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.

Characteristics that discriminate youth soccer players vary by age group. Talent identification models should thus be dynamic and provide opportunities for changing parameters in a long-term developmental context.

During the 1997 Fédération Internationale des Sociétés d'Aviron World Junior Rowing Championships, anthropometric data on 383 male junior rowers were assessed. With 430 participating athletes, the sample represented 89% of the population. In addition to age, 27 dimensions were measured: body mass, six heights or lengths, four breadths, 10 girths, and six skinfolds. The elite male junior rowers were tall (187.4 (5.8) cm; mean (SD)) and heavy (82.2 (7.4) kg), with larger length, breadth, and girth dimensions than a nationally representative sample of Belgian boys of the same chronological age. A rowing specific anthropometric profile chart with norms was constructed. The stature of the junior rowers is similar to that of adult heavyweight elite rowers, except that the junior rowers are lighter. Compared with non-finalists, finalists are heavier (but still lighter than the adult heavyweight elite rower) and taller, with greater length, breadth (except for the bicristal diameter), and girth dimensions. (Br J Sports Med 2000;34:213-217)

During the 1997 Federation Internationale des Sociétés d'Aviron (FISA) World Junior Rowing Championships, the anthropometric characteristics of 245 female junior rowers aged 17.5 +/- 0.8 years (mean +/- s) were assessed. Twenty-seven body dimensions (body mass, 6 heights or lengths, 4 breadths, 10 girths and 6 skinfolds) were measured in total. The elite female junior rowers were taller (174.5 +/- 6.2 cm) and heavier (69.5 +/- 6.2 kg), with greater length, breadth and girth dimensions, but lower skinfold thicknesses than a representative sample of Flemish (Belgian) girls of the same chronological age. An anthropometric profile chart was constructed that was rowing-specific and norms were established. Compared with scullers, sweep rowers were heavier (+4.2 kg) and taller (+2.8 cm), with greater length, breadth (except for femur width) and girth dimensions (except for calf girth). Sweep rowers also had greater skinfold thicknesses (except for the thigh and calf skinfolds). Finalists were heavier (+3.6 kg) and taller (+3.9 cm), with greater length, breadth (except for femur width) and girth dimensions (except for calf girth) than non-finalists. No significant differences were found for skinfold thicknesses between finalists and non-finalists.

Whereas in the past dental stools typically facilitated a 90° hip angle, a number of currently available alternative designs allow for a more extended hip posture. The present study investigated the influence of different stool types on muscle activity and lumbar posture. Twenty five participants completed a simulated dental procedure on a standard stool, a saddle and the Ghopec. The latter stool comprises a seat pan consisting of a horizontal rear part for the pelvis and an inclinable sloping down front part for the upper legs, with a vertically and horizontally adjustable back rest. Lumbar posture was most close to neutral on the Ghopec, whereas sitting on a standard/saddle stool resulted in more flexed/extended postures respectively. Sitting with a 90° angle (standard stool) resulted in higher activation of back muscles while sitting with a 125° angle (saddle and Ghopec) activated abdominal muscles more, although less in the presence of a backrest (Ghopec). To maintain neutral posture during dental screening, the Ghopec is considered the most suitable design for the tasks undertaken.