What Type of Run Training Improves VO2max, the Aerobic Threshold, and Running economy? | EP#91

What do we know from science about training to improve three of the greatest determinants of running performance; VO2max, the aerobic threshold, and running economy? This episode is about hard evidence from training intervention studies, not anecdotal evidence and best practices. 

• The impact of training volume, threshold training, VO2max training, and more, on VO2max
• What works best for improving the aerobic threshold? Training below the aerobic threshold, at the aerobic threshold, or at the anaerobic threshold or VO2max?
• Does training volume, high-intensity interval training, and strength training improve running economy?

10:04 -

There is no solid evidence that an increase in training volume can result in increased VO2max in well-trained runners.

• A review examining this by Paul Laursen et al can be found here.
• For example, a study by Jack Daniels showed that well-trained athletes did not get an increase in their VO2max despite a two-fold increase in training volume. In this study, the baseline training volume was only 20-30 km per week, making it difficult to interpret the results.
• One contradictory study by Tanaka et al. suggested that well-trained distance runners gained a 4.8% increase in VO2max by increasing their weekly training volume from 90 to 120km. But, the athletes also trained twice a week at an intensity above their aerobic threshold during the study, while their training before the study started is unknown. It's therefore difficult to know if the volume or the intensity was responsible for the increased VO2max.

Training intensity seems to be the thing to focus on when it comes to increasing VO2max. 

• For example, according to a study by Billat et al. the VO2max of well-trained long distance runners increased by 5.4 percent in response to the inclusion of training between 90 to 100% of VO2max, despite a decrease in training volume by 10 percent.
• Several other studies have shown contradictory results, were training between 90-100% of VO2max did not increase VO2max. It should be said that the average increase in VO2max in most of these studies did increase, but the increase was not statistically significant. It's possible that the reason for this is simply the small sample sizes in these studies. 
• There are also studies that have shown increases in VO2max in response to training between 70-85% of VO2max (corresponding to training at or a bit below the anaerobic threshold). 
• If you have taken a lab test, you should know what your vVO2max (speed at VO2max) is. However, you don't need training at vVO2max to actually reach your full aerobic capacity (VO2max) in training. Running at around 92 percent of vVO2max has been shown to get you to your VO2max. This may allow you to accumulate a longer duration at VO2max, which may be more beneficial for improving VO2max.
  • Related listening: ​Muscle Oxygen Saturation (SmO2) with Roger Schmitz | EP#85​​​
• What about intervals even more intense than vVO2max? A study by Bickham et al. found that VO2max did not change with 5- to 15-second intervals (work to rest ratios between 1:5 and 1:3). Even though the subjects previously performed only long, slow distance running.
• Franch et al. showed that VO2max can be increased with 15-second intervals at 132% of vVO2max, when equally short recoveries were applied (1:1 work to rest ratio).
• An interesting aspect about Franch's study was that he compared several different intensities​ of training:
  • Training at 106% vVO2max resulted in a 6% VO2max improvement (significantly greater improvement than at 132% of vVO2max).
  • Training at 132% vVO2 max resulted in a 3.6% VO2max improvement
  • Training at 94% VVO2 max resulted in a 5.9% VO2max improvement

While resistance training has been shown to be ineffective in increasing VO2max (but there are tons of other benefits from strength training for triathletes). 

A number of studies have shown that training close to the anearobic threshold or between the aerobic and anaerobic threshold can be effective to improve VO2max.

• For example, training two times per week at close to the anaerobic threshold (MLSS - maximum lactate steady state) as a continuous run resulted in a 3.3% VO2max improvement.
• There are a number of additional examples in the review publication.

24:40 -

If you're not quite clear on what the aerobic and anaerobic thresholds really are, make sure to check out this episode:
​Threshold Confusion: Aerobic, Anaerobic, Lactate, Functional – Help! | EP#71​​​

• Training volume, where the volume increased by 33% per week over the course of 4 weeks of sub-aerobic threshold training and up to training at the aerobic threshold has been shown not to improve the aerobic threshold.
• Other than this study, which really doesn't tell us a lot, no other direct studies on the effect of volume on aerobic threshold have been done.
• There's more research available on how training right at the aerobic threshold impacts the threshold itself. One problem with these studies, though, is that most of them have been done on sedentary, non-trained individuals, who generally will improve no matter what kind of training you throw at them. 
• What about higher intensities than the aerobic threshold? Several studies have been done, and not surprisingly, results are conflicting. 
• Two studies that included intervals at v∆50 (the velocity midway between the aerobic threshold and vVO2max) saw no significant increase in the aerobic threshold. 
• However, interval training at velocities at the maximal lactate steady-state (vMLSS) and onset of blood lactate accumulation (vOBLA) (both of which are close to the anaerobic threshold) did report significant increases in aerobic threshold. 
• The largest reported aerobic threshold mean increase from any of the studies was 10.6%. This was achieved by athletes who did workouts with 20 minutes of running at vOBLA for 6 days per week. This is a pretty crazy protocol. Don't do this at home!

