Of 102 potential participants, 35 agreed
to participate in the study, 9 required
further time to consider, and 58 declined
participation in the study. Reasons for
not participating included time constraints,
difficulty7 traveling to the testing
center, lack of interest in participating,
mobility limitations because of pain or
injury, and current or previous participation
in other research studies. Ultimately,
24 people participated in the study. Participant
characteristics are shown in
Table 1. Data from 20 participants were
included in the final analysis. Reasons for
exclusion (n=4) w ere that data from 2
participants’ activPAL activity monitors
w ere not recorded because of a technical
fault w hen data were downloaded from
the activity monitors, 1 participant failed
to complete all 7 ADLs, and full video
recording data were not available for 1
participant.
Step Counts
The regression analysis (Fig. 1) showed
P
hysical activity is recognized globally
as a key factor in health, with
guidelines recommending the
amount and intensity of activity required
for adults who are healthy.1 At present,
most people with rheumatoid arthritis
(RA) do not meet these recommendations
for achieving improved health outcomes.2-4
Sedentary behavior is also a
key factor in health and is an independent
risk factor for cardiovascular disease
and mortality.5 Given that people
with RA have a higher risk of cardiovascular
disease than the general adult population,6
investigating both sedentary
and physical activity behavior patterns is
important for establishing how these
behavior patterns may contribute to the
overall health of this population.
One such accelerometer, the activ PAL
(PAL Technologies Ltd, Glasgow, United
Kingdom) activity monitor, classifies an
individual's free-living activity' into periods
spent in sedentary, standing, and
walking behaviors through the use of
proprietary algorithms. The activ PAL
activity monitor has been found to be a
reliable and valid measure of sedentary
and physical activity behaviors and transition
and step counts in other populations,
including adults who are healthy
and adults who are overweight and inactive.9-11
The activPAL also has been
shown to be valid in another population
with chronic musculoskeletal pain: people
with chronic low back pain.12 However,
the activVAL may not be sensitive
enough to detect changes in gait in people
with RA because of the functional
problems often experienced by this population
as a result of symptoms such as
pain and fatigue.13
To date, the activPAL