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JOINT POWER CONTRIBUTIONS DURING 90-DEGREES CHANGE OF DIRECTION IN KNEES FOLLOWING MENISCECTOMY
Get PDFArthroscopic partial meniscectomies (APM) are common following a traumatic meniscus injury and can result in long-term knee dysfunction. It is unclear how individuals distribute their lower limb loads during sporting movements. This study compared hip, knee, and ankle joint power contributions during a 90-degree change of direction (CoD) between APM limbs, contralateral limbs, and healthy individuals using kinematic and kinetic data. APM limbs had lower negative knee power contribution compared to contralateral limbs, with no differences in ankle and hip contributions. Compared to healthy limbs, APM limbs showed lower positive knee power contributions, greater hip power generation contributions, and slower CoD exit velocities. The APM group altered their joint contributions away from the knee, which could lead to muscle weakness, atrophy, and knee dysfunction
ACCELERATION DERIVED FROM INSTRUMENTED MOUTHGUARDS DURING HEADING IN WOMEN’S SOCCER WITH REGULAR AND ‘LIGHT’ SOCCER BALLS
Get PDFThis study investigated the specific types of header that occur in elite women’s football (Bentley et al., 2022). Launch speed and angle were replicated in laboratory conditions. An intervention of reduced ball mass (0.29kg v’s 0.41kg) was investigated. Common headers were categorised as a) slow controlling header; b) from a throw-in; c) from long-pass/cross; d) from goal kick. A custom fit Instrumented Mouthguard (Prevent Biometrics) sampled at 3200Hz to gain linear and angular accelerations of the skull. Seven female players performed 3 trials of each header, with kinematics also recorded at 1000Hz using 10 Vicon cameras. For the ‘light’ ball intervention, peak linear velocity of the head was significantly (
RELATIONSHIPS BETWEEN LOWER LIMB JOINT KINEMATICS AND VERTICAL STIFFNESS DURING THE 400-M SPRINT
Get PDFWe aimed to examine whether the lower limb joint kinematics related to the vertical stiffness differ between the early and the late phases of the 400-m sprint. An inertial measurement unit was used to collect the step-to-step whole-body kinematics during a 400-m sprint from twenty male collegiate track and field athletes. This study showed that larger knee flexion and ankle dorsiflexion angles were associated with larger vertical stiffness during the late phase, whereas there are no relationships between the vertical stiffness and lower limb joint kinematics during the early phase of the 400-m sprint. The magnitude of vertical stiffness during both the early and the late phases was negatively related to the 400-m sprint time. The current findings indicate that the 400-m sprint mechanics regulating the vertical stiffness differ between the early and the late phases
WOLF HOMESITE SELECTION AND DEN CHARACTERISTICS IN NORTHERN MINNESOTA
Get PDFGray wolves (Canis lupus) are social carnivores that rear their offspring cooperatively at locations called homesites. To assess homesite selection patterns in each month, I fitted a mixed-effects logistic regression model for each month in the pup-rearing season using data from 285 homesites documented from 2015 to 2021. Wolf homesite selection in northern Minnesota was a dynamic process. Wolves selected different characteristics for homesites in each month of the pup-rearing season, demonstrating for the first time that wolf homesite selection varies throughout the pup-rearing season (April-August). In August, wolves likely selected homesites that facilitate blueberry (Vaccinium spp.) foraging opportunities, especially for pups. Wolves avoided locating homesites near neighboring pack home ranges in all months of the pup-rearing season, likely to mitigate the risk of infanticide by neighboring packs. Wolves likely made decisions about where to locate homesites in response to seasonal environmental changes and the changing needs of pups as they mature. Because other social carnivores often rear their offspring under similarly variable conditions, it is likely that homesite selection behaviors among other social carnivores are also dynamic. I have summarized the characteristics of wolf den structures in northern Minnesota more rigorously than previous studies. Wolves chose to den in a wide variety of structures and dimensions of dens varied substantially. These results highlight an additional facet of the behavioral flexibility that has allowed wolves to inhabit a wide range of ecosystems across their Holarctic distribution
Charles H. Schaffer: “Alger County Charcoal King”
Get PDFOne of Michigan’s Upper Peninsula’s earliest industries was iron production. Iron furnaces (smelters) were part of that industry; these were primarily fueled by charcoal, produced in hundreds of charcoal kilns scattered across the Upper Peninsula. Charcoal burning was a major industry in its own right, and one person, Charles H. Schaffer, came to dominate it, earning the name “Alger County Charcoal King.” His empire began when the Detroit, Mackinac and Marquette Railroad expanded east from Marquette and was centered on charcoal kilns at the Onota station in Alger County. When wood supplies near Lake Superior declined, he expanded his charcoal locations to Delta and Menominee Counties, along the Chicago and North Western Railway. Eventually, Schaffer became an ironmaker to ensure a market for his charcoal, expanding beyond the Upper Peninsula. Schaffer was unarguably the central figure in the Upper Peninsula charcoal industry for most of the reign of the charcoal iron furnaces
The LTAR Grazing Land Common Experiment at Walnut Gulch Experimental Watershed
