Polarised Endurance Training

Endurance training approaches have traditionally centred on one of three models:

• Threshold Training
• High Volume Training
• High-Intensity Training

Most of the above are relatively well-known methods of endurance training that need little explanation. However, there is a new endurance training paradigm called 'polarised training' that is rapidly gaining in popularity. This is largely due to the fact that it is thought to produce better training results than the above (more traditional) approaches; especially in well-trained endurance athletes.

What Is Polarised Training?

A polarised training program is characterised by an undulating non-linear periodization model with nearly all the training time spent as "light" and "very hard" pace, with little to none spent at "hard" or race pace. As such, polarised training programs typically include high-intensity workouts separated by one or more long slow distance workouts, where the intensity is equivalent or less than 2 mM lactate (i.e. below race pace and able to carry out a conversation). 

Defining Different Endurance Training Models

To better characterise polarised training, it's useful to compare it with other popular forms of endurance training in terms of time spent at different exercise intensities. The table below provides an overview of these aspects.

The most basic measure is simply rating of perceived exertion (i.e. RPE), while measures such as ventilory threshold and blood lactate are typically reserved for the laboratory. Other useful measures include heart rate zone and power output when cycling.

Definitions and Parameters for Endurance Training Models
Definitions of Each Training Zone
Perceptual and Physiological Measures	Zone 1	Zone 2	Zone 3
REP Scales	≤ Somewhat Hard	Hard	≥ Very Hard
1-10	≤4	5-6	≥7
6-20	≤13	14-16	≥17
Ventilory Threshold (VT)	≤VT1	VT1 to VT2	≥VT2
Blood Lactate	≤2 mM	2-4 mM	> 4 mM
Percent Time Spent in Each Zone
Training Type	Zone 1	Zone 2	Zone 3
Polarised Training	75-80%	0-10%	15-20%
Threshold Training	50-60%	40-60%	0%
High Volume	100%	0%	0%
High Intensity Interval Training	50%	0%	50%

Advantages of Polarised Training

Polarised Training More Effective than Threshold Training

The main drawcard of polarised training is that current studies indicate endurance athletes respond more favourably when compared to traditional threshold training approaches. When analysed in statistical terms, studies measuring the effect of a given training approach on endurance produce what is called an 'effect size'.

For example an effect size of 0.85 means that the average treatment participant outperformed 85% of the control group. Alternatively, a negative effect size of -0.50 means that the average participant was outperformed by 50% of the control group. Meta-analyses of polarised studies have shown an effect size for changes in endurance performance was 0.85 to 2.80, which is considered very large². In contrast, effect sizes from meta-analysis of studies employing the traditional threshold training approach range from -0.42 to 2.16². This suggests that while some athletes respond very favourably to threshold training, in some cases it can actually decrease performance.

Polarised Training Minimises Risk of Overtraining

Because only a small portion of overall training time is spent at high intensity, some feel a polarised training model may be a more enjoyable method of training that can minimise the risk of overreaching/overtraining. To support this notion, there are studies showing that reducing high intensity exercise volume is linked to a lower overall injury.

Comparitive Effect of Polarised Training Schemes

The table below is taken from a 2015 study soon-to-be published in the prestigious Journal of Strength and Conditioning. It provides a useful overview of studies that have compared the effects of polarised training with more conventional threshold endurance training. It is evident that in all studies, endurance athletes of different types generally respond more favourably to polarised training. While the total number of studies are still relatively small, the early signs are very encouraging.

Example of Polarised Training Regime

So what does a polarised training regime look like? The table below provides a sample two-week regime for both pre-season and in-season. When performing polarised training, all intervals are performed very hard at a high intensity. In practical terms this usually means it is hard to carry out a conversation during and heart rate will be within 10-20% of maximum.

Sample Pre- and In-Season Polarised Training Programs
Wk		Sun	Mon	Tues	Wed	Thu	Fri	Sat	%Zone Training	%Zone Week
	1
Pre-Season			Interval		Interval		Interval		Z1=92%	Z1=92%
		LSD	W/C: 10m	Off	W/C: 15m	LSD	W/C: 10m	LSD	Z2=0%	Z2=0%
		90 mins	5s-2m-3r		8s-2m-3r	90m	5s-3m-3r	120m	Z3=8%	Z3=8%
	2
				Interval	Interval			LSD 165m w/	Z1=90%	Z1=90%
		LSD	Off	W/C: 15m	W/C: 10m	LSD	Off	Interval	Z2=0%	Z2=0%
		90 mins		8s-2m-3r	5s-2m-3r	90m		3s-4m-3r	Z3=10%	Z3=10%
In-Season	1							Event/
		Interval		Interval				Competitions	Z1=90%	Z1=76%
		W/C: 10m	LSD 180m	W/C: 15m	LSD 90m	Off	Off	Z1=60m	Z2=0%	Z2=12%
		5s-3m-3r		8s-3m-3r				Z2=60m	Z3=10%	Z3=9%
								Z3=15m
	2	Event/						Event/
		Competitions	Recovery					Competitions
		Z1=20m	(Warm Up &	LSD 60m w/				Z1=30m	Z1=95%	Z1=57%
		Z2=90m	Stretch)	Interval	LSD 120m	Off	Off	Z2=60m	Z2=0%	Z2=34%
		Z3=13m	W/C 20m	5s-3m-3r				Z3=5m	Z3=7%	Z3=8%
m = Time in minutes
W/C = Warm up and cool down
LSD = Long slow distance
Intervals are Sets (s) by time zone 3 (interval length in minutes, "m") by rest interval time in zone 1 (r, rest length in minutes).

Summary

If you are keen or competitive endurance athlete that has been prone to injury or lack of progress with your existing training regime, you might want to consider a polarised approach that incoporates more low intensity time as well as more very high intensity efforts, with little to no 'threshold' efforts. 

Some authors have summarised polairsed training as:

"going easy on long slow distance workouts, avoiding "race pace" and really going after it during interval workouts.“¹

1. Hydren JR, et al. Current scientific evidence for a polarised cardiovascular endurance training model. Journal of Strength and Conditioning. 2015 Ahead of Print

Fonte:http://www.mrsupplement.com.au/workout-articles