Theses and Dissertations at Montana State University (MSU)
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Item The effects of L-citrulline supplementation on physical performance(Montana State University - Bozeman, College of Education, Health & Human Development, 2019) Stordahl, Peter Lawrence; Chairperson, Graduate Committee: John G. Seifert; John G. Seifert, Mary Miles and Dawn Tarabochia were co-authors of the article, 'The effects of l-citrulline supplementation on physical performance' submitted to the journal 'Journal of strength and conditioning research' which is contained within this thesis.INTRODUCTION. Recent studies have investigated l-citrulline (CIT) as a possible ergogenic aid. A small number of studies have explored the performance question, with varying methodologies and results. The purpose of this study was to examine CIT influence on cycling time to exhaustion, cardiovascular function, and muscle activity. METHODS. Thirteen healthy subjects volunteered for this study. The first visit was to obtain a maximal power output, where 80% and 50% of maximal power were calculated for the following two visits. Subjects were then randomly assigned into either treatment or placebo groups for the second visit and the opposite treatment for the third visit. Subjects were instructed to drink their treatment 1 hour prior to coming into the laboratory. The treatment drink contained 10g of CIT while the placebo (PBO) was formulated to look and taste like the CIT drink. The second and third visits to the laboratory consisted of EMG from the rectus femoris, vastus medialis, and medial gastrocnemius of the right leg, along with HR monitor and BP. Subjects completed a 40-minute interval ride, consisting of 8 5-minute intervals of 3 minutes at 50% maximal power and 2-minutes at 80% maximal power. After the interval ride, subjects received a second dose of either treatment, 5g of CIT or PBO and were allowed 1-hour rest before the ramped time to exhaustion (TTE) test. RESULTS. There was no significant difference in TTE by treatment (CIT, 20.79 + or - 4.48 and PBO, 20.86 + or - 3.99). There was no significant main effect of treatment on percent of maximum heart rate (p = 0.084), mean arterial pressure (p = 0.714), or muscle activity of the rectus femoris (p =0.300), vastus medialis (p = 0.641), or medial gastrocnemius (p = 0.133) during the TTE test. CONCLUSIONS. There were no differences in cycling TTE between treatments. Further research should investigate the metabolism of CIT under different physiological conditions.Item The influence of splitboard bindings and touring-specific boots on muscle activity, stride length, and joint kinematics during splitboard touring(Montana State University - Bozeman, College of Education, Health & Human Development, 2017) Valentin, Celine McShea; Chairperson, Graduate Committee: John G. SeifertSplitboarding is a form of alpine recreation that involves using a snowboard that splits into two skis to tour in backcountry terrain. At the summit, the skis are attached together and used as a normal snowboard to ride downhill. As splitboarding has grown in popularity, manufacturers have developed splitboard-specific equipment, such as bindings and boots. This crossover study investigated the effects of highback lean settings on Spark R&D splitboard bindings and two Burton Snowboards boot models while touring uphill. Subjects toured on a treadmill at a 10% incline in four test conditions: the Driver X boot with positive lean, the Driver X boot with negative lean, the Tourist boot with positive lean, and the Tourist boot with negative lean. Lower limb muscle activity was recorded as average root-mean-square (RMS) for gluteus medius (GM), biceps femoris (BF), rectus femoris (RF), medial gastrocnemius (MG), and tibialis anterior (TA). Kinematics variables of stride length, and ankle and knee range of motion (ROM) were also measured. The effects of the boots and bindings were determined using a two-way repeated measures analysis of variance (alpha < 0.05). The main effect of binding on average RMS was not significant for all muscles except MG (F = 8.821, p = 0.018, f = 1.05), with the negative lean having higher average RMS than the positive lean. The main effect of boot on stride length was significant (F = 15.791, p = 0.003, f = 1.33), with the Tourist resulting in a 3.56 cm longer stride length that the Driver X. The main effect of binding on stride length was also significant (F = 9.875, p = 0.012, f = 1.05), with negative lean resulting in a 2.21 cm longer stride length than the positive lean. The main effect of boot model on ankle ROM was significant (F = 36.325, p = 0.000, f = 2.00), with the Tourist having a larger ROM than the Driver X. There were no significant effects or interactions for knee ROM. The results of this study demonstrate that boot model and binding settings can affect biomechanical and physiological variables while splitboard touring.Item Physiological and sport skill characteristics of Olympic developmental soccer athletes(Montana State University - Bozeman, College of Education, Health & Human Development, 1997) Vanderford, Miriam LydiaItem A kinematic analysis of a telemark ski turn(Montana State University - Bozeman, College of Education, Health & Human Development, 1998) Trafton, Thomas AllenItem Effect of oral creatine supplementation on upper extremity anaerobic response in females(Montana State University - Bozeman, College of Education, Health & Human Development, 1996) Ward, Karyn HamiltonItem Digestibility characteristics of barley lines from the USDA Barley World Core Collection in rats(Montana State University - Bozeman, College of Education, Health & Human Development, 1999) Regli, Donna ColeenItem The effect of exercising in the cold on markers of fluid balance in women(Montana State University - Bozeman, College of Education, Health & Human Development, 2011) Cornachione, Kristen Marie; Chairperson, Graduate Committee: Daniel P. Heil; John Seifert (co-chair)The purpose of the study was to examine the effects of a cold temperature environment on markers of fluid balance in women during submaximal exercise. Nine women completed a 90-minute submaximal cycling protocol in both a cold (-5°C) and temperate (24°C) environment. The dependent variables were heart rate (HR), systolic and diastolic blood pressure (SBP, DBP), ratings of perceived exertion (RPE), percent change in plasma