Thesis (M.S.)--Portland State University, 2005. / Includes bibliographical references (leaves 29-30). Also available online (PDF file) by a subscription to the set or by purchasing the individual file.

Thesis (M.S.)--Portland State University, 2005. / Includes bibliographical references (leaves 29-30).

It is often difficult to optimize strength qualities in-season due to the conflicting influences of extensive skill practices combined with frequent game play of the competition schedule. The purpose of this study was to investigate the effects of two interventions on strength qualities and CMJ performance. Thirteen women volleyball players competing in NCAA Division I were tested before and after four weeks of an inseason strength training program with emphasis on heavy squatting (6-IORM), and then before and after three weeks of unloaded jump training. Dynamic squat strength, isometric squat strength, optimal power, CMJ, SJ and approach jump and reach were all tested before and after both cycles. There was a significant increase in both average 1RM squat strength (5%) and vertical jump (1%) following the strength cycle. Following the unloaded training, there was a significant increase in both peak power output (18%) and peak velocity (14%) in the CMJ. SJ performance significantly increased in both peak force (6%) and maximum height (10%). Throughout training, there were no decreases in maximal strength levels or post-test Vertec jump and reach. This study indicates that heavy squatting can improve vertical jump as well as 1RM squat despite a high volume in-season practice and competition schedule. Furthermore, unloaded training can improve the explosive qualities of athletes when used as a peaking cycle late in-season. Athletes maintained dynamic strength and jumping ability from pre-testing scores, while significantly increasing both peak velocity and power in the CMJ. / School of Physical Education

Participation in athletics is a popular pastime and form of entertainment. Children often begin to specialize in one sport at a young age in an effort to excel, which increases physical stress and the potential for injuries. Athletes participating in overhead sports are at increased risk of upper body chronic injuries, in part because the shoulder is an unstable hypermobile joint. Posture may also be affected in these athletes because of the demands placed on the upper body. The purpose of this study was to measure the upper body posture in a sample of Division I collegiate volleyball and softball athletes to investigate the prevalence of postural abnormalities and their relationship to pain or injury. Twenty-one Division I collegiate female athletes (seven volleyball; fourteen softball) who participated in their sport during the fall 2014 to spring 2015 seasons were studied. Athletes completed a pain and injury questionnaire, after which individual upper body posture measurements were made. Measurements included resting bilateral scapula position, head position, and shoulder position. An iPad mini camera was used with a commercial application (PostureCo, Inc.) to perform a photographic plumb line posture assessment with photographs taken in anterior, posterior, and lateral views. Posture analysis revealed a high prevalence (85.7 %) of forward head posture in this sample. Forward shoulder was noted in 42.9 % of the athletes and abnormal horizontal scapula position appeared to occur more frequently in the dominant arm (71.4 %) than in the non-dominant arm (47.6 %). Chi square tests determined that there was no statistically significant relationship between posture abnormalities and self-reported pain in this group of athletes. Results of this study -- although preliminary -- should be used to inform future research to investigate potential relationships between posture and pain/injury in overhead athletes.