title: Early phase interference between low-intensity running and power training in moderately trained females.
abstract: OBJECTIVE
  The aim of the study was to investigate the effects of low-intensity running performed immediately after lower-body power-training sessions on power development.
  
  
  METHODS
  Twenty young females participated in 6 weeks, 3/week, of either lower body power training (PT) or lower body power training followed by 30 min of low-intensity running (PET) eliciting 60-70 % of maximal heart rate. The following were measured before and after the training period: counter-movement jump, isometric leg press force and rate of force development (RFD), half squat 1-RM, vastus lateralis fiber type composition and cross sectional area, resting intramuscular fiber conduction velocity (MFCV), and heart rate during the modified Bruce treadmill test.
  
  
  RESULTS
  Counter-movement jump height and peak power increased after PT (10.7 ± 6.2 and 12.9 ± 18.7 %, p < 0.05) but not after PET (3.4 ± 7.6 and 5.11 ± 10.94 %, p > 0.05). Maximum isometric force, RFD, and half squat 1-RM increased similarly in both groups. Muscle fiber type composition was not altered in either group. Muscle fiber cross sectional area increased only after PT (17.5 ± 17.4, 14.5 ± 10.4, 20.36 ± 11.3 %, in type I, IIA, and IIX fibers, respectively, p < 0.05). Likewise, mean MFCV increased with PT only (before: 4.53 ± 0.38 m s(-1), after: 5.09 ± 0.39 m s(-1), p = 0.027). Submaximal heart rate during the Bruce treadmill test remained unchanged after PT but decreased after PET.
  
  
  CONCLUSIONS
  These results suggest that low-intensity running performed after lower-body power training impairs the exercise-induced adaptation in stretch-shortening cycle jumping performance (vertical jump height, peak power), during the first 6 weeks of training, which may be partially linked to inhibited muscle fiber hypertrophy and muscle fiber conduction velocity.
authors.affiliation: Athletics Laboratory, School of Physical Education and Sport Science, University of Athens, Ethnikis Antistassis 41, 172 37, Daphne, Athens, Greece. gterzis@phed.uoa.gr.
authors.forename: Gerasimos
authors.initials: G
authors.lastname: Terzis
authors.affiliation: Division of Public Health, Psychiatry and Neurology, 1st Department of Neurology, Aiginition Hospital, Medical School, University of Athens, Athens, Greece.
authors.forename: Kostas
authors.initials: K
authors.lastname: Spengos
authors.affiliation: Athletics Laboratory, School of Physical Education and Sport Science, University of Athens, Ethnikis Antistassis 41, 172 37, Daphne, Athens, Greece.
authors.forename: Spyros
authors.initials: S
authors.lastname: Methenitis
authors.affiliation: Muscle Physiology and Biomechanics Research Unit, Institute of Sports Science and Clinical Biomechanics, University of Southern Denmark, Odense, Denmark.
authors.forename: Per
authors.initials: P
authors.lastname: Aagaard
authors.affiliation: Division of Public Health, Psychiatry and Neurology, 1st Department of Neurology, Aiginition Hospital, Medical School, University of Athens, Athens, Greece.
authors.forename: Nikos
authors.initials: N
authors.lastname: Karandreas
authors.affiliation: Athletics Laboratory, School of Physical Education and Sport Science, University of Athens, Ethnikis Antistassis 41, 172 37, Daphne, Athens, Greece.
authors.forename: Gregory
authors.initials: G
authors.lastname: Bogdanis
mesh_terms: D000222:Adaptation, Physiological / Q000502:physiology; D000328:Adult; D015444:Exercise / Q000502:physiology*; D005080:Exercise Test / Q000379:methods; D005260:Female; D006339:Heart Rate / Q000502:physiology; D006801:Humans; D018485:Muscle Fibers, Skeletal / Q000502:physiology; D010807:Physical Endurance / Q000502:physiology*; D052097:Quadriceps Muscle / Q000502:physiology; D055070:Resistance Training / Q000379:methods; D012420:Running / Q000502:physiology*; D055815:Young Adult
keywords: Concurrent training; Muscle hypertrophy; Neural adaptations; Power training