Theses and Dissertations
This collection includes both ASU Theses and Dissertations, submitted by graduate students, and the Barrett, Honors College theses submitted by undergraduate students.
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- Creators: School of Nutrition and Health Promotion
Description
Dancers tend to injure the anterior cruciate ligament in their left leg more often than the right. It is unclear whether this trend is due to biased choreography or if leg dominance and left versus right asymmetries are contributing factors. The purpose of this study was to investigate asymmetries between the left and right leg, in knee abduction during landing, hip external rotation (ER) and internal rotation (IR) strength, and hip ER and IR range of motion in dancers compared to non-dancers. This study aimed to determine whether these asymmetries can be linked to leg dominance, and if this puts one leg at higher risk for ACL injury. Ten dancers and eleven non-dancers performed three maximal effort countermovement vertical jumps off of two feet, as well as three maximal effort single leg jumps on each leg. Knee abduction angles during the landing phase of the jumps were calculated using motion capture data. Maximum isometric hip ER and IR strength was measured at 15, 30, 45, 60, and 90 of knee flexion, and hip ER and IR range of motion was measured at 90 of knee flexion. Contrary to the hypothesis, few significant differences were found between the left and right leg, as well as between dancers and non-dancers. Dancers exhibited significantly greater IR range of motion than non-dancers, and knee abduction angles were greater on the right than left leg during double leg jumps. This opposes the hypothesis that knee abduction angles would be greater in dancers on the left leg. However, significant positive correlations were found
between IR strength and knee abduction angles during single leg jumps on the left leg, suggesting that IR strength may be a contributing factor to knee valgus. Further studies may want to utilize qualitative analyses, more relevant jumping tasks, and a different marker set to elucidate asymmetries of the lower limbs that may truly be present.
between IR strength and knee abduction angles during single leg jumps on the left leg, suggesting that IR strength may be a contributing factor to knee valgus. Further studies may want to utilize qualitative analyses, more relevant jumping tasks, and a different marker set to elucidate asymmetries of the lower limbs that may truly be present.
ContributorsOberbillig, Megan (Author) / Wiley, Alexander (Committee member) / Hinrichs, Richard (Committee member) / Barrett, The Honors College (Contributor) / School of Nutrition and Health Promotion (Contributor)
Created2013-05
Description
Most athletic or daily activities require the use of force production at a given velocity, in other words, power is needed to complete these activities. There are different methods for how this can be done, but the main two are heavy resistance training and plyometric training (Kawamori and Haff, 2004). However, resistance bands are another option of training that is available at a low cost and equipment needs. Resistance bands can also be used by athletes and elderly alike, but so far the benefits have barely been studied. Two participants were recruited to be followed as a case study. Both were of college age and were currently recreationally active with no health or musculoskeletal problems. Both participants were given a 35 lb. resistance band and instructed to do four different lower extremity exercises (three sets of four repetitions each) that were designed to target the muscles used for jumping. The study ran for five weeks, requiring three workouts per week separated by at least 24 hours. Participants were tested at three points; initial, halfway, and after all 15 workouts had been completed. Tests included measuring for changes in maximal vertical jump height as well as maximal broad jump. Results showed that both participants were able to increase their vertical jump and broad jump measurements from the initial testing day. Participant one had a 22.95% and 39.40% increase in broad jump and vertical jump respectively. Participant two had a 7.84% and 11.72% increase in broad jump and vertical jump respectively. Based on this study, it would appear that the power training program is effective in producing an increase in power based off the measured performance variables. There may be some effect from familiarity with testing protocol but most likely increased were caused by neural adaptation from speed aspect of program, as well as some increase in force production.
ContributorsBrown, Eric Preston (Author) / Harper, Erin (Thesis director) / Hinrichs, Richard (Committee member) / Barrett, The Honors College (Contributor) / School of Nutrition and Health Promotion (Contributor)
Created2014-05