BASES Webinar: 5 simple rules for more reliable and valid isokinetic dynamometry data

Bill Baltzopoulos – Professor of Biomechanics, Head of the Research Institute for Sport and Exercise Sciences (RISES), Liverpool John Moores University

On Tuesday 23^rd February BASES organised a webinar on assessment of muscular strength using the Isokinetic dynamometer. This is a piece of equipment is often used here at the University of St Mark and St John as both working with athletes, clients and for student research projects. This webinar provided further insight to how the equipment works, what is measures and how we can improve our ability to collect reliable and valid data. The webinar was hosted by Bill Baltzopoulos whose main interest includes the structure and function of the musculoskeletal system and the measurement and modelling of joint muscle and function during different activities including the isokinetic dynamometry. Prof. Bill Baltzopoulos has also contributed to The BASES Expert Statement on Measurement of Muscle Strength with Isokinetic Dynamometry. Prof. Bill Baltzopoulos provided an excellent insight to the isokinetic dynamometer and how we can improve our methods for assessing muscular strength in the future - see below for the 5 simple rules for improving muscle strength assessment with the isokinetic dynamometer.

About the Webinar

The webinar provided a discussion on appropriate techniques when using the isokinetic dynamometry for assessing strength.

Key areas included:

• Mechanical parameters used to describe human strength and joint function
• Differences between dynamometer moment, joint moment and muscle moments
• Background on how isokinetic dynamometer works and the implications
• Factors that affect reliability and validity of isokinetic dynamometry measurement
• Appropriate corrections to improve reliability and validity and ensure accurate measurements of muscle strength
• Application of isokinetic dynamometry measures – differences between strength assessments and functional assessments

Key things to take away: 5 simple rules:

The webinar highlighted key concepts and methods for ensure improved validity and reliability for future isokinetic dynamometry assessments of muscle strength and joint function. Five simple rules were proposed based on Prof. Baltzopoulos research and expertise. These rules should be considered when using the isokinetic dynamometer:

1. Axes of rotation alignment – accurate, under contraction conditions, near position of expected maximum joint moment
2. Isokinetic (constant angular velocity) phase – ensure monitoring of angular velocity to identify isokinetic data at appropriate velocities
3.  Stabilisation – reduce extraneous movement of segments
4. Positioning – control segments positioning when biarticular muscles are involved
5. Recording of test settings and subject position to improve intra-subject reliability

By Chelsea Starbuck