Related Experiment Video
Updated: Apr 11, 2026
07:30
Muscle Imbalances: Testing and Training Functional Eccentric Hamstring Strength in Athletic Populations
Published on: May 1, 2018
16.1K
Reliability and Validity of Ankle Muscle Strength Testing Using the ISOTIB Device
Sean Drew1, Sean A Horan1, Steven Duhig1
1School of Allied Health, Sport and Social Work, Griffith University, Gold Coast, Australia.
Journal of Foot and Ankle Research
|April 10, 2026
Summary
The novel ISOTIB device shows excellent reliability and validity for measuring maximal ankle strength. This free-weight tool provides a practical and accessible alternative for assessing strength, especially compared to expensive, large equipment.
Area of Science:
- Biomechanics and Exercise Physiology
- Musculoskeletal Strength Assessment
- Sports Medicine and Rehabilitation
Background:
- One repetition maximum (1RM) testing is a standard for assessing maximal muscle strength.
- Limited research exists on free-weight methods for measuring maximal ankle strength.
- A novel free-weight device, ISOTIB, was developed to address this gap.
Purpose of the Study:
- To evaluate the test-retest reliability of the ISOTIB device for ankle strength measurement.
- To determine the concurrent validity of the ISOTIB by comparing it with an isokinetic dynamometer.
- To assess the ISOTIB's effectiveness in measuring maximal strength across different ankle movements (dorsiflexion, inversion, eversion).
Main Methods:
- Fifteen healthy adults participated in two testing sessions one week apart.
- Intraclass correlation coefficients (ICC) and Bland-Altman analysis were used for reliability.
- Concurrent validity was assessed by comparing ISOTIB 1RM ankle strength with isokinetic dynamometry and surface electromyography (sEMG) during dorsiflexion, inversion, and eversion.
Main Results:
- The ISOTIB demonstrated excellent test-retest reliability for dorsiflexion (ICC=0.99), inversion (ICC=0.99), and eversion (ICC=0.97).
- High positive correlations confirmed concurrent validity between the ISOTIB and isokinetic dynamometer for dorsiflexion (r=0.90), inversion (r=0.67), and eversion (r=0.87).
- sEMG data supported concurrent validity, showing comparable muscle activity in key ankle muscles.
Conclusions:
- The ISOTIB device is a reliable and valid tool for assessing maximal ankle strength.
- It offers a practical and potentially more affordable alternative to existing strength assessment methods.
- The ISOTIB can be effectively used for measuring ankle strength in dorsiflexion, inversion, and eversion.
