title: VO₂ kinetics and metabolic contributions during full and upper body extreme swimming intensity.
abstract: OBJECTIVE
  Our purpose was to characterize the oxygen uptake ([Formula: see text]) kinetics, assess the energy systems contributions and determine the energy cost when swimming front crawl at extreme intensity. Complementarily, we compared swimming full body with upper body only.
  
  
  METHODS
  Seventeen swimmers performed a 100 m maximal front crawl in two conditions: once swimming with full body and other using only the upper propulsive segments. The [Formula: see text] was continuously measured using a telemetric portable gas analyser (connected to a respiratory snorkel), and the capillary blood samples for lactate concentration analysis were collected.
  
  
  RESULTS
  A sudden increase in [Formula: see text] in the beginning of exercise, which continuously rose until the end of the bout (time: 63.82 ± 3.38 s; [Formula: see text]: 56.07 ± 5.19 ml min(-1) kg(-1); [Formula: see text] amplitude: 41.88 ± 4.74 ml min(-1) kg(-1); time constant: 12.73 ± 3.09 s), was observed. Aerobic, anaerobic lactic and alactic pathways were estimated and accounted for 43.4, 33.1 and 23.5 % of energy contribution and 1.16 ± 0.10 kJ m(-1) was the energy cost. Complementarily, the absence of lower limbs lead to a longer time to cover 100 m (71.96 ± 5.13 s), slower [Formula: see text] kinetics, lower aerobic and anaerobic (lactic and alactic) energy production and lower energy cost.
  
  
  CONCLUSIONS
  Despite the short duration of the event, the aerobic energy contribution covers about 50 % of total metabolic energy liberation, highlighting that both aerobic and anaerobic energy processes should be developed to improve the 100 m swimming performance. Lower limbs action provided an important contribution in the energy availability in working muscles being advised its full use in this short duration and very high-intensity event.
authors.affiliation: Centre of Research, Education, Innovation and Intervention in Sport, Faculty of Sport, University of Porto, Rua Dr. Plácido Costa, 91, 4200-450, Porto, Portugal, jamribeiro.fadeup@gmail.com.
authors.forename: J
authors.initials: J
authors.lastname: Ribeiro
authors.forename: P
authors.initials: P
authors.lastname: Figueiredo
authors.forename: A
authors.initials: A
authors.lastname: Sousa
authors.forename: J
authors.initials: J
authors.lastname: Monteiro
authors.forename: J
authors.initials: J
authors.lastname: Pelarigo
authors.forename: J P
authors.initials: JP
authors.lastname: Vilas-Boas
authors.forename: H M
authors.initials: HM
authors.lastname: Toussaint
authors.forename: R F
authors.initials: RF
authors.lastname: Fernandes
mesh_terms: D000293:Adolescent; D004734:Energy Metabolism / Q000502:physiology*; D006801:Humans; D007700:Kinetics; D008297:Male; D010101:Oxygen Consumption / Q000502:physiology*; D013550:Swimming / Q000502:physiology*; D055815:Young Adult