title: Validation of GPS and accelerometer technology in swimming.
abstract: OBJECTIVE
  To evaluate the validity of an integrated accelerometer and Global Positioning System (GPS) device to quantify swimming kinematics variables in swimming.
  
  
  METHODS
  Criterion validation study.
  
  
  METHODS
  Twenty-one sub-elite swimmers completed three 100 m efforts (one butterfly, breaststroke and freestyle) in an outdoor 50 m Olympic pool. A GPS device with an integrated tri-axial accelerometer was used to obtain mid-pool velocity and stroke count of each effort. This data was compared to velocity and stroke count data obtained from concurrently recorded digital video of the performance.
  
  
  RESULTS
  A strong relationship was detected between the accelerometer stroke count and the video criterion measure for both breaststroke (r>0.98) and butterfly (r>0.99). Also, no significant differences were detected between the GPS velocity and video obtained velocity for both freestyle and breaststroke. There was a significant difference between the GPS velocity and criterion measure for butterfly. Acceptable standard error and 95% limits of agreement were obtained for freestyle (0.13 m s(-1), 0.36 m s(-1)) and breaststroke (0.12 m s(-1), 0.33 m s(-1)) compared to butterfly (0.18 m s(-1), 0.50 m s(-1)). Relative error measurements ranged between 10.2 and 13.4% across the three strokes.
  
  
  CONCLUSIONS
  The integrated accelerometer and GPS device offers a valid and accurate tool for stroke count quantification in breaststroke and butterfly as well as measuring mid-pool swimming velocity in freestyle and breaststroke. The application of GPS technology in the outdoor training environment suggests advantageous practical benefits for swimmers, coaches and sports scientists.
authors.affiliation: Centre for Exercise and Sports Science (C-ESS), School of Exercise and Nutrition Sciences, Deakin University, Australia.
authors.forename: Emma
authors.initials: E
authors.lastname: Beanland
authors.affiliation: Centre for Exercise and Sports Science (C-ESS), School of Exercise and Nutrition Sciences, Deakin University, Australia.
authors.forename: Luana C
authors.initials: LC
authors.lastname: Main
authors.affiliation: Centre for Exercise and Sports Science (C-ESS), School of Exercise and Nutrition Sciences, Deakin University, Australia.
authors.forename: Brad
authors.initials: B
authors.lastname: Aisbett
authors.affiliation: Centre for Exercise and Sports Science (C-ESS), School of Exercise and Nutrition Sciences, Deakin University, Australia.
authors.forename: Paul
authors.initials: P
authors.lastname: Gastin
authors.affiliation: Centre for Exercise and Sports Science (C-ESS), School of Exercise and Nutrition Sciences, Deakin University, Australia; School of Physiotherapy, Curtin University, Australia. Electronic address: kevin.netto@deakin.edu.au.
authors.forename: Kevin
authors.initials: K
authors.lastname: Netto
mesh_terms: D061725:Accelerometry; D000293:Adolescent; D054874:Athletic Performance / Q000502:physiology*; D001696:Biomechanical Phenomena; D002648:Child; D005260:Female; D040362:Geographic Information Systems; D006801:Humans; D008297:Male; D013550:Swimming / Q000502:physiology*; D013647:Task Performance and Analysis
keywords: Breaststroke; Butterfly; Freestyle; Stroke count; Velocity