title: Repeated apnea-induced contraction of the spleen in cyclists does not enhance performance in a subsequent time-trial.
abstract: OBJECTIVE
  Splenic contraction induced by repeated apneas has been shown to increase oxygen availability. Our aim was to determine whether repeated maximal voluntary apnea enhances the performance of cyclists in a subsequent 4-km time trial.
  
  
  METHODS
  Seven male cyclists [age: 27.1 ± 2.1 years; height: 182 ± 8 cm; body mass: 74.8 ± 9.2 kg; peak oxygen uptake: 56.9 ± 6.6 mL min(-1) kg(-1) (mean ± SD)] performed a 4-km time trial on an ergometer with and without four prior maximal bouts of apnea interspersed with 2 min of recovery.
  
  
  RESULTS
  The average power output during the time trial was similar with (293 ± 48 W) and without (305 ± 42 W) prior apnea (P = 0.11, d = 0.27). The spleen was reduced in size after the fourth bout of apnea (-12.4 ± 9.0 %), as well as one (-36.6 ± 10.3 %) and 10 min (-19.5 ± 17.9 %) after the time trial, while with normal breathing the spleen was smaller one (-35.0 ± 11.3 %) and 10 min (-23.4 ± 19.7 %) after the time trial. Heart rate; oxygen uptake and carbon dioxide production; tissue oxygen saturation; and the lactate concentration, pH, oxygen saturation, level of hemoglobin and hematocrit of the blood were similar under both conditions.
  
  
  CONCLUSIONS
  Our present findings reveal that four apneas by cyclists prior to a 4-km time trial led to splenic contraction, but no change in mean power output, the level of hemoglobin, hematocrit, oxygen saturation of the m. vastus lateralis or oxygen uptake.
authors.affiliation: Integrative and Experimental Training Science, Department of Sport Science, Julius-Maximilians-Universität Würzburg, University of Würzburg, Judenbühlweg 11, 97082, Würzburg, Germany, billy.sperlich@uni-wuerzburg.de.
authors.forename: Billy
authors.initials: B
authors.lastname: Sperlich
authors.forename: Christoph
authors.initials: C
authors.lastname: Zinner
authors.forename: Roman
authors.initials: R
authors.lastname: Pfister
authors.forename: Hans-Christer
authors.initials: HC
authors.lastname: Holmberg
authors.forename: Guido
authors.initials: G
authors.lastname: Michels
mesh_terms: D000328:Adult; D056352:Athletes; D054874:Athletic Performance; D062485:Breath Holding; D015444:Exercise; D006801:Humans; D008297:Male; D009119:Muscle Contraction; D010101:Oxygen Consumption; D013154:Spleen / Q000502:physiology*