The purpose of this study was to examine the differences in the squat kinematics and kinetics while wearing two different types of footwear. Ten men that compete at a collegiate level of powerlifting participated in the study. The participants performed the squat in both Chuck Taylor (flat soled) and Adidas (raised heel) shoes 3 times per shoe at 80% of 1 RM. During the testing sessions, sagittal plane kinematics of the shank were measured using 2-D video analysis. A force plate was used to measure the ground reaction forces of the right foot. There was no significant difference (p>0.05) in the medial lateral ground reaction forces (raised heel 63.58 N, flat soled 65.79 N), or the shank angles (raised heel 67.4 degrees, flat soled 65.7 degrees) of the participants. In conclusion, the participants were able to accommodate for a 1 inch raised heel in their shoe without altering shank position of medial-lateral ground reaction forces. / School of Physical Education, Sport, and Exercise Science

The primary purpose of this study is to use three-dimensional motion analysis to determine and compare certain kinematic joint and segmental variables at defined events (bar off and knee passing) between the conventional and sumo styles of deadlifts. The secondary purpose of this study is to investigate bar path profiles and vertical bar velocity patterns (including attempting to determine a "sticking region") and compare these variables between the two styles and two sub-maximal loads (50% and 75%). Five subjects performed each style at each load. Each trial was filmed, digitized, and imported for 3-D reconstruction. This data was utilized to determine hip, knee, inter-thigh, trunk, thigh, and shank angles at bar off and knee passing; bar path profiles; and bar velocity values (including determining the "sticking region"). A two way ANOVA showed statistically significant differences between the two styles for most joint and segmental variables at both events and the range between the two events. There was a significant difference between the two styles for total time and horizontal and vertical bar displacement. Only one trial showed a sticking region. Based on the results of this study, it can be stated that kinematic differences do occur between the two styles of deadlifts at submaximal loads. A sticking region does not appear to occur at loads of 75% of a 1 rep maximum or less. / School of Physical Education

The purpose of this investigation was to determine the influence of post exercise carbohydrate (CHO) intake on the rate of muscle glycogen restorage after high intensity weight resistance exercise in untrained subjects. In a cross over design, eight male subjects performed sets (mean= 8.8) of 6 single leg knee extensions at 70% of one repletion max until 50% of full knee extension was no longer possible. Total force application was equated between trials using a strain gauge interfaced to a computer. Post exercise supplementation was administered at 0 and 1 hrs consisting of either a 23% CHO solution (1.5g•kg-1•hr-1) or an equal volume of water (H20). Total force production, pre-exercise muscle glycogen content, and degree of depletion (-40.6 and -44.3 mmol•kg-1) were not significantly different between H2O and CHO trials, respectively. During the initial 2 hrs recovery, the CHO trial had a significantly greater rate of muscle glycogen resynthesis as compared to the H2O trial. In the final 4 hrs of recovery no difference in repletion rates were observed. The glycogen content (mmol•kg-1 w.w.) and rates of restorage (mmol•kg-1 w.w.) during the recovery period were (mean + SE):TrialPost2 Hr6 HrRate (0-2 hrs)H2O101.3+ 13.1105.1+ 13.1105.5+ 13.01.3+ 2.2CHO91.7+ 11.8117.6+ 16.5123.4+ 15.1 *12.9+ 4.0*significance between trials, p <0.01Only the CHO supplementation trial restored pre-exercise muscle glycogen content after 6 hrs. The spectrophotometric analysis of glycogen stained muscle sections (PAS) indicated no difference between trials in the pre and post glycogen content for Type I and II fibers. The change in absorbance, when these samples were combined demonstrate greater glycogenolysis in the Type II (0.284 + 0.58) as compared to Type I (0.014 ± 0.076). During the recovery period, the change in absorbance supports greater glycogenesis in the Type II ( 0.096 + 0.060) when compared to no observed change in absorbance in the Type I fibers.Supported by a grant from Ross Laboratories. / Human Performance Laboratory

Skeletal muscle glycogenolysis was investigated in eight subjects during both high (HI) (70% 1 RM) and low (LO) intensity (35% 1 RM) leg extension weight-resistance exercise. Total force application to the machine lever arm was determined and equated between trials via a strain gauge and computer interfaced system. After the sixth set, muscle glycogen degradation was similar in the HI and LO trials (46.9 ± 6.6 and 46.6 ± 6.0 mmol•kg-1 wet wt, respectively), with the LO trial characterized by almost double the repetitions (6.0 and 12.7 ± 1.1) and half the peak concentric torque per repetition (24.2 ± 1.0 and 12.4 ± 0.5). After the sixth set, muscle lactate accumulation was also similar (13.8 ± 0.7 and 16.7 ± 4.2 mmol•kg-1 wet wt for HI and LO trials, respectively). After two hours of passive recovery with no feedings, muscle glycogen storage during the HI and LO trials was 22.2 (±6.8) and 14.2 (±2.5) mmol•kg-1 wet wt, respectively These values represented glycogen synthesis rates of 11.1 (±3.4) and 7.1 (±1.3) mmol•kg-1 •hr-1 , and occurred without significant increases in blood glucose relative to resting concentrations. Optical absorbance measurement of PAS stained muscle sections revealed no differences in the glycogen content of fast (FT) and slow twitch (ST) fibers between trials. When data from each trial were combined, declines in absorbance were larger in FT than ST fibers after the sixth set (0.356 ± 0.048) than in slow twitch fibers (0.222 ± 0.039, p < 0.05). The increase in absorbanceduring the two hour recovery was also larger in FT than ST fibers (0.119 ± 0.024 and 0.055 ± 0.024, p < 0.05). When total force application was constant, muscle glycogenolysis was the same regardless of the intensity of resistance exercise. Glycogenolysis was greater in fast twitch fibers, as was glycogen storage during the immediate post-exercise recovery. The relatively high rate of glycogen synthesis after exercise may be evidence of glycogenesis from intramuscular metabolites. / Human Performance Laboratory

