In competitive swimming a spread in time of only 0.10, and 0.16 seconds constituted the difference between finishing second and seventh, and first and eighth, respectively, in the women's 50 yard freestyle at the 1993 NCAA Division III National Swimming & Diving Championships. Based on data collected over a period of years Maglischo (1993) noted that "improving the start can reduce race times by at least 0.10 second" (p. 544). Therefore it is beneficial to the outcome of a race to direct attention to maximizing the effectiveness of the racing start. The primary purpose of this study therefore was to compare kinetic and kinematic components of the grab and track style starts. During the past two decades extensive kinematic research has been done using cinematography. These studies used time, velocity, displacement, and the measure of angles (i.e. at takeoff and entry) to measure the relative effectiveness of various racing starts. Conversely, there has been limited analysis of racing starts using kinetic measurements. Four kinetic and five kinematic variables were evaluated in this study to compare the relative effectiveness of the starting techniques. Ten female varsity swimmers, who had used both starts interchangeably in competition, were selected for this study. Force components were obtained directly from a Kistler force platform. Block time, horizontal and vertical impulse, and average horizontal and vertical force values were obtained in subsequent analysis of the Force-time data. Each subject was videotaped as she executed three trials of each start. The video data were digitized and then analyzed using two dimensional video analysis techniques. The type of start technique used on each trial was randomly ordered. Kinematic variables of horizontal and vertical displacement of the center of mass, average horizontal velocity and vertical velocity were also obtained from the video data in order to determine which of the two starting techniques (i.e. grab vs. track) was the most effective. 2x10 (starting technique x subject) repeated measures Analyses of Variance indicated significant differences (p<0.01) between the starting styles for five of the nine dependent variables measured which provided support for the original contention that the track style start was the more effective of the two racing start techniques investigated. The results of this study provide support to the empirical and observational findings of earlier researchers. / Graduation date: 1995

Thesis (M.S.)--University of Hawaii at Manoa, 2005. / Includes bibliographical references (leaves 48-49). / vi, 49 leaves, bound ill. 29 cm

Swim turns are a component of competitive swimming where considerable advantage can be gained or lost. This thesis investigates underwater dolphin and flutter kicking techniques and their application to exits following the turn in freestyle swimming. Five separate investigations were conducted to examine the kinetics and kinematics of each underwater kicking technique and are presented in expanded journal manuscript form. Studies one, two and three involved the comparison of freestyle turns when using flutter and dolphin kicking wall exit techniques. The results obtained indicated that freestyle turns using flutter kicking were faster than dolphin kicking in age-group swimmers. For this group, significant and equal improvements were made to flutter and dolphin kick turn performances following six weeks of dolphin kick and dolphin kick turn training. However, no difference in turn times were observed between kicking conditions by older and more highly skilled swimmers. Study four involved a kinematical comparison of maximal underwater free-swimming dolphin and flutter kicking. Results showed dolphin kick to be a superior underwater free-swimming technique. Greater foot width, increased ankle range of movement and greater vertical displacement of the ankle and foot during kicking were shown to be highly predictive of faster underwater dolphin kicking. Investigation five compared the drag forces and kinematics between the dolphin and flutter kicking techniques while subjects were towed at velocities representing those experienced following wall turn push-off. Results favour the dolphin kick as a superior underwater technique at these higher velocities. Increased underwater dolphin kicking efficiency, as measured by decreased net towing force, was found to be associated with larger kick amplitude – rate ratios, and higher kick amplitude – streamline length ratios. / Doctor of Philosophy

