System identification of human ankle dynamics: intersubject variability and intrasubject reliability.

Area of Science:

• Biomechanics
• Human physiology
• Orthopedics

Background:

• Understanding normal human ankle mechanics is crucial for diagnosing and treating musculoskeletal disorders.
• Quantitative measures offer objective assessments of joint function.
• Assessing the reliability and variability of these measures is essential for clinical application.

Purpose of the Study:

• To evaluate the intrasubject reliability and intersubject variability of quantitative measures of normal human ankle mechanics.
• To compare the reliability and variability of quantitative measures with those used in clinical practice.

Main Methods:

• Fifteen young adults participated in the study.
• Each subject underwent two examination sessions.
• Passive and active joint dynamics, including position-stiffness and torque-stiffness relations, were characterized.
• Quantitative, objective joint property measures were taken for comparison with clinical methods.

Main Results:

• Measures of passive and active joint dynamics demonstrated high intrasubject reliability.
• The reliability of quantitative measures was generally found to be as good as or better than most clinical measures.
• Intersubject variability for quantitative measures was slightly larger than intrasubject reliability, consistent with clinical measures.

Conclusions:

• Quantitative measures of normal human ankle mechanics exhibit good to excellent intrasubject reliability.
• These objective measures provide a reliable basis for assessing ankle function.
• The findings support the use of quantitative measures in clinical settings for evaluating ankle mechanics.