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Control of Pausing in Rich-Lean Transitions by Spatially Localized and Spatially Diffuse Stimuli
Get PDFSignaled transitions from rich (favorable) to lean (less favorable) schedules of reinforcement (i.e., rich-lean transitions) can disrupt operant behavior. Previous literature suggests that disruptions in these transitions could occur because individuals engage in other behavior that reduces contact with the schedule-correlated stimuli. My thesis project evaluated this possibility by using different stimuli to manipulate the ease by which rats could reduce contact with schedule-correlated stimuli during signaled rich-lean transitions. We arranged a two-component multiple fixed ratio-fixed ratio (FR-FR) schedule to evaluate effects of different types of schedule-correlated stimuli on pausing in rich-lean transitions using rat subjects. Components had equivalent FR requirements and were each signaled by unique schedule-correlated stimuli. In one component, rich, satisfying the FR requirement produced 3 food pellets. In the other component, lean, satisfying the FR requirement produced 1 food pellet. Each session consisted of 41 components arranged to produce 10 transitions of four types (rich-lean, rich-rich, lean-lean, lean-rich). Across conditions, we manipulated the type of stimuli that signaled the components. In one condition, Localized, the components were signaled by inserting one of two levers (e.g., right = rich, left = lean). In the other condition, Diffuse, the components operated on the same lever and were signaled by different tones (e.g., 500 Hz = rich, 1500 Hz = lean). Results obtained suggest that reducing contact with schedule-correlated stimuli could play a role in maintaining disruptions normally observed during rich-lean transitions
DETERMINING RELATIONSHIPS BETWEEN KINEMATIC SEQUENCING AND BASEBALL PITCH VELOCITY USING MARKERLESS MOTION CAPTURE
Get PDFThe purpose of this study was to determine how the timings and magnitudes of peak pelvis rotational velocity, peak trunk rotational velocity, peak elbow extension velocity, and peak shoulder internal rotation velocity affect pitch velocity. Eighty pitchers (187.2 ± 8.2cm, 89.3 ± 13.0kg, 20.1 ± 3.3yrs) had a minimum of 3 fastballs recorded and video was processed using pitchAITM. Average pitch velocity was 38.1 ± 2.5 m/s. A multilinear regression generated a significant prediction for pitch velocity (R2 = 0.368 and p \u3c 0.01). Pitcher weight (β = 0.535, p \u3c 0.001), peak pelvis rotational velocity timing (β = -0.157, p = 0.001), peak elbow extension timing (β = 0.122, p = 0.006), and peak shoulder internal rotation timing (β = -0.113, p = 0.018), were significant contributors to the multilinear model. In conclusion, player weight and their kinematic sequence metrics from pitchAITM can be significant predictors of pitch velocity
COMPARISON OF KINEMATICS AND EMG IN THE LAST REPETITION DURING DIFFERENT MAXIMUM REPETITION SETS IN THE BILATERAL BACK SQUAT
Get PDFThis study compared kinematics and electromyography (EMG) in the lower extremities during different phases of the last repetition, when performing the squat of different repetition maximums. Thirteen strength trained men performed a 1-, 3-, 6-, and 10-RM squat, in a randomized order. The main findings were that kinematics was very similar, except for a smaller inclination of the trunk at V0 in the 1-RM compared to other repetitions, and at Vmax1 compared to 10-RM. Furthermore the 1-RM revealed significantly higher EMG amplitude in the vastus lateralis in the sticking- and post-sticking region when compared to 10-RM. It was concluded a 10-RM may fatigue the vastus lateralis, explaining the lower EMG amplitude, accompanied with a greater inclination of the trunk, which is possibly a compensatory strategy of the body to reduce knee-extensor torque
EFFECTS OF MOVEMENT SONIFICATION AUDITORY FEEDBACK ON REPETITIONS AND BRAIN ACTIVITY DURING THE BENCH PRESS
Get PDFThe purpose of this study was to investigate the effects of movement sonification auditory feedback on repetitions and brain activity during bench press. Twenty participants performed bench press until failure in three different sound conditions: no-sound, self-selected music, and movement sonification. Repetition maximum was measured to assess bench press performance. Beta wave representing arousal level and frontal alpha asymmetry indicating motivation level and type were also measured. Results showed that frontal alpha asymmetry in movement sonification was significantly higher than that in music and no-sound, but no statistically significant differences were observed in repetition maximum and beta wave among the three conditions. In conclusion, this study concluded movement sonification auditory feedback can be used to motivate individuals rather than listening to music during bench press
“TEARING UP THE TURF”: HOW NATURAL GRASS RESPONDS TO REPEATED TRACTIONAL TRIALS FOR SOCCER BOOT ANALYSIS
Get PDFThe shoe-surface interaction carries both performance and health-based implications for soccer players. As soccer is often played on natural grass surfaces, previous mechanical tests observing shoe-surface traction have examined the interaction on natural grass and reported averaged traction coefficient values. The aim for this study was to explore spatial changes within the playing surface, as well as examine if degradation over the testing period can alter these values. Through translational testing on a custom apparatus, this study showed that the average maximum traction coefficient on the same location of the playing surface was significantly lower than results reported at different locations (2.66 vs 3.05). The influence of the initial trial, however, was highlighted. Isolating and reporting this trial, as well the average result that excluded the first trial, presented traction data that accurately reflected the maximum traction of the playing surface as well as tractional changes over the entire trial
