T. J. Hullfish

Markerless motion capture estimates of lower extremity kinematics and kinetics are comparable to marker-based across 8 movements

This study compares markerless and marker-based motion capture for 8 movements, finding high agreement in ankle and knee metrics but more discrepancies in hip measurements.

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

This study evaluates how errors in segment mass and shear ground reaction force affect joint load estimates during daily activities using musculoskeletal models.

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

This study evaluates a markerless motion capture approach for quantifying sagittal plane kinematics during vertical jumps, finding strong agreement with gold standard motion capture.

Passive Novel Isodamping Dynamometer for Mobile Measurement of Plantar Flexor Function

This paper introduces a portable isodamping dynamometer for measuring plantar flexor function, showing strong correlation with commercial devices and significant size, weight, and cost advantages.

Instrumented immobilizing boot quantifies reduced Achilles tendon loading during gait

This study develops an instrumented immobilizing boot to quantify Achilles tendon loading during gait and finds that plantar flexion reduces loading by 60%.

Novel instrumented insole algorithm accurately approximates plantar flexor loading

This study develops and validates an algorithm using an instrumented insole to accurately measure plantar flexor loading during various functional activities.

Ultrasound Echogenicity is Associated with Achilles Tendon Fatigue Damage in a Cadaveric Loading Model

This study shows that changes in ultrasound echogenicity correlate with Achilles tendon fatigue damage in cadaveric models, suggesting it as a potential predictor of tendon failure.

Designing and validating a staircase to leverage floor mounted force plates

The paper designs and validates a modular staircase system for measuring ground reaction forces during stair navigation, improving calibration accuracy and providing implementation resources.

Muscle structure governs joint function: linking natural variation in medial gastrocnemius structure with isokinetic plantar flexor function

The paper links medial gastrocnemius muscle structure with isokinetic plantarflexor function, finding fascicle length correlates with peak torque and total work.

Gastrocnemius muscle remodeling explains functional deficits three months following Achilles tendon rupture

This study shows that muscle-tendon structural changes after Achilles tendon rupture correlate with functional deficits, emphasizing the need to preserve muscle structure for recovery.

Gastrocnemius fascicles are shorter and more pennate throughout the first month following acute Achilles tendon rupture

This study examines changes in medial gastrocnemius muscle structure after Achilles tendon rupture, finding shorter fascicles and altered echo intensity that partially recover by 4 weeks.

Tendon Structure Quantified using Ultrasound Imaging Differs Based on Location and Training Type

This study uses quantitative ultrasound imaging to show that Achilles and patellar tendons respond differently to training loads, with patellar tendon structure changing during seasonal transitions.

Measuring Clinically Relevant Knee Motions With A Self-Calibrated Wearable Sensor

This study validates a low-cost wearable sensor for measuring knee motion during clinical exercises, showing accuracy within 5 degrees for some tasks but larger errors in others.

Achilles tendon structure in distance runners does not change following a competitive season

This study examines Achilles tendon structure in distance runners over a competitive season and finds no significant changes in organization or echogenicity, but a small increase in thickness.

The Impact Of Thigh And Shank Marker Quantity On Lower Extremity Kinematics Using A Constrained Model

This study evaluates how marker quantity and placement affect kinematic accuracy in constrained-kinematic models during lower extremity motion.