Send to

Choose Destination
BMC Geriatr. 2018 May 3;18(1):103. doi: 10.1186/s12877-018-0793-4.

Reliability and validity of two fitness tracker devices in the laboratory and home environment for older community-dwelling people.

Author information

School of Physiotherapy & Exercise Science, Curtin University, Perth, Australia.
School of Physiotherapy & Exercise Science, Curtin University, Perth, Australia.
Department of Psychiatry, Academic Unit for Psychiatry of Old Age, The University of Melbourne and NorthWestern Mental Health, Melbourne Health, Melbourne, Australia.
School of Psychology, Curtin University, Perth, Australia.
School of Nursing, Midwifery & Paramedicine, Curtin University, Perth, Australia.
Department of Health, Human Performance & Recreation, University of Arkansas, Fayetteville, USA.



Two-thirds of older Australians are sedentary. Fitness trackers have been popular with younger people and may encourage older adults to become more active. Older adults may have different gait patterns and as such it is important to establish whether fitness trackers are valid and reliable for this population. The aim of the study was to test the reliability and validity of two fitness trackers (Fitbit Flex and ChargeHR) by step count when worn by older adults. Reliability and validity were tested in two conditions: 1) in the laboratory using a two-minute-walk-test (2MWT) and 2) in a free-living environment.


Two 2MWTs were completed while wearing the fitness trackers. Participants were videoed during each test. Participants were then given one fitness tracker and a GENEactiv accelerometer to wear at home for 14-days.


Thirty-one participants completed two 2MWTs and 30 completed the free-living procedure. Intra Class Correlation's of the fitness trackers with direct observation of steps (criterion validity) was high (ICC:0.86,95%CI:0.76,0.93). However, both fitness trackers underestimated steps. Excellent test-retest reliability (ICC ≥ 0.75) was found between the two 2MWTs for each device, particularly the ChargeHR devices. Good strength of agreement was found for total distance and steps (fitness tracker) and moderate-to-vigorous physical activity (GENEactiv) for the free-living environment (Spearman Rho's 0.78 and 0.74 respectively).


Reliability and validity of the Flex and ChargeHR when worn by older adults is good, however both devices underestimated step count within the laboratory environment. These fitness trackers appear suitable for consumer use and promoting physical activity for older adults.


Accelerometer; Activity tracker; Ageing

[Indexed for MEDLINE]
Free PMC Article

Supplemental Content

Full text links

Icon for BioMed Central Icon for PubMed Central
Loading ...
Support Center