title: Validity and Reliability of Smartphone Applications for the Assessment of Walking and Running in Normal-weight and Overweight/Obese Young Adults.
abstract: The suitability of smartphone applications (apps) currently used to track walking/running may differ depending on a person's weight condition. This study aimed to examine the validity and reliability of apps for both normal-weight and overweight/obese young adults.
  
  
  
  Thirty normal-weight (aged 21.7 ± 1.0 years, BMI 21.3 ± 1.9 kg/m2) and 30 overweight/ obese young adults (aged 21.0 ± 1.4 years, BMI 28.6 ± 3.7 kg/m2) wore a smartphone and pedometer on their right hip while walking/running at 3 different intensities on treadmills. Apps was randomly assigned to each individual for measuring average velocity, step count, distance, and energy expenditure (EE), and these measurements were then analyzed.
  
  
  
  The apps were not accurate in counting most of the measured variables and data fell significantly lower in the parameters than those measured with standard-reference instruments in both light and moderate intensity activity among the normal-weight group. Among the overweight and obese group, the apps were not accurate in detecting velocity, distance, or EE during either light or vigorous intensities. The percentages of mean difference were 30.1% to 48.9%.
  
  
  
  Apps may not have sufficient accuracy to monitor important physical parameters of human body movement. Apps need to be developed that can, in particular, respond differently based on a person's weight status.
authors.forename: Kurusart
authors.initials: K
authors.lastname: Konharn
authors.forename: Wichai
authors.initials: W
authors.lastname: Eungpinichpong
authors.forename: Kluaymai
authors.initials: K
authors.lastname: Promdee
authors.forename: Paramaporn
authors.initials: P
authors.lastname: Sangpara
authors.forename: Settapong
authors.initials: S
authors.lastname: Nongharnpitak
authors.forename: Waradanai
authors.initials: W
authors.lastname: Malila
authors.forename: Jirachai
authors.initials: J
authors.lastname: Karawa
mesh_terms: D015992:Body Mass Index; D005260:Female; D006801:Humans; D008297:Male; D009765:Obesity / Q000517:prevention & control*; D015203:Reproducibility of Results; D012420:Running; D000068997:Smartphone / Q000295:instrumentation*; D016138:Walking; D055815:Young Adult
keywords: measurement; motion sensors; obesity; physical activity assessment