Browsing by Author "Baltich, Jennifer"

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    Footwear Decreases Gait Asymmetry during Running
    (PLoS ONE, 2015-10-21) Hoerzer, Stefan; Federolf, Peter A; Maurer, Christian; Baltich, Jennifer; Nigg, Benno M
    Previous research on elderly people has suggested that footwear may improve neuromuscular control of motion. If footwear does in fact improve neuromuscular control, then such an influence might already be present in young, healthy adults. A feature that is often used to assess neuromuscular control of motion is the level of gait asymmetry. The objectives of the study were (a) to develop a comprehensive asymmetry index (CAI) that is capable of detecting gait asymmetry changes caused by external boundary conditions such as footwear, and (b) to use the CAI to investigate whether footwear influences gait asymmetry during running in a healthy, young cohort. Kinematic and kinetic data were collected for both legs of 15 subjects performing five barefoot and five shod over-ground running trials. Thirty continuous gait variables including ground reaction forces and variables of the hip, knee, and ankle joints were computed for each leg. For each individual, the differences between the variables for the right and left leg were calculated. Using this data, a principal component analysis was conducted to obtain the CAI. This study had two main outcomes. First, a sensitivity analysis suggested that the CAI had an improved sensitivity for detecting changes in gait asymmetry caused by external boundary conditions. The CAI may, therefore, have important clinical applications such as monitoring the progress of neuromuscular diseases (e.g. stroke or cerebral palsy). Second, the mean CAI for shod running (131.2 ± 48.5; mean ± standard deviation) was significantly lower (p = 0.041) than the CAI for barefoot running (155.7 ± 39.5). This finding suggests that in healthy, young adults gait asymmetry is reduced when running in shoes compared to running barefoot, which may be a result of improved neuromuscular control caused by changes in the afferent sensory feedback.
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    The Effects of Resistance Strength Training and Functional Strength Training on Risk Factors for Running Injury
    (2016) Baltich, Jennifer; Nigg, Benno; Emery, Carolyn; Stefanyshyn, Darren; Edwards, Brent; Hamill, Joseph; Matyas, John
    Reduced muscular strength and relatively larger magnitudes of movements and moments at the lower extremity joints during running have been proposed as risk factors for sustaining an injury. Some have suggested that increased movements at the joints are partially due to reduced muscular strength. However, the influence of strength training on running mechanics has yet to be evaluated in a group of novice runners, which have been shown to be particularly prone to injury. Therefore, the purposes of this thesis were to 1) compare changes in strength, running mechanics, and balance and 2) to explore injury risk for novice runners enrolled in a resistance strength training program, a functional movement strength training program or a stretching control program. One hundred and twenty nine novice runners (18-60 years old, less than two years running experience) were randomly assigned to one of three groups: a “resistance” strength training group (n=43), a “functional” strength training group (n=43) or a stretching “control” group (n=43). Participants were asked to complete a home-based training program three to five times a week for the eight week training period. Following this training period, participants were asked to complete their respective training at least twice a week for a sixteen week maintenance period. Changes in strength, running mechanics, and balance pre- to post-training were compared between groups. Running injuries were self-reported and defined as any complaint sustained in relation to running that caused a restriction in running for at least one week. Eighty-six participants completed the follow up assessment (functional=34, resistance=28, control=24). Changes in lower extremity strength were similar between the training groups with all groups demonstrating strength gains at multiple lower extremity joints. Changes in running mechanics were small in magnitude and within the measurement error of the testing protocol. The functional training group demonstrated improved balance using force plate and field based measures of balance. Though exploratory in nature, injury rates were not different between the three training groups. The results of this thesis indicate that running and completing a home-based strength training program did not increase strength or reduce joint movements more than running and stretching for a group of novice runners.