19 Questions
What is the flexion relaxation phenomenon?
It is a sudden cessation of muscular activity in the back extensors during trunk flexion.
What is the Flexion Relaxation Phenomenon?
A sudden cessation of muscular activity during trunk flexion
What is the difference in muscle activity between active erect and slouched sitting postures?
Muscle activity in the active erect sitting posture is greater than in both relaxed erect and slouched sitting.
Which sitting posture requires less muscle activity due to flexion relaxation?
Slouched sitting posture
What is the position of the LoG in relaxed erect sitting compared to active erect sitting?
The LoG is only slightly anterior to its position in active erect sitting.
What happens to interdiscal pressure and disc degeneration with sustained slumped postures?
They increase
What is the position of the LoG in the slouched posture?
The LoG is posterior to the spine and hips.
Which posture requires a greater number of trunk muscles and increased level of activity in some muscles?
Active erect sitting posture
What is the effect of sustained slumped postures on interdiscal pressure?
Sustained slumped postures increase interdiscal pressure
Which muscles show greater activity in erect sitting than in slumped sitting?
Superficial lumbar multifidus, thoracic erector spinae, and internal oblique abdominal muscles
What happens to the Load on Passive tissues in relaxed erect and slumped postures?
It remains the same
Which muscles experience flexion relaxation in slumped and relaxed erect sitting, but not in active erect sitting?
The thoracic erector spinae muscles.
What is the difference in LoG between active erect sitting posture and slumped posture?
LoG is more anterior in slumped posture than in active or relaxed erect sitting postures
How does muscle activity in the lumbar erector spinae compare between slumped and relaxed erect sitting?
Muscle activity is the same in both sitting postures.
What is the role of passive tissues in the relaxed erect and slouched postures?
Passive tissues are able to assume the load in both the relaxed erect and slouched postures.
What was the method used by O'Sullivan and associates to monitor muscle activity in different sitting postures?
Electromyography (EMG
Why do the thoracic erector spinae muscles cease their activity in slumped sitting?
Due to the passive tissues assuming the load
Which posture requires a sudden increase of muscular activity during trunk flexion?
All sitting postures require a sudden increase of muscular activity during trunk flexion
Which posture requires the least amount of muscle activity?
Slouched sitting posture
Study Notes
- Flexion relaxation phenomenon explains why slumped sitting posture requires less muscle activity than active erect sitting posture.
- Flexion relaxation is a sudden cessation of muscular activity in the back extensors during trunk flexion.
- Muscle activity in the active erect sitting posture is greater than in both relaxed erect and slouched sitting.
- In relaxed erect sitting, the LoG is only slightly anterior to its position in active erect sitting.
- In the slouched posture, the LoG is posterior to the spine and hips.
- Sustained slumped postures increase interdiscal pressure and may lead to disc degeneration.
- Flexion relaxation occurred in the thoracic erector spinae muscles in 21 of 22 subjects in slumped sitting and relaxed erect sitting but not in active erect sitting.
- Muscle activity in the lumbar erector spinae remained the same in both postures.
- Passive tissues are able to assume the load in the relaxed erect and slumped postures.
- The thoracic erector spinae muscles ceased their activity in slumped sitting due to the passive tissues assuming the load.
Make Your Own Quizzes and Flashcards
Convert your notes into interactive study material.
Get started for free
