Utility of Pedometers for Assessing Physical Activity

Abstract

Valid assessment of physical activity is necessary to fully understand this important health-related behaviour for research, surveillance, intervention and evaluation purposes. This article is the second in a companion set exploring the validity of pedometer-assessed physical activity. The previous article published in Sports Medicine dealt with convergent validity (i.e. the extent to which an instrument's output is associated with that of other instruments intended to measure the same exposure of interest). The present focus is on construct validity. Construct validity is the extent to which the measurement corresponds with other measures of theoretically-related parameters. Construct validity is typically evaluated by correlational analysis, that is, the magnitude of concordance between two measures (e.g. pedometer-determined steps/day and a theoretically-related parameter such as age, anthropometric measures and fitness). A systematic literature review produced 29 articles published since > or =1980 directly relevant to construct validity of pedometers in relation to age, anthropometric measures and fitness. Reported correlations were combined and a median r-value was computed. Overall, there was a weak inverse relationship (median r = -0.21) between age and pedometer-determined physical activity. A weak inverse relationship was also apparent with both body mass index and percentage overweight (median r = -0.27 and r = -0.22, respectively). Positive relationships regarding indicators of fitness ranged from weak to moderate depending on the fitness measure utilised: 6-minute walk test (median r = 0.69), timed treadmill test (median r = 0.41) and estimated maximum oxygen uptake (median r = 0.22). Studies are warranted to assess the relationship of pedometer-determined physical activity with other important health-related outcomes including blood pressure and physiological parameters such as blood glucose and lipid profiles. The aggregated evidence of convergent validity (presented in the previous companion article) and construct validity herein provides support for considering simple and inexpensive pedometers in both research and practice.

The effects of a lifestyle physical activity counseling program with feedback of a pedometer during pulmonary rehabilitation in patients with COPD: A pilot study

“…cycling, swimming, weight-training). Nevertheless, walking is one of the most common forms of activity, and aggregate evidence provides abundant support for using pedometers to assess physical activity [57]. For future research, it would be helpful to develop step equivalents for the non-ambulatory activities, so that these activities can be taken into account.…”

Physical activity in persons with late effects of polio: A descriptive study

“…In the present study, 37% of participants had a mean value less than 5000 steps per day. Pedometers are considered less valid during slow walking which may have affected our results (30,32). In addition, pedometers may undercount the number of steps in people with neurological disabilities (31), which means that the participants' daily number of steps could have been somewhat higher.…”

“…The Yamax pedometer is considered to have good validity and reliability (30). Although no study has validated the use of a pedometer for people with late effects of polio, available evidence suggests that pedometers are valid for use in clinical and research settings in people with physical disabilities (31,32).…”

A telephone-based intervention to promote physical activity during smoking cessation: a randomized controlled proof-of-concept study

“…Steps per day was obtained by pedometers, a reliable and valid device to measure physical activity [38][39][40]. The Omron™ pedometers in this study record the last 7 days' total step counts.…”