Shading the Future: A GIS-Based Approach to Optimal Tree Planting for Urban Heat Mitigation at Northern Michigan University
Get PDFIncreasing tree canopy cover is a powerful tool for mitigating the effects of urban heat on the natural and built environment, specifically the effects of ecosystem stress and air quality. Heat can also place stress on human health. Northern Michigan University (NMU) is proposing to build a new tree nursery on campus, which would help alleviate urban heat in Marquette. Finding suitable areas at NMU to plant new trees from this nursery is an essential component of this effort. A goal of my project was to provide this helpful information. Using GIS and remote sensing techniques in ArcGIS Pro and ERDAS Imagine, I mapped existing tree canopy cover, soils, and elevation on NMU’s campus. I also analyzed satellite imagery to determine Land Surface Temperature (LST) values. The maps demonstrated that the area around the Jacobetti Complex is the warmest and has the lowest percentage of canopy cover. The soils of this area of campus are well-drained and the terrain is moderate. When NMU Facilities is ready to plant more trees, they should consider the area surrounding the Jacobetti Complex to offset the urban heat effect of the building
ESTIMATION OF GROUND REACTION FORCES FROM MARKERLESS KINEMATICS AND COMPARISON AGAINST MEASURED FORCE PLATE DATA
Get PDFThis study investigated how accurately ground reaction forces (GRFs) can be estimated from body centre of mass (BCOM) motion derived using markerless motion capture. Fifteen participants performed a countermovement jump (CMJ) on, and a running trial across, force plates. Kinematics captured using markerless and marker-based systems were used to drive IK-constrained OpenSim models. The resulting BCOM displacements were double differentiated to inversely estimate GRFs and compared to force plate data. Markerless-derived estimates were similar to measured GRFs (RMSD = ~70-150 N) and vertical peak force, impulse and rate of force development were also accurately estimated (effect sizes \u3c 0.2), similarly to marker-based outputs. Our markerless workflow shows promise for the estimation of vertical GRF parameters out in the field, without markers or force plates
DEVELOPING METHODS TO ASSESS THE RELATIONSHIP BETWEEN ERGOMETER AND ON-WATER ROWING PERFORMANCE FROM INDEPENDENT DATASETS
Get PDFRowing ergometers are often used by internationally competitive athletes alongside on-water rowing. This study proposes methods to develop a generalisable relationship between maximal effort 2000 m ergometer and on-water rowing performance using independent datasets. Ergometer times for 2000 m tests (n = 153) and 2000 m on-water times from international races (n = 139) were collated. Percentiles from the raw data and fitted probability density functions were mapped to develop a generalisable performance relationship. Bootstrapping was utilised to estimate the uncertainty in the percentile mappings. When built on a larger sample of athletes, this approach could be useful to identify athletes who under or overperform on water compared to ergometers, and this could provide valuable context for future biomechanical investigations of rowing technique
Ground Reaction Forces of Dart-Throwing at Different Target Heights
Get PDFThe purpose of the study was to explore whether dart players produce different lower limb control strategies when throwing darts at spatially separated targets in the vertical direction. Eight experienced darts players (height 1.75±0.04 m, mass 83.4±19.3 kg) participated in this research. Two Multi-Axis Force Plates were used to collect GRF data on both legs and synchronized with a Motion Capture System. The participants threw darts at three targets at different heights, which were the upper section of the 20 point area, bullseye and lower section of the 3 point area. The results showed that the amplitude of anterior-posterior GRF of their front legs were significantly different when darts was thrown at the 20 zone, bullseye and 3 zone respectively. Our study found that the braking forces of the front legs were greater when a dart was being thrown at the highest target (20 points) than when it was being thrown at the lowest target (3 points)
VARIATION IN RECENT CITATION METRICS FOR BIOMECHANICS JOURNALS
Get PDFThis study documented recent citation metrics in 14 biomechanics journals from 2017 until 2021. Five recent metrics were extracted to report 2021 values, absolute and relative variability and slope over the five years. Mean usage were typical based on normalized metrics (0.6 to 1.1 for SJR3 & SNIP3) and IF5 and CS4 (2.7 & 3.5). Year-to-year absolute and relative variability were 0.11 - 0.48 and 12% - 21%, respectively. There was considerable variation of journal metrics in biomechanics journals supporting previous research journal metrics should not be reported to greater than one decimal place precision and meaningful differences across time need to be at least 0.3-0.5 or 30 percent