title: The development of an estimation model for energy expenditure during water walking by acceleration and walking speed.
abstract: OBJECTIVE
  The aim of this study was to develop an estimation equation for energy expenditure during water walking based on the acceleration and walking speed.
  
  
  METHODS
  Cross-validation study.
  
  
  METHODS
  Fifty participants, males (n=29, age: 27-73) and females (n=21, age: 33-70) volunteered for this study. Based on their physical condition water walking was conducted at three self-selected walking speeds from a range of: 20, 25, 30, 35 and 40 m/min. Energy expenditure during each trial was calculated. During water walking, an accelerometer was attached to the occipital region and recorded three-dimensional accelerations at 100 Hz. A stopwatch was used for timing the participant's walking speed. The estimation model for energy expenditure included three components; (i) resting metabolic rate, (ii) internal energy expenditure for moving participants' body, and (iii) external energy expenditure due to water drag force.
  
  
  RESULTS
  When comparing the measured and estimated energy expenditure with the acceleration data being the third component of the estimation model, high correlation coefficients were found in both male (r=0.73) and female (r=0.77) groups. When walking speeds were applied to the third component of the model, higher correlation coefficients were found (r=0.82 in male and r=0.88 in female). Good agreements of the developed estimation model were found in both methods, regardless of gender.
  
  
  CONCLUSIONS
  This study developed a valid estimation model for energy expenditure during water walking by using head acceleration and walking speed.
authors.affiliation: Education Center, Chiba Institute of Technology, Japan. Electronic address: kkaneda@sea.it-chiba.ac.jp.
authors.forename: Koichi
authors.initials: K
authors.lastname: Kaneda
authors.affiliation: Graduate School of Media and Governance, Keio University, Japan.
authors.forename: Yuji
authors.initials: Y
authors.lastname: Ohgi
authors.affiliation: Division of Integrated Sciences, J. F. Oberlin University, Japan.
authors.forename: Chiaki
authors.initials: C
authors.lastname: Tanaka
authors.affiliation: Faculty of Science, Health and Education, University of the Sunshine Coast, Australia.
authors.forename: Brendan
authors.initials: B
authors.lastname: Burkett
mesh_terms: D061725:Accelerometry; D000328:Adult; D000368:Aged; D000465:Algorithms; D004734:Energy Metabolism; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D008954:Models, Biological; D013550:Swimming; D016138:Walking / Q000502:physiology*; D014867:Water
chemical_list: D014867:Water
keywords: External energy expenditure; Internal energy expenditure; Power dimension; Resting metabolic rate; Third-ordered equation