Thursday, 2 June 2011

1st

Standing Postural Muscles
The diagram to the right illustrates how the body is held erect. The thick black lines represent the principal muscles involved in standing. The vertical dotted line indicates the center of gravity. Note this line falls behind the axis of rotation of the hip and in front of the knee. This renders the ligaments of the joints tense, which are represented by dotted lines passing in front of the hip (ilio-femoral) and behind the knee (posterior ligament).



Lordosis

Pelvis is position forward and downward. Hips are slightly flexed and lumbar spine is excessively hyperextended. Hip flexors, erector spinae are short. Abdominal, hamstrings, gluteus maximus muscles may be weak. Increased risk of lower back injury during standing or lying hip extension, flexion, or stabilization activities, and weighted overhead activities. See abdominal weakness and hip flexor inflexibility.

Posterior Pelvic Tilt

Sometimes referred to as flat back, posterior pelvic tilt involves the reduction of the natural lumbar curvature. This posture is characterized by the shortening of the hip extensors (Hamstrings & Gluteus Maximus inflexibility), tight abdominals, and lax hip flexors. It is rarely brought about by lack of muscular strength. The posterior pelvic tilt is less common as the anterior tilt as seen with lordosis.

Kyphosis

Exaggerated anterior-posterior curvature of the vertebral column, most often involves an excessive forward bending in the thoracic area. Kyphosis occurs in older adults, particularly women with osteoporosis and osteoarthritis. Kyphosis is sometime accompanied with other posterior problems such as posterior pelvic tilt and protracted shoulder girdle. Kyphosis makes it difficult to include overhead exercises particularly when combined with a winged scapula condition or shoulder external rotation inflexibility.

Forward Head Posture

An anterior positioning of the cervical spine is caracteristic of forward head posture. Forward head posture may may make it more difficult to perform exercises with the bar in front of head or neck. Evaluate neck position at night since elevating head too high with additional pillows may act as a continuous neck stretch throughout the evening exacerbating the forward head posture.

Winged Scapula

Inferior angle of scapula protrude slightly from body. A winged scapula condition may be accompanied by a protracted shoulder girdle. Risk of shoulder injury is compounded with a supraspinatus weakness or an external shoulder rotation inflexibility. Because of the forward tilt of the scapula, complete flexion of the shoulder may be seemingly restricted. A winged scapula condition indicates a definite serratus anterior weakness. The rhomboids may weak and the pectoralis minor may be short.

Protracted Shoulder Girdle

The shoulders are pulled forward. Medial border of the scapula may also protrude slightly from body. Increased risk of shoulder injury during shoulder transverse flexion and transverse adduction activities, specifically when elbow travels behind shoulder. Risk of shoulder injury is compounded with a infraspinatus weakness. Possible limited range of motion during retraction of the shoulder girdle. A protracted shoulder girdle may be accompanied by a winged scapula condition or transverse adduction / flexion inflexibility. The subscapularis and Pectoralis minor and clavicular & sternal heads of the pectoralis major muscles may be short. The trapezius (middle fibers) and particularly the rhomboids may be weak if the medial borders of the scapula also protrude slightly from body.
Evaluate shoulder position during sleeping since lying on ones side with the arm down (protracted shoulder girdle) may act as a continuous stretch throughout the night exacerbating this condition.

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