I recently finished reading the book, How to Think Like Einstein. Its theme is that you have to break rules to solve problems and find answers to difficult questions. One of the ‘rules’ of distance running is that you must run lots of kilometres. Indeed, most runners link their fitness level to the number of kilometres they run, inevitably believing that more is better. A friend of mine who missed the 2004 U.S. Olympic Trials in the 1,500m by four seconds ran 160k per week.
Frankly, I thought he was nuts. And I began to wonder, is it really necessary to run 160k per week to run a race that takes less than four minutes? As legendary coach Arthur Lydiard so ardently claimed, lots of aerobic running forms the basis of any distance runner’s training programme. Whether you’re training for the 1,500m or the marathon, it all starts with running lots of kilometres.That’s because endurance training stimulates many physiological, biochemical, and molecular adaptations.
For example, endurance training stimulates more fuel (glycogen) to be stored in your muscles, increases the use of intramuscular fat at the same speed to spare glycogen, improves your blood vessels’ oxygen-carrying capability by increasing the number of red blood cells and hemoglobin, creates a greater capillary network for a more rapid diffusion of oxygen into the muscles and through the complex activation of gene expression, increases mitochondrial density (mitochondria can be viewed as cellular powerplants) and the number of aerobic enzymes, increasing your aerobic metabolic capacity.RELATED: RECOMMENDED PLANS FOR YOU
The link between an increase in mitochondrial enzyme activity and an increase in mitochondria’s capacity to consume oxygen, first identified in rats’ muscles, has provided much insight into the adaptability of skeletal muscle – generally, the greater the demand the greater the adaptation. Although many scientists have acknowledged there is an upper limit to the volume of training that will cause further adaptations, what research has not documented is at what point these adaptations stop occurring in response to the demand.
In other words, how much running is enough? The answer depends on a number of factors, primary among them your genetically determined propensity to continually adapt to greater amounts of running and the amount of running that you can physically and psychologically handle.
Effect of Training Volume on Physiology and Performance
As runners, we all know that the better we get, the harder it is to improve. Unfortunately, none of the adaptations associated with training continue indefinitely. Obviously, the more untrained you are, the more you can expect to improve by increasing your running volume.
For example, a study published in the Journal of Applied Physiology in 1992 found that weekly volume ranging from eight to 120k per week explained 86.5 percent of the difference in VO2max between runners (VO2max refers to the maximum amount of oxygen your muscles consume).
Another study published in the European Journal of Applied Physiology and Occupational Physiology in 1986 found that runners training more than 100k per week ran significantly faster in races from 10k to 90k compared to those who ran less than 100k per week. While it is likely, and even probable, that running more leads to a higher VO2max and faster race times due to all of the previously described adaptations, we cannot conclude cause and effect from cross-sectional studies comparing separate groups of runners.
It’s likely that genetically gifted runners who have high a VO2max are capable of running more kilometres and run faster races. Research has shown that VO2max and other physiological changes plateau at about 95-112k per week, with the exact amount at which the plateau occurs depending on the individual. So, if VO2max and muscle cellular adaptations plateau at about 95 to 112k per week, why do accomplished runners run much more than that?
How Much Do Elite Athletes Run?
In 2004, I conducted a study on the training characteristics of the U.S. Olympic Marathon Trials qualifiers. My findings, which were published in the International Journal of Sports Physiology and Performance in March, 2007 revealed that the men averaged 144k per week with a peak volume of 192, while the women averaged 115k per week with a peak volume of 152k for the year of training leading up to the Olympic Trials.
However, the elite male marathoners (sub 2:15hr) didn’t run statistically more than the national-class marathoners (2:15-2:22hr). The elite men averaged 155k per week with a peak volume of 201k, while their national-class counterparts averaged 144k per week with a peak volume of 190k. There was however, a statistical difference in volume between women’s performance levels, likely due to their greater range in performance.
The elite women (sub 2:40hr) averaged 134k per week with a peak weekly volume of 179, while their national-class counterparts (2:40-2:48hr) averaged 110k per week with a peak weekly volume of 145k. While the faster female marathoners ran more, only a quarter of the difference in marathon performance between women could be explained by the amount of weekly running distance.
