There are two important variables in run training. These are volume (how far you run) and intensity (how fast you run). A third factor, frequency (how often you run) feeds into the volume part of the equation, so volume is actually distance x frequency.
Since any improvement in athletic performance must be assumed to take place due to the use and manipulation of the two key factors of volume and intensity, it has become a fundamental part of the way in which coaches prepare training plans and how athletes follow the plans. As an aside, it is important to note that within the world of trail running other factors such as nutrition, hydration, equipment, technical ability and psychological resilience can have a greater effect than in the world of road or track running, however the basic training strategy remains the same.
If we look at the history of training over the last century or so we can observe that runners during the late 18th century and early nineteenth century did very little run training at all. There was a belief that running was a natural talent and that only a small amount of volume or intensity was needed to unleash this talent. The Englishman, Walter George, set the world record for the mile in 1886 (4:12:75) while training about 25 miles a week. This record stood for 29 years until it was lowered by just 0,15 seconds (Norman Taber, USA).
Only in 1923 did Paavo Nurmi of Finland lower it by a substantial amount to 4:10:4. This would suggest that training methods hadn’t advanced much in the nearly 40 years from the time that Walter George set his record on such a small amount of training.
It was only after the Second World War that training philosophy received an electric shock in the figure of Emil Zatopek from Czechoslovakia. In the London Olympics of 1948, he won gold and set a new world record in the 5000m, while winning silver in the 1000m. He then won the 5000 and 1000m gold medals in the 1950 European Championships of Bruxelles, and in the 1952 Helsinki Olympics he won gold in the 5000m, the 10000m and the marathon, establishing new world records in each. This was an unprecedented feat, which, has never been equalled, and the world of athletics took note, particularly in regards to his training methods. Zatopek had discovered that his body, and the race performance which he was able to produce, benefitted greatly from an extremely intense training routine. At the time of the London Olympics a standard training session could involve 5 x 200m in 34/35 seconds, 20 x 400m around the 60 second range and finally another 5 x 200m, with each hard interval being separated by a short active recovery or jog. Having found success with this method he reasoned that doing even more hard intervals would produce even better results. By the time of the Helsinki Olympics he was doing workouts that consisted of up to 50 x 400m at race pace, sometimes twice a day. Zatopek had shown that hard intervals could improve athletic performance. However by 1955 Zatopek, at the age of 33, was burnt out, his body was rebelling to the training overload and he was never able to compete at such high levels again. Zatopek’s method was also copied by a young Russian athlete, Vladimir Kuts. He won gold medals in the 5000m and 10000m at the 1956 Olympics, again lowering the World Records, but he also found out that a similar training load was not sustainable and was forced to retire prematurely from competition. Hard, intense training obviously had a part to play in optimising performance but it was clearly not the whole story and seemed to have negative effects on long term health when taken to extreme levels.
At the same time, on the other side of the world in New Zealand, an amateur runner named Arthur Lydiard was experimenting on himself with a completely different method. The basis of his training was high volume but at an extremely low intensity. With this method he was able to sustain a very high weekly mileage without injury problems, and he discovered that adding just a small amount of high intensity work on top of this volume allowed him to improve his performance. His reasoning was that the true limiter on performance in mid to long distance races was not speed but endurance. The runner who had the ability to maintain a slightly higher race pace for the entire race would win. But Lydiard was not a world-class runner, though he did win national marathon championships in 1953 and 1955, and at the time, was not even a coach. That all changed in the mid 50’s when firstly a group of friends, then a succession of elite runners, started adhering to Lydiard’s training methods.
This group, often known as “Lydiard’s Boys” sent 5 athletes to the 1960 Rome Olympics, they returned home with 2 gold medals in the 5000 and 800m and a bronze in the marathon. Peter Snell, who had won the 800m gold medal, repeated his exploit in the 1964 Tokyo Olympics and added also the gold in the 1500m. At the same games another Lydiard adherent, Billy Mills of the USA, took the gold medal in the marathon.
While 4 years later in Munich, Lasse Viren of Finland, another Lydiard disciple, took gold in both the 5000 and 10000m. Other famous runners who followed the Lydiard method are Bill Rodgers (USA – 4 x Boston Marathon and 4 x NY marathon victories), Alberto Salazar (USA – 3 x NY marathon and 1 x Boston marathon victories, American records in 5000m, 10000m and marathon, winner of the 90km Comrades Marathon) and Joan Benoit (USA – 3 x Boston marathon victories and gold medal in the first ever Olympic Women’s marathon). From that time on the stage was set for the proliferation of Lydiard style training programs but there was no clear agreement on the correct amount of easy volume and hard intensity, nor even where the exact levels of what should be considered easy or hard were. It was more or less left to the individual coach or athlete, to work it out for them selves.
One of the first studies to investigate what athletes were actually doing in training was the Arizona State University investigation of female college runners, “The Use of Heart Rates to Monitor Exercise Intensity in Relation to Metabolic Variables. Gilman MB, Welles CL. Int. J. Sports Med. 1993. In this study each of the runners wore a heart monitor during all of their training sessions. On a scale where easy was defined below the first Ventilatory Threshold (V1T), high intensity was at or above the Lactate Threshold and moderate intensity was considered between the two, they found that the average scores were 45,8% at low intensity, 45,7% at moderate intensity and 8,9 % at high intensity. One of the most surprising results of the test was that “Self-reports of how training time was spent differed from actual training as revealed by the monitored heart rates.” The runners actually believed to have spent far more time at low intensity and much less at moderate intensity showing the existence of “intensity blindness” among non-elite runners. This is an important insight and goes some way to explaining why amateur runners believe that they are training in a low intensity zone while, in reality, they are training in the moderate zone of intensity.
