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 positioned 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.
- Examples of affected exercises:
- Example preventative / corrective exercises:
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. Sitting on the back of the hips may indicate a posterior
pelvic tilt. 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.
- Examples of affected exercises:
- Example preventative / corrective exercises:
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 or anterior pelvic
tilt (compensates for altered line of gravity) and protracted
shoulder girdle (unrelated). Kyphosis makes it difficult to include
overhead exercises particularly when combined with a winged
scapula condition or shoulder
external rotation inflexibility.
- Examples of affected exercises:
- Corrective exercises for gravity induced kyphosis:
Forward Head Posture
An anterior positioning of the cervical
spine is characteristic of forward head posture, or protracted
neck. 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.
- Examples of affected exercises:
- Corrective exercises for gravity induced kyphosis:
Winged Scapula
Medial border or 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
or external rotation
of the shoulder may be seemingly restricted. A winged scapula
condition indicates a serratus
anterior weakness. The rhomboids
may be weak and the pectoralis
minor may be short. A winged scapula is considered normal
posture in young children, but not older children and adults.
- Examples of affected exercises:
- Example preventative / corrective exercises:
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.
- Examples of affected exercises:
- Example preventative / corrective exercises:
Those with this posture deficiency, avoid stretches that protract
the shoulder such as Rear
Delt Stretches and holding protracted
position during rowing
resistive exercises. If lying on one's side, position upper
arm under head (with or without pillow in between) since lying
on one's side with one's arm down or in front (protracting shoulder
girdle) may act as a continuous stretch throughout the night
exacerbating this condition.
Mediatorial curve of the vertebral column.
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