Movement Control and Long-Latency Reflexes Are Reproducible Measures of Shoulder Neuromuscular Control

Area of Science:

• Biomechanics
• Neuroscience
• Human Performance Evaluation

Background:

• Human performance evaluation relies on physiological biomarkers like transcortical long-latency reflexes (LLRs) and movement control.
• A custom visuomotor device was developed to assess performance accuracy and neurophysiological responses to perturbations.
• The study focused on the internal consistency and reproducibility of this device for shoulder tracking tasks.

Purpose of the Study:

• To evaluate the internal consistency and test-retest reliability of a novel visuomotor device for assessing shoulder performance.
• To determine the neurophysiological and performance-based biomarkers' ability to predict responses to unexpected perturbations.
• To establish the reliability of performance accuracy and transcortical LLRs during shoulder perturbation tasks.

Main Methods:

• 86 healthy adults were assessed for internal consistency across varying resistance and velocity conditions.
• Test-retest reliability was determined in 31 participants.
• Receiver operating characteristic (ROC) analysis was used to predict LLRs and performance error during perturbations.

Main Results:

• The device demonstrated excellent internal consistency (McDonald's omega > 0.9).
• Fair-to-good test-retest reliability was found for task performance accuracy and transcortical LLRs (ICCs: 0.63-0.82).
• Tracking accuracy, velocity changes, and infraspinatus LLRs predicted perturbation conditions (AUC: 0.72-0.90).

Conclusions:

• Performance-based biomarkers show moderate-to-good reliability, while neurophysiology-based biomarkers (LLRs) exhibit fair-to-good reliability for shoulder performance assessment in healthy adults.
• The developed visuomotor device is a reliable tool for evaluating human shoulder performance.
• Further research is ongoing to assess reproducibility across different joints and in patient populations with musculoskeletal or central nervous system injuries.