V^˙O₂ kinetics and metabolic contributions during full and upper body extreme swimming intensity

Purpose: Our purpose was to characterize the oxygen uptake V^˙O₂ 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 V^˙O₂ 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 V^˙O₂ in the beginning of exercise, which continuously rose until the end of the bout (time: 63.82 ± 3.38 s; V^˙O_2peak: 56.07 ± 5.19 ml min⁻¹ kg⁻¹; V^˙O₂ 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 V^˙O₂ kinetics, lower aerobic and anaerobic (lactic and alactic) energy production and lower energy cost. Conclusion: 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.