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Ideal Physiological Characteristics for Marathon Runners

Liam Hallam is a sports science graduate. He is also a keen cyclist and a lover of the Derbyshire Dales and Peak District.

A guide to the physiology of elite marathon runners. Photo taken from the 2012 Carver Wolverhampton Marathon.

A guide to the physiology of elite marathon runners. Photo taken from the 2012 Carver Wolverhampton Marathon.

An Insight Into Marathon Running Physiology

Successful marathon runners (alongside other long-distance runners) have many factors in common with each other which help to determine just how successful they can be over 26.2 miles.

These physiological running performance markers are all influenced by a marathoner's genetics while having potential room for improvement through training and environment. Detailed below is an insight into the physiological characteristics of elite marathon runners, with insights into how you can train to improve your running fitness and marathon times.

Physiological Variables Necessary for Marathon Success

Successful long-distance runners have the following in common. Each factor is tackled in more detail further down the page.

  • High proportion of slow-twitch muscle fibres in their running muscles
  • A high lactate threshold
  • Excellent biomechanics
  • A high VO2 max
  • High glycogen storage
  • Well-developed fat utilization as a fuel for running
  • The ability to recover quickly after running workouts

The Best Muscle Fibre Types for Marathon Running

The key characteristic a marathon runner wants in their muscles is endurance. Our muscle fibres can be either slow-twitch, type fast-twitch A, and type fast-twitch B. Successful marathon runners have a predisposition towards a predominance of slow-twitch muscle fibres. Slow-twitch muscle fibres have a highly aerobic capacity for energy production and resistance to fatigue which is vital over a 26.2-mile race.

How to Calculate Your Percentage of Slow-Twitch Fibres

The technique used to calculate percentages of muscle fibres is a biopsy. Essentially this involves drilling into your muscle to take a vertical section of fibres to analyse the percentages of fast-twitch and slow-twitch muscle fibres. This is done with a device which is more like a corkscrew, so it can be painful to the athlete and should only be done outside of competition periods.

While it's good to know the muscle fibre type percentages of elite and world-class marathon runners, there is effectively nothing that can be done in training to change the figures as they are largely set by genetics. Therefore if you have a high percentage of fast-twitch muscles you can blame your parents, as they're the reason the odds are stacked against you of winning a gold medal in an Olympic Marathon.

Elite Endurance Athletes Have a High Lactate Threshold

Your lactate threshold is the determinant of when your body starts to accumulate lactic acid from anaerobic respiration. This greatly influences your marathon race pace; the higher your lactate threshold, the faster you can run.

In general, the average marathon runner's lactate threshold will occur at around 75-80% of their VO2 max. Elite and world-class marathon runners often have a lactate threshold of above 85% of their VO2 max. This allows those elite marathoners to use a significant proportion of their maximal oxygen uptake capacity before significant lactate accumulation occurs to limit distance running performance.

How to Test for Your Lactate Threshold

An excellent running gait is a key characteristic of elite marathon runners. Photo taken at the Carver 2012 Wolverhampton Marathon

An excellent running gait is a key characteristic of elite marathon runners. Photo taken at the Carver 2012 Wolverhampton Marathon

Elite Marathon Runners Have Excellent Biomechanics

When people consider running physiology they often overlook the impact of biomechanics. Many coaches and athletes assume that their running form develops optimally for their development, however running is not a natural movement and therefore you are putting your body through forces it is not necessarily designed to do. Even something so simple as the running shoe you choose to wear can have a great biomechanical impact on your body from running.

In addition, the repetitive nature of running tends to lead to overuse injuries.

Elite runners usually have excellent running form:

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  1. Body position is upright with a slight lean from ground.
  2. Head, face, and shoulders relaxed while running.
  3. Footfall lands mid or forefoot underneath the knee, which puts minimal lateral strain on the joints as landing is close to midline of the body.
  4. Use arm strokes for rhythm, not for balance.
  5. Partial hip extension.
  6. Elite runners often use their arm stroke and hip extensions to control rhythm.

