Running Economy

Running economy? What's that? Whilst I am sure we could talk for hours about the best value running, cycling and gym gear, for now that is not what I am getting at, no instead this is 'running economy'.

So, running economy – I’ve never heard of it…how can it help me?

Running economy basically refers to how efficiently you use oxygen at a giving running speed (or for that matter cycling, swimming or other endurance sport) and is still one of the least understood and poorly recognised aspects of the sport but is in fact crucial to your ultimate performance.

 

So in developing our running economy we are looking to ensure than we are running at our optimum speed with as small an energy expenditure as possible. Tucker et al (2009) draw an analogy to cruising efficiency in a car which I think is helpful - think of it as you trying to develop an ‘eco-engine’ burning as little fuel as possible at the speeds you race at the most….simple! Running economy is typically expressed as a ml/kg/km - the amount of O2 used per KG of by weight per km.

Aren’t you just talking about VO2Max? Or Lactate Threshold?

 

Well no not really, although they are linked. VO2max refers to the maximum about of oxygen you take up and use whilst training at maximum effort and whilst this can be developed it is largely governed by genetics (simply measured by subtracting the amount of oxygen exhaled from the amount taken in). VO2max has been widely used in the past as a predictor of your potential performance in endurance sport, though increasingly this assumption is being called into question - a more important measure is what % of your Vo2 max you can sustainably use. Steve Magness in his 2014 book 'The Science of Running' provides a useful chapter summarising the lack of efficacy and effectiveness in training to improve VO2 max - in particular Noakes' work on the Central Governor Model. 

 

Lactate Threshold (or as EA refer to it, lactate turn point) or Anaerobic Threshold is different again in that it refers to the point at which during intense activity the level of lactate in your blood is building up faster than it can be absorbed and thus inhibits muscle performance through an increase in hydrogen ions and change in blood PH balance. This can be trained and developed significantly.

 

Running economy is to both different in that it relates to oxygen consumption and utilisation at a given sub-maximal speed. Quite simply the goal of improving your running economy is to make you as efficient as possible at using oxygen and thus producing energy as you can at your training and, more critically, race paces. 

 

What I need to do about it?

 

That’s what you want to know I guess? How can I become the most economical runner I can? Well there are quite a few aspects to this - some of these I’ll just touch on below, some I’ll cover in more depth. It's not an easy topic for many runners to understand because improving running economy involves the interplay between many factors. Barnes and Kilding (2015) make this clear by separating factors influencing running economy into three main areas

 

'Metabolic efficiency refers to the utilization of available energy to facilitate optimal performance, whereas cardiopulmonary efficiency refers to a reduced work output for the processes related to oxygen transport and utilization. Biomechanical and neuromuscular characteristics refer to the interaction between the neural and musculoskeletal systems and their ability to convert power output into translocation and therefore performance.' 

Train at 'threshold' & 'race pace'...a lot

As running economy relates to the specific pace you are running at it's pretty clear that including plenty of race pace running and looking to build this up in sustainable blocks the closer you get to your goal race is of critical importance. Your neuromuscular system gradually adapts to the demands the speed of that movement and your body is able to produce less fatigue metabolites as your body becomes gradually more economical at those critical race paces. 

We would suggest most runners should be aiming for it least one 'threshold' session a week 

Increased volumes

Bodyweight

It might seem odd but there is plenty of research to suggest running economy actually improves in heavier individuals (Canova, 1999) (​P. Taboga et al, 2012) (Bourdin, M et al. 1993) - this could be down to lower vertical oscillation or even a greater degree of elastic return required in the muscles. However that doesn't mean that bodyweight doesn't have an impact on running performance. Running economy is calculated by dividing energy demand by weight so whilst running economy may be stable or even go up in heavier athletes they require more energy for a given sub maximal speed.

 

A conservative estimate would be that, all other variables being equal, each extra KG of bodyweight will cost you between 4-6 seconds a mile any given running speed. That certainly does not mean that all runners would perform better if they lost weight. Managed poorly and at the wrong time weight loss can lead athletes under fuelled and subsequent poor training and racing performance, limited ability to recover between sessions and in more serious cases increase injury risk or other long term health implications. Many athletes will lose a bit of weight naturally through sound day to day healthy eating and good training. For those at the more performance end or with specific heath concerns investing in a nutritional review and working with a fully qualified sports nutritionist or dietician is the way to go if you think this applies to you.  

