title: Short-term interval training at both lower and higher intensities in the severe exercise domain result in improvements in V̇O₂ on-kinetics.
abstract: Although high-intensity interval training (HIT) seems to promote greater improvements in aerobic parameters than continuous training, the influence of exercise intensity on [Formula: see text] on-kinetics remains under investigation.
  
  
  
  After an incremental test, twenty-one recreationally trained cyclists performed several time-to-exhaustion tests to determine critical power (CP), and the highest intensity (I HIGH), and the lowest exercise duration (T LOW) at which [Formula: see text] is attained during constant exercise. Subjects also completed a series of step transitions to moderate- and heavy-intensity work rates to determine pulmonary [Formula: see text] on-kinetics. Surface electromyography (EMG) of vastus lateralis muscle and blood lactate accumulation (∆BLC) was measured during heavy exercise. Subjects were assigned to one of two 4-week work-matched training groups: the lower [105 % CP: n = 11; 4 × 5 min at 105 % CP (218 ± 39 W), 1 min recovery] or the upper [I HIGH: n = 10; 8 × 100 % I HIGH (355 ± 60 W), 1:2 work:recovery ratio] intensity of the severe exercise domain.
  
  
  
  The two interventions were similarly effective in reducing the phase II [Formula: see text] time constant during moderate (105 % CP: 34 ± 13 to 25 ± 8 s; I HIGH: 31 ± 9 to 23 ± 6 s) and heavy exercise (105 % CP: 25 ± 7 to 18 ± 5 s; I HIGH: 27 ± 7 to 16 ± 5 s) and in reducing the amplitude of [Formula: see text] slow component, EMG amplitude, and ∆BLC during heavy exercise.
  
  
  
  In conclusion, the short-term adjustments in response to step transitions to moderate and heavy exercise were independent of training intensity within the severe exercise domain.
authors: Human Performance Research Group, Center for Health and Sport Science (CEFID), Santa Catarina State University (UDESC), Pascoal Simone, 358, Coqueiros, Florianópolis, SC, CEP 88080-350, Brazil. tiagoturnes89@gmail.com.
authors: Tiago
authors: T
authors: Turnes
authors: Human Performance Research Group, Center for Health and Sport Science (CEFID), Santa Catarina State University (UDESC), Pascoal Simone, 358, Coqueiros, Florianópolis, SC, CEP 88080-350, Brazil.
authors: Rafael Alves
authors: RA
authors: de Aguiar
authors: Human Performance Research Group, Center for Health and Sport Science (CEFID), Santa Catarina State University (UDESC), Pascoal Simone, 358, Coqueiros, Florianópolis, SC, CEP 88080-350, Brazil.
authors: Rogério Santos
authors: RS
authors: de Oliveira Cruz
authors: Human Performance Research Group, Center for Health and Sport Science (CEFID), Santa Catarina State University (UDESC), Pascoal Simone, 358, Coqueiros, Florianópolis, SC, CEP 88080-350, Brazil.
authors: Felipe Domingos
authors: FD
authors: Lisbôa
authors: Human Performance Research Group, Center for Health and Sport Science (CEFID), Santa Catarina State University (UDESC), Pascoal Simone, 358, Coqueiros, Florianópolis, SC, CEP 88080-350, Brazil.
authors: Kayo Leonardo
authors: KL
authors: Pereira
authors: Human Performance Research Group, Center for Health and Sport Science (CEFID), Santa Catarina State University (UDESC), Pascoal Simone, 358, Coqueiros, Florianópolis, SC, CEP 88080-350, Brazil.
authors: Fabrizio
authors: F
authors: Caputo
mesh_terms: D015308:Anaerobic Threshold / Q000502:physiology; D001642:Bicycling / Q000502:physiology; D004734:Energy Metabolism / Q000502:physiology; D017079:Exercise Tolerance / Q000502:physiology*; D005260:Female; D000072696:High-Intensity Interval Training / Q000379:methods*; D006801:Humans; D007700:Kinetics; D019344:Lactic Acid / Q000097:blood; D008297:Male; D008657:Metabolic Clearance Rate; D053580:Muscle Strength / Q000502:physiology; D018482:Muscle, Skeletal / Q000502:physiology*; D010100:Oxygen / Q000378:metabolism*; D010101:Oxygen Consumption / Q000502:physiology*; D005082:Physical Exertion / Q000502:physiology*; D013997:Time Factors; D055815:Young Adult
chemical_list: D019344:Lactic Acid; D010100:Oxygen
keywords: Cycling; Exercise intensity domains; Exercise tolerance; Lactate threshold