Biology subjects

Drazan, J. F.

Publications and source records attributed to Drazan, J. F..

5 recordsLinked to original sources

bioRxiv2025

Basketball interest as gateway to STEM interest: Testing a large-scale intervention to enhance STEM interest in sports-engaged populations

BackgroundTo address documented demographic disparities in Science, Technology, Engineering, and Math (STEM) disciplines, targeted interventions have been designed to close achievement gaps and remedy the "leaky STEM pipeline". However, much less work has focused on designing complementary interventions that to seek to broaden the population of youth who "enter the pipeline" or who are exposed to STEM and interest is stoked from the onset. The current work seeks to broaden STEM engagement in youth by developing a STEM intervention using unrecognized forms of cultural capital. Rather than situating STEM learning within traditional "STEM-Intensive" programs that require a pre-existing level of STEM interest, the current work developed and tested interventions designed to broaden engagement of youth with pre-existing interest in sports. These basketball-based STEM education interventions utilized sports as a venue for informal STEM learning. The current work tested 3 variations of this novel STEM education intervention: a single hour event, a one-day clinic, and a multi-day camp. Each of these programs was delivered to naturally-occurring, targeted populations of students with high levels of pre-existing sport engagement and low levels of STEM engagement. The sample populations included students from 2nd grade to 12th grade, with middle school students being the most heavily represented. ResultsInterest in pursuing a STEM career significantly increased across all 3 variations of the basketball-based STEM education intervention. Notably, these effect sizes were descriptively larger for programs of longer duration (e.g. multi-day camp vs. one hour event) and were significantly stronger for students who reported playing basketball prior to the program. ConclusionsThe current work introduces a novel STEM education intervention that utilizes students pre-existing interest (e.g. basketball) as a bridge to STEM engagement. This approach was shown to be repeatedly successful in enhancing participants STEM career interest, especially for participants from underserved communities with high levels of sport interest.

scientific communication and education↗

bioRxiv2021

Experimental recommendations for estimating lower extremity loading based on joint and activity

Researchers often estimate joint loading using musculoskeletal models to solve the inverse dynamics problem. This approach is powerful because it can be done non-invasively, however, it relies on assumptions and physical measurements that are prone to measurement error. The purpose of this study was to determine the impact of these errors - specifically, segment mass and shear ground reaction force - have on analyzing joint loads during activities of daily living. We preformed traditional marker-based motion capture analysis on 8 healthy adults while they completed a battery of exercises on 6 degree of freedom force plates. We then scaled the mass of each segment as well as the shear component of the ground reaction force in 5% increments between 0 and 200% and iteratively performed inverse dynamics calculations, resulting in 1,681 mass-shear combinations per activity. We compared the peak joint moments of the ankle, knee, and hip at each mass-shear combination to the 100% mass and 100% shear combination to determine the percent error. We found that the ankle was most resistant to changes in both mass and shear and the knee was resistant to changes in mass while the hip was sensitive to changes in both mass and shear. These results can help guide researchers who are pursuing lower-cost or more convenient data collection setups.

bioengineering↗

bioRxiv2021

Moving outside the lab: markerless motion capture accurately quantifies sagittal plane kinematics during the vertical jump

Markerless motion capture using deep learning approaches have potential to revolutionize the field of biomechanics by allowing researchers to collect data outside of the laboratory environment, yet there remain questions regarding the accuracy and ease of use of these approaches. The purpose of this study was to apply a markerless motion capture approach to extract lower limb angles in the sagittal plane during the vertical jump and to evaluate agreement between the custom trained model and gold stand motion capture. We performed this study using a large open source data set (N=84) that included synchronized commercial video and gold standard motion capture. We split these data into a training set for model development (n=69) and test set to evaluate capture performance relative to gold standard motion capture using coefficient of multiple correlations (CMC) (n=15). We found very strong agreement between the custom trained markerless approach and marker-based motion capture within the test set across the entire movement (CMC>0.991, RMSE<3.22{degrees}), with at least strong CMC values across all trials for the hip (0.853 {+/-} 0.23), knee (0.963 {+/-} 0.471), and ankle (0.970 {+/-} 0.055). The strong agreement between markerless and marker-based motion capture provides evidence that markerless motion capture is a viable tool to extend data collection to outside of the laboratory. As biomechanical research struggles with representative sampling practices, markerless motion capture has potential to transform biomechanical research away from traditional laboratory settings into venues convenient to populations that are under sampled without sacrificing measurement fidelity.

bioengineering↗

bioRxiv2020

Passive Novel Isodamping Dynamometer for Mobile Measurement of Plantar Flexor Function

Isokinetic dynamometers are the gold standard tools used to assess in vivo joint and muscle function in human subjects, however, the large size and high cost of these devices prevents their widespread use outside of biomechanics lab. In this study, we developed a mobile dynamometer to allow for field measurements of joint level function. To ensure subject safety, we designed a new "isodamping" dynamometer that acted as passive energy sink which constrains velocity by forcing incompressible oil through an orifice with an adjustable diameter. We validated the performance of this device by testing plantar flexor function in six healthy adults on both a commercial isokinetic dynamometer and this novel device at three velocities/damper settings and at three different effort levels. During maximal effort contraction, measurements of peak moment and velocity at peak moment of the novel device and the commercial device were strongly correlated along the predicted quadratic line (R2 > 0.708, p [≤] 0.008). The setting of the damper prescribed the relationship between peak moment and velocity at peak moment across all subjects and effort levels (R2 > 0.91, p < 0.001). The novel device was significantly smaller (0.75 m2 footprint), lighter (30 kg), and lower cost (~$2,200 US) than commercial devices compared to commercially-available isokinetic dynamometers (5.95 m2 footprint, 450 kg, and ~$40,000 US respectively).

bioengineering↗

bioRxiv2019

Plantarflexor Torque and Work is Positively Correlated with Medial Gastrocnemius Fascicle Length in Healthy Young Adults

Ankle kinetics are critical for ambulatory function in elite athletes, the elderly, and many patient populations. Despite the robust findings linking plantarflexor muscle structure to gross function with these populations, the link between plantarflexor fascicle length and ankle kinetics has not been established in the literature. In this study, we determined the relationship between muscle structure and peak torque and total work produced by the plantarflexors during maximal effort contractions. We measured resting fascicle length and pennation angle of the medial gastrocnemius using ultrasound in healthy adult subjects (n=12). Subjects performed contractions on a dynamometer during isokinetic and isometric conditions. Longer fascicles were positively correlated with higher peak torque and total work (R2 > 0.41, p < 0.013) across all isokinetic velocities. Higher pennation angles were negatively correlated with peak torque and total work (R2 > 0.296, p < 0.067). None of these correlations were significant in isometric conditions. This provides experimental evidence demonstrating the link between plantarflexor muscle structure and ankle kinetics in healthy young adults which has hitherto not been experimentally demonstrated in existing literature.

bioengineering↗