Theses and Dissertations at Montana State University (MSU)
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Item An induced acceleration analysis of the barbell back squat(Montana State University - Bozeman, College of Education, Health & Human Development, 2024) Goodman, William Wesley; Chairperson, Graduate Committee: Dawn Tarabochia; This is a manuscript style paper that includes co-authored chapters.The barbell squat exercise is performed in settings ranging from rehabilitation through to developing muscle size, strength and power. Unfortunately, the lower extremity coordination producing the squat is not clearly understood. This thesis involves three studies evaluating how lower limb joints and muscles coordinate varied squat performance. Study one-three included 13 females who performed squats at three randomized depths (above parallel, parallel, below parallel) using 85% of their 1 repetition maximum at each respective depth. In study one, performance was evaluated by estimating the individual muscle force production and the individual muscle contribution to whole body acceleration using a musculoskeletal model. In study two, performance was evaluated by estimating the individual muscle force production and the individual muscle contribution to the lower body joint accelerations using a musculoskeletal model. In study three, knee joint contact loads were estimated using an advanced musculoskeletal model. Because muscles can accelerate all joints in the body, including a joint that it does not span, musculoskeletal models are necessary to determine muscle function. Varied coordination indicates that depth and load specificity is important and should be taken into consideration when programming based on the status and goals of the individual.Item Using a beam theory model to quantify metatarsal bone stress during running(Montana State University - Bozeman, College of Education, Health & Human Development, 2023) McKibben, Kaitlyn Marie; Chairperson, Graduate Committee: James N. Becker; This is a manuscript style paper that includes co-authored chapters.Running is a common fitness activity that is associated with a high incidence of overuse injuries, including metatarsal stress fractures. One contributor to stress injury is repetitive loading of the metatarsals without adequate recovery time and experiencing larger volumes and magnitudes of bone loading may increase injury risk. Thus, quantifying metatarsal loads can be beneficial to understanding injury risk. However, it is currently difficult to estimate bone stress in clinical settings and unclear how bone stress changes following a long run. Therefore, the purpose of this thesis was to 1) characterize changes in metatarsal bone stress before and after the completion of a long-distance run, and 2) suggest a clinically feasible method for estimating metatarsal bone stress. Study 1 involved 21 healthy long-distance runners who ran 25% of their average weekly mileage on an instrumented treadmill. Foot kinematics, ground reaction forces, and in-shoe plantar pressures were collected at the beginning and end of the run and a mathematical model was used to estimate bone stresses and bending moments for all five metatarsals. Plantar stress, dorsal stress, and midshaft bending moments in the second and third metatarsals were greater after the completion of the run. This is consequential for injury risk because the second and third metatarsals are the most susceptible to stress fracture development. In study 2, seventeen runners ran barefoot across a force plate overlaid with a plantar pressure mat while foot kinematics were recorded. The same mathematical model of the metatarsals was used to estimate third metatarsal bone stresses and bending moments, and linear regressions determined whether force or pressure beneath the metatarsal predicted bone loads. A model containing head and base pressure differentials and force beneath the metatarsal head was the best predictor of bone loading, indicating that the use of plantar pressure measurements as a surrogate measure of bone stress could be a time and cost-effective method for estimating bone stress in clinical settings. Moving forward, elucidating how metatarsal bone stress changes over the course of a long run and finding more accessible ways to quantify bone stress could help alleviate injury risk.