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The purpose of this study was to examine the effect that load has on the mechanics of the jump shrug. Fifteen track and field and club/intramural athletes (age 21.7 ± 1.3 y, height 180.9 ± 6.6 cm, body mass 84.7 ± 13.2 kg, 1-repetition-maximum (1RM) hang power clean 109.1 ± 17.2 kg) performed repetitions of the jump shrug at 30%, 45%, 65%, and 80% of their 1RM hang power clean. Jump height, peak landing force, and potential energy of the system at jump-shrug apex were compared between loads using a series of 1-way repeated-measures ANOVAs. Statistical differences in jump height (P <.001), peak landing force (P =.012), and potential energy of the system (P <.001) existed; however, there were no statistically significant pairwise comparisons in peak landing force between loads (P >.05). The greatest magnitudes of jump height, peak landing force, and potential energy of the system at the apex of the jump shrug occurred at 30% 1RM hang power clean and decreased as the external load increased from 45% to 80% 1RM hang power clean. Relationships between peak landing force and potential energy of the system at jump-shrug apex indicate that the landing forces produced during the jump shrug may be due to the landing strategy used by the athletes, especially at lighter loads. Practitioners may prescribe heavier loads during the jump-shrug exercise without viewing landing force as a potential limitation.

Recent studies have demonstrated that increases in dynamic strength after weight-training in healthy subjects were associated with reductions in heart rate (HR) and arterial blood pressure (ABP) during formal lifting of identical absolute loads (McCartney et al., 1989; Sale et al., 1990). This study investigated whether the effect could be transferred to strength-related activities of daily living in healthy older men. The effects of 10 weeks (30 sessions) of progressive dynamic weightlifting training on HR and ABP in 10 weight-trained (wttrain) subjects were compared with 5 control subjects. Before and after training intra-brachial artery pressure and HR were monitored continuously during: 10 repetitions of single-arm curl (SAC) and single-arm military press (SAMP) at 70 % of initial 1 repetition maximum (1 RM); 12 repetitions of single- (SLP) and double-leg press (DLP) exercise at 80% of initial 1 RM; 10 mins treadmill walking at 2.5 mph, carrying 20 and 30 pound loads between mins 4-6 and 8-10 respectively (T-10); 4 mins of treadmill walking at 3.0 mph up an incline of 8% (T-4); 12 flights of stairclimbing at 60 steps/min on a Stairmaster 6000 Ergometer (STR). In the wttrain group the 1 RM in SAC, SAMP, SLP and DLP increased overall by 61 (p < 0.007), 30 (p < 0.001), 27 (p<0.001) and 27 per cent (p < 0.001), respectively. After training the mean maximal systolic blood pressure (SBP), diastolic blood pressure (DBP), mean arterial pressure (MAP), heart rate (HR), and rate-pressure product (RPP; 10^3) values in all 4 weightlifting exercises were lower. The decreases were only significant however, for the DBP in the SAC (144.0 ± 14.9 to 110.0 ± 5.2 Torr; p < 0.001), SAMP (151.0 ± 5.9 to 144.0 ± 5.4 Torr; p < 0.007), the MAP for the DLP ( 154.0 ± 5.0 to 147.0 ±5.0 Torr; p < 0.021) and RPP for the SAC (22.7 ± 2.2 to 19.1 ± 1.4; p < 0.041). The same respective measurements in the control group were either unchanged or higher. After training, there were overall reductions in the SBP (p < 0.05, mins 8-10), DBP , MAP and RPP (P < 0.05, mins 1-4) responses during T-10 with consistently higher values found in the control group. Similar, but nonsignificant patterns emerged for T-4. In contrast, there was little or no reduction in any of the measured parameters during stairclimbing. It was concluded that improved strength in older subjects results in an attenuated HR and ABP response during weightlifting, and there is a modest transfer of this effect to certain activities of daily living which involve the trained muscles. / Thesis / Master of Science (MSc)

