Theses and Dissertations - Department of Kinesiology

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Browsing Theses and Dissertations - Department of Kinesiology by Subject "Biomechanics"

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    Impact of heat stress and cooling strategies on body temperature and performance in elite tennis players
    (University of Alabama Libraries, 2017) Crew, Kermit Ray; Esco, Michael R.; Bishop, Phillip A.; University of Alabama Tuscaloosa
    Tennis matches are intense, of long induration, with brief recovery periods, played in hot environments. This subjects elite tennis athlete to heat stress. Whether high core temperature impacts performance, and whether performance decrements are attenuated with cooling, remains unknown. Three studies evaluated heat stress on rectal temperature (Tre), skin temperature (Tsk) and shot accuracy (SA) after performing high intensity exercise at 22 °C and 38 °C and relative humidities of 31% and 38% respectively. Study 1 compared Tre, Tsk, SA in a temperate environment (TE) and a hot environment (HOT). HOT trial Tre (38.5 ± 0.4 °C) and Tsk (35.0 ± 1.6 °C) were higher than TE (37.8 ± 0.7 °C and 32.0 ± 1.3 °C, respectively). SA decreased (p = 0.003) between TE [57.5 ± 17.9 au out of 100] and HOT (33.4 ± 4.0 au), with greatest reduction in players with highest scores. Study 2 examined cooling of abdominal walls and thighs during rest periods and recovery on Tre, SA. Tre increased between start and end of both trials (p < 0.008). Treatments didn’t mitigate increased Tre. Treatment SA increased (p < 0.05). Study 3 evaluated continuous cooling device (vest) plus ice-pack applications on thighs, during rest periods in the high intensity protocol and recovery in hot condition verses control on Tre, SA. A significant time by condition effect for Tre (p < 0.05). Tre at end of high intensity protocol in control was 38.3 ± 0.6 °C. Tre at end recovery in control was 38.4 ± 0.4 ° C. No difference between Tre at start of treatment condition (37.5 ± 0.6 °C) and end of high intensity exercise (38.0 ± 0.7 °C). Tre at the end of recovery (37.0 ± 1.4 °C) was lower than Tre at end of high intensity exercise (p < 0.008). Tre at the end of recovery in control was higher than Tre at end of recovery in treatment. SA increased in treatment condition versus control [(p < 0.05) and large effect size (Cohen’s d = 1.38)]. Combined cooling mitigated the rise of Tre and increased SA in elite tennis athletes.
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    Muscle bilateral electromyographical activity in unilateral transfemoral amputees a case study
    (University of Alabama Libraries, 2015) Ouellet, Cindy; Bishop, Phillip A.; University of Alabama Tuscaloosa
    Microprocessor-controlled prosthetics knees are highly developed and allow above-knee amputees to perform daily tasks as well as able-bodied. However, microprocessor-controlled prosthetics are not financially practical for all. Very few investigations have focused on un-powered mechanical prosthetics for above-knee amputees when it comes to comparing the bilateral muscle activity. Surface electromyographical (EMG) was used to measure the muscle activity of 8 different muscles on both amputated and non-amputated sides while completing 5 daily routine tasks in one participant with a unilateral transfemoral amputation who used a mechanical prosthetic knee. After averaging each muscle for all the tests, the results indicated that the leg muscles on the amputated side averaged 34% lower mean EMG microvolts than the non-amputated side. The gluteus medius, lumbo-sacral erector spinae and external oblique muscles on the amputated side had higher mean microvolts than the non-amputated side (20%,6%, 9%) possibly trying to compensate for the weaker muscles in the amputated leg. The pectoralis major, gluteus maximus and rectus abdominis showed no major lateral muscular imbalance (2%, 2%, 2%).
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    Posture and sports performance
    (University of Alabama Libraries, 2011) Illian, Travis; Bishop, Phillip A.; University of Alabama Tuscaloosa
    The purpose of these investigations was to examine the influence of a device intended to "modify posture" and its influence on sports performance. We investigated the impact of a hand-grip device (e3 Fitness Grips, BioGrip, Sacramento, CA) designed to put the human skeleton in a "more favorable anatomical position," on 3.2-kilometer (2-mile) running performance by measuring time and counting steps. We observed no change in running time but a significant change (F(1,8)=5.7, p=0.04) in step count, but only for participants who could run 3.2-kilometers (2-miles) under 14 minutes. If a person is able to run 3.2-kilometers under 14 minutes, then using the fitness grips may decrease the number of steps it takes to run a given distance, but may not improve time. In the second study, we evaluated the impact of an isometric exercise treatment with grips designed to put the human skeleton in a "more advantageous position" (e3 Swing Grips, BioGrip, Sacramento, CA) on bat speed. We observed that the grip exercise treatment significantly (F(2,44)=7.6, p<.001) increased mean bat speed immediately after doing the treatment by 33.4 ± 2.5 m/s (0.45 m/s) and after five minutes of rest by 34.0 ± 2.8 ms (0.9 m/s) for collegiate baseball players when compared with a triceps pushdown treatment (placebo post treatment 32.3 ± 2.3 and 5 min rest 33.2 ± 2.7 m/s) and no treatment (control post treatment 32.5 ± 3.1 and 5 min rest 33.2 ± 2.7 m/s), but not for softball players (grip treatment post 28.7 ± 1.5 and 5 min rest 28.9 ± 2.1 m/s). The ease in use of the postural grip treatment may be a practical way to incorporate intense isometric muscle contractions of the core musculature into practice or game conditions as a means of enhancing bat speed velocity in baseball players similar to those tested. A review of literature was conducted examining posture and sports performance. The literature is clear that there are sport-specific postural deviations. It is unclear if these postural deviations lead to better performance or if a specific training plan should be developed to help build and maintain a more balanced body posture. Future research should examine the effect of posture control on static and dynamic movement.