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 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 Habituation during repeated exposure to balance recovery from a forward loss of balance in younger adults(Montana State University - Bozeman, College of Education, Health & Human Development, 2021) Whitten, Justin Mark Moeller; Chairperson, Graduate Committee: David Graham; Dawn S. Tarabochia, John G. Siefert and David F. Graham were co-authors of the article, 'Changes in margin of stability during repeated exposure to forward loss of balance in young adults' submitted to the journal 'Journal of biomechanics' which is contained within this thesis.; Dawn S. Tarabochia, John G. Siefert and David F. Graham were co-authors of the article, 'Changes in muscular effort during repeated exposure to forward loss of balance in young adults' submitted to the journal 'Journal of biomechanics' which is contained within this thesis.The purpose of this study was to begin to develop within session volume parameters for perturbation-based balance training by determining the minimum number of exposures needed for participants to habituate to balance recovery from a substantial perturbation. Two young adult participants were exposed to 15 substantial perturbations induced via release from a static forward lean. All participants were instructed to attempt to recover balance by taking a single rapid step. A scalable anatomical model consisting of 36 degrees-of-freedom and 94 muscle actuators was used to compute kinematics and joint moments from motion capture and force plate data. Margin of stability was calculated at heel strike and maximum knee joint flexion to quantify balance recovery performance. Balance recovery trials were divided in to three blocks (early, middle, and late) with 5 trials in each block and static optimization was used to compute estimates of the mean and peak force generated by key muscle groups during recovery for each block. Participant margin of stability declined rapidly during early balance recovery trials and plateaued between trials 5-8. Hip abductor forces remained relatively consistent across trials while the force produced by the Vastus Femoris group decreased during the mid and late trial blocks. Mean force produced by the Soleus during balance recovery decreased across trial blocks. In contrast, the peak force and impulse generated by the Soleus increased across trial blocks. We interpret these data to reflect an adaptation in balance recovery coordination strategy, which appears to occur sometime between the early and middle trial blocks and stems from young participants desire to minimize the effort associated with successful recovery of balance. These results further suggest participants became habituated to balance recovery after exposure to 5-8 substantial perturbations.Item Rehabilitation outcomes following a periacetabular osteotomy (PAO): a case study(Montana State University - Bozeman, College of Education, Health & Human Development, 2021) Schroeder, Cailyn Marie; Chairperson, Graduate Committee: James P. Becker; Linnea Zavala, Laura Opstedal and James Becker were co-authors of the article, 'Recovery of lower extremity function in the initial year following periacetabular osteotomy: a single subject analysis' in the journal 'Physiotherapy theory and practice' which is contained within this thesis.; Laura Opstedal, David Graham and James Becker were co-authors of the article, 'Return of gait symmetry following real-time biofeedback gait retraining in periacetabular osteotomy: a single subject analysis' submitted to the journal 'Physiotherapy theory and practice' which is contained within this thesis.Hip dysplasia is a joint deformity creating instability at the hip due to decreased acetabular coverage of the femoral head and often leads to osteoarthritis. A periacetabular osteotomy is a procedure designed to preserve the bony anatomy and delay the development of osteoarthritis. There is little known about the resulting biomechanical outcomes following periacetabular osteotomy. Two studies on a single subject having undergone periacetabular osteotomy are addressed here: 1) how does lower extremity function during a sit-to-walk change throughout recovery compared to preoperative values following a unilateral periacetabular osteotomy and 2) does gait retraining using real-time biofeedback of ground reaction forces improve return of gait function, with regard to internal hip joint moments, hip and pelvis kinematics, whole body center of mass velocity, and step length following bilateral periacetabular osteotomy in a single patient. In study one, patient reported outcomes, hip strength, and lower extremity joint moments and contributions to peak support moment during the sit-to-stand were assessed pre-operatively and at 6 weeks, 12 weeks, 6 months, and 13 months following periacetabular osteotomy. Patient reported outcome scores returned to normative ranges, however overall quality of life scores remained low. By 13 months muscle strength recovered to baseline values. Following surgery, peak support and hip extensor moments were higher on the non-surgical limb, but the contributions of hip, knee, and ankle to peak support moment did not change. On the surgical limb, while peak support moments were lower, the hip contributed less, and the knee contributed more. These asymmetric loading patterns gradually normalized over one year. In study two, hip joint kinematics, moments, vertical ground reaction forces, and symmetry between limbs during gait were assessed at 6 and 12 weeks following bilateral periacetabular osteotomy - one with gait intervention, and one without. Limb symmetry across dependent variables was not improved in the gait retraining