The influence of full-thickness supraspinatus tears on abduction moments: the importance of the central tendon.

Background: Detachment of the central tendon of the supraspinatus from its insertion is considered to be crucial to functional deficit. The aim of the present study was to assess the function of the supraspinatus in terms of abduction moments by introducing different tear configurations to assess the functional effect of the central tendon insertion.

Methods: Ten fresh frozen shoulders from five cadavers were prepared for testing.

Scapula kinematics of pull-up techniques: Avoiding impingement risk with training changes.

Objectives: Overhead athletic activities and scapula dyskinesia are linked with shoulder pathology; pull-ups are a common training method for some overhead sports. Different pull-up techniques exist: anecdotally some are easier to perform, and others linked to greater incidences of pathology. This study aims to quantify scapular kinematics and external forces for three pull-up techniques, thus discussing potential injury implications.

A Patient-Specific Foot Model for the Estimate of Ankle Joint Forces in Patients with Juvenile Idiopathic Arthritis.

Juvenile idiopathic arthritis (JIA) is the leading cause of childhood disability from a musculoskeletal disorder. It generally affects large joints such as the knee and the ankle, often causing structural damage. Different factors contribute to the damage onset, including altered joint loading and other mechanical factors, associated with pain and inflammation.

Shoulder muscle forces during driving: Sudden steering can load the rotator cuff beyond its repair limit.

Background: Driving is one of the most common everyday tasks and the rotator cuff muscles are the primary shoulder stabilisers. Muscle forces during driving are not currently known, yet knowledge of these would influence important clinical advice such as return to activities after surgery. The aim of this study is to quantify shoulder and rotator cuff muscle forces during driving in different postures.

Scaling and kinematics optimisation of the scapula and thorax in upper limb musculoskeletal models.

Accurate representation of individual scapula kinematics and subject geometries is vital in musculoskeletal models applied to upper limb pathology and performance. In applying individual kinematics to a model's cadaveric geometry, model constraints are commonly prescriptive. These rely on thorax scaling to effectively define the scapula's path but do not consider the area underneath the scapula in scaling, and assume a fixed conoid ligament length.

The influence of extreme speeds on scapula kinematics and the importance of controlling the plane of elevation.

Background: The effect of high-speed movement on scapula kinematics is not clear from the literature. Understanding these effects is important for clinicians examining, managing and understanding scapula kinematic pathologies: impingement, glenohumeral instability, muscle patterning instability and athletic injuries. The scapula tracking methodology and the lack of quantified control of the movement's plane of elevation limits previous studies.

Musculoskeletal shoulder models: a technical review and proposals for research foci.

Musculoskeletal shoulder models allow non-invasive prediction of parameters that cannot be measured, particularly the loading applied to morphological structures and neurological control. This insight improves treatment and avoidance of pathology and performance evaluation and optimisation. A lack of appropriate validation and knowledge of model parameters' accuracy may cause reduced clinical success for these models.

Skin-fixed scapula trackers: a comparison of two dynamic methods across a range of calibration positions.

The aim of this study was to establish the optimal methodology for skin-fixed measurement of the scapula during dynamic movement. This was achieved by comparing an optimally positioned Scapula Tracker device (ST) to a previously described palpation device, taken as the true measure of scapular kinematics. These measurements were compared across a range of calibration positions, including the use of multiple calibration positions for a single movement, in order to establish an optimal calibration approach.