title: Respiratory and Muscular Perceived Exertion During Official Games in Professional Soccer Players.
abstract: OBJECTIVE
  The aim of this study was to assess the respiratory and muscular session ratings of perceived exertion (PE) after official soccer matches over an extended period of time (ie, 2 competition seasons) in relation to playing time (>20, 20-45, 45-70, and >70 min) and to determine the between-matches variability of both scores in young professional soccer players.
  
  
  METHODS
  Forty players belonging to the same reserve team of a Spanish La Liga club participated in this study. Respiratory and muscular PE were collected 10 min after every game. A total of 841 individual PE ratings were undertaken on outfield players.
  
  
  RESULTS
  The differences between match respiratory and muscular load differ depending on the playing time, the respiratory PE being greater for the players that competed less than 45 min (effect size = -0.45 ± 0.45 for the 20- to 45-min group) and the muscular PE greater for players that played more than 45 min (effect size = 0.23 ± 0.30, for the 45- to 70-min group). Match-to-match PE variability was considerable (CV = 14-54%) for all levels of participation, but it was lower the longer the players participated.
  
  
  CONCLUSIONS
  Playing time influenced the relative exertion that players' respiratory and leg musculature were exposed to during a game, suggesting that differential PE scores might provide a more accurate evaluation of match-imposed internal load. However, the small-magnitude differences between respiratory and muscular session ratings of PE observed in the current study might question the practical relevance of assessing both scores.
authors.affiliation: School of Teaching, University of the Basque Country, Vitoria-Gasteiz, Spain.
authors.forename: Asier
authors.initials: A
authors.lastname: Los Arcos
authors.forename: Alberto
authors.initials: A
authors.lastname: Méndez-Villanueva
authors.forename: Javier
authors.initials: J
authors.lastname: Yanci
authors.forename: Raúl
authors.initials: R
authors.lastname: Martínez-Santos
mesh_terms: D056352:Athletes; D054874:Athletic Performance / Q000502:physiology*; D006801:Humans; D007866:Leg; D018482:Muscle, Skeletal / Q000502:physiology; D010807:Physical Endurance; D005082:Physical Exertion; D012916:Soccer / Q000502:physiology*; D013030:Spain; D013997:Time Factors