intervention compared to the control. Future research examining biomechanical outcomes in the immediate window following periacetabular osteotomy are needed in addition to evaluation of similar interventions to better inform the rehabilitation protocols currently in place and improve patient return to baseline activity.Item Coordination and coordination variability during running with respect to internal loading and age(Montana State University - Bozeman, College of Education, Health & Human Development, 2021) Hoffee, Allison Jane; Chairperson, Graduate Committee: James P. Becker; David Graham, Scott Monfort and James Becker were co-authors of the article, 'Coordination variability predicts achilles tendon and peak patellofemoral loading in healthy runners' submitted to the journal 'Clinical biomechanics' which is contained within this thesis.; Scott Monfort, David Graham and James Becker were co-authors of the article, 'Comparison of coordination and coordination variability between adolescent and adult runners' submitted to the journal 'Journal of sports sciences' which is contained within this thesis.Running is a largely popular and widely accessible form of exercise. However, running may pose risks to individuals due to its associations with high rates of injuries. Coordination between lower extremity joints and segments as well as coordination variability have linked to these running injuries. While mechanisms of injury are multifactorial, one theory suggests that reduced coordination variability may cause injury by increasing cumulative loading of soft tissue structures. This relationship may be important when assessing age, as prevalence of injuries differ between adolescents and adults. Therefore, this thesis aimed to 1) assess the relationship between coordination variability and loads in the Achilles tendon and patellofemoral joint during running 2) and evaluate differences in segmental coordination and variability between adolescent and collegiate runners. In Study 1, 64 healthy, adult runners ran on an instrumented treadmill while kinematics and kinetics were recorded. Coordination variability for knee-shank, knee-rearfoot, and shank-rearfoot couplings were calculated using vector coding. Achilles tendon and patellofemoral kinetics were calculated with musculoskeletal models. Surrogate variables were created for Achilles tendon and patellofemoral metrics using principal component analyses, and regressions were used to determine whether variability metrics predicted loading surrogates. One surrogate variable was created for Achilles loading, and lower knee-rearfoot variability predicted greater Achilles loading. Two surrogate variables were created for patellofemoral loading. Lower knee-rearfoot and knee-shank variability predicted greater peak patellofemoral loading, but no variability predicted cumulative patellofemoral loading. This suggests that a combination of low variability and large loads may be important for injury risk rather than cumulative loading. Study 2 assessed 21 competitive adolescent and 21 collegiate runners. Coordination variability was calculated using vector coding for various thigh, shank, and rearfoot couplings. Coordination patterns were analyzed using a binning frequency analysis. Adolescent and collegiate runners displayed different coordination patterns while running that primarily emerged from the transverse plane. Adolescent runners displayed greater coordination variability on average than collegiate runners. Combined with previous literature, this suggests a downward trend in coordination variability starting in adolescence and continuing through adulthood. In conclusion, coordination and its variability may be consequential in terms of injury mechanisms and different age populations.Item Patellofemoral joint loading in females during back squats of varying depth, weight load, and stance width(Montana State University - Bozeman, College of Education, Health & Human Development, 2019) Zavala, Linnea Joy; Chairperson, Graduate Committee: James P. Becker; Victoria Flores, Joshua Cotter and James Becker were co-authors of the article, 'Patellofemoral joint loading in females when using different depths and loads in the back squat' submitted to the journal 'Journal of applied biomechanics' which is contained within this thesis.; James Becker was a co-author of the article, 'Patellofemoral joint loading in females during back squats with varying stance widths' submitted to the journal 'Journal of orthopedic sports physical therapy' which is contained within this thesis.As a repetitive and loaded exercise, the back squat can lead to tissue injury. One concern is patellofemoral pain syndrome, a common knee diagnoses over twice as prevalent in females as in males. Patellofemoral joint stress is cited as a cause of the syndrome. To manage the syndrome, quadriceps strength is important. Although the back squat is a good exercise for quadricep strength, modifications to squat technique may be necessary to decrease patellofemoral joint stress. Two studies