Measurement of talent in volleyball: 15-month follow-up of elite adolescent players

AIM

The purpose of this study was two-fold: first, to examine the contribution of a battery of physical and motor tests to early phases of talent detection and early development in volleyball, and second, to differentiate between and compare the motor ability of 16-year-old starter (S) and non-starter (NS) volleyball players.

METHODS

Fifteen male adolescent volleyball players underwent assessment of physical and motor ability 6 times during a 15-month training program; however, not all of them took part in each testing phase. The battery was composed of 8 physical and motor tests and 2 skill tests. The physical and motor tests included 2 speed tests, an agility run, 4 explosive power tests, and an endurance test. The skill tests evaluated service accuracy at rest and following effort.

RESULTS

All participants improved their results in all but 2 tests (endurance and skill tests) across testing phases. Comparisons between the S (n=8) and NS (n=7) revealed that only one physical explosive power test (vertical jump with approach), was found to be a good indicator for distinguishing between the 2 groups of players.

CONCLUSION

It was concluded that the volleyball battery of tests was not sensitive enough to distinguish between the ''good'' and ''very good'' players suggesting that physical and motor tests do not reflect open skill ability in volleyball.

Measurement of talent in judo using a unique, judo-specific ability test

AIM

Coaches of young athletes at early phases of development often use batteries of tests in order to obtain information that will be helpful in predicting their future success. However, little scientific inquiry has been conducted on the relevance of the testing process to the final selection and success of young prospects. The purpose of this study was to examine the benefits of a unique judo-specific ability test in early phases of talent development and selection.

METHODS

Ten judokas (12-15 years of age) underwent assessment of general ability and specific judo ability 3 times during 1994 and 1995, at about 6-month intervals. The general ability test included: sit-ups, push-ups, and side-to-side jumps. The specific judo ability test was comprised of 10 stations in which the judokas performed physical ability and skill tasks. Following the 12-month training program the judokas were ranked by the 2 national judo coaches. Eight years after the beginning of the training program, the judokas were ranked once again by the national coaches.

RESULTS

Data analysis revealed that the specific judo ability test did not correlate with either the 1995 or with the 2003 ranking.

CONCLUSIONS

Because the unique judo-specific ability test was not found to be sensitive enough to accurately measure talent, it is suggested that future studies investigate the usefulness of tests reflecting a more open-skill environment.

The association between adiposity and the response to resistance training among pre- and early-pubertal boys

Resistance training has been shown to be effective in enhancing muscle strength among prepubertal and adolescent boys. Lately, it has been recommended for obese children. We hypothesized that resistance training will be similarly effective among boys of different adiposity. Thirty boys, aged 9.2 +/- 0.3 years, participated in progressive resistance training twice weekly during the first and second school years and thrice weekly during the third year. Training sessions included 1-4 sets of 3-6 exercises, with 5-30 repetitions/set. The mean load was 50-60% of 1 repetition maximum. Subjects were divided into responders (R--upper tertile) and non-responders (NR--lower tertile), according to the three-year improvement in muscle strength, as assessed by means of changes in concentric strength of knee flexors and extensors. Differences between groups were observed at baseline (p <0.05) in all variables reflecting adiposity (mean +/- SD): % body fat (14.1 +/- 2.6 vs 23.5 +/- 7.5% for R and NR, respectively), sum of four skinfolds (25.4 +/- 4.7 vs 47.8 +/- 21.6 mm for R and NR, respectively), BMI (15.5 +/- 1.1 vs 18.6 +/- 2.6 kg x m(-2) for R and NR, respectively). Additionally, the changes in adiposity were inversely related to the training effect (r = -0.60 to -0.34). No differences were observed in initial height and maturation between R and NR groups and there was no difference in linear growth and physical maturation with time between groups. These data suggest that resistance-training loads which may be appropriate to increase strength of knee flexors and extensors in normal-weight children may be insufficient to do so in overweight children. More research is required to elucidate the efficacy of resistance training among overweight children.

