5954 research outputs found
Sort by
EVALUATING PERFORMANCE MEASURES FOR THE BOBSLEIGH PUSH START
Get PDFQuantification of performance is essential to understand performance determinants. Therefore, the purpose of this study was to evaluate different performance measures applied to the bobsleigh push start and to discuss the choice of an appropriate measure for research and coaching. Measures based on the change in kinetic energy and based on the change in momentum were calculated for the early acceleration phase during the push start and compared by means of correlation analyses. Both energy-based and momentum-based methods lead to similar results while it is important to consider the athlete and the bob as a system. Further clarification is required on whether the flight phase should be taken into account when calculating performance measures
PREDICTING ACTIVE FOOT CONTACT IN THE ACCELERATION PHASE OF ATHLETIC SPRINTING THROUGH ACCELEROMETER MEASUREMENTS
Get PDFActive foot contact (absence of a braking impulse) during the acceleration phase of athletic sprinting is associated with the motion of the foot before touchdown (TD). Since the identification of braking impulses through force plate measurements is cost-expensive, the aim of this study was to develop a machine learning algorithm to predict active foot contact occurrences based on ankle-mounted accelerometer measurements. Ten recreationally active athletes (three females, seven males) performed 30 sprint-block-starts each, which were used as input to the machine learning model. Model performance was assessed by the AUC for both validation (AUC = 0.96) and testing (AUC = 0.94). It is therefore possible to predict active foot contact occurrence by a machine learning algorithm solely based on ankle-mounted accelerometer measurement data
THE STATUS OF INVASIVE DUSKY SLUG (ARION) SPECIES IN THE UPPER GREAT LAKES: A MOLECULAR APPROACH
Get PDFI update the distribution of two cryptic slug species, Arion fuscus and Arion subfuscus, in the Upper Great Lakes of the United States using molecular identification methods. Arion fuscus has not previously been reported in the literature in this region, and Arion subfuscus has previously been reported as abundant. However, all previous distribution studies were determined using visual identification tools, which can result in misidentification between cryptic species. To molecularly re-examine these distribution maps, I used a mitochondrial ribosomal subunit 16S PCR amplification and subsequent SSpI and MfeI restriction enzyme digest to identify slug specimens. I collected slugs in 11 locations around Lake Superior, Lake Michigan, and Lake Huron using beer-baited pitfall traps from May to September of 2022. I collected slugs at one location in Marquette, Michigan biweekly, a total of eight times, throughout the summer to monitor fine-scale slug activity. I found Arion fuscus at 9 of the 11 locations and Arion subfuscus at no locations. Arion fuscus was found early in the spring before other slug species were active. This confirms the inaccuracy of previous distributions determined through visual identification, and calls for the widespread molecular re-examination of current slug distributions
HERE NOR THERE
No full textHere Nor There is a collection of poetry that interrogates dreams and dreaming—both wakefulness and unconsciousness. The book examines themes of family and the environment through the lens of Consciousness Studies in relation to lucid dreaming, memory, and cultural practices. More specifically, Here Nor There is an ode to immigrant families, especially young immigrants who are still attempting to find a way to communicate with their family. This is the in-between, all the questions and conversations we were afraid to speak of or couldn’t
Science, Community, and Culture: A Holistic Approach to Ecological Research and Education
Get PDFGlobal biodiversity has declined at an alarming rate over the past century as a result of many complex human-induced environmental changes. Standardized surveys have historically been used to identify drivers of species declines, but such studies are often resource-intensive, resulting in significant spatial and temporal data gaps when researchers lack the resources necessary to maintain such studies. One promising solution for overcoming gaps in standardized studies is the integration of species observations by community members (e.g., community science). Along with improving modeling techniques to address biodiversity declines, the education of future ecologists on the importance of Indigenous ecological knowledge, robust scientific research, and community engagement in addressing myriad environmental problems is also imperative in addressing ecological challenges. Thus, my goals are 1) determine the efficacy of integrating standardized survey data with community-sourced observations to create species distribution models (SDMs) for species with varying responses to human-mediated environmental change and 2) create a curriculum that synergizes Indigenous ecological knowledge, scientific research techniques, and community science to establish a more holistic learning experience. I used data from Snapshot USA, a standardized nation-wide camera trap survey, and iNaturalist, an online community science platform, to create species distribution models and hands-on ecology lessons. My results demonstrate that integrated SDMs do produce informative predictions of the environmental factors that influence species distributions and provide a scaffolded framework for creating a more holistic approach to ecological education