on female recreational athletes are addressed here: 1) how patellofemoral joint loading changes with squat depth and load and 2) how it changes with squat load and stance width. Depth-specific 1-repetition maximums were measured, and weight loads were based on percentages of the maximum. Peak knee extensor moments, patellofemoral joint reaction forces, and patellofemoral joint stresses were calculated using inverse dynamics and previously reported equations. First, participants squatted to 90°, ~°110, and ~135° of knee flexion with loads of 0%, 50%, and 85% of 1RM. A depth-by-load interaction was found such that within each depth, moments increased as load increased, while decreasing with increased depth. Patellofemoral joint reaction force had main effects of load and depth such that as load increased or depth decreased, reaction force increased. Another depth-by-load interaction was found such that within each depth, as load increased the stress increased, while increasing with increased depth. From these results, squats to full depth or loaded squats to less than 90° of knee flexion are recommended to minimize patellofemoral joint stress. Second, when squatting to ~110° with loads of 35% and 85% and stance widths of 90%, 100%, 110%, and 120% of natural stance, there was a main effect of load for knee extensor moment, patellofemoral joint reaction force, and patellofemoral joint stress. Although altering stance width does not appear to change joint loading, some research suggests that there may be a relationship between foot turnout and joint loading. Continuing relatively simple studies, like these, reveal trends which more individualized approaches can later use, accounting for individuals' anatomy to fully understand patellofemoral joint loading during the back squat.Item Support moment distribution and induced acceleration analysis of the barbell back squat(Montana State University - Bozeman, College of Education, Health & Human Development, 2020) Goodman, William Wesley; Chairperson, Graduate Committee: David Graham and James P. Becker (co-chair); Victoria Flores, Joshua Cotter, David Graham and James Becker were co-authors of the article, 'Support moment distribution during the barbell back squat at different depths and loads in recreationally trained females' submitted to the journal 'Journal of strength and conditioning research' which is contained within this thesis.; James Becker and David Graham were co-authors of the article, 'An induced acceleration analysis of the barbell back squat at different depths in trained females' submitted to the journal 'Journal of strength and conditioning research' which is contained within this thesis.The barbell squat exercise is performed in settings ranging from rehabilitation through to developing muscle size, strength and power. Unfortunately, the lower extremity coordination producing the squat is not clearly understood. This thesis involves two studies evaluating how lower limb joints and muscles coordinate varied squat performance. Study one included 19 females who performed squats at three randomized depths (above parallel, parallel, below parallel) and three loads (unloaded, 50%, 85% 1 repetition maximum). Inverse dynamics analysis revealed that peak hip and ankle extensor moments varied with load but not depth and were greatest when using 85% 1 repetition maximum. Within each depth, as load increased so did peak knee extensor moments. Peak knee extensor moments were greatest when squatting below parallel with load. Within each depth as load increased contribution of the hip increased whereas the knee decreased. Ankle contribution was only influenced by load. When squatting to deep depths with load, the contribution of the hip decreased while the knee increased. In study two, 13 females squatted to the same 3 depths using 85% of their 1 repetition maximum at each respective depth. Performance was evaluated by estimating the individual muscle force production and the individual muscle contribution to whole body acceleration using a musculoskeletal model. The gluteus maximus and adductors increased peak force to parallel while the hamstrings and rectus femoris increased to below parallel. At deep depths, the vasti decreased peak force while the hamstrings and rectus femoris increased peak force. The induced acceleration of the vasti at transition decreased with depth while the hamstrings and rectus femoris increased. Because muscles can instantaneously accelerate all joints in the body, it's possible that at transition the hamstrings accelerated the hip and knee into extension while the rectus femoris also accelerated the knee and hip into extension while the soleus accelerated the ankle and knee into extension. In conclusion, a complex coordination of the lower extremity is used performing the squat. Varied coordination indicates that depth and load specificity is important and should be taken into consideration when programming based on the status and goals of the individual.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.