The overall purpose of this dissertation was to address mechanistic and performance changes following a peaking phase in individual event and team sport strength-power athletes. This purpose was addressed by conducting 4 separate investigations with track and field athletes, volleyball athletes, and a national level weightlifter. The following are the primary findings from these investigations. Division I collegiate throwers increased competition throwing performance, jumping performance, and preserved muscle architecture characteristics following an overreach and taper. There were moderate decreases in division I female collegiate volleyball athlete’s vastus lateralis muscle thickness with no statistical changes in jumping performance following a taper with no prior overreach in. There were moderate to very large differences in countermovement jump height supercompensation during the peaking phase in favor of the returners over the new players on a similar team of female volleyball athletes. Changes in serum concentrations of inflammatory, hypertrophic and endocrine markers corresponded with alterations in training volume-load and partially explained changes in jump, dynamic mid-thigh pull, and weightlifting performance following multiple competition phases in a national level weightlifter. Additionally, vastus lateralis cross-sectional area can be maintained following a competition phase in a high level weightlifter provided large changes in body mass are not attempted close to competition. The findings of these investigations support the use of overreach and tapering for strength-power athletes and provide an underlying biochemical, morphological, and biomechanical basis for the observed changes in performance.

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American women have been accessing fitness spaces since fitness became an industry in the United States starting in the 1960s. Since that time the fitness industry has grown exponentially. Though a majority of Americans do not engage in fitness regimens on a regular basis, the cultural mandate for fitness (a combination of health and aesthetics) permeates American society. Though seemingly gender neutral, the fitness imperative has gendered prescriptions and results; some of which are on display in fitness spaces. Because of a presumption of equal access, supported by data illustrating that women use gyms in greater numbers than men, little research has focused on their specific uses of gym spaces and potential barriers they encounter in trying to access all the spaces in the gym. This dissertation is a qualitative study of the gendered barriers and fitness prescriptions in the contemporary American fitness center, or gym, as it is colloquially known. Using qualitative interviews (N=25) and participant observation at three gyms, I discuss the sociocultural creation of gym space and gym practices focusing on their gendered implications. The study focuses on specific spaces (i.e., the aerobics room, the weight room) as well as the more general uses of "open" gym space. I examine the sources of women's fitness knowledge, their entry points into fitness spaces, and their use of fitness technologies. I found that while women's movements within the gym and their choice of fitness regimens varied, they all understood the gendered nature of fitness as a whole and how it manifest on women's bodies. I discuss the pleasures gained as well as anxieties women had about using both traditional and non-traditional gendered gym spaces. Women's fitness regimens comprise part of their identities, in and outside the gym. In fitness spaces women earned social, cultural, and physical capital based on their fitness abilities, physiques, and fitness knowledge. These rewards were available to all women in all fitness spaces but the amount of capital accumulation varied depending on age, race, sexuality, ability and which fitness spaces they accessed and for what purpose.

PURPOSE: To quantify squat jump and isometric mid-thigh pull performance characteristics of an international level male weightlifter relative to a group of male weightlifters at an Olympic training site. METHODS: An 85kg international level male weightlifter (22.0y, 81.63kg, 168.5cm) representing the USA was recruited for this study and compared to a group of male weightlifters (n=41, 24.2±4.6y, 93.14±21.10kg, 173.8±8.6cm). Data was collected as part of an on-going athlete monitoring program and athletes were familiar with all tests performed. Unloaded squat jumps and isometric mid-thigh pulls were performed on force plates sampling at 1000Hz and analyzed with LabView software. Variables analyzed included squat jump height (JH) and allometrically scaled peak power (PPa), isometric mid-thigh pull allometrically scaled peak force (IPFa) and rate of force development at 200ms (RFD200). Standardized (z) scores were calculated for the athlete on each testing variable. RESULTS: Testing results for the athlete and group were as follows: JH=47.0 vs. 33.9±6.1cm (z=2.13), PPa=309.14 vs 278.68±81.76W·kg0.67 (z=0.37), IPFa=263.78 vs 270.31±48.27N·kg0.67 (z= -0.14), RFD200=4701.93 vs 10241.4±5422.6N·s-1 (z= -1.02). CONCLUSION: Despite having the highest absolute (total=326kg) and relative (Sinclair=389.54) weightlifting total, the only variable that corresponded with the athlete’s competition success was JH. These findings suggest that coaches and sport scientists can use squat jumps to predict competition success and identify talent in male weightlifters.

Abstract available in the The Journal of Strength and Conditioning Research.