Theses and Dissertations at Montana State University (MSU)
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Item Genu valgum : can observable or symptomatic changes occur with an exercise protocol in collegiate women?(Montana State University - Bozeman, College of Education, Health & Human Development, 2002) McCafferty, Jaime ErinItem The effects of acute muscular fatigue on the functional ability of the knee joint(Montana State University - Bozeman, College of Education, Health & Human Development, 2005) Brown, Tyler Nolan; Chairperson, Graduate Committee: Michael E. Hahn.Results of preliminary data collection indicate an increase of electromyography (EMG) amplitude in fatiguing isokinetic contractions of the knee extensors. The primary purpose of this study was to determine if the EMG/Torque relationship of vastus lateralis changes as a result of fatigue. The second purpose of this study was to determine if tests of functional ability are affected by fatigue. Twenty-two subjects (13 males and 9 females) were sampled from two populations with different types of training (strength versus endurance) experience. The procedures included a five-minute self-selected warmup on a cycle ergometer, pre-fatigue functional ability tests, fatigue protocol and postfatigue functional ability tests. The functional ability test protocol included four singleleg hopping drills to assess the functional performance of the knee joint. Torque was measured on an isokinetic dynamometer at 60 degrees per second through a functional range of motion until acute fatigue was reached during the fatigue protocol. Surface EMG electrodes were placed over the vastus lateralis to develop an EMG/Torque ratio during the dynamic contractions. The results indicate training type did not significantly affect torque production (p = 0.373) or the EMG/Torque ratio (p = 0.744) during isokinetic knee extensions in response to acute muscular fatigue. The strength-trained sample tended to have a greater increase of the EMG/Torque ratio during the fatigue protocol. The results did indicate that there were two significantly different types of response to acute muscular fatigue (p < 0.001). There were significant differences between the preand post-fatigue functional ability tests for the M/L (p < 0.001) and Up/Down (p = 0.011) but not for 3-Forward (p = 0.408) or Figure-8 (p = 0.286). One group doubled their activation magnitude during the fatigue protocol, while another group did not increase their activation magnitude during the fatigue protocol. It is possible that the increase of activation magnitude seen during the fatigue protocol is a result of transition of fiber type utilization. Further study is needed to determine what is the primary cause of the muscleαs response to acute muscular fatigue.Item Neuromuscular performance and the menstrual cycle(Montana State University - Bozeman, College of Education, Health & Human Development, 2007) Lemke, Shayna Marie; Chairperson, Graduate Committee: Mary P. Miles.Women athletes are more likely to tear their anterior cruciate ligament than their male counterparts. The female athlete has a complex system of steroid hormones that are continually changing. These sex hormones that fluctuate throughout each month may influence knee injuries, specifically the anterior cruciate ligament. The increased incidence in women is thought to be multifactorial, a combination of structural, anatomical, or biomechanical factors. The NCAA has reported that 75 percent of anterior cruciate ligament injuries are non-contact in competitive jumping or pivoting sports. In this study, the effects of the menstrual cycle on neuromuscular performance were investigated. Fifteen healthy females with regular menstrual cycles completed the various tests of this study for three phases of the menstrual cycle. All females were categorized as moderate or vigorous exercisers from an activity questionnaire. This study used a repeated measures experimental design; therefore, each participant served as her own control. The participants completed a series of two tests, including functional balance and fatigability.