STUDY DESIGN: Cross-sectional study. OBJECTIVES: To assess age-related changes and determine reference values for passive range of motion of the cervical spine in healthy women of working age. BACKGROUND: Although cervical mobility is age dependent, the amount in which aging affects passive range of motion has not been previously reported. It is clinically important to know the effect of normal aging process on cervical motion to be able to separate and evaluate the possible effect of pathological processes. METHODS AND MEASURES: Two hundred twenty healthy women, aged 20 to 59 years, participated in the study. Passive range of motion of the cervical spine in flexion, extension, lateral flexion, and axial rotation was measured with the Cervical Measurement System. Measurements to calculate intrarater reliability were obtained on 22 subjects. RESULTS: Passive range of motion of the cervical spine diminished linearly with increasing age in all measured movement planes (P<.001 for all movements except for flexion which was P = .018). Mean body mass index adjusted reduction in passive range of motion was 0.5° per 1-year increase in age. Intraclass correlation coefficients for intrarater reliability ranged from 0.79 to 0.92. CONCLUSION: A gradual age-related reduction in passive cervical range of motion was observed in women of working age.

J Orthop Sports Phys Ther 2009;39(6):478-483, Epub 17 December 2008. doi:10.2519/jospt.2009.2933

KEY WORDS: cervical motion, female, neck

Study Design: Cross-sectional descriptive study.
Objectives: To determine the maximal isometric strength of the flexor, extensor, and rotator muscles of the cervical spine in healthy females of working age to document reference values for diagnostic and rehabilitation purposes.
Background: Reference values for the isometric strength of the cervical muscles have often been based on small samples. To date, reference values for rotator muscles of the cervical spine have not been published.
Methods and Measures: The group consisted of 220 volunteer healthy females in 4 age groups (20-29 years, n = 57; 30-39 years, n = 51; 40-49 years, n = 51; 50-59 years, n = 61) from Jyväskylä, Finland. Isometric cervical muscle strength in flexion, extension, and rotation was evaluated with a specially designed measurement system.
Results: Across all age groups, mean (±SD) maximal isometric neck strength was 73.8 ± 20.0 N in flexion and 190.8 ± 31.3 N in extension. Mean (±SD) rotation strength was 8.1 ± 2.3 Nm to the right and 7.9 ± 2.3 Nm to the left. Absolute strength values did not differ among the age groups. A weak but significant correlation between body mass and neck flexion (r = 0.31, P<.01) and extension (r = 0.25, P<.01) strength was found. Intratester reliability varied from 0.87 to 0.96.
Conclusions: Women aged 20 to 59 years appear to have similar absolute isometric neck muscle strength levels. Thus these values can be used as reference for the working-age female population.

J Orthop Sports Phys Ther. 2006;36(7):495-502. doi:10.2519/jospt.2006.2122

Key Words: cervical spine, neck, muscle strength, women