Swim turns are a component of competitive swimming where considerable advantage can be gained or lost. This thesis investigates underwater dolphin and flutter kicking techniques and their application to exits following the turn in freestyle swimming. Five separate investigations were conducted to examine the kinetics and kinematics of each underwater kicking technique and are presented in expanded journal manuscript form. Studies one, two and three involved the comparison of freestyle turns when using flutter and dolphin kicking wall exit techniques. The results obtained indicated that freestyle turns using flutter kicking were faster than dolphin kicking in age-group swimmers. For this group, significant and equal improvements were made to flutter and dolphin kick turn performances following six weeks of dolphin kick and dolphin kick turn training. However, no difference in turn times were observed between kicking conditions by older and more highly skilled swimmers. Study four involved a kinematical comparison of maximal underwater free-swimming dolphin and flutter kicking. Results showed dolphin kick to be a superior underwater free-swimming technique. Greater foot width, increased ankle range of movement and greater vertical displacement of the ankle and foot during kicking were shown to be highly predictive of faster underwater dolphin kicking. Investigation five compared the drag forces and kinematics between the dolphin and flutter kicking techniques while subjects were towed at velocities representing those experienced following wall turn push-off. Results favour the dolphin kick as a superior underwater technique at these higher velocities. Increased underwater dolphin kicking efficiency, as measured by decreased net towing force, was found to be associated with larger kick amplitude – rate ratios, and higher kick amplitude – streamline length ratios. / Doctor of Philosophy

The primary purpose of this study was to gain a better understanding of the turn interval and the factors that influence turn performance. A secondary purpose was to investigate the relationship between turn time, the components that influence turn time, and performance in competitive swimming. Fifty-eight swimmers (24 female, 34 male) from four NCAA Division I schools were videotaped in the 100 and 200 yd freestyle and backstroke events during three collegiate competitions. The freestyle was shown to be significantly different from the backstroke in race time, turn time, and time during the in phase of the turn for both genders in the 100 and 200 yard events. Significant positive correlations were found between turn time and race time across both genders and all four events. Inspecting the velocity curves of the turns allowed the key outphase variables to be defined. Turn time is an important determinant of race time in collegiate swimming. Using the dolphin kick technique during a turn causes large fluctuations in velocity during the active glide phase of the turn. / School of Physical Education

The swimming track start is a complex motor skill that utilizes asymmetric lower limb action. The purpose of this study was to explore whether it could be optimized by applying the commonly accepted view that there are asymmetries in the function and behaviors of the lower limbs. Initially, the study aimed to examine the relationship between various measures of lower limb asymmetry and the swimmers' preferences for forward foot placement in the swimming track start. Participants underwent a 7 week training period whereby both the left foot forward (LFF) and the right foot forward (RFF) track starts were practiced. The philosophy behind this training protocol was to ensure that participants received equal practice with the preferred and non-preferred stance so that a dominant stance, if it existed, could emerge. Consequently, the relationships between the dominant track start stance and the lower limb asymmetry measures could be determined more accurately. Participants were male (N=11) and female (N=11) swimmers, aged 12-16 years, from the UWA-Uniswim National Age Squad. Kinetic and kinematic data were collected for the track start prior to and following the 7 week training intervention. The intervention was finished when a participant had completed approximately 14 dive sessions where both the LFF and RFF track starts were practiced. The performance criterion measure was time to 5 m. Despite significant differences in vertical force and velocity contributions following the intervention, time to 5 m did not improve for either the LFF or the RFF track start. Four different measures of lower limb asymmetry were collected, including footedness, the preferred track start stance, and the dominant take-off limb for the unilateral and bilateral counter-movement jump (CMJ). Sixteen of 22 participants displayed changes in their dominant track start stance. Eleven participants showed biases for one stance (6 for the LFF & 5 for the RFF), and 11 participants remained or became more symmetrical. Results indicated that the preferred track start stance was the only measure of asymmetry that was significantly related to track start performance (x2[2]= 6.71, p=.04 for pre-intervention & x2[2]=7.77, p=.02 for post-intervention). All other measures of lower limb asymmetry were shown to be unrelated to track start preference and performance. It was suggested that the 7 week training intervention did not provide a sufficient amount of time to see conclusive effects on 5 m time or to make conclusive comparisons between the dominant track start stance and measures of asymmetry. Since the preferred track start corresponded with better performance less than 50% of the time, it was suggested that swimmers and coaches experiment with different dive techniques to find the start which is most effective for them and spend more time on them during training.