What should be considered when training someone for an endurance event?

Whether a client is looking to complete a 10km run or an Iron Man, it is likely that they will look to their Personal Trainer for support. If you are asked, there are several things which should be considered.


The predominant energy system for long-distance events is the aerobic energy system, which converts glucose, fat or amino acids into ATP - the body’s source of energy. Glucose is the most efficient fuel for cellular respiration, so you should ensure that your client isn’t restricting their carbohydrate intake, without good reason. Once their glucose levels and glycogen stores have depleted, their event will start to feel more difficult, so finding a way to ingest carbohydrate and maintain blood glucose levels during the event is important. They can experiment with drinks, gels or even jelly babies, but should ingest little and often. By doing this, they will avoid a spike in blood glucose, which would cause an insulin release and subsequently decrease blood glucose levels.

Hydration is also key. A client can estimate their fluid loss by weighing themselves before and after a run of a set distance. Don’t make them run for too long, as they won’t be drinking and you don’t want them to get dehydrated. Each 1kg loss of body mass is approximately 1 litre of water that would be required. You can then estimate how much fluid would be needed during their event. The amount of fluid required will vary depending on the temperature, so you can test this in different weather conditions. If your client is wanting to get a good time in their event, remember that overhydration can also have an effect, as they may need to stop to go to the toilet.

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Exercise economy, the oxygen cost for a given activity, is often overlooked. The more economical that someone is, the less oxygen they will require for the same activity. Whilst running biomechanics are complicated, there are two simple things you can recommend:

  1. They aren’t carrying any unnecessary weight; bodyweight or clothing.

  2. That they maintain good technique whilst training, to get into good habits; standing tall, not swinging their arms across their body and looking about 50 metres ahead.


There is a high correlation between increased Vo2 Max and performance in aerobic events. The reason for this is that an individual with a higher Vo2 max will generally be able to maintain the highest output, without accumulating lactic acid. For this reason, high intensity, anaerobic training, which will bring about skeletal muscle adaptations and improve cardiovascular and respiratory function, should be incorporated into their training.

Your client’s training should be varied to get the best results. There are a few types that you can try:

  1. Long/slow training (30-120 minutes, 70% Vo2 Max), can be used to improve endurance.

  2. Pace/tempo training is conducted at (or slightly above) event speed, at