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Item The influence of external load during hiking on markers of joint stress and movement efficacy(Montana State University - Bozeman, College of Education, Health & Human Development, 2022) Rowland, Isaac Franco; Chairperson, Graduate Committee: Mary P. Miles; Mary Miles, David Graham, Ron June, Brian Bothner and Hunter Fausset were co-authors of the article, 'The influence of external load during hiking on markers of joint stress and movement efficacy' which is contained within this thesis.PURPOSE: Complications to lower extremity joints, including injury and inflammation, are prevalent issues that arise during prolonged external load-bearing exercise. Metabolomic blood analysis can provide insight into the metabolic processes that occurs during this type of exercise. METHODS: Eight healthy, active men and women participated in a series of blood sample collections and motion capture recording before and after completing a 7.2-mile hiking protocol under two separate conditions. Blood was collected prior to hiking, 15-20 minutes after hiking, 8-hours after, 24-hours after, and 48 hours after. Movement coordination and efficacy was measured with a motion capture system while performing the y-balance test and an obstacle clearance task. Hiking conditions were randomized as backpacking with 20% of body mass external load or daypacking with minimal external load for each participant and separated by two weeks. Serum was analyzed to detect differences in metabolite upregulation between conditions. Biomechanical data were analyzed for inter- and intra-differential values relevant to fatigue between conditions. RESULTS: Analysis found clear differences between conditional metabolite upregulation at all post-hike timepoints. The upregulation of cortisol was significant in backpacking conditions at the post-hike timepoint. Glycerophospholipids were significantly upregulated in backpacking at 8-hours post-hike All significant metabolite upregulation switched to daypacking conditions at 24-hours post-hike. Significant metabolite upregulation varied between conditions at 48-hours post-hike. The only findings of significance in movement coordination and efficacy were between the y-balance lateral leg movement. CONCLUSIONS: The presence of cortisol is consistent with the physiological and mental stress of external loadcarriage and alludes to exposure that can lead to decreased bone mineral content. Glycerophospholipid metabolism pathways play an important role in joint degradation, which could explain their upregulation in backpacking conditions. Ceramide, omega-3s, and fatty acid/triglyceride cycling are functions of cell proliferation and turnover which may be upregulated with more efficiency in daypacking conditions. Upregulation of anserine at 48-hours post-hike in daypacking supports the idea of more efficient exercise recovery occurring in this condition. While significant differences were not clear in motor control measures, the findings show potential reliability for future study designs.Item The use of GPS to predict energy expenditure for outdoor walking(Montana State University - Bozeman, College of Education, Health & Human Development, 2007) McKenzie, James Michael; Chairperson, Graduate Committee: Daniel P. HeilThe purpose of this study was to determine the ability of GPS-reported position and elevation to estimate actual energy expenditure (EEACT) for outdoor walking. An accurate method for assessing EE in the field could greatly influence the scope of future studies of free-living activities. Thirteen subjects (8 male, 5 female) completed a 2303 m course of varying grades at slow and fast self-selected paces. Data from a portable metabolic unit was used to compare the GPS-predicted EE (EEGPS). Calculations of EEGPS were made by compiling an equation accounting for ground speed, grade, (Minetti, et al., 2002) and wind resistance (Pugh, 1970). Differences between EEACT and EEGPS were statistically and practically significant for the slow walking trials. Fast trials showed no significant differences. The combined data differed significantly from EEACT, but was similar to the error for accelerometer-based activity monitors. The wrist and hip-worn GPS monitors provided similar results for EEGPS throughout the data set. Separating the data by grade type showed that EEGPS was most problematic for uphill walking.