[Scapula dyskinesis in medium size full-thickness supraspinatus muscle tears].

Introduction: Scapular motion abnormality in rotator cuff tears is a well-known symptom, but its significance is not clear. Some authors consider it as a cause of rotator cuff tear, others as a consequence of the disease.

Objective: The aim of our study was to assess the changes in scapular motion in medium size full-thickness rotator cuff tear of degenerative origin compared to a healthy control group.

Critical delay as a measure for the difficulty of frontal plane balancing on rolling balance board.

The relation between balancing performance on rolling balance board and reaction time is investigated. Ten young healthy adults performed balancing trials on a rolling balance board with different wheel radius R and stance widths d in the frontal plane. A 2- and a 3-degree-of-freedom models subject to delayed state feedback with a single lumped reaction delay were created in order to describe hip and hip-lumbar strategies.

Rolling balance board of adjustable geometry as a tool to assess balancing skill and to estimate reaction time delay.

The relation between balancing performance and reaction time is investigated for human subjects balancing on rolling balance board of adjustable physical parameters: adjustable rolling radius and adjustable board elevation . A well-defined measure of balancing performance is whether a subject can or cannot balance on balance board with a given geometry (, ). The balancing ability is linked to the stabilizability of the underlying two-degree-of-freedom mechanical model subject to a delayed proportional-derivative feedback control.