Weekly running distance accounted for even less of the difference among the men. So running more doesn’t necessarily make you faster. Regardless of how much you run, genetics plays a large role in your performance. A person with a lot of talent will almost always outperform a person with little talent who does a lot of training. Since a fast runner will cover a greater distance in the same amount of time as a slower runner, the time spent running may be more important than the number of kilometres ran.
Beyond VO2max and Metabolism
“So running more doesn’t necessarily make you faster. Regardless of how much you run, genetics plays a large role in your performance”
If there is little or no improvement in VO2max and the metabolic profile of muscles running more than 112k per week, is there any benefit at all to running more? Maybe. Research has shown that runners who run a high volume tend to be more economical, which has led to the suggestion among scientists that running more than 112k per week improves running economy (the amount of oxygen used to maintain a given pace).
It is possible that, just as repetition of the walking movement decreases the ‘jerkiness’ of a toddler’s walk to the point that it becomes smooth, repetition of the running movement has an under-recognised neural component. With countless repetitions, muscle fibre recruitment patterns and possibly even the relationship between breathing and stride rhythms are optimised to minimise the oxygen cost.
In other words, practice makes perfect. Additionally, a high running volume reduces body weight, which further reduces the oxygen cost. Because it is hard to prove cause and effect, it is not clear whether high volume runners become more economical by running more kilometres or are innately more economical and can therefore handle a higher volume without getting injured.
While most runners and coaches agree that training volume is important, training intensity is more important than volume for improving fitness and performance, especially in highly trained runners. Research has shown that a high training intensity is vital for maximising cardiovascular improvement and that VO2max and other physiological variables can continue to improve with the inclusion of high intensity training.
For example, interval training performed at 95 to 100 percent VO2max is the most potent stimulus for its improvement and is necessary for further improvement in highly trained runners. Given that training volume will impact training intensity, the better question may not be how much running is necessary or enough, but how much running is too much to sacrifice intensity? So, as you prepare for your next 5k or marathon, how much should you run?
If you’ve read this far, you know that the answer is not an easy one (for some guidance, see ‘Should I Run More?’ below). The best way to determine how much to run is to slowly and systematically increase your volume from month to month and year to year, taking care to note how you respond to the training stimulus. And remember that more is not always better. Like Einstein, sometimes you have to break the rules.
New Zealand coach Arthur Lydiard, who passed away in 2005, was most well known for his high volume approach. Even his middle-distance runners ran 160k per week, like Peter Snell, who won gold medals in the 800 and 1,500m at the 1960 Olympics. But is that amount of running necessary? Was Lydiard right, or did his talented athletes run well despite their training rather than because of it? Like my friend trying to qualify for the Olympic Trials, many of today’s middle-distance runners run nearly as many kilometres as marathoners.
While 160k per week is probably not necessary to maximise your potential for the 1,500m, a moderate amount of running can help. Since any race lasting longer than about three minutes relies more on aerobic than on oxygen-independent (anaerobic) metabolism, having a well-trained aerobic system is still important for the shorter distances.
Although Lydiard argued that runners should build a solid aerobic base that includes a high volume before progressing to various forms of speed work, doing too much training too early may have detrimental effects when it’s time to peak. A study published in Journal of Strength and Conditioning Research in 2000 found that the pre-season training phase (May to August) of university cross-country teams had the greatest impact on performance during the peaking phase (November).
Teams that qualified for the national championships took more rest days during the pre-season phase and actually ran shorter weekly long runs than teams that did not qualify (18.4 vs. 21.9k). During the competition phase (August to October), there was no statistical difference in weekly running distance between qualifying and non-qualifying teams (115 vs. 100k per week, respectively).
Among the qualifiers, the teams that ran more kilometres (above 112k per week) and ran twice per day during the summer months actually ran slower at the national championships in November than teams that ran less. It’s possible that running too much in the summer makes you too fatigued to race at your peak in the autumn.