PHYSICAL AND BIOMECHANICAL ASPECTS THAT CAN INFLUENCE THE PREFERENCE FOR THE UCHIMATA TECHNIQUE IN JUDO: A CASE STUDY
Get PDFThe aim of this study was to compare the handgrip strength, flexibility level (sit and reach test), kumikata and biomechanical aspects of the uchimata technique of two national level judokas, one who favors to use the uchimata (tokui-waza), and one who selects another judo technique in combat. We recorded the highest value of three attempts for handgrip strength (handgrip test), and flexibility (sit and reach); we recorded the highest value of three attempts for strength (handgrip test) and flexibility (sit and reach test); we analyzed the uchimata phases (kuzushi, tsukuri, kake and zanshi) in 3D using Vicon® system. We found that non-traditional kumikata during combat (grips with both hands on the same side), greater level of flexibility (45 vs. 36 cm), greater leg opening distance (113 vs. 66 cm) and greater displacement speed of the center of mass performing the technique (75 vs. 49 cm/s) may be indicators for the choice of uchimata technique as tokui-waza
EFFECTS OF CALF ANCHORING COMPRESSION LEVELS ON ANKLE KINEMATICS, MOTOR UNIT BEHAVIOR, ENERGY COST, AND DISCOMFORT DURING WALKING
Get PDFWe propose a method for quantifying the anchoring compression of wearable devices using limb occlusion pressure (LOP). Under 0%, 20%, 40%, and 60% of LOP, five healthy male participants performed an isometric ankle plantarflexion task before and after walking on an inclined treadmill. Significant differences were shown in calf discomfort (p \u3c 0.001), and ankle plantarflexion angle (p = 0.013) during walking. Although no significant difference was found for oxygen consumption and motor unit behavior of the gastrocnemius medialis, the maintenance of ankle plantarflexion angle was related to an increase in peak motor unit action potential amplitude and average firing rate at 60% of LOP. The results suggest that subjective assessment is more sensitive than the physiological indices, and calf anchoring force should not exceed 60% LOP to avoid any possible negative effect on the muscle
COMPARISON OF MARKERLESS AND MARKER-BASED MOTION CAPTURE FOR ESTIMATING EXTERNAL MECHANICAL WORK IN TENNIS: A PILOT STUDY
Get PDFThis pilot study assessed the accuracy of markerless motion capture to estimate the external mechanical work performed during tennis serves. One tennis player performed 9 serves whilst motion data were captured concurrently with a criterion marker-based and a custom markerless system (utilising HRNet and OpenPose). Centre of mass kinetic and potential energy were calculated and used to compute external mechanical work for all 3 approaches. Markerless methods yielded differences of 2-3% (HRNet) and 6-9% (OpenPose) for external work compared to the criterion measure, with the former regarded as a high level of agreement. Our markerless system, paired with HRNet, shows promise for accurately estimating external work during the tennis serve and has potential to provide players and coaches with a non-invasive tool for monitoring training ‘load’ in the field
CLINICAL AND BIOMECHANICAL COMPARISONS BETWEEN YOUTH PITCHERS WITH AND WITHOUT A HISTORY OF THROWING ARM PAIN OR INJUR
Get PDFThis study aimed to determine if there are clinical and kinematic differences in youth pitchers with a self-reported history of throwing arm pain or injury (PI) to those without (NPI). Forty male baseball pitchers ages 9 to 14 years old were divided into a PI group (n=20) and a NPI group (n=20). Injury history, pitching exposure, subject demographics, range of motion, and strength measurements were collected, along with throwing arm kinematics via a motion capture system. When comparing PI and NPI, significant physical differences were observed, with a greater presence of axillary hair, increased forearm length and decreased shoulder internal rotation strength in PI. No significant differences of upper limb motion during pitching were reported. When considering youth pitchers, evidence of physical maturity, arm length, and strength could be important factors in developing pain or injury
HEAD ACCELERATION EVENTS USING INSTRUMENTED MOUTHGUARDS IN FEMALE RINGETTE PLAYERS
Get PDFRingette is a contact sport which prompts high rates of head contacts and concussion, some of the highest reported rates in youth sport. Biomechanical forces at the head can cause concussion injury, therefore examination of head acceleration events and head biomechanics during ringette is useful to understand injury risk and mechanism. The purpose of this study was to describe head acceleration events (HAEs) in female youth ringette players and examine head biomechanics during video-verified head acceleration events. Instrumented mouthguards were worn by 8 players and 36 video-verified HAEs were accumulated from in-game exposure. Results indicate athletes sustain HAEs from both direct and indirect head contacts. Mann Whitney U tests reveal no significant differences in biomechanics between direct and indirect HAEs. Most direct head impacts were related to mechanism of head-head contacts or head contact with the boards and typically involved impact high on the head. Indirect HAEs were usually due to whiplash or stabilization. Data also show most HAEs result from deliberate physical contacts initiated by non-ring carriers. Future work with greater data accumulation and verification of head acceleration events can inform coaches and players on the risks of head injury associated with specific mechanisms