title: Optimal Loading for Maximizing Power During Sled-Resisted Sprinting.
abstract: OBJECTIVE
  To ascertain whether force-velocity-power relationships could be compiled from a battery of sled-resisted overground sprints and to clarify and compare the optimal loading conditions for maximizing power production for different athlete cohorts.
  
  
  METHODS
  Recreational mixed-sport athletes (n = 12) and sprinters (n = 15) performed multiple trials of maximal sprints unloaded and towing a selection of sled masses (20-120% body mass [BM]). Velocity data were collected by sports radar, and kinetics at peak velocity were quantified using friction coefficients and aerodynamic drag. Individual force-velocity and power-velocity relationships were generated using linear and quadratic relationships, respectively. Mechanical and optimal loading variables were subsequently calculated and test-retest reliability assessed.
  
  
  RESULTS
  Individual force-velocity and power-velocity relationships were accurately fitted with regression models (R2> .977, P < .001) and were reliable (ES = 0.05-0.50, ICC = .73-.97, CV = 1.0-5.4%). The normal loading that maximized peak power was 78% ± 6% and 82% ± 8% of BM, representing a resistance of 3.37 and 3.62 N/kg at 4.19 ± 0.19 and 4.90 ± 0.18 m/s (recreational athletes and sprinters, respectively). Optimal force and normal load did not clearly differentiate between cohorts, although sprinters developed greater maximal power (17.2-26.5%, ES = 0.97-2.13, P < .02) at much greater velocities (16.9%, ES = 3.73, P < .001).
  
  
  CONCLUSIONS
  Mechanical relationships can be accurately profiled using common sled-training equipment. Notably, the optimal loading conditions determined in this study (69-96% of BM, dependent on friction conditions) represent much greater resistance than current guidelines (~7-20% of BM). This method has potential value in quantifying individualized training parameters for optimized development of horizontal power.
authors.forename: Matt R
authors.initials: MR
authors.lastname: Cross
authors.forename: Matt
authors.initials: M
authors.lastname: Brughelli
authors.forename: Pierre
authors.initials: P
authors.lastname: Samozino
authors.forename: Scott R
authors.initials: SR
authors.lastname: Brown
authors.forename: Jean-Benoit
authors.initials: JB
authors.lastname: Morin
mesh_terms: D000054:Acceleration; D000328:Adult; D054874:Athletic Performance / Q000523:psychology*; D001696:Biomechanical Phenomena; D015992:Body Mass Index; D017276:Friction; D006801:Humans; D055070:Resistance Training / Q000295:instrumentation / Q000379:methods*; D012420:Running / Q000502:physiology*; D019876:Sports Equipment; D055815:Young Adult
keywords: horizontal force; mechanical profiling; sprint training