The effect of ball carrying method on sprint speed in rugby union football players

Different methods of ball carrying can be used when a player runs with the ball in rugby union. We examined how three methods of ball carrying influenced sprinting speed: using both hands, under the left arm and under the right arm. These methods were compared with running without the ball. Our aim was to determine which method of ball carrying optimizes sprinting speed. Altogether, 48 rugby union players (age 21 +/- 2 years, height 1.83 +/- 0.1 m, body mass 85.3 +/- 12 kg, body fat 14 +/- 5%; mean +/- s) were recruited. The players performed twelve 30-m sprints in total (each player performed three trials under each of three methods of carrying the ball and sprinting without the ball). The design of the study was a form of Latin rectangle, balanced across the trial order for each of the methods and for pairwise combinations of the methods in blocks of four per trial. Each sprint consisted of a 10-m rolling start, followed by a 20-m timed section using electronic timing gates. Compared with sprinting 20 m without the ball (2.58 +/- 0.16 s), using both hands (2.62 +/- 0.16 s) led to a significantly slower time (P < 0.05). Sprinting 20 m with the ball under the left arm (2.61 +/- 0.15 s) or under the right arm (2.60 +/- 0.17 s) was significantly quicker than when using 'both hands' (P < 0.05), and both these methods were significantly slower than when running without the ball (P < 0.05). Accordingly, running with the ball in both hands led to the greatest decrement in sprinting performance, although carrying the ball under one arm also reduced the players' sprinting ability. Our results indicate that to gain a speed advantage players should carry the ball under one arm.     

Resilience of anthropometric data assembly strategies to imposed error

The aim of this study was to examine strategies for selecting a criterion value during anthropometric data assembly and their resilience to imposed error. Sixty-seven women aged 16-60 years were subjected to three separate series of measurements, which included six skinfolds and three girths. A random error term was added to the first of the three series of measurements to produce a pseudo-series containing error, termed the 'erroneous replicated series'. Five strategies were then used to determine the criterion value of each of the replication series: the first measurement, the mean of the first two measurements, the mean of all three measurements, the mean of the closest two measurements and the median of the three measurements. The technical error between the criterion values of the true and the flawed replication series for each of the selection strategies was calculated. We found that, for five of the skinfolds and all of the girths, the median value provided the smallest technical error of measurement between the criterion values for the true and erroneous replication series. We conclude that the strategy of selecting the median of three measurements is the most resilient to imposed error.     

The Nature of Teacher Leadership in Schools as Reciprocal Influences Between Teacher Leaders and Principals

As part of a comprehensive qualitative study of 6 schools noted for teacher leadership 28 respondents were interviewed. It was noted that teacher leadership often involved the mutual influence between teacher leaders and principals. These influences are discussed from the perspectives of each of the 6 schools and respondent status as teacher leader, teacher nominator, and administrator. Further to these influences, the data suggest relationships between teachers, teacher leaders, and principals, in these schools, which are reflective of 3 models of “leadership reciprocity” based on unique features found to be typical of these schools.