Physiotherapists in Sheffield treat many different conditions including the issues profiled below.

The Sacro-Iliac Joint

The sacro-iliac joints are a pair of large irregular joints at the base of the spine which connect the sacrum, the triangular bone below the lumbar vertebrae, with the ilium, the large wings of the pelvis. It is a synovial joint like the fingers or knees but has very limited movement and functions to transfer the weight of the upper body from the spine to the hips. The sacro-iliac joint has very strong ligaments which travel the very short distances between the two highly irregular joint surfaces. There are no muscles which can act to produce real movements of the joint as other joints move and it functions as the weight transmitting and stress relieving pelvic joint.

The sacro-iliac joints are designed to absorb the torsional stresses which occur in the pelvis during gait and do have small degree of movement to help them manage this function. The irregular joint surfaces with its depressions and prominences allow the sacrum to lock between the iliac bones so that it cannot be driven downwards by the weight of the body. The irregular joint surfaces also prevent the sacrum being rotated inappropriately, with its strong ligaments being responsible for absorbing pelvis stresses during walking.

Losing and Gaining Muscle

Muscle is a dynamic tissue, changing greatly to accommodate to changing requirements. If a person.s leg is immobilised the thickness of the quadriceps muscle decreases by 15-20% in six weeks as the Type 1 muscle fibres reduce their protein production. This is the reason why immobilisation of a fracture or sprain is kept to an absolute minimum as losses of muscle and bone tissue are important, with joint stiffness another potential damaging side effect. Muscle will also respond quickly and strongly to increases in loading, with a maximum weight to be lifted increasing by 100% over a 12 month training period.

Much of the increased strength of muscle is due to hypertrophy of the muscle fibres, although other factors contributing are muscle endurance and learned coordination of the movement. A 30% increase of muscle mass can occur in four days after a muscle is overloaded in a stretched position, indicating the speed by which this part of the musculoskeletal system can adapt to new conditions. Exactly what makes muscles increase in strength is under discussion, but unexpectedly high activity, particularly in eccentric contractions, can cause the exercise induced damage which leads to repair and hypertrophy.