title: Energy requirements of tire pulling.
abstract: BACKGROUND
  We have investigated the effect using walking poles and pulling tires at 4 and 6 km·h-1 (1.11 and 1.67 m·s-1) speeds on oxygen uptake (V̇O2) and heart rate.
  
  
  METHODS
  Eleven subjects, 6 males, with a mean (SD) age of 25.2 (6.9) years participated in field tests involving walking without poles, walking with poles and tire pulling with poles.
  
  
  RESULTS
  Increasing the load caused the largest increases in energy demand, more than 4 MET. Speed increase also caused substantial energy increase, approximately 4 MET. Increasing the inclination only modestly increased the oxygen uptake, approximately 2 MET. In both level walking and uphill walking, using poles marginally increased oxygen uptake compared to working without poles. Pulling one tire (12.5 kg) required an oxygen uptake of 27 (4) mL·kg-1·min-1 at 4 km·h-1 and 0% inclination. Adding one more tire (6 kg) drove the oxygen uptake further up to 39 (4) mL·kg-1·min-1. This is close to the requirement of level running at 10.5 km·h-1. Pulling both tires at 6 km·h-1 and 5% inclination required a V̇O2 of 54 (6) mL·kg-1·min-1, equal to running uphill at 5% inclination and 12.5 km·h-1 speed. Heart rate rose comparably with oxygen uptake. At 4 km·h-1 and 0% inclination the increase was 29 bpm, from 134 (21) to 163 (22) bpm when going from pulling one tire to two tires. In the hardest exercise, 6 km·h-1 and 5% inclination, heart rate reached 174 (14) bpm.
  
  
  CONCLUSIONS
  The study showed that tire pulling even at slow speeds has an energy requirement that is so large that the activity may be feasible as endurance training.
authors.affiliation: Kristiania University College, Institute of Health Sciences, Oslo, Norway.
authors.forename: Per M
authors.initials: PM
authors.lastname: Fredriksen
authors.affiliation: Kristiania University College, Institute of Health Sciences, Oslo, Norway - asgeir.mamen@kristiania.no.
authors.forename: Asgeir
authors.initials: A
authors.lastname: Mamen
mesh_terms: D000328:Adult; D004734:Energy Metabolism / Q000502:physiology*; D005260:Female; D006339:Heart Rate / Q000502:physiology*; D006801:Humans; D008297:Male; D010101:Oxygen Consumption / Q000502:physiology*; D010807:Physical Endurance / Q000502:physiology; D055070:Resistance Training / Q000379:methods*; D016138:Walking / Q000502:physiology*; D055815:Young Adult