Measuring eccentric hip adductor strength during the Copenhagen adduction exercise : A proof-of-concept and test re-test reliability study

Objectives
To describe a novel method for measuring eccentric hip adductor (EHAD) strength during the Copenhagen adduction exercise (CAE) and investigate the test re-test reliability of this measure.

Design
Test re-test reliability study.

Participants
Twenty male athletes aged 24 ± 6 years participated in two data collection sessions 7 ± 2 days apart.

Main outcome measures
During each data collection session, participants performed three maximal effort repetitions of the CAE with their leg supported by an ankle strap hung from a fixed barbell. We attached a commercially available load cell in-series with the ankle strap to measure peak force in Newtons (N) during the eccentric lowering phase of the CAE. The intraclass correlation coefficient (ICC), standard error of measurement (SEM), SEM as a percentage of the mean (SEM%) and minimal detectable change at a 95% confidence interval (MDC95) were calculated for this measure of EHAD strength.

Results
Test re-test reliability was good for EHAD strength measured during the CAE on dominant (ICC = 0.84; SEM% = 3.6%; MDC95 = 33 N) and non-dominant (ICC = 0.87; SEM% = 3.3%; MDC95 = 29 N) legs.

Conclusions
This study provides proof-of-concept that EHAD strength can be measured during the CAE with good test re-test reliability.

2025 The Authors. Published by Elsevier Ltd. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).