The relationship between peak height velocity and physical performance in youth soccer players

Longitudinal changes in height, weight and physical performance were studied in 33 Flemish male youth soccer players from the Ghent Youth Soccer Project. The players' ages at the start of the study ranged from 10.4 to 13.7 years, with a mean age of 12.2 +/- 0.7 years. Longitudinal changes were studied over a 5 year period. Peak height velocity and peak weight velocity were determined using non-smoothed polynomials. The estimations of peak height velocity, peak weight velocity and age at peak height velocity were 9.7 +/- 1.5 cm x year-1, 8.4 +/- 3.0 kg x year-1 and 13.8 +/- 0.8 years, respectively. Peak weight velocity occurred, on average, at the same age as peak height velocity. Balance, speed of limb movement, trunk strength, upper-body muscular endurance, explosive strength, running speed and agility, cardiorespiratory endurance and anaerobic capacity showed peak development at peak height velocity. A plateau in the velocity curves was observed after peak height velocity for upper-body muscular endurance, explosive strength and running speed. Flexibility exhibited peak development during the tear after peak height velocity. Trainers and coaches should be aware of the individual characteristics of the adolescent growth spurt and the training load should also be individualized at this time.     

Three-axis platform simulation: Bond graph and Lagrangian approach

A bond graph model is derived for the geometric constraints of a three-axis flight table. Gimbal dynamics are easily added even in asymmetrical and unbalanced cases. A method is introduced to make the local dependent inertias computable. The bond graph compares favourably to the Lagrangian approach as to modelling effort and accessibility of intermediate variables as well as having computational advantages.     

One hundred and fifty years of sprint and distance running – Past trends and future prospects

Sprint and distance running have experienced remarkable performance improvements over the past century. Attempts to forecast running performances share an almost similarly long history but have relied so far on relatively short data series. Here, we compile a comprehensive set of season-best performances for eight Olympically contested running events. With this data set, we conduct (1) an exponential time series analysis and (2) a power-law experience curve analysis to quantify the rate of past performance improvements and to forecast future performances until the year 2100. We find that the sprint and distance running performances of women and men improve exponentially with time and converge at yearly rates of 4% ± 3% and 2% ± 2%, respectively, towards their asymptotic limits. Running performances can also be modelled with the experience curve approach, yielding learning rates of 3% ± 1% and 6% ± 2% for the women's and men's events, respectively. Long-term trends suggest that: (1) women will continue to run 10–20% slower than men, (2) 9.50 s over 100 m dash may only be broken at the end of this century and (3) several middle- and long-distance records may be broken within the next two to three decades. The prospects of witnessing a sub-2 hour marathon before 2100 remain inconclusive. Our results should be interpreted cautiously as forecasting human behaviour is intrinsically uncertain. The future season-best sprint and distance running performances will continue to scatter around the trends identified here and may yield unexpected improvements of standing world records.     

Provider documentation of patient education: a lean investigation

Purpose

The study evaluates how providers give patient education materials and identifies improvements to comply with Meaningful Use (MU) requirements.

Methods

Thirty-eight patient-provider interactions in two health care outpatient clinics were observed.

Results

Providers do not uniformly know MU patient education requirements. Providers have individual preferences and find gaps in what is available. Accessing and documenting patient education varies among providers. Embedded electronic health record (EHR) materials, while available, have technical access barriers.

Conclusions

Providers'' EHR skills and knowledge levels contribute to non-standardized patient education delivery.     

Maltreatment of children in The Netherlands: an update after ten years

Governmental consultation and advice on child abuse and neglect in the Netherlands started in 1972 as a two-year experiment with four offices for "confidential doctors" in four major cities of the country. After these two experimental years, a governmental institute for prevention of child abuse and neglect was organized. Over the ensuing decade the number of offices increased to ten, covering the whole country. The State Department of Welfare, Public Health, and Environment collected data from the confidential doctors and their coworkers every year. This study compares the data of the first year 1974 with those of 1983 in order to detect changing patterns over a 10-year period. The major changes are as follows: a threefold increase in cases, an extraordinary increase in cases of emotional maltreatment, an increase in detection of child fatalities but decrease in severity of physical abuse. Sexual abuse was hardly recognized in 1974 but gradually was recognized more frequently during the study decade and accounted for an alarming 7.2% of detected cases of maltreatment in 1983. No change was found in the social conditions of the family and the identity of the perpetrators--primarily fathers and/or mothers. A decrease was noted in the percentage of married parents. The increased percentage of single parents was primarily represented by mothers alone. An increase in the numbers of victims residing at home and a decrease in the need for children's homes as a temporary or permanent residence is attributed to aftercare. The discrepancy between the results of this voluntary notification system in the Netherlands and the results of a mandatory reporting system as used in the U.S.A. is still very high. The hope is that the government will decide to make reporting of maltreatment mandatory for everyone.     

Effects of writing instruction and assessment on functional composition performance

In this study the relationships between writing instruction and functional composition performance were analyzed. The data were obtained in a national assessment on the language proficiency of students in the third year of Dutch secondary education (age ±15). Multivariate multilevel analysis showed that 10 out of 36 instructional characteristics were related to functional composition performance. The effective instructional characteristics included: instruction and exercises in writing functional texts, writing for a specific purpose, tailoring to a particular audience, global rating of writing products by the teacher, and frequent evaluation of Dutch language proficiency through teacher-made tests and written assignments. No effects were found for the rather popular subskill exercises on idiom, syntax, spelling and punctuation, and for pre-writing activities, text revisions and peer-review. Furthermore, the effect of instructional characteristics was often different on one task than on another. Finally, there was little differential effectiveness for different groups of students. If one instructional characteristic was more effective than the other, this was generally true, to an equal degree, for boys and girls and for promoted and non-promoted students.