Reagents for the chemical development of latent fingerprints: scope and limitations of benzo[f]ninhydrin in comparison to ninhydrin

Benzo[f]ninhydrin was compared to ninhydrin for fingerprint development on paper. Overall, the performance of ninhydrin on exhibits was slightly better than that of benzo[f]ninhydrin. The significant advantages of the benzo[f]ninhydrin over ninhydrin were the much stronger fluorescence it gave after treatment with zinc salts and a slightly quicker reaction under ambient conditions. This fluorescence is, however, similar to that obtained with other reagents, such as DFO or ninhydrin analogs. These advantages apparently are not sufficient to justify regular usage of benzo[f]ninhydrin, especially when one considers its low solubility and high cost.

An exploratory study of perceptual-motor abilities of women: novice and skilled players of team handball

Comparisons of ability between skilled performers and novices have been made for activities such as basketball, volleyball, tennis, squash, and badminton, but there is little work on team-handball which is not a well-recognized sport in North America. To examine a variety of perceptual, e.g., anticipation time, reaction time, and motor, e.g., throwing tasks, abilities of skilled and novice female team-handball players 13 First Division (skilled) and 10 recreational (novice) players (M age = 25.3 yr.) performed 2 laboratory activities (for measurement of anticipation time, reaction time and movement time) and 3 field tasks (for measurement of accuracy and speed of throwing abilities) in random order. Reaction time and movement time were collected during a unique team-handball motor activity. Analyses of variance with repeated measures on trial blocks indicated high mean proficiency for the skilled participants in reaction time and all field-throwing tests compared with the novice participants. These reliable differences in team-handball activities further support superiority in sport settings gained by physical achievements and psychomotor excellence. In other words, skilled female team-handball players threw faster and more accurately and responded more rapidly than novice players.

Effectiveness of a structured learning strategy on acquisition of game-related gross motor tasks in school settings

The effectiveness of learning strategies, e.g., the Five-step Approach, has been examined extensively under well-controlled laboratory conditions in the motor learning and physical education literature. This study examined the application of the Five-step Approach as an instructional technique in field settings. Two experiments were conducted in which a similar strategy was used in school settings. In Exp. 1, 40 third-grade children were randomly assigned to two groups, one to whom the Five-step' Approach was explained (readying, imaging, focusing-attention, executing and evaluating), and a Control (Nonstrategy). Both then performed an activity similar to bowling. In Exp. 2, 33 seventh-grade children were assigned to the same learning conditions but performed a team-handball throwing task. Accuracy of performance was measured as a dependent variable in both experiments. Analysis of variance with repeated measures on the second factor indicated high values of accuracy for the Five-step Approach group in Exps. 1 and 2 compared with the Nonstrategy group. It was concluded that the Five-step Approach can enhance performance on motor tasks not only in laboratory settings but also in real world environments such as physical education classes. Physical educators might consider the use of task-pertinent learning strategies during their practical work.

Motor skill acquisition, auditory distractors, and the encoding specificity hypothesis

28 women and 28 men threw a paddleball at a target in 4 conditions of noise and quiet, being given 150 trials on 2 days. Analysis of absolute constant error and total error indicated the encoding-specificity hypothesis was not supported and no transfer was noted across conditions, perhaps because the noise was not demanding enough.

Focus of attention during motor skill performance

The effect of strategy instruction on response time in a sequential keypressing task was compared during acquisition and retention. Specifically, this study determined the influence of: (1) an awareness strategy, (2) a non-awareness strategy, (3) a Five-Step Approach strategy and (4) a control condition. Sixty-four subjects completed 250 trials of nine sequential keypresses, and 50 trials of a dual task (keypresses and verbal report). Faster response times were found for the Five-Step Approach and non-awareness strategies during both acquisition and retention. Introducing beginners to strategies that are used by highly skilled performers facilitated response times.