Comparisons of the ski turn techniques of experienced and intermediate skiers

We compared selected kinematic variables for four different ski turn techniques performed by five experienced and five intermediate male skiers. The four ski turn techniques were the upstem turn, the downstem turn, the parallel turn and the parallel step turn. Each turn was divided into the initiation phase and the first and second steering phases. Most of the statistically significant differences (P < 0.05) between the two groups were found for the initiation phases of the four turns. Both the hip axis-hand axis angle and the edging angle of the uphill ski were significantly different between the two groups for the upstem turn at the beginning of the initiation phase. For the downstem turn, significant differences between the groups were found at the start of the initiation phase for the hip axis-hand axis angle, the shoulder axis-fall line angle, and the edging angle of the uphill ski. The standard deviation of the distance between the tips of the two skis over the second steering phase also differed significantly between the two groups. For the parallel step turn, significant differences were found at the start of the initiation phase for the edging angle of the downhill ski and the downhill ski to movement direction angle. Significant differences were also found for the edging angle of the downhill ski in the middle of the second steering phase and the shoulder axis to movement direction angle at the end of this phase. For the initiation phase of the parallel turn, significant differences were found for the timing of setting the ski pole, the uphill knee angle at the start of this phase and the range of the knee angle of the uphill leg from the start to the end of this phase. For this turn, significant differences between the two groups were also found for the edging angle of the downhill ski in the middle of the second steering phase and the shoulder axis to movement direction angle at the end of this phase. One of the reasons it was possible to identify a few significant differences only for the turns analysed, was the variability within the intermediate group: for most of the variables analysed, the standard deviation was much higher for the intermediate than for the experienced group.     

The effect of individual differences in the development of metacognitive strategy knowledge

The aim of this study was to investigate the development of metacognitive strategy knowledge (MSK) during schooling at the upper secondary education level and to examine its relation with individual student characteristics. This longitudinal study with two measurement points analyzed a sample of students in grades 10 and 11 from 19 schools preparing students for university in Switzerland. The findings showed no development of MSK within a single year of school. Individual differences appeared in the level and the change of MSK over time. Female students as well as students with higher SES displayed higher MSK than male students and students with lower SES at the first measurement point. Furthermore, SES predicted changes in MSK over time. Between learning motivation and MSK as well as self-efficacy and MSK, high correlations were found at t1. Neither learning motivation nor self-efficacy had an effect on the change of MSK over time. The results show that there is still substantial potential for MSK development at the upper secondary education level. Implications for education and further studies are discussed.     

The Graphic Arts

Max Gallo's The Poster in History (New York: American Heritage/McGraw- Hill, 1974—$22.95)

Erich Salomon's Portrait of an Age ((New York: Collier Books/Macmillan, 1974—$7.50, paper)

M. Thomas Inge's “American Comic Art: A Bibliographic Guide,” Choice XI:1581-1593

Stan Lee's Origins of Marvel Comics (New York: Simon and Schuster, 1974—$5.95, paper)

John Hedgecoe and Michael Langford's Photography: Materials and Methods published by Oxford University Press. Apparently Focal Press picked it up in London, and now a new smaller format but hardcover edition is just out from Hastings House (N.Y.) for $12.95     

Electron coincidence spectroscopy: a new way of looking into matter

In electron coincidence spectroscopy, kinematically complete measurements are made of symmetric ionising collisions initiated by an electron beam on a gaseous atomic or molecular target. The reaction measures the shapes of individual orbitals, and provides a sensitive measurement of the charge density far from the atomic nuclei. The technique promises to be of outstanding importance in developing an improved understanding of molecular structures.     

Skill-dependent proximal-to-distal sequence in team-handball throwing

The importance of proximal-to-distal sequencing in human performance throwing has been reported previously. However, a comprehensive comparison of the proximal-to-distal sequence in team-handball throwing in athletes with different training experience and competition is lacking. Therefore, the aim of the study was to compare the ball velocity and proximal-to-distal sequence in the team-handball standing throw with run-up of players of different skill (less experienced, experienced, and elite). Twenty-four male team-handball players (n = 8 for each group) performed five standing throws with run-up with maximal ball velocity and accuracy. Kinematics and ball trajectories were recorded with a Vicon motion capture system and joint movements were calculated. A specific proximal-to-distal sequence, where elbow flexion occurred before shoulder internal rotation, was found in all three groups. These results are in line with previous studies in team-handball. Furthermore, the results of the present study suggest that in the team-handball standing throw with run-up, increased playing experience is associated with an increase in ball velocity as well as a delayed start to trunk flexion.