Reliability of ankle evertors, invertors and dorsiflexors one-repetition maximal (1-RM)

INTRODUCTION: After a Musculo-skeletal injury, monitoring rehabilitation could help practitioners to objectify improvement and to decide how to adapt their treatment. Muscle strength is one essential component of rehabilitation in general. One – Repetition Maximal (1-RM) is a reliable measure that helps practitioners to quantitatively assess muscle strength (Grgic et al., 2020). A large majority of muscles could be assessed with 1-RM, however we do not know if the assessment of ankle muscle strength could be assessed using 1-RM in reliable way. The aim of this study was to determine the level of Intrarater agreement of ankle 1-RM.
METHODS: Twenty-fou r healthy young adults (10 women and 14 men) volunteered to participate in this study. One – Repetition maximal of ankle evertors, invertors and dorsiflexors were measured with participants lying supine with the calf of tested ankle on a step (knee flexed approximately to 30-40°) and a complete flexion of the other leg. The measurement were performed over one week by the same assessor on the same vertical pulley. Intrarater reliability was determined using the intra-class correlation coefficient (ICC) and the measurement error was determine using the standard errors of measurement (SEM) minimal detectable change (MDC).
RESULTS: Intrarater reliability in healthy women for inversion, eversion and dorsiflexion 1-RM was good to excellent (ICC=0.69–0.95) with relatively low measurement errors (SEM=1.31 - 1.84 and MDC=3.62-5.10). Intrarater reliability in healthy men for inversion, eversion and dorsiflexion 1-RM was fair to excellent (ICC=0.54–0.84) with relatively low measurement errors (SEM=2.94 - 4.45 and MDC=8.14 – 12.3).
CONCLUSION: The assessment of ankle evertors, investors and dorsiflexors 1-RM is reliable in healthy young adults. This results has to be studied on injured adults but it is a promising method easy to use in rehabilitation after ankle injury.
Reference: Grgic, J., Lazinica, B., Schoenfeld, B. J., & Pedisic, Z. (2020). Test–Retest Reliability of the One-Repetition Maximum (1RM) Strength Assessment: a Systematic Review. Sports Medicine - Open, 6(1). https://doi.org/10.1186/s40798-020-00260-z