In a 2004 study from the University of Agder, Kristiansand in Norway “Quantifying training intensity distribution in elite endurance athletes: is there evidence for an ‘‘optimal’’ distribution? Seiler KS, Kjerland GO, the authors set out to discover if elite junior cross-country skiers utilized a fixed distribution of training intensities. Again they set the first intensity at V1T (roughly equivalent to the Aerobic Lactate Threshold at 2mmol/L), and the hard intensity at V2T (slightly below Anaerobic Lactate Threshold at 4mmol/L). They discovered that the athletes spent approximately 75% of their training time at the lowest intensity and between 15-20% at the highest intensity with only a small percentage of 5-10% at moderate intensity. Seiler followed up this initial research with similar studies on elites in other sports and reached the conclusion that “……the training characteristics of nationally or internationally competitive endurance athletes training 10 to 13 times per week seem to converge on a typical intensity distribution in which about 80% of training sessions are performed at low intensity (2 mM blood lactate), with about 20% dominated by periods of high-intensity work, such as interval training at approx. 90% VO2max. Endurance athletes appear to self-organize toward a high-volume training approach with careful application of high-intensity training incorporated throughout the training cycle.” Seiler and other began to refer to this colloquially as the 80/20 rule, but the training protocol was referred to as “Polarised Training”, in which the majority of training is conducted in the easy, below VT1 zone and a smaller part in the high, above VT2 zone.
Having established that elite athletes had, in some way, gravitated to this model of training it now remained to prove that this was the most efficient method of training and that it provided the best results. Seiler teamed up with Esteve-Lanao and his team at the University of Madrid in order to investigate this. Luckily Esteve-Lanao was also part of a running club in Madrid who provided many willing participants in the various trials. In one of their first studies, “Does polarized training improve performance in recreational runners?” (Seiler KS, Esteve-Lanao J et al. 2014) randomly chosen groups of recreational runners were assigned to one of two groups. These were defined as PET (polarised endurance training distribution – 80% low intensity, 20% high intensity) or BThET (between threshold – moderately high intensity). At the end of a 10 week period both groups had improved their 10k times but the members of the PET group had greater improvements, 5% compared to 3,6%. It is important to note however, that not all participants had followed the precise limits of the two protocols. A further analysis was made to include only those runners who had adhered faithfully to the protocols. In this follow up analysis the difference in improvement was even more significant for the PET group.
A further study from the University of Salzburg, “Polarized training has greater impact on key endurance variables than threshold, high intensity or high volume training, Stöggl T and Sperlich B, Frontiers in Physiology 2014”, investigated performance variables using athletes from 4 different disciplines, running, triathlon, cycling and cross-country skiing and the use of 4 different training protocols. These protocols were HVT (high volume training), THR (threshold/medium high intensity training), HIIT (high intensity interval training) and POL (polarised training mixing HVT and HIIT). Following a nine week training period, performance was evaluated for Vo2peak (maximum consumption of oxygen), TTE (time to exhaustion), and peak velocity/power at Lactate Threshold (4mmol/L). The results showed that the POL group showed the greatest increases in Vo2peak (11,7%) and TTE (5,1%) while both POL (8,1%) and HIIT (5,6%) groups showed improvement in peak velocity/power at 4mmol/L. The HIIT group also showed a 3,7% improvement in body mass index, presumably due to the lipid oxidation effect of high intensity training. The conclusion of the authors was that “POL resulted in the greatest improvements in most key variables of endurance performance in well-trained endurance athletes. THR or HVT did not lead to further improvements in performance related variables.”
All of the above studies show quite clearly that there is a significant, and cross discipline, advantage to a polarised training protocol, where 80% of the training time is spent in low intensity exercise and 20% of time is spent in high intensity VO2max training sessions.
The polarised training philosophy can be summarised within these extracts from the 2009 article, “Intervals, Thresholds, and Long Slow Distance: the Role of Intensity and Duration in Endurance Training.” Seiler KS and Tonnesson E.), in which the authors published their conclusions regarding the optimal division of training stimulus. Here below we have listed those that would seem most pertinent to the creation of a training plan for trail racing.
“There is reasonable evidence that an ~80:20 ratio of low to high intensity training (HIT) gives excellent long-term results among endurance athletes training daily.”
“Low intensity (typically below 2 mM blood lactate), longer duration training is effective in stimulating physiological adaptations and should not be viewed as wasted training time.”
“HIIT should be a part of the training program of all exercisers and endurance athletes. However, about two training sessions per week using this modality seems to be sufficient for achieving performance gains without inducing excessive stress.”
“An established endurance base built from reasonably high volumes of training may be an important precondition for tolerating and responding well to a substantial increase in training intensity over the short term.”
If you have found this article interesting and would like to learn more about the concept of 80/20 training I would recommend this excellent book by Matt Fitzgerald available in both paperback and kindle versions.