Kinetic (3-D force plate), kinematic (videography) and temporal characteristics of backstroke turns by 20 male and 16 female swimmers were recorded to identify and describe key elements of backstroke turning performance. Data were recorded during a 50 m maximum effort swim in a 25 metre pool. A Pearson product moment correlation matrix revealed that the 5 m RTT was significantly correlated with anthropometric measures of height, mass, trochanteric height and age; kinetic measures of horizontal impulse and peak force; and kinematic measures of wall contact time and peak velocity. The stepwise multiple regression equation to predict 5 m RTT was: 19.6-0.75 trochanteric height-1.8 wall exit velocity-0.03 peak vertical force. Four key factors were identified from a principle components factor analysis--anthropometry and force, post-turn velocity, force preparation and rotational skills. Implications from the findings were that age-group backstrokers should 'hit the wall hard' with relatively extended legs to reduce swim distance and push-off deceleration; use minimal wall contact time, and maximise forces to develop high horizontal velocities in a streamlined position.

Kinetic (3‐D force plate), kinematic (videography) and temporal characteristics of backstroke turns by 20 male and 16 female swimmers were recorded to identify and describe key elements of backstroke turning performance. Data were recorded during a 50m maximum effort swim in a 25 metre pool. A Pearson product moment correlation matrix revealed that the 5 m RTT was significantly correlated with anthropometric measures of height, mass, trochanteric height and age; kinetic measures of horizontal impulse and peak force; and kinematic measures of wall contact time and peak velocity. The stepwise multiple regression equation to predict 5 m RTT was: 19.6‐0.75 trochanteric height‐1.8 wall exit velocity‐0.03 peak vertical force. Four key factors were identified from a principle components factor analysis ‐ anthropometry and force, post‐turn velocity, force preparation and rotational skills. Implications from the findings were that age‐group backstrokers should 'hit the wall hard' with relatively extended legs to reduce swim distance and push‐off deceleration; use minimal wall contact time, and maximise forces to develop high horizontal velocities in a streamlined position.

Abstract There is an abundance of research to support the idea that cooperative learning benefits students in many ways. Moreover, about two out of three middle school teachers use cooperative learning as an instructional strategy. However, cooperative learning is not always implemented effectively, and its use poses certain challenges and dilemmas for middle school teachers. This paper examines what one middle school teacher learned as she directed her students to complete a structural engineering task as a cooperative learning activity. She found that students were on task and collaborated to accomplish the goal, but that teachers' decisions about how tasks are set up, carried out, and completed affected students' interactions in cooperative groups. This study provides middle school teachers with research by teachers and helps to bridge gap between research and practice.

Because turning can account for one-third of breaststroke race time in 25 m pools, it is possible that enhancing turning techniques can improve performance significantly. Underwater video cameras and a force platform were used to analyze turning techniques of 23 age-group breaststrokers during three 50 m push-start maximum-effort swims. The criterion measure was the time elapsed between passing the 5 m mark on the approach and departure from the wall (5 m round-trip time [RTT]), Correlations revealed significant commonality of variance (p <.01) between the 5 m RTT and the 2.5 m RTT, 50 m times average single-stroke velocity, peak reaction force, pivot time, impulse, peak horizontal velocity off the wall. arm and leg split-stroke resumption distances, surfacing distance, surfacing time, and horizontal velocity, height, and mass of the subjects. All swimmers achieved a net gain at the turn in that the mean 5 m RTT (20% of the distance) represented 18.26% of the total swimming time. Following stepwise regression, a successful turn was predicted by the equation 17.113 - 0.322 surfacing distance -0.036 height -0.723 surfacing horizontal velocity +0.723 pivot time -0.65 peak horizontal velocity.