Moderate or polarized training for amateur athletes?

Sports Performance Bulletin looks at more new research on training intensity distribution; what works for the pros may not in be ideal for amateur and recreational athletes

The two most commonly asked questions by recreational and non-elite (ie amateur) athletes preparing for an endurance event such as a marathon, triathlon or sportive, are: ‘how much training should I be doing’ and ‘how much of this should be hard or easy’? A commonly used approach by many non-elite athletes is to focus on moderate intensity training⁽¹⁾, which is hard enough to push the body out of its comfort zone and promote gains in endurance, but not so hard that exhaustion ensues. Compared to a training regime of mainly long, slow distance training, this approach almost always leads further gains in fitness and performance. But is this kind of training intensity distribution really optimal?

Polarized options

In recent years, a growing body of evidence from elite athletes has accumulated that for maximum performance gains, there could be a better way. This better way revolves around a concept known as ‘polarized training’^(2-4). The polarized approach to training proposes that endurance athletes spend a large proportion of their training time working at low intensity (ie in the ‘easy’ purely aerobic zone – zone 1) and a small proportion at a very high intensity (near maximum power output – zone 3) with very little time spent training at or near to lactate threshold (zone 2 – see table 1). The theory behind a polarized approach is that it provides an excellent ‘aerobic foundation’ yet allows for high-intensity work that really stimulates training adaptation (ie aerobic fitness gains) without excessive fatigue. This is in contrast to the moderate-intensity distribution approach, where much of the time training is intense enough to induce fatigue but never hard enough to provide the intense training stimulus needed to make maximum fitness gains.

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Table 1: Training zones and intensities

The polarized theory of training uses the concept of three ‘intensity zones’ - 1, 2 and 3. Studies on elite athletes such as runners and rowers suggest that the best way of achieving maximum endurance potential is to spend the bulk of training time in zone 1, at least some time in zone 3 but not to spend too much time in zone 2 (the moderately hard zone).

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Does one size fit all?

The recent data on the use of polarized training approaches for elite athletes has led many amateur and recreational athletes to completely rethink their training structure, cutting back on moderate-hard intensity workouts and adopting a more polarized approach instead. However, the training backgrounds and volumes undertaken by amateur and recreational athletes are very different to elite athletes, and until recently, no studies had investigated whether a polarized training structure is equally appropriate for non-elite athletes.

Eighteen months ago however, research on triathletes competing in a Half-Ironman triathlon conducted by Spanish scientists raised serious questions about the validity of the polarized approach for recreational and amateur athletes⁽⁵⁾. In this study, two groups of triathletes followed two different training intensity distributions:

• Polarized – 84.4%4.3%/11.2% distribution of total training time for zones 1,2 and 3, respectively (typical profile of intensity distribution recommended for elite endurance athletes).
• Pyramidal – 77.9%/18.8%/3.3% distribution of total training time for zones 1,2 and 3, respectively (the typical kind of intensity distribution followed by non-elite endurance athletes when left to their own devices).

Importantly, the total training volume prescribed was identical for both groups (155 training hours over the 12-week period), and all the triathletes followed the same periodisation protocols, performing increased training loads and decreased training loads at the same time points over the 12-week period. In addition, the nutrition and hydration needs of the athletes were controlled across both groups to ensure a level playing field. Both groups also spent the same amount of time practicing transitions and swimming skills. In fact, the only real difference between the groups was their training intensity distributions over the 12 weeks, which are shown in figure 1.

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Figure 1: Time percentage in each zone by segment during specific training period

NB: <VT1 = zone 1; VT1-VT2 = zone 2; >VT2 = zone 3

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The key finding was that no significant differences were observed between the polarized and pyramidal race times, and both training distributions showed produced significant fitness gains in the triathletes – in all three disciplines. In fact, the pyramidal group showed a statistically significant improvement in maximum running speed at VT2 (lactate threshold) and the maximum aerobic speed - gains that led the pyramidal group to turn in slighter faster times in the Half-Ironman race - whereas the polarized group did NOT experience these gains. In short, this research showed that although the ‘polarized is best’ mantra might be correct for elite athletes, the same is not necessarily true for recreational/amateur athletes.

The latest research

Coming right up to date, more research published at the end of last year suggests that while polarized training might be great for elite athletes, amateur athletes might not experience any benefits⁽⁶⁾. This study examined six weeks of a training intervention comparing a polarized intensity distribution to a moderate training intensity distribution, in particular how it affected sub-maximal and maximal performance indices during running and cycling in recreational, non-elite triathletes who were averaging around 11 hours of total training per week.

Fifteen moderately-trained triathletes were either assigned to a polarized training group or a moderate training intensity group. The groups were matched as closely as possible in order to minimize gender, age competition times, and training history differences between the groups. The training structure of the two groups during the 6-week intervention is shown in figure 2. As in the above study, the total training volume was equalized between the two groups. Before and after the intervention, all the participants underwent incremental cycling and running testing to assess performance indices until exhaustion.

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Figure 2: Weekly training schedule of polarized group (A) and moderate-intensity group (B)

Weekly schedule repeated for six weeks. LIT, low intensity training; MIT, medium intensity training; HIT, high intensity training.

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The findings

The key finding was that while both groups notably improved their second lactate threshold (the intensity at which fatiguing lactate begins to rapidly accumulate in muscles) by around 2.8% and their running performance by around 5.4%, neither cycling nor running performances in the two groups differed between the two groups after the intervention. In plain English, both of the training interventions produced the same benefits - or to put it another way, the polarized approach was NOT any superior to the commonly used moderate-intensity training distribution.

Summary

As we concluded in an earlier article on this topic, the benefits of a polarized approach in elite athletes but NOT in amateur athletes might arise because elite athletes (who are already highly aerobically trained with superb lactate threshold abilities) can only really achieve further gains by spending more time in zone 3. However, less fit non-elite athletes can still get good gains by zone 2 training. More research is definitely needed! In summary then, although the ‘polarized is best’ mantra might be correct for elite athletes, the same seems not necessarily true for recreational/amateur athletes. So although we need more data, in the meantime it seems amateur athletes have little to gain by switching to a polarized approach. This still means that 70-80% of recreational athletes’ training volumes should be conducted in zone 1. But it also suggests that they shouldn’t avoid zone-2 sessions working at or near lactate threshold, because these might the very sessions that generate the biggest gains in performance!

References

1. Int J Sports Physiol Perform. 2014 Mar; 9(2):332-9
2. Int J Sports Physiol Perform. 2014 Jan;9(1):93-9
3. Int J Sports Physiol Perform. 2012 Jun;7(2):103-12
4. Front Physiol. 2014 Feb 4;5:33. doi: 10.3389/fphys.2014.000335
5. Journal of Sports Science and Medicine (2019) 18, 708-715
6. Front Physiol. 2020 Nov 12;11:534688. doi: 10.3389/fphys.2020.534688. eCollection 2020