SPINAL MUSCLE ACTIVITY DURING DIFFERENT RUGBY SCRUM ENGAGEMENT PROCEDURES

Biomechanical studies of rugby union scrummaging have focussed on kinetic and kinematic analyses, whilst muscle activation strategies employed by front row players during scrummaging are still unknown. The aim of this study was to investigate the activity of the sternocleidomastoid, upper trapezius and erector spinae muscles during machine and live scrums. Nine male front-row forwards scrummaged individually against a scrum machine under „crouch-touch-set? and „crouch-bind-set? conditions, and against a two-player opposition in a simulated live condition. Results suggest that the pre-bind technique, may effectively prepare the cervical spine by stiffening joints before the impact phase. Additionally, machine scrummaging does not replicate the muscular demands of live scrummaging for the erector spinae

Distal stem features improve torsional resistance of long-stem cemented revision hip stems:An in vitro biomechanical study

When proximal bone stock is compromised at revision hip arthroplasty, distal fixation is often relied upon for stability of the femoral component. In such circumstances, torsional forces can result in debonding and loosening. This study compared the torsional behaviour of a cemented, polished and featureless (plain) stem with cemented, polished stems featuring fins or flutes. The finned stem construct was found to be significantly stiffer than the fluted stem. The maximum torque of the finned and fluted stems was significantly higher than the plain stem, with no difference between the finned and fluted stems. Distal stem features may provide a more reliable and greater resistance to torque in polished, cemented revision hip stems. Finned stem features may also increase the stiffness of the construct.</jats:p