T. J. Hullfish

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.

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

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

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.

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

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

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.

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

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

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.

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.

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.

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.

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.

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