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Updated: Jun 2, 2026

An Inertial Measurement Unit Based Method to Estimate Hip and Knee Joint Kinematics in Team Sport Athletes on the Field
Published on: May 26, 2020
Knee joint angular velocities and accelerations during the patellar tendon jerk.
Maria K Lebiedowska1, Siddhartha Sikdar, Avinash Eranki
1Health Effects Lab Division, Engineering and Control Technology Branch, National Institutes of Occupational Safety and Health, 1095 Willowdale Road MS 2027, Morgantown, WV 26505, USA. MLebiedowska@cdc.gov
The tendon jerk (TJ) test generates muscle accelerations exceeding those in daily activities, but velocities remain within normal ranges. This finding clarifies the physiological interpretation of the tendon jerk test in diagnosing motor disorders.
Area of Science:
- Biomechanics
- Neurophysiology
- Musculoskeletal Medicine
Background:
- Tendon jerk (TJ) testing is crucial for diagnosing human motor disorders.
- Physiological interpretation of TJ test remains ambiguous regarding patient functional status.
- The extent to which TJ-induced kinematics surpass activities of daily living (ADLs) is unclear.
Purpose of the Study:
- To quantify angular knee kinematics during TJ.
- To compare TJ-induced muscle stretch kinematics with those in ADLs.
Main Methods:
- In vivo measurement of rectus femoris muscle longitudinal kinematics using vector tissue Doppler imaging.
- Electrogoniometry to measure angular knee kinematics during tendon taps.
Main Results:
- TJ elicits muscle longitudinal elongation accelerations significantly higher than those in ADLs (104.40-4534.20 rads⁻²).
- TJ-induced angular velocities (0.82-6.21 rads⁻¹) are comparable to those encountered in ADLs.
Conclusions:
- TJ involves supra-physiological accelerations but not velocities compared to ADLs.
- Findings contribute to a clearer physiological understanding of the TJ test.
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