotor fitness reaction time, an analysis was measured by the "Vienna System Test". Functional fitness was measured on the basis of selected tests from "The Senior Fitness Test". The complexity of the multiple mechanisms underlying postural control does not allow for clear indication of the risks of stability loss. The experimental group of men over 70 yrs who had fallen (F) was characterised by lower body strength (p<0.05) and endurance (p<0.05), compared to NF group. Exercise programs designed to prevent accidental falls should incorporate strength and aerobic exercises.

Twenty obese (BMI>30) women with an average age of 22.00 ± 1.50 years volunteered to participate in this study. They were randomly assigned to exercise (n=10) and control (n=10) groups. Before and after the training program, both groups were evaluated for anthropometric measurements and blood analysis. Bone mass density (BMD) was evaluated by using dual-energy X-ray absorptiometry (DXA) at the hip and spine (L_2- L₄). Each walking session was 30 min walking at 50-75% of maximal heart rate, 3 days per week, for 2 months. After 2 months, the exercise group showed no significant effect on BMD at the spine (L_2- L₄) and hip (p>0.05). However, there was a slightly increase in BMD at both regions, while the control group did not. Also, no change was observed in bloods factors. Percent body fat, fat mass and lean mass changes in response to training were significant in the exercise group (all p=0.000). As a result, it may be suggested that walking programs of longer duration and higher intensity can influence BMD and related factors in obese girls, however to achieve this result, more studies are needed.

This study investigated the effects of supplementation with Krill oil on levels of pro-oxidant/antioxidant balance markers and levels of pro-inflammatory cytokines in professional rowers submitted to exhaustive exercise.

This double-blind study included 17 members of the Polish National Rowing Team. Subjects were randomly assigned a supplemented group (n=9) which received two capsules (500 mg) of Krill oil daily for 6 weeks, or a placebo group (n=8). At the beginning and at the end of preparatory camp, subjects performed a 2000 m maximum effort test on a rowing ergometer. Blood samples were taken from the antecubital vein prior to each exercise test, 1 minute after completing the test, and after 24-hours of rest. The following redox parameters were assessed in erythrocytes: superoxide dismutase (SOD), glutathione peroxidase (GPx), and thiobarbituric acid reactive substances (TBARS) concentration. Additionally, creatine kinase (CK) activity was measured in plasma samples, while tumor necrosis factor (TNF-α) concentrations were measured in the serum.

Exercise significantly increased values of SOD, TNF-α and TBARS in both groups, but recovery levels of TBARS were significantly lower in athletes receiving Krill oil compared with the control group.

Based on these results we conclude that supplementation with Krill oil (1 g per day) in trained rowers diminished post exercise oxidative damage to erythrocytes during recovery, but had no effect on antioxidant enzymes, TNF-α and serum lipid profiles.

The present study aimed at assessing air way resistance indexes that include FEV1 (Force expiration Volume in one second), FVC (Forced vital capacity) and FEV1/FVC and exercise-induced asthma (EIA) after one session of sub maximal incremental aerobic exercise. Fifty healthy male subjects (age 19-26) from the faculty of Physical Education, University of Shahid Chamran served as the participants of the study. They were randomly assigned to either exercise or control groups. Body height, body mass and pulmonary factors were measured in the pre-test conditions. The study protocol included a sub maximal incremental Astrand - Rhyming test on an ergocycle. After performing this test by the exercise group, FEV1, FVC and FEV1/FVC, were measured again for both groups and compared with pre test evaluations. The data were analyzed through descriptive and inferential statistics (dependent and independent t test). Results showed that there was a significant difference in FEV1 between the two groups after the exercise protocol (p ≤ 0.05). There was no significant difference in FVC between the two groups after exercise, and a significant difference was registered in FEV1 and FEV1/FVC between pre-test and post-test results in the group that performed the aerobic test protocol (p ≤ 0.05). Our results indicate that one sub maximal incremental aerobic exercise session causes a significant change in FEV1 and FEV1/FVC, and causes exercise-induced asthma.

