The training intensity distribution among well-trained and elite endurance athletes

Abstract

Researchers have retrospectively analyzed the training intensity distribution (TID) of nationally and internationally competitive athletes in different endurance disciplines to determine the optimal volume and intensity for maximal adaptation. The majority of studies present a "pyramidal" TID with a high proportion of high volume, low intensity training (HVLIT). Some world-class athletes appear to adopt a so-called "polarized" TID (i.e., significant % of HVLIT and high-intensity training) during certain phases of the season. However, emerging prospective randomized controlled studies have demonstrated superior responses of variables related to endurance when applying a polarized TID in well-trained and recreational individuals when compared with a TID that emphasizes HVLIT or threshold training. The aims of the present review are to: (1) summarize the main responses of retrospective and prospective studies exploring TID; (2) provide a systematic overview on TIDs during preparation, pre-competition, and competition phases in different endurance disciplines and performance levels; (3) address whether one TID has demonstrated greater efficacy than another; and (4) highlight research gaps in an effort to direct future scientific studies.

Keywords: high intensity training; high volume; low intensity; polarized training; prospective; pyramidal; retrospective; threshold training.

Figure 1

The training-intensity distribution (i.e., percentage time spent in zone 1: < first ventilatory threshold or steady-state lactate at ~2 mM; zone 2: at or near lactate threshold (~4 mM) or second ventilatory threshold; zone 3: high-intensity training above lactate or second ventilatory threshold) in well-trained to elite endurance athletes in retrospective analyses during (A) preparation phase, (B) pre-competition phase, (C) competition phase, and (D) seasonal analysis.