volume (%DeltaPV), and percent change in body mass (%DeltaBM). A two-way RMANOVA was used to detect differences over time and temperature condition. Over time, HR, SBP, and RPE increased during exercise irrespective of temperature environment, while DBP did not change significantly. Between condition, %DeltaPV and %DeltaBM were significantly lower in the cold environment. The combination of results indicates that water is shifting out of the plasma volume, but is then being restored after termination of cold exposure and exercise.Item Influence of pedometer tilt angle on step counting validity during controlled treadmill walking trials(Montana State University - Bozeman, College of Education, Health & Human Development, 2008) Dock, Melissa; Chairperson, Graduate Committee: Daniel P. HeilPedometers are tools frequently used to monitor walking-related physical activity patterns of overweight and obese populations. However, there is a known association between increasing body mass index (BMI) and decreasing pedometer accuracy. The decrease in pedometer accuracy has been attributed to tilt angle, but the specific tilt angle where pedometers fail to maintain accuracy is unclear. PURPOSE: The purpose of this study was to test two popular pedometer mechanisms, accelerometry- and pendulum-based, to determine the specific tilt angle where the pedometers fail to maintain step counts accurately. METHODS: Twenty subjects (10 men, Mean±SD: 25.4±4.2 yrs, 184.4±5.3 cm, 76.7±6.3 kg; 10 women: 21.6±3 yrs, 166.1±6.3 cm, 56.7±6.7 kg) walked two sets of 21 trials at a combination of treadmill speed (67.0, 80.4, 93.8 m/min) and tilt angle (-30,-20,-10, 0,+10,+20,+30°) while wearing two pedometers; the experimental pedometer attached to a custom-built pedometer gimbal for altering tilt angle, and the control pedometer in a neutral position (±2° of 0°). The pedometers were worn on each hip just anterior to the iliac crest in line with the mid-axillary line of the thigh. The first set of trials tested one pedometer mechanism, while the second set of trials tested the second pedometer mechanism in a counterbalanced order. Mean steps from the experimental pedometer were compared to the control pedometer for each trial (ÄStep=Experimental-Control) using a 3-factor RMANOVA at an alpha level of 0.05. RESULTS: Mean Ästeps for the accelerometry-based pedometer and the pendulum-based pedometer differed significantly (P<0.05) at tilt angles >±10° for treadmill speeds 0° (-30, -20, -10, +10, +20, +30°, respectively). CONCLUSIONS: Increasing tilt angle caused a decrease in pedometer accuracy for both pedometer mechanisms, although the accelerometry-based pedometers were less affected. Negative tilt angles had less effect on pedometer accuracy than positive tilt angles, and the combination of increasing positive tilt angle and slower speeds had the greatest impact on step count accuracy.Item The effects of carbohydrate on inflammation following an acute bout of resistance exercise(Montana State University - Bozeman, College of Education, Health & Human Development, 2006) Pearson, Sherri Diane; Chairperson, Graduate Committee: Mary P. Miles.The immune response to inflammation involves the release of cytokines, which determine the intensity and duration of the immune response (Kuby, 1997). The cytokine interleukin-6 (IL-6), functions as a negative feedback signal that turns off pro-inflammatory mediators during the immune response. IL-6 also initiates the release of CRP, which induces inflammation. Therefore, IL-6 is known as both a pro and anti-inflammatory mediator of the immune response. IL-6 is released during the immune response to inflammation. IL-6 peaks about 8 hours after an eccentric exercise session that induces muscle damage. Carbohydrate ingestion during endurance exercise attenuates the rise in IL-6 immediately post-exercise during recovery. IL-6 along with the acute phase protein C-reactive protein (CRP) (a marker of the systemic inflammatory response), and creatine kinase (CK) (a semi-quantitative marker of muscle damage), will be used to determine the affects of eccentric exercise on muscle damage and the inflammatory response.Item The influence of bout interruptions on measured and predicted physical activity during treadmill walking and running(Montana State University - Bozeman, College of Education, Health & Human Development, 2008) Howe, Stephanie Marie; Chairperson, Graduate Committee: Daniel P. HeilThe importance of daily physical activity (PA) has been established as a means of decreasing risk for chronic diseases. However, the presence of bout interruptions ((BI), defined as a brief pause (< 2 min) PA), can complicate measures of PA. This study was designed to evaluate the influence of different BI rules on PA during treadmill locomotion. Fifteen runners (6 women, 9 men) completed a series of walking (53.6, 107.2 m/min) and running (160.8 m/min) trials while using a metabolic measurement system to measure actual activity energy expenditure (AEEA) and four activity monitors to measure predicted AEE (AEEP). Treadmill speeds were selected to elicit light (L), moderate (M), and vigorous (V) PA intensities. Both AEEA and AEEP, were calculated as the sum within and between the start and end of each defined trial using 3 BI rules: 1) without an allowance for a BI (BI0), 2) or a 1-min BI allowance (BI1), 3) or a 2-min BI allowance (BI2). TA and TP were defined as the time spent at or above a moderate intensity during each PA bout for BI0, BI1, and BI2. Values of AEEA and AEEP for each BI definition and PA intensity were compared within intensities categories using a 2-factor RMANOVA, while data for all three PA intensities were evaluated simultaneously using a RMANOVA. Similarly, values of TA and TP for each BI definition were compared using the same multivariate RMANOVA model. Mean AEEA and AEEP for BI0 were significantly lower than those for BI1 and for BI2 at all PA intensities (p<0.05). When expressed as a percentage, the increase in AEEA and AEEP between BI0 and BI1, or BI1 and BI2, was 0.3-3.9% and between 5.5-11.0% for TA and TP across all intensities. Allowing for 1- or 2-min BIs within a PA bout significantly influences AEE and time during locomotion. These results suggest that rules for the number of BIs allowed should be established since an increase in BIs will cause PA outcome variables to become more dependent on the BIs than the PA itself.