Get PDFThe Walnut Gulch Experimental Watershed (WGEW) Long-Term Agroecosystem Research (LTAR) network common experiment addresses the aspirational practice of brush management (BM) to reverse the prevailing condition of woody plant encroachment (WPE) and increase perennial native grass production. Across the western United States, the decision to implement BM includes consideration of management objectives, cost, and the expected impact on a diverse suite of ecosystem services.Maintaining or restoring grass cover will help meet the LTAR sustainable production, economic, and social goals, and averting degradation will meet environmental goals. This common experiment, focused on hydrologic and erosion impacts of BM, aims to inform land management decisions on three major plant communities in the Southwestern United States: creosote bush (Larrea tridentata), mesquite (Prosopis velutina), and pinyon–juniper (PJ, Pinus and Juniperus spp.). On the WGEW, applying tebuthiuron pellets to creosote bush increased grass cover and reduced runoff and erosion. The 2016 BM experiment on the Santa Rita Experimental Range applied a commonly used liquid herbicide cocktail but achieved only 7% mortality on mesquite, probably because of the timing of the aerial application. Experiments manipulating rainfall amount and intensity on plots receiving fire, chemical, or mechanical BM treatments on PJ communities aim to improve process representation in simulation models. The deliverables of these BM experiments will be to (i) improve the performance of runoff and erosion models, (ii) enhance our ability to identify areas most at risk from reduced hydrologic function and soil erosion after shrub proliferation, and (iii) better predict how landscapes will respond to BM interventions. Ranchers, land management agencies, and watershed conservation organizations will benefit from training and availability of improved tools to focus treatments on areas where greatest net benefits might be realized
Italians, Finns, Methodists, and the Klan: a Look into the Complex Identities and Relationships that were Prominent in the Upper Peninsula during the 1920s
Get PDFThis essay focuses on the Upper Peninsula of Michigan in the 1920s and the resurgence of the Ku Klux Klan. Using interviews from the Italian Oral History Collection, this essay explores the relationship between Italians, Finns, and the KKK. Rather than focusing on labor relations, this essay explores how these groups saw exogamy, the value placed on maintaining one’s religious connection and perceived racial identity. This research touches on the intersectionality of racialized ethnicity, religion, and class, concluding that the predominantly Methodist KKK would be more open to relationships, both personal and professional, with Finnish immigrants, even though they do not inhabit the same social class. Exploring the complex relationships between everyday people and how their identities inform their actions. This project uses the voices of historical figures living in Marquette County and adjacent areas to understand how these groups interacted with one another and their feelings towar
Throwing The Bones
No full textThis collection of nonfiction lyrical essays is concerned with embodied grief. Looking closely at my mother’s cancer through an interrogation of her medical records, her bodily scans, and my own memories of her final months, these essays explore the way cancer manifests in the body; the way it presents outwardly and the ways in which it refuses to be known. This is a collection of true things but also of speculation; of unknowability. How does a tick experience her world? What can a mouse in a wall tell me about cancerous cell growth? What role do dreams play in remembering? How does the night sky connect humans to non-human animals and them both to the earth? Driven by my fierce desire to know, these essays engage deeply and creatively with research, narrative, and place in an effort to make meaning and forge connections between grief, loss, and what we leave behind
AN ACCURACY-INTEGRATED METRIC FOR EVALUATING THROWING PERFORMANCE
Get PDFThe purpose of this study was to present a proof-of-concept for a novel Accuracy-Integrated Metric (AIM) to evaluate throwing performance. Ball velocity, displacement from target, and throw distance data were simulated for ten throws, and an AIM score calculated for each. Throws were ranked per conventional evaluation methods (by ball velocity), and by AIM score. When ranked on ball velocity, throw 7 ranked highest (36.0 m.s-1); however, it scored lowest with AIM (10.2) owing to a large displacement value. Discrepancies in these rankings highlight the limitations of relying solely on one aspect of performance when evaluating throwing. By considering ball velocity and accuracy together, AIM provides a more objective way to assess throwing performance which it is hoped will facilitate greater in-depth analyses of throwing biomechanics, and the aspects related to performance
INFLUENCE OF INERTIAL MEASUREMENT UNIT PLACEMENT ON KNEE FLEXION ANGLE MEASUREMENT DURING CYCLING
Get PDFInertial measurement units (IMUs) enable measurements of joint kinematics during sports in the field. The purpose of this study was to investigate the use of IMUs for measuring the knee flexion angle during cycling. To expand the limited research on optimal placement of IMUs on body segments, three different IMU placement setups were tested. Joint angles were calculated from the IMU orientations via OpenSim. Kinematics were captured from six experienced cyclists and compared to optical motion capture. Apart from an amplitude offset between the angle courses measured by IMUs and optical motion capture, no significant differences were observed between measurement systems, regardless of the IMU placement setup. Thus, all IMU setups are comparable to optical motion capture in relative terms (RMSE between 3 deg and 3.9 deg), but not in absolute values