Task-specific frequencies of neck motion measured in healthy young adults over a five-day period.

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 degrees 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 degrees of lateral bending, while greater range of movement requirements were observed for flexion-extension and axial rotation. Less than 6% of movements exceeded 50 degrees. 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.