Footwear

The impact of footwear choice on running economy is still not widely researched and where it has been results at mixed. The recent claims of one major company that their newest range can improve running economy by 4% is interesting but perhaps (hard to believe I know!) is over sampling a complicated area. Does a firmer, more responsive shoe improve running economy over a more flexible or more cushioned shoe? Many runners believe that a lower profile shoe allows them to have a quicker footstrike and reduced ground contact time (see below) and there is some evidence to suggest new foam technologies implemented by most major brands or even carbon fibre inserts can improve energy return. However the main advice would still be to pick shoes that both fit you correctly and are suited to your own gait and biomechanics and suited to the distances your are running and racing.

Bio-mechanics & Technique

Ground Contact Time - Why is it some runners seem to float over the ground, barely touching – running like a deer I call it, whereas some runners appear to ‘plod’ (sometimes very fast!)? Much of this is down to running technique and whilst I could write many articles on running technique, for the purposes of today's post on economy we are going to focus on ground contact time. Whilst only a matter of milliseconds, every moment your foot sits on the ground you are losing a little momentum. Trying to increase the speed at which your foot strikes and returns from the ground is crucial to increasing running economy. As Chapman points out ‘at any common speed, elite runners spend less time in contact with the ground and take longer strides compared to average runners or untrained individuals.’

 

Next time you head out for a run consider the following;

 

·   Tread lightly – consciously try to limit the sound of your foot strike on the ground

 

·   Imagine the road or trail as super heated, anything longer than a fraction of a second and your foot is going to burn!

Ground contact time can be improved/reduced through including drills and plyometric conditioning into your training as well as spending time focusing on hip positioning. See below for exercises to help with this. 

 

Cadence - Count how many times your left foot strikes the ground in a minute. Work towards an optimum of 90 with each foot but be aware this does not necessarily require you to take shorter strides as many coaches will suggest, it is quickness of transition that counts, unless of course you know you over-stride. A low stride rate can lead to increase vertical movement in your running action (believe it or not those runners you see bouncing high off the ground are not running efficiently). This is now as black and white as many coaches will suggest however. Some of the best distance athletes in the world run with a cadence lower than 90 (less than 180 steps a minute)...the converse will also be too - you will become less economical and efficient if your cadence increases beyond a certain point. 

 

Rhythm – try to consciously coordinate your breathing with your stride pattern. Karp (2006) highlights that oxygen isn’t just used by the muscles in your legs and arms as you run but also by your diaphragm and intercostal muscles as you breath – coordinating the two has been shown to improve running economy.

Overall 'form' - running bio-mechanics centres on a concept called the ‘stretch-shortening’ cycle whereby the muscles and tendons act like a spring – your foot strikes the ground and your muscles lengthen, as you transition off into your next stride, your muscles contract. I could write for hours on good running technique but for the purposes of running economy focus on the following basics;

 

·       Core Engagement and Hip Position – Create a strong and stable base for economic movement by thinking about bringing your sit bones together, bring them in and up. Activating your deeper core muscles such as the Transverse Abdominus. If you are not sure what I mean here have a look at some pilates classes – they will really help. Your nice strong, high hip position creates a block like a railway sleeper of strength – your arms and legs simply move off this base

·       Ankle Lean – A gentle lean forwards from your ankles, with your weight on the balls of your feet will automatically create momentum in your running. Note this is a lean from your ankles, NOT your hips.

·       Foot Strike and Position – practice some of the drills below to encourage a foot strike below your hips and centre of gravity with each stride – not landing in front of you breaking your momentum.

·       Keep everything moving forward! – Check your arms which should be moving freely and smoothly from the shoulder in a straight line backwards and forwards – NOT rotating across your body

 

The key to understanding how to further enhance your technique is to realise that your running ‘foot strike’ actually occurs before your foot hits the ground – when neurons fire muscle groups to pre-emptively prepare your body for the impact of the for strike. So speed is also about your brain – a neuromuscular process – check out the plyometric drills below…

 

Strength and Power

The words that put the fear of god into many endurance athletes. Storen et al (2008) amongst many other studies, showed that strength training, particularly when including heavier more powerful loading, improved endrunces athletes running economy over an 8 week period. S&C has a crucial role to play in your training whether you are a runner, cyclist or triathlete. This is not about getting ripped and adding masses of unnecessary muscle. Strength and power training in the RIGHT way will increase the muscle fibres you recruit (you have many that sit latent when you run, even in your legs) – think of it like someone swapping in a new pair of legs for the last 6 miles of your marathon! It is also about the SPEED at which these muscles contract and exact force in your running and that's where plyometrics come in.

Plyometric exercises involve maximum application of force in the minimum possible time. They are power based exercises - meaning its about strength and speed and are crucial to developing and improving running economy and include a range of hopping, bounding and jumping movements designed to improve your muscles ‘energy storage and return’ capacity – think back to the spring we mentioned earlier.

 

If you are serious about your training and unsure about what to do to take your next big step forward, introducing plyometric exercises could be a great solution. To emphasise this further, in training for her world record marathon performance of 2003 Paula Radcliffe included a range of plyometric training, increasing her vertical jump from 26cm in 1996 to 38cm in 2006 (Hartmann, G) which many have seen as vital to her subsequent performance – still nearly 3 minutes faster than any other woman has run.

 

I specifically haven’t gone into detail on strength training – make contact with us to look at this before you start. Instead I will outline some of the key plyometric exercises that will get you started.

 

Please be aware that plyometric exercises are by their nature intense and require good technique to remain effective and reduce any likelihood of injury – again get in touch with me or another sports conditioning expert to explore how they can be incorporated effective for you.

 

Key General Rules

·       Plyometric training should be about quality not quantity – even experienced athletes will only complete a total of 150 jumping movements in a session, a beginner or less experienced athlete far fewer (40-60).

·       Use a softer surface such as a track or grass

·       Every plyometric workout should only be undertaken after a good warm up, as you would do for a track session, and should only be carried out once a week.

·       Speed is the key – spend as little time in contact with the ground has possible – quick, powerful movements are required

 

Beginners

 

* Squat Jumps - In a squat position pop your hands on your hips or behind your head; jump straight. Upon landing, lower back into a squat position in one smooth motion, and immediately jump up again. Crucial to this will landing softly – anticipate the ground contact and cushion with your knees.

 

High Knees – Good old high knees. Over the course of about 20m run forward driving your knees up as fast as you feel you can, ensuring your upper body is not leaning backward – focus on the speed of your legs not how faster you are moving forward.

 

Hill Sprints – Covering about 50-60m find a hill with a gradient of about 7-10%, drive up the hill with light springy movements, driving your knees high in front of you, walk down for recovery and complete 5-8 repetitions. 

Tuck Jumps – Similar to a squat jump but this time you are going to jump and pick your knees up in front of you, really focusing here on speed more than height. I certainly wouldn’t expect you to jump as high as the guy in this video!

More Experienced

 

Single Leg Hops – Over 20m hop forward on one leg, driving your knee up has you hop forward, balancing yourself with your arms aiming to be as light and fast as you can be. Repeat twice on each leg.

Box Jumps – Find a box or a step between 40 and 60cm high, squat down and jump up landing with your full foot on the box with very soft knees, creating a soft landing. The key is to move as quickly as you can from the squat into the jump. Complete 10-15 repetitions 2-3 sets with 90s recovery. Step down from the box, don't jump down;

Bounding – Again over 20-25m run forward with big strides, driving your knees high with very light and quick feet – remember it is running economy and ‘quickness’ we are developing here. Powerful movements are important complete this exercise. Repeat 4 times in total.

Jumping Split Lunge – This is a great exercise for developing fast, explosive power in your legs and developing your neuromuscular system. Come into a lunge position and jump up, switching legs in the air to come down into a lunge of your opposite leg and keep repeating. Complete 12-16 repetitions in total and repeat twice.

References;

 

Barnes, K & Kilding, E. 2015. 'Running economy: measurement, norms, and determining factors'. Sports Med Open

Blagrove, R, 2015. 'Strength & Conditioning for Endurance Running'. Crowood.

Bourdin, M et al. 1993. 'Influence of training, sex, age and body mass on the energy cost of running', European Journal of Appl Physiology & Occupational Physiology

Canova, R & Arcelli, 1999. E. IAF Marathon Training: A Scientific Approach'. IAF.

Chapman, R. 'Measurement of Ground Contact Time in Elite Distance Runners', HP Lab, University of Indiana

Karp, J. 2006, 'The 3 Players of Distance Running', Track Coach Article.

Magness, S. 2014, 'The Science of Running'. Origin. 

Pulao, J & Milroy, P, 2010. 'Running Anatomy'. Human Kinetics

P. Taboga et al, 2012. 'Energetics and mechanics of running men: the influence of body mass.', European Journal of Applied Physiology, volume 112, issue 12

Storen et al, 2008. 'Maximal strength training improves running economy in distance runners.' Med Sci Sports Exerc. 2008 Jun;40(6)

Tucker, R & Dugas, J. 2009, 'The Runners Body', Rodale