Insights into proprioceptive acuity assessed with a dynamic joint position reproduction task

This study investigated proprioceptive acuity using the conventional joint position reproduction (JPR) task and a modified version, the Dynamic JPR task (D-JPR), during Concentric and Eccentric muscle contractions. Seventeen participants were recruited and received a tactile stimulus indicating the position cue at Initial (INI), Intermediate (INT), and Final (FIN) phases of movements, during either the concentric or eccentric phases. After the movement, they replicated the position where they received the stimulus. Angular error (AE) and movement velocity were analysed. AE was higher in the D-JPR than in JPR Task, and in Concentric than Eccentric contractions. Within the D-JPR Task, during Concentric contractions, AE was lower at FIN phase compared to INI and INT phases, and at INT phase compared to INI phase, whereas in Eccentric contraction AE was lower in FIN compared to INI phase. Significant correlations between movement velocity at the time of stimulus delivery and AE were found in both types of contractions. Proprioceptive acuity was affected by task type, muscle contraction, movement phase, and movement velocity, highlighting the need to consider these factors for accurate and ecological assessments of proprioception.