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Task-Specific Frequencies of Neck Motion Measured in Healthy Young Adults Over a Five-Day Period

Cobian, Daniel G. BS*; Sterling, Andrew C. MS†; Anderson, Paul A. MD*‡; Heiderscheit, Bryan C. PT, PhD*‡

doi: 10.1097/BRS.0b013e3181908c7b
Cervical Spine

Study Design. Observational cohort design.

Objective. To provide initial estimates of the frequencies and magnitudes of neck motion during daily activities in healthy subjects.

Summary of Background Data. Previous studies have measured the maximum excursions during recreated activities of daily living (ADLs) in laboratory settings, but there is a lack of information available on frequencies and excursions of neck motion with ADLs in nonartificial settings.

Methods. Ten healthy young adults were fitted with a portable motion measurement device that recorded movement about each primary axis. Participants were instructed to wear the unit continuously over a 5-day period and record their daily activities with corresponding times. After the collection period, subjects’ activity logs were analyzed and data were partitioned into 5 categories, which provided the most primary representation of ADLs: athletics, work, travel, sleep, and miscellaneous. Each category was further divided into increasingly specific activities (e.g., running and walking). Frequency of motions within 5° increments was determined and an hourly rate was calculated for each activity. Median motion about each axis for each activity was also determined.

Results. The total number of movements per hour for all axes, regardless of amplitude, was highest during athletic activity and lowest during sleeping. The majority of movements (92% of athletic activity, 90% of work) required less than 25° of lateral bending, while greater range of movement requirements were observed for flexion–extension and axial rotation. Less than 6% of movements exceeded 50°. The median range of motion along all axes was highest for athletic activity and lowest for sleeping.

Conclusion. The results of this study provide preliminary observations of the frequency and magnitude of neck motion during normal ADLs for the specified population. These findings can assist physicians and physical therapists in determining the extent of disability and identifying activities that will likely be problematic for patients with limited cervical motion.

To provide initial estimates of the frequencies and magnitudes of neck motion during inartificial daily activities, 10 healthy young adults wore a portable motion measurement device for a 5-day period. Subject activity logs were used to calculate hourly rates of motion for specific activities.

From the Departments of *Orthopedics and Rehabilitation, †Mechanical Engineering, and ‡Biomedical Engineering, University of Wisconsin-Madison, Madison, WI.

Acknowledgment date: June 6, 2008. Revision date: July 31, 2008. Acceptance date: September 2, 2008.

The manuscript submitted does not contain information about medical device(s)/drug(s).

Corporate/Industry funds were received in support of this work. One or more of the author(s) has/have received or will receive benefits for personal or professional use from a commercial party related directly or indirectly to the subject of this manuscript: e.g., honoraria, gifts, consultancies.

Supported by a research grant from Medtronic.

Address correspondence and reprint requests to Bryan Heiderscheit, PT, PhD, Department of Orthopedics and Rehabilitation, University of Wisconsin-Madison, 1300 University Ave, MSC 4120, Madison, WI 53706-1532; E-mail:

© 2009 Lippincott Williams & Wilkins, Inc.