Theses and Dissertations at Montana State University (MSU)
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Item High versus low carbohydrate in Skimo race performance: a randomized controlled trial(Montana State University - Bozeman, College of Education, Health & Human Development, 2024) Topf, Rachel Marie; Chairperson, Graduate Committee: Mary P. Miles; This is a manuscript style paper that includes co-authored chapters.Ski mountaineering (skimo) is a high-intensity sport with several race disciplines of varying lengths in which competitors face many challenges that can make consuming food and fluids difficult. There is currently a scarcity of literature on skimo, particularly on nutrition in individual-format races. Exercise >1.5 h, as in an individual skimo race, may benefit from high carbohydrate consumption of > or = 90 g/h compared to lower recommendations of 60 g/h. However, gastrointestinal upset is worsened with increasing amounts of carbohydrate consumption, especially during high-intensity exercise. Highly-branched cyclic dextrin is a glucose polymer with a low osmolality allowing it to have a fast gastric emptying rate which can decrease gastrointestinal upset during exercise. The first purpose of this study was to survey skimo athletes about their nutrition knowledge and practices. With this new information combined with recommendations on carbohydrate and fluid intake, the second purpose of this study was to test an 18% solution of highly-branched cyclic dextrin + fructose (3:1) in a skimo race. It was hypothesized that an 18% solution (90G) would improve performance in an individual race compared to a 6% solution (30G) without contributing to gastrointestinal upset. Fifteen participants completed the randomized controlled crossover trials. Average carbohydrate consumed was 27 and 85 g/h and race time 105 and 107 min in 30G and 90G, respectively. Overall race times were not significantly different. Gastrointestinal upset trended higher in 90G (p=0.07). When the four participants with high gastrointestinal upset (rating >4/10) were removed from analysis, there was a main effect for drink on percent lap time change (p<0.001), with 30G having a greater percent increase in lap time throughout the trial. In conclusion, a high-carbohydrate drink was created to address the needs of skimo athletes. It was found that an 18% carbohydrate solution had significantly higher gastrointestinal upset ratings and did not confer additional performance benefit compared to a 6% solution. Additionally, high gastrointestinal upset with the 18% solution appears to have contributed to slower time; however, those without high gastrointestinal upset with the 18% solution had a lesser percentage change in lap time throughout the trial compared to 6%.Item Manipulating implement weight during warm up to improve shot put performance(Montana State University - Bozeman, College of Education, Health & Human Development, 2023) Klein, Leah Nicole; Chairperson, Graduate Committee: James N. Becker; This is a manuscript style paper that includes co-authored chapters.The purpose of this study was to investigate the use of overweight and underweight implements impacts on shot putting performance along with technical and physiological changes. Ten collegiate shot putters participated in this study (6 male, 4 female). Each participant completed 3 non consecutive days of data collection. Each day consisted of 3 warm up throws followed by 6 maximal effort regulation weighted throws. Warm up throws consisted of one of three conditions: (1) overweight (2) underweight or (3) regulation. In agreement with prior literature on post-activation potentiation (PAP), those who threw with overweight implements showed significant increases in performance. No changes in critical factor kinematics or ground reaction force measures were affected by warm up weight. Results of this study conclude that using a heavy implement during warmups is a functional way to improve performance, however more research is needed to further uncover the underlying mechanisms.Item The Y-balance test in runners: relationships between performance and running mechanics, and the influence of fatigue(Montana State University - Bozeman, College of Education, Health & Human Development, 2020) Wilson, Charles Scott; Chairperson, Graduate Committee: James P. Becker; Allison Theobold, Sara Skammer, Sam Nelson and James Becker were co-authors of the article, 'A multivariate analysis between the Y-balance test and injury-linked running mechanics' submitted to the journal 'The American journal of sports medicine' which is contained within this thesis.; Sam Nelson, Sara Skammer and James Becker were co-authors of the article, 'The relationship between Y-balance test performance and running mechanics at the hip following fatigue' submitted to the journal 'The journal of orthopedic and sports physical therapy' which is contained within this thesis.The YBT is a widely known clinical movement screen used to measure strength, dynamic stability and neuromuscular control in a variety of athletic and clinical populations. The YBT is also used to predict injury risk across a range of sports. Strength and neuromuscular control of the muscles surrounding the hip are strong predictors of YBT performance. These same variables are also essential for running performance and the prevention of injury. Changes in injury-related running mechanics have been shown to occur along the course of a fatiguing run. Thus, the purpose of this thesis was twofold: 1) to evaluate the relationship between YBT performance and running mechanics and 2) to evaluate whether YBT performance can predict changes in injury-linked running mechanics after a run to fatigue. For the remainder of this paper the previous manuscripts will be referred to as Study 1 (A Multivariate Analysis of the Relationships Between Y-Balance Test Performance and Running Mechanics) and Study 2 (The Relationship Between Y-Balance Test Performance and Running Mechanics at the Hip Following Fatigue).