title: Does polarized training improve performance in recreational runners?
abstract: OBJECTIVE
  To quantify the impact of training-intensity distribution on 10K performance in recreational athletes.
  
  
  METHODS
  30 endurance runners were randomly assigned to a training program emphasizing low-intensity, sub-ventilatory-threshold (VT), polarized endurance-training distribution (PET) or a moderately high-intensity (between-thresholds) endurance-training program (BThET). Before the study, the subjects performed a maximal exercise test to determine VT and respiratory-compensation threshold (RCT), which allowed training to be controlled based on heart rate during each training session over the 10-wk intervention period. Subjects performed a 10-km race on the same course before and after the intervention period. Training was quantified based on the cumulative time spent in 3 intensity zones: zone 1 (low intensity, <VT), zone 2 (moderate intensity, between VT and RCT), and zone 3 (high intensity, >RCT). The contribution of total training time in each zone was controlled to have more low-intensity training in PET (±77/3/20), whereas for BThET the distribution was higher in zone 2 and lower in zone 1 (±46/35/19).
  
  
  RESULTS
  Both groups significantly improved their 10K time (39min18s ± 4min54s vs 37min19s ± 4min42s, P < .0001 for PET; 39min24s ± 3min54s vs 38min0s ± 4min24s, P < .001 for BThET). Improvements were 5.0% vs 3.6%, ~41 s difference at post-training-intervention. This difference was not significant. However, a subset analysis comparing the 12 runners who actually performed the most PET (n = 6) and BThET (n = 16) distributions showed greater improvement in PET by 1.29 standardized Cohen effect-size units (90% CI 0.31-2.27, P = .038).
  
  
  CONCLUSIONS
  Polarized training can stimulate greater training effects than between-thresholds training in recreational runners.
authors.affiliation: European University of Madrid, Madrid, Spain.
authors.forename: Iker
authors.initials: I
authors.lastname: Muñoz
authors.forename: Stephen
authors.initials: S
authors.lastname: Seiler
authors.forename: Javier
authors.initials: J
authors.lastname: Bautista
authors.forename: Javier
authors.initials: J
authors.lastname: España
authors.forename: Eneko
authors.initials: E
authors.lastname: Larumbe
authors.forename: Jonathan
authors.initials: J
authors.lastname: Esteve-Lanao
mesh_terms: D000328:Adult; D000704:Analysis of Variance; D005080:Exercise Test; D006339:Heart Rate; D006801:Humans; D010101:Oxygen Consumption; D064797:Physical Conditioning, Human / Q000379:methods*; D010807:Physical Endurance; D012123:Pulmonary Ventilation; D055070:Resistance Training; D012420:Running; D013030:Spain; D013647:Task Performance and Analysis; D013997:Time Factors