Recently growth hormone therapy has been used as an age delaying drug in middle aged men and women as well as in the elderly. Positive effects have been shown in regards to body mass and body composition changes, fat metabolism, bone mineral density and muscle strength. Exercise is a potent physiological stimulus for growth hormone secretion and both aerobic and resistance exercise results in significant, acute serum increases in GH concentration. It is unclear however whether a combination of exercise and hGH therapy further increases physical performance in adults and increases changes in body composition and biochemical variables related to health. For this purpose a group of 15 middle aged men (45,7±5,8 years, 93,2±16,3kg and 183,3±4cm), slightly overweight were randomly divided into an experimental and control groups. Both groups exercised for 3 month, performing 2 aerobic sessions per week and 2 resistance workouts, increasing training loads every two weeks. The experimental group received additionally hGH subcutaneous injections beginning with 0,2 IU daily for the first month and then increasing it to 0,4 and 0,6 IU in successive month. VO_2max was evaluated during a progressive ergocycle test to volitional exhaustion, while anaerobic power and capacity were measured during the 30s Wingate test. Additionally body mass and body composition were evaluated as well as the lipoprotein profile and the concentration of chosen anabolic hormones. The results indicate a significant rise in resting concentrations of GH and IGF-1 after the replacement therapy but no additional benefits in regards to aerobic fitness and fat metabolism in comparison to exercise only. A more profound effect was observed in case of anaerobic performance, thus it was concluded that even small doses of hGH stimulated additional protein synthesis following resistance exercise what allowed for significant increases in FFM, anaerobic power (W/kg) and capacity (J/kg) as evaluated obtained during the Wingate test. It was concluded that for a more significant effect of hGH therapy in regards to physical performance greater doses of this hormone have to be used, along with an intensive exercise program.

Every sports discipline is characterized by specific movements which are symmetric or asymmetric. Field hockey belongs to a asymmetric activity. There is suspicion that players, who use more frequently one side of the body during training or the game, have also side-to-side morphological diversification. The main aim of the study is to determine the degree of asymmetry which manifests itself in somatic characteristics. The analysis was done among twenty competitive Polish male field hockey players. All athletes undertook total body Dual X-Ray Absorptiometry (DXA) scans, which divided the body into anatomic segments: arms, trunk, and legs. Professional field hockey participation showed significantly enhanced muscle mass and higher bone mineral density on the left side of the body. The present data should help better understand complicated morphology of highly trained athletes with more comprehensive and accurate approach to their anthropometrical description.

The aim of this study was to identify specific performance indicators that discriminate the top clubs from the others based on significantly different pitch action performance in the Spanish Soccer League. All 380 games corresponding to the 2008-2009 season have been analyzed. The studied variables were divided into three groups related to goals scored (goals for, goals against, total shots, shots on goal, shooting accuracy, shots for a goal), offense (assists, crosses, offsides committed, fouls received, corners, ball possession) and defense (crosses against, offsides received, fouls committed, corners against, yellow cards, red cards). Data were analyzed performing a one-way ANOVA. Significant differences across sections of the league table were found for the following pitch actions: goals for, total shots, shots on goal, shots for a goal, assists and ball possession. The main findings of this study suggest that top teams had a higher average of goals for, total shots and shots on goal than middle and bottom teams (p<0.05). Bottom teams needed a higher number of shots for scoring a goal than the other groups of teams (p<0.05). Middle teams showed a lower value in assists and ball possession than top teams (p<0.05). In conclusion, this paper presents values that can be used as normative data to design and evaluate practices and competitions for peak performance soccer teams in a collective way.

In soccer, the ability to retain possession of the ball for prolonged periods of time has been suggested to be linked to success. The accuracy of this assertion was investigated by examining 380 matches involving Spanish League First Division teams during the 2008-2009 season. Possession of the ball, according to the status of the match (winning, drawing and losing), was recorded during the different matches using a multiple-camera match analysis system (Gecasport®). The results suggest that the best classified teams maintained a higher percentage of ball possession and that their pattern of play was more stable. The coefficient of variation, with respect to ball possession per match, was smaller for the best placed teams. Indeed, first placed F.C. Barcelona had the smallest coefficient of variation for possession time (8.4%), while bottom placed Recreativo showed the highest values with 17.1%. Linear regression analysis showed that possession strategies were influenced by situation variables. Team possession was greater when losing than when winning (p<0.01) or drawing (p<0.01), home teams enjoyed greater possession than visiting teams (p<0.01), and playing against strong opposition was associated with a reduction in time spent in possession (p<0.01). The findings indicate that strategies in soccer are influenced by situational variables and that teams alter their playing style accordingly during the match.

