Six 9-, 11-, and 13-year-old, anthropometrically matched males and females were towed on the water surface via a mechanical winch at 1.3 to 2.5 ms−1 in increments of 0.3 ms−1 during a prone streamlined glide. Passive drag force of the 13-year age group was significantly larger than that of the 9-year age group at 1.9, 2.2, and 2.5 ms−1, but not at 1.3-1.6 ms−1. While anthropometry did not feature in any regression equation at any age for passive drag at velocities of 1.3 and 1.6 ms−1, body mass was the best predictor of drag at 1.9 and 2.5 ms−1.
Nataphoom Benjanuvatra, Brian A. Blanksby, and Bruce C. Elliott
Helen E. Parker, Brian A. Blanksby, and Kian L. Quek
The use of buoyancy and propulsion aides in teaching young swimmers is contentious. Some believe that such aides provide an artificial crutch that retards learning of independent swimming. Others believe they provide valuable learning cues for progress. This study investigated the progress made by 7 year olds learning to swim with and without buoyancy and propulsion aides. A single primary class was divided into 2 matched-ability groups: aides (n = 10) and self-support (n = 9). Each group attended 10 daily, 40-min lessons prior to the school day. Unsupported stroking and kicking actions were videotaped in the last 10 min of each lesson and scored using the MERS-F scale. As a whole, significant improvements were revealed by the third lesson (p < .05), although no significant differences existed between groups. Case studies of the most rudimentary swimmers in each group confirmed that teaching frontcrawl to beginner swimmers using multiple buoyancy aides failed to enhance skills beyond those gained by using a kickboard only in 10 lessons.
Sacha M. Bradley, Helen E. Parker, and Brian A. Blanksby
The Modified Erbaugh Rating Scale–Front Crawl (MERS-F) (a rating scale for assessing stages of front-crawl swimming patterns) was used to measure performance change by 6-year-old male and female beginner swimmers participating in either 10 daily (Group D) or 10 weekly (Group W) lessons. The MERS-F was found to be a relatively objective (r = .98) and moderately valid (r = .78) assessment instrument. The maximal front-crawl skill rating of each lesson was subjected to a three-way ANOVA (Group × Gender × Lesson–repeated), which revealed that (a) the rate of improvement was the same for daily and weekly lesson schedules despite the higher performance rating for children in the daily lessons throughout; (b) front-crawl swimming skill increased significantly for both groups after the third of 10 lessons; and (c) there was no significant difference in the performance of boys and girls (p < .05).
Andrew D. Lyttle, Brian A. Blanksby, Bruce C. Elliott, and David G. Lloyd
Thirty experienced male swimmers with body types ± 1 SD of the mean of selected body form parameters reported for elite male swimmers were recruited for the study. During three freestyle flip turns, selected kinetic, hydrodynamic, and kinematic variables of the push-off following a flip turn were recorded. Kinetics were recorded via a 2D vertically mounted forceplate that recorded peak push-off force and total impulse. The acceleration of each swimmer’s center of gravity and wall exit velocity were calculated from underwater videography. Hydrodynamic peak drag force and drag impulse were calculated from the kinetic and kinematic data using a derivative of Newton’s second law. A stepwise regression yielded peak drag force, peak propulsive force, and push-off time in the final regression equation (R = 0.80; R 2 = 0.64). Beta values indicated that the peak drag force carried the highest weighting of the three variables. The results of the stepwise regression indicated that a combination of a low peak drag force high peak propulsive force, and increased wall push-off time produced the fastest final push-off velocity.
Brian A. Blanksby, Jennifer R. Simpson, Bruce C. Elliott, and Keith McElroy
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 time, 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.