Thesis (M.S.)--Eastern Illinois University, 2009. / Includes bibliographical references (leaves 44-47).

The purpose of this study was to investigate on a beat-by-beat basis, the nature of the instantaneous cardioacceleration resulting from short-duration, high-intensity, isometric contractions; to determine the relationship between relative muscular tension and cycle time, actual change in cycle time and relative change in cycle time; and to determine the effect of short-duration, high-intensity, isometric contractions on the recovery rate of cycle time. Muscular tensions and electrocardiograms were recorded before, during and after the isometric task and relative muscular tension, cycle time, actual change in cycle time and relative change in cycle time were calculated from these recordings. The sample population consisted of thirty university males. Each subject was randomly assigned to one of three groups. The task consisted of either a 50% MVC, 75% MVC or 100% MVC to be held for 10-seconds. Dynamometer and ECG recordings were monitered for the 15-seconds immediately before the contraction, the 10-seconds during the contraction and the 15-seconds immediately following the contraction. The hypotheses were: at the onset of an isometric contraction, the initial rate of increase of the relative change in cycle time is directly related to the magnitude of the percent maximal voluntary contraction; during the isometric contraction, the relative muscular tension is more closely related to the relative change in cycle time than either cycle time or actual change in cycle time; and, upon release of the isometric contraction, the initial rate of decrease of the relative change in cycle time is directly related to the magnitude of the percent maximal voluntary contraction. The trend analysis of the relative change in cycle time, during contraction, indicated that the linear and quadratic trends were different between the three groups. However, trend analyses of paired comparisons between the three groups indicated that the trends of the 50% MVC and 75% MVC groups were significantly different from the trend of the 100% MVC group, but, were not significantly different from each other. The post-hoc Newman-Keuls analysis indicated that the heart responded differently over the first five beats than over the last five beats, suggesting that there are at least two phases in the cardio-acceleratory response to isometric contractions and these two phases may be a result of a central and a peripheral heart-trigger mechanism. The trend analysis of the relative change in cycle time, during recovery, indicated a significant linear trend in beats with a significant difference in this trend between groups. However, observation of the graphic plot of means indicated that the data did not support the hypothesis, that the initial rate of decrease of relative change in cycle time was directly related to the magnitude of the %MVC. The non-support may have been due to the masking effect of respiration. / Education, Faculty of / Curriculum and Pedagogy (EDCP), Department of / Graduate

Thesis (M.A.)--University of North Carolina at Chapel Hill, 2005. / Includes bibliographical references (leaves 96-98). Also available online (PDF file) by a subscription to the set or by purchasing the individual file.

Thesis (M.A.)--University of North Carolina at Chapel Hill, 2005. / Includes bibliographical references (leaves 96-98).

No description available.

No description available.

This is a study to determine whether the teaching of isometric drawing will affect spatial perception.

Thesis (M.S.)--University of Wisconsin -- La Crosse, 2009. / Includes bibliographical references.

The primary purpose of this study was to examine if the coupling effect could be overcome in a bimanual isometric tracking task, using methods similar to those of the Kovacs et al. team in previous bimanual kinematic research. Thirty right-handed participants, with a mean age 22.5 (SD 3.5) years, free from any neurological disorder or physical ailment, were randomly assigned to one of three groups that differed in percent of feedback provided during the practice trials (100%, 50% or 0%). The participants then performed a bimanual isometric manipulation tracking task that was a 2:1 rhythm (backwards C shape) scaled to 30% maximum voluntary contraction (MVC). Participants performed five blocks of five trials with the feedback schedule assigned to their group, rested for 30 minutes, then performed a retention task. Significant differences (p<.05) in Root Mean Square Error (RMSE) occurred between the 100% group and both the 50% and 0% groups during the practice blocks. Significant differences (p<.05) also occurred between the 50% group and the 100% and 0% group for the first four practice blocks. Though differences occurred between the groups during the practice trials, no differences occurred between the groups during the retention block. These findings support the position that the coupling effect in bimanual isometric manipulation tasks is very strong and cannot be as easily overcome as it is in kinematic bimanual task. This may be due to the feedback systems used in isometric conditions versus kinematic tasks (i.e. force and pressure sensation vs. position and motion proprioception). / text

The purpose of this study was to assess athletic performance measures following two different loading conditions in the back squat exercise. Fourteen NCAA Division I tennis players were randomly assigned to either a low-resistance (50-60% of 1 repetition maximum [1RM]) training group or a high-resistance (65-90% 1RM) training group. The eight weeks of training consisted of 3 training sessions per week using a complete strength training program designed for sport performance enhancement. Performance in the 1RM back squat, 10 yard sprint and a countermovement vertical jump (CMJ) was assessed. There were no significant pretest to posttest differences in improving lower-body power production as measured by the 1 RM back squat, 10yd sprint and countermovement vertical jump in either group. The results of this study indicate that low-resistance, high-velocity training and high-resistance, low-velocity training is equally effective for improving lower-body power production. / School of Physical Education, Sport, and Exercise Science