The purpose of this study was to compare the myocardial structure and function among endurance athletes (n.12), powerlifters/steroid users (n=5), powerlifters/non-steroid users (n=6), and sedentary controls (n=4). All subjects had a M-mode echocardiographic examination of their left ventricles under resting conditions. The echocardiographic measurements recorded and analyzed were of the left ventricular posterior wall at diastole and systole, left ventricular internal diameter at diastole and systole, and inter-ventricular septal thickness at diastole and systole. Myocardial function measurements consisting of left ventricle ejection time, left ventricular mass, mean ventricular contractile force, and percent fractional shortening were also recorded and analyzed. A One Way Analysis of Variance was used to analyze the data for statistical significance. A Tukey's HSD post-hoc test was used to determine statistical significance between the groups. A significant difference (p =0.02) was found for inter-ventricular septal thickness during diastole. All three athletic groups had significantly thicker inter-ventricular septa' thickness during diastole as compared to the controls. Power lifters/steroid users had the thickest inter-ventricular septal thickness (18.7 mm), followed by endurance athletes (18.6 mm), and powerlifters/nonsteroid users (16.5 mm). Overall, powerlifters/steroid users had the thickest walls at systole and diastole, while endurance athletes had the greatest internal diameters relative to the size of the left ventricle. Statistically significant differences among the groups were found for all four myocardial functional parameters: left ventricular ejection time (p = 0.03), left ventricular mass (p = 0.002), mean ventricular contractile force of (p 0.0013), and percent fractional shortening (p = 0.05). Power lifters/steroid users had the fastest left ventricular ejection times, largest left ventricular mass, greatest mean ventricular contractile force, and greatest percent fractional shortening. Endurance athletes had the slowest left ventricular ejection times, second largest left ventricular mass, lowest mean ventricular contractile force, and third lowest percent fractional shortening. The results indicated that not all individuals participating in high level endurance or powerlifting training and competition demonstrated complete adaptations in myocardial structure and function. Power lifters/steroid users however, demonstrated myocardial functional adaptations that were significantly different from powerlifters/non-steroid users, endurance athletes, and controls. The results of this study cannot attribute these changes either to the use of large amounts of anabolic steroids, or long-term, high-intensity training and competition in powerlifting. However, the study identified alterations in myocardial functions in powerlifters/steroid users, and contributes to the existing body of knowledge regarding the use of anabolic steroids by athletes. / Graduation date: 1990

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The purpose of this study was to use EMG data of the erector spinae muscles synchronized with three-dimensional video techniques to determine the body's responses to asymmetric lifting under weight belt conditions. The subjects performed static maximum voluntary exertions and dynamic lifts from 0° and 45° from the midline of the body. Three weight belt conditions were used. EMG data revealed significant differences in EMG variables with belt conditions. Weight belt use decreased burst area, peak voltage, and maximum frequency. Kinematic data indicated a significant difference in the left knee and left and right elbow range of motion when the type of lift, symmetric or asymmetric, was considered. Lifting technique also produced a significant effect on the maximum and minimum velocity of the center of mass. The results of the study indicate that weight belt use is an effective means of reducing spinal compression and thus may be helpful in preventing low back injury. / School of Physical Education

Graduation date: 1993

Comparison kinematic models of the traditional style deadlift are presented. Data was obtained through film and analyzed via computer and computer graphics. The comparison between the models revealed that the greater-skilled: 1. used less trunk flexion from the instant of initial trunk lean to the instant of maximum trunk lean, 2. used less knee extension (in same time interval as 1), and 3. demonstrated a smaller horizontal distance between the body center of mass (CM) and the CM of the bar at the instant the bar left the platform. A trend was also observed in which the greater-skilled subjects demonstrated less thoracic lean than the lesser-skilled group at the time the bar reached knee level.

The purpose of this research was to investigate the effects of eccentric phase duration on concentric outcomes at 60% and 80% of one-repetition maximum (1RM) in the squat and bench press. Sixteen resistance-trained males completed four laboratory visits as follows: Day 1- 1RM testing; Day 2- establishment of normative eccentric durations; Days 3 and 4- randomized fast (0.75 times) or slow (2 times) eccentric duration variations, which were controlled by visual and auditory metronomes. Eccentric duration was significantly and inversely correlated with average concentric velocity (ACV) at 60% (r = 0.408) and 80% (r = -0.477) of 1RM squat and at 100% of 1RM bench press. At 60% of 1RM squat, both fast and slow eccentric conditions produced greater (p<0.001) peak concentric velocity (PCV) than normative duration with fast also producing greater PCV than slow (p=0.044). Therefore, fast eccentric durations may benefit concentric velocity. / Includes bibliography. / Thesis (M.S.)--Florida Atlantic University, 2018. / FAU Electronic Theses and Dissertations Collection