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 Effects of backpack chest straps on simulated shooting performance following repeated bouts of treadmill marching(Montana State University - Bozeman, College of Education & Health & Human Development, 2019) Kidd, Dustin Todd; Chairperson, Graduate Committee: John G. Seifert; Mary P. Miles (co-chair); John G. Seifert, Mary Miles and Rob M. Orr were co-authors of the article, 'Effects of backpack chest straps on simulated shooting performance following repeated bouts of treadmill marching' which is contained within this thesis of the same title.Soldiers must quickly take action when called upon and normally carry heavy loads in the process. One piece of equipment that is vital to carrying this load is a backpack. While load carriage and physical performance have been researched in the past, it is unknown if changing the location of the shoulder and chest straps will influence physiological measures or marksmanship performance. PURPOSE: The purpose of this study was to examine how changing the location of backpack shoulder straps affect physiological and marksmanship values during a simulated road march while under army assault load conditions. METHODS: Seven young healthy men (Mean + or - SD: 22 + or - 3.5 yrs; 24.75 + or - 1.38 kg/m 2 BMI) participated in this study. Subjects wore load carriage equipment (body armor 8.05 kg, backpack 21.7 kg, rifle 3.25 kg) during three separate testing periods. Each period consisted of 120 minutes of marching and 6 minutes of shooting with an airsoft rifle equipped with a laser-based shooting system. Each of the lab visits corresponded to testing one of three chest strap conditions: modified chest strap (MCS), standard chest strap (SCS) and no chest strap (NCS). Heart rate, upper limb oxygen saturation, discomfort, shot accuracy and shot score were analyzed using repeated measures ANOVA (alpha=.05). RESULTS: There were significant main effects of trial (p=0.018) and time (p=0.000) when examining discomfort. There was a significant main effect of trial (p=0.002) for upper limb oxygenation. There was also a significant trial (p=0.017) main effect for heart rate. There were no main effects for either shot score or shot accuracy. CONCLUSION: There were no significant differences in any marksmanship value. However, there were significant differences in heart rate, discomfort and upper limb oxygen saturation. This would suggest that the location of backpack shoulder straps may have an effect on physiological measures while having no effect on performance measures during a simulated road march.Item The influence of a directional compression garment on muscle activity and performance in recreational alpine skiers(Montana State University - Bozeman, College of Education, Health & Human Development, 2018) Snyder, Cory James; Chairperson, Graduate Committee: John G. Seifert; John G. Seifert, James Becker and Ed Adams were co-authors of the article, 'The influence of a directioanl compression garment on muscle activity and performance in recreational alpine skiers' submitted to the journal 'Journal of sports sciences' which is contained within this thesis.Recent studies reported reduced muscle activity in competitive alpine skiers using directional compression (DC). It is not known whether the effects of DC are limited to competitive skiers, or if similar changes would be observed in recreational skiers during a full day of skiing. The purpose of this study was to examine changes in hip and leg muscle EMG patterns in recreational alpine skiers when skiing with and without a lower body DC garment. METHODS 11 intermediate and expert skiers volunteered for this study. Subjects completed 2 randomized trials, one in a DC garment, and one in a non-compressive (NC) base layer. EMG of the gluteus medius (GMED), gluteus maximus (GMAX), rectus femoris (RF), adductor longus (ADL), and vastus lateralis (VL) were recorded using EMG during three measurement runs with standardized turns on each visit. Standardized turns were used to compare EMG response between conditions and measurement runs. Subjects also completed self-paced skiing bouts (SP) between measurement runs. Skiing performance (heart rate, velocity, and skiing load (vertical/runs) were measured during the SP bouts. 2x3 repeated measures ANOVA's was used to compare kinematic and EMG changes during measurement runs, as well as performance during self-paced skiing between (p < or = 0.05). RESULTS Subjects skied more runs (DC 18.60 + or = 0.98, NC 13.55 + or = 1.06, p=0.001) and vertical (DC 4805.31 + or = 304.31 m, NC 2373.56 + or = 219.60 m, p=0.001) during free skiing with DC than NC. Heart rate and ski velocity were not different between SP bouts. Peak edge angle was lower in the DC treatment (DC 55.06 + or = 10.70°, NC 57.90 + or = 9.10°, p=0.008). Absolute muscle activity was lower in the DC condition for all muscles (p < or = 0.05), although no differences were observed in relative muscle activity. CONCLUSIONS No differences in relative muscle activity were detected, absolute muscle activity was lower in the DC condition. Subjects improved their self-paced skiing performance in the DC condition. There was also a trend towards lower RMS for all muscles in the DC treatment. Further research should investigate the influence of DC garments on repeated bouts of recreational alpine skiing on consecutive days.Item Validity of a stationary cycling protocol for tracking changes in uphill cycling time-trial performance(Montana State University - Bozeman, College of Education, Health & Human Development, 2001) Murphy, Owen Frederic