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Axial neck rotation strength in neutral and prerotated postures
Jari Ylinen1, Semi Nuorala, Keijo Häkkinen
1Department of Physical and Rehabilitation Medicine, Jyväskylä Central Hospital, Keskussairaalantie 19, Jyväskylä 40620, Finland. jari.ylinen@medirehab.com
Clinical Biomechanics (Bristol, Avon)
|June 28, 2003
Summary
Neck rotation strength is significantly influenced by head position. Maximal isometric strength is greatest at larger prerotation angles, not the neutral position, highlighting the need for varied measurement angles.
Area of Science:
- Biomechanics of human movement
- Musculoskeletal system function
- Exercise physiology
Background:
- Limited research exists on neck rotator muscle strength in neutral positions.
- Previous studies have not extensively examined maximal neck strength in various prerotation positions.
Purpose of the Study:
- To characterize isometric rotation strength in the neutral and different prerotated neck positions.
- To investigate the relationship between neck prerotation angles and maximal voluntary strength.
Main Methods:
- Descriptive study utilizing maximal isometric strength measurements of cervical musculature.
- Twenty healthy men performed maximal axial rotation strength tests in neutral, 30°, and 60° prerotated positions.
- Isometric maximum voluntary contractions for neck flexion and extension were also assessed.
Main Results:
- Maximal isometric neck rotation strength was not highest in the neutral position.
- Strength increased with larger joint angles, with 60° prerotation yielding 44% greater rightward and 27% greater leftward rotation strength compared to neutral.
- Lowest strength values occurred at the largest prerotation angles in the same direction of rotation.
Conclusions:
- A clear relationship exists between neck prerotation position and maximal voluntary rotational strength.
- Neck strength is highly dependent on the prerotation angle, necessitating measurements across multiple positions for accurate assessment.
- Maximal neck rotation strength differences between individuals are most apparent at the greatest prerotation angles.