Running Economy - Eccentric Muscle Damage / Technique

Hi, welcome back.

If you are on my blog for the first time, a warm welcome to you. Unfortunately though, my posts often follow on from a previous post or two. Sorry for this, but often I get useful feedback form the comments left, which make me think and therefore requires further expansion in a subsequent blog. So you may wish to read some of the earlier posts to 'get into the flow'.

The aim of tonight's blog is to 'tie up a few loose ends' on "running economy" first introduced in the "Is More Always Better?" post and expanded within the "Running Economy" post.

Firstly I will briefly recap on "endurance fitness" which is related to three factors: VO2 max, lactate threshold, and running economy. Within the "Running Economy" post I proposed that for ultra running, it is running economy that is most important, mainly due to the intensity one runs at during an ultra race, which is way below VO2 max pace, and even significantly below lactate threshold pace.

Although my blog consists of my ideas, wherever possible I will try to acknowledge the source of any material that helped me formulate my ideas, however, quite often I can't recall where I read the interesting bit of information. (As this isn't an academic paper I wont list the full reference within the post, but if anyone would like the full reference, so they can read the original paper, just send me an e-mail.)

With regards to running economy, Midgley et al (2007) conclude that the enhancement of running economy may be due to the cumulative distance the runners has covered over the years of training. They state this may be due to: (i) the continued long-term adaptations in skeletal muscle, or (ii) a slow but progressive long-term improvement in mechanical efficiency.

Looking at skeletal muscle adaptations first, mention is made of increased musculotendous stiffness which increases the storage and return of elastic energy, thereby improving the overall efficiency of running as less additional energy is required. One would also expect that as the number of miles ran increases the muscles, tendons etc. become stronger, more resistant to damage.

A recent study by Lucia et al (2010) found a link between running economy and muscle damage, with reference to Zerisenay Tadesse the current world record holder for the half marathon (58:23 set in March 2010). They believe his running economy is the most efficient ever reported, in terms of the amount of oxygen required to run at 17, 19 and 21 km/hr. What is interesting is that they also found that his levels of serum activity of creatine kinase (an indicator of skeletal muscle damage) measured following a half marathon, was extremely different to typical values indicating "minimal muscle tissue damage, suggesting an extreme ability to minimise eccentric muscle damage".

Eccentric muscle damage occurs during an eccentric contraction, which happens on every foot strike as the muscle e.g. quadriceps, lengthens at the same time as it is contracting. So it therefore appears that if one has very good running economy, then they are likely to have less muscle damage, and hence therefore able to continue running at a good pace for a longer duration, i.e. during ultra races. The muscle damage will still occur, which will lead to a decrease in running economy as the duration of the race progresses, however, for those runners with good running economy their rate at which this decline in running economy occurs will be lower.

Now lets look at the second issue related to the improvement in running economy over the years; a slow but progressive long-term improvement in mechanical efficiency. Running is often not thought of as a technical event, however, if you watch people run, they all have slightly different styles, with some appearing 'smooth', others appearing 'inefficient'. For most activities, the more one practices, the better one gets at the movement. I also believe that this occurs during running. Yes, some runners have a more natural efficient running style, but over time, I would suggest that all runners will become more efficient at running as their technique gradually improves to become more efficient, to have less vertical oscillations of the body, to have less eccentric damage. Hence, why running economy continues to improve over the years, (e.g Paula Radcliffe - see Running Economy post) as the total distance ran increases.

So, is it possible to do specific training to improve running economy, or do you just have to be patient and wait for it to slowly improve over the years?

One easy way to improve running economy is to simply loose weight, as the lighter one is the more efficient they are. The location of the mass is also very important. Ideally you want to have light legs especially the lower legs and feet. My size 7 feet are therefore an advantage, which I further utilise by always racing (including UTMB) in lightweight road shoes, rather that heavier trail shoes!

With regards to trying to change one's running technique, I haven't read much on this, there are a few articles on the 'Pose' technique of running, and there is lots of current interest in 'Newton' running shoes, or the barefoot running sock type shoes. When I get some time, I'll do some reading and get back to this aspect.

In relation to actual training, there has been some research that suggsts strength training via heavy-weight training or plyometric training may improve running economy. But to summarise from Saunders et al (2004) little is known on how to train to improve running economy, with there being relatively few documented interventions, that manipulate physiological or biomechanical variables, that have shown to improve running economy in distance runners.

Interestingly, shortly after reading that strength training may be beneficial at improving running economy, I was on William Sichel's website, as I followed his progress during his absolutely awesome 1000 mile race in Athens and discovered that he includes loads of strength training within his ultra training. On this webpage link, http://www.williamsichel.co.uk/training.php I encourage you to take a look at his training that includes: running carrying extra load in a weight vest or dragging a weighted sled. He also does plyometrics and "spends a lot of time in the weight room using extremely heavy weights"!

So do I do any specific strength training - weight training/plyometics? NO, and that is a definite NO!

Although, I am quite a competitive person, and I love racing. At the 'end of the day', I am a runner, and I love running. Yes, I may perform better if I did some specific strength training, but the race result isn't the motivation for my running. Yes, it is satisfying and rewarding to finish near the front end of the field, and I always aim to run as hard and as fast as I can, BUT as I signed off in one of my previous posts, and to sign off from this post:

"It's journeys that bring us happiness, not the destination." The journey of run training, not weight training!

Well, I seem to have gone off the topic a bit there! I can see what the topic for my next post will be: "Motivation: Why are you doing this?"

Until my next post. Enjoy the running, racing and everything else that brings you happiness,

Stuart