The purpose of this study was to quantify and compare asymmetry of stride length during 200 m sprint in different levels of performance. Six sprinters from national and regional levels participated in the study. They were assigned to 3 groups: school-boys (novice sprinters) junior (intermediate) and senior (advance - national and regional level) category. This study investigated selected kinematic parameters with special focus on stride length. The resulting values were measurements of each stride length (rounded-off to nearest full centimeter) during a 200 m sprint, using a manual stride measurement method. The findings indicate that the asymmetry of stride length exists in all categories, and the impact on decreasing velocities of the youngest sprinters (school-boys) are significantly associated with shorter strides, whereas cadence has little change. However, when a statistical adjustment was made for each group of runners it was found that more advanced runners did not have a significantly higher level of asymmetry with stride length at any given velocity.

In this study, a descriptive method was used in order to assess the demographic and personality characteristics of athletes in dancing sports.

Data collected with ACL scale were evaluated with a computer programme and subscale scores were obtained. Five subscale categories which have the highest mean scores among all, were decided as typical characteristics of the athletes. The distributions of subscale scores according to demographic variables were analyzed by Mann-Whitney U test, and Pearson correlation test. In all analysis, results were tested two-sided and level of significance was accepted as 0.05.

Preponderance over others, decisiveness, high self-esteem, masculine behavior were found significantly higher in younger athletes compared to old ones. On the other hand, acceptance of psychological consultation was found to be significantly higher among old athletes.

The purpose of this study was to compare body composition and physical fitness development of children participating in soccer and different education programs. Nineteen adolescence children (age=12.8±0.3) participated in soccer training and eleven adolescence children (age=13.4±1) participated in multi-purpose physical education program for three weeks. Physical fitness tests were applied for determining the motor fitness, flexibility, agility, explosive power, general balance and endurance of children. Tests were applied before and after two educational programs and paired t-tests were applied between pre- and post-tests of the group. According to results, the weight of children who participated in the multi-purpose physical education program did not change significantly, whereas the weight of children in the soccer training program changed significantly (p<0.05). Standing-broad jump performance, 10 × 5 m speed shuttle run performance, flamingo balance test, abdominal sit-ups and medicine ball performance were significantly increased after two multi-purpose education programs (p<0.05). Furthermore, strength endurance of abdominal muscle group performance increased in only the soccer training group (p<0.05). In conclusion, both training programs had positive effects on performance. However, soccer training is more effective for development of strength and endurance of the abdominal muscle group, because soccer training is more specific for development of motor abilities.

The aim of this study was to evaluate the correlations of anthropometric and body composition variables with the performance (i.e., snatch; clean & jerk; front squat; back squat) of Iranian elite weightlifters. Forty-two subjects (mean ± SD of age 16.21 ± 3.22 years) volunteered to participate in the study.

All subjects competed at the Iranian National Championship. Anthropometric and body composition variables, including height, sitting height, cormic index, lean body mass (LBM), body mass index (BMI), modified BMI (by the cormic index), %fat, shoulder circumference, chest circumference, WHR (wrist to hip ratio), as well as performance of weightlifters (i.e., snatch; clean & jerk; front squat; back squat) were measured.

Results showed that the snatch and clean & jerk records significantly correlated with height, sitting height, weight, shoulder and chest circumference, LBM, BMI; whereas we showed negative correlations between the snatch and clean & jerk records with the %fat as well as WHR values. Results also showed that the snatch and clean & jerk records significantly correlated with body mass index (BMI) (r= 0.357, and r= 0.374; p<0.05); however there was no relationship between snatch and clean & jerk records and the modified body mass index (MBMI).

According to the results, it was concluded that there was strong correlations existing between weightlifter performance and the anthropometric and body composition variables. Also, it is recommended that the cormic index (CI) is a corrective factor for BMI values.

Modern Saber Fencing by Zbigniew Borysiuk (SKA SwordPlay Books, New York, USA) is a product of the author's many years of experience as a fencing coach and a researcher of talent identification, mental and motor coaching, with particular interests in information processes, perception, sensori-motor reactions, spacial and temporal anticipation as well as selection in sport and fencing training at all stages of an athlete's development. The greatest asset of the book is the wealth of photographs and presentations of technical and tactical actions by elite saber fencers on a DVD. This book should be extremely useful in fencing training and attract the interest of the fencing community, including collegiate fencing clubs, in the United States, Poland and other countries.