There is a hypothesis that you have to train at significantly above the aerobic threshold to actually improve it. The reasoning behind this hypothesis is that:

• Type 2 (fast-twitch) skeletal muscle fibers are not recruited to any great  extent until close to 90 percent of VO2max.  
• Training responses associated with aerobic threshold improvements could be related to muscle adaptations that reduce lactate production and increase its disposal at higher running velocities.
• These kinds of muscle adaptations in the Type 2 muscle fibers (which requires high intensity training) may be what causes improvements in the aerobic threshold. 

In well-trained runners, the amount of lactate in the blood can be surprisingly low, even at intensities up to 90% of vVO2max, So to summarise, VO2max training could be needed to improve aerobic threshold, at least in well-trained runners. (Note again that this is just a theory, and not yet proven to be true).

38:00 -

Training Volume

• There is some indicative evidence that volume and other related factors make runners become more economical over time.
• However, no direct training interventions have been done on this topic, so we can't really tell whether this is true or not at this point. 
• A review study found that there's a significant correlation between years in running and running economy. 

High Intensity Training

• The review study listed both positive and negative results of high intensity training on running economy. For example, both interval training at 93% to 106% of vVO2max and continuous training at OBLA have been shown to improve running economy significantly.
• But other studies did not show any of these kinds of improvements. Although, as we previously discussed, in many cases there seem to be an average improvement in running economy from high intensity training, but it can't be shown with statistical significance in the small sample sizes of these studies.
• Interestingly, in the study by Franch et al (that compared 94%, 106%, & 132% vVO2max), there were significant improvements in running economy at 94% & 106% of vVO2max but not in 132% of vVO2max. Running too fast may not be the best way to improve running economy?

Strength Training (heavy weights, explosive strength training, plyometrics)

• Strength training definitely improves running economy.

Stretching

• Excessive lack of flexibility in certain joints can be detrimental to running performance.
• However, in recent years it has been suggested that improving flexibility may cause loss of elasticity which results in a reduced running economy.
• According to the review paper, however, there is no correlation between flexibility running economy. They state that no controlled intervention studies have shown this to be true.

47:40 

• The basis of most the studies included in this review was that they added some specific type of training to the runners' normal training. What this "normal training" actually consisted of was often not described in many of these studies.
• Also, the phase of the season that the runners were in weren't typically described. These factors make comparing the runners' training before and during the study difficult, or impossible.
• Very few of the studies presented had more than one group. So, there are very few comparisons we can make to tell which training intervention actually works better compared to others. 
• A lot of the studies included in the paper had very low statistical power due to small sample sizes.
• Some studies have been done in a sedentary population, which means results aren't really relevant or applicable for trained runners or triathletes.
• To summarise, "it would difficult to argue against the view that there is insufficient direct scientific evidence to formulate training recommendations based on the limited research."

• Training to Enhance the Physiological Determinants of Long-Distance Running Performance - Can Valid Recommendations be Given to Runners and Coaches Based on Current Scientific Knowledge?
• Related episode: Threshold Confusion: Aerobic, Anaerobic, Lactate, Functional - Help! | EP#71
• Related episode: The Triathlete's Strength Training Formula | EP#81
• Related episode: To lab test or not to lab test with Alan Couzens | EP#79
• Related episode: Running Science with John Brewer | EP#80
• Related episode: Masters Athletes: How to minimize the performance decline for aging triathletes | EP#20
• Related episode: Muscle Oxygen Saturation (SmO2) with Roger Schmitz | EP#85
• 4 things we learned from getting our Sweat Test data published in an academic journal - Precision Hydration blog
• That Triathlon Show 2018 Survey

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Hi! I'm your host Mikael,

I am a full-time triathlon coach and an ambitious age-group triathlete. My goal is podium at the Finnish national championships within the next few years.

I first started the website Scientific Triathlon in autumn 2015 as a passion project to share my learnings with a larger triathlon audience. Later on, in early 2017 I started the podcast That Triathlon Show. 

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