Top Marathon Runners Have a High VO2 Max

Your VO2 max relates to the body's ability to transport and utilise a large amount of oxygen for the working muscles. This is judged by how aerobically you exercise. The higher your VO2 max, the more oxygen your body has the ability to utilise.

Typical population VO2 Max levels:

  • Sedentary adult: 45 ml/kg/min
  • Average club runner: 55 ml/kg/min
  • Experienced marathon runner: 60-65 ml/kg/min
  • Elite marathon runner: 70-75 ml/kg/min

Physiological Factors That Affect Your VO2 Max

There are four key physiological factors which affect your VO2 max. Some of these can be developed through training however some are set genetically.

1. Maximal heart rate

Ironically, successful marathon running is not deemed in relation to high maximal potential heart rate. It is the physiology that occurs at lower than maximal heart rates that influence marathon running performance/

2. Stroke volume of the heart (how much it can pump out with each beat)

This is the maximal volume of blood your heart can force out with every beat to your working muscles. It is a result of two factors: the volume of blood that the left ventricle can hold, and the amount of blood it can force out with every heartbeat. Increased stroke volume is developed through endurance training and is the main athlete controllable adaptation through marathon training.

3. Blood haemoglobin content (the component that helps your blood transport oxygen)

The higher the haemoglobin content of your blood, the more oxygen that can be transported within the bloodstream to the workout muscles while running for aerobic energy production.

4. Proportion of blood transported to the working muscles

Increases in heart rate and stroke volume while exercising can lead to your body pumping around 20 litres of blood around your body each minute. At rest only around 20% of blood flow is to your muscles. The rest goes to all the other organs responsible for your body processes.

However, when you're running a marathon that figure goes up to around 70%. As with training, your body becomes more efficient at redirecting blood away from your unnecessary body organs such as digestion to ensure an optimal percentage of blood goes to your running muscles.

Marathon Running Physiology and Glycogen Storage

Your body stores carbohydrate to meet your energy needs for marathon running in the form of glycogen. Glycogen is always going to be your primary fuel when running a marathon, therefore you do not want to run out of it mid-race.

How to Ensure Your Glycogen Stores Last

There are a number of key ways to ensure your glycogen stores last the length of your marathon.

  1. Train your body to utilise fat and optimise glycogen consumption. Long, slow-distance running workouts help to develop your body's ability to utilise your fat stores for energy while running. This spares your glycogen stores for longer and longer at marathon race pace. If your glycogen stores run out you "hit the wall," as it is commonly known where running becomes extremely difficult to maintain. It is also often known as "bonking."
  2. Train your body to store more glycogen. There are many carbo-loading strategies that you can utilise to ensure that your glycogen stores are topped up prior to your race or long-distance training sessions. (It is always best to test any techniques out prior to race day to ensure they work for you).

Recovering Quickly After Running Workouts

To be a successful marathon runner you need to do a lot of training volumes. This places an extremely large amount of stress and the need to recover from running workouts on your body.

Your recovery ability can be affected by a large number of factors:

  • Correct periodisation of your training programme.
  • Your age. The younger you are, the greater your body has potential to recover.
  • Diet. Eat right to aid your recovery.
  • Sleep patterns and volume. Are you getting enough sleep?
  • Training history. Your body adapts over time to volumes of training. Your first 15-mile run is going to feel a lot worse than your 15th!

Recovery runs and intervals are just important as your long runs and hard intervals. If you make your recovery runs too hard, you'll lack the ability to push yourself harder in your main workouts and increase your risk of muscular injuries and upper respiratory tract infection.

Don't Have the Characteristics Above? Don't Let That Stop You!

Can someone that's overweight run a marathon? Of course they can. Is age a factor in running a marathon? No. As long as you're healthy and pay attention to your body it's a possibility.

Good luck!

This content is accurate and true to the best of the author’s knowledge and is not meant to substitute for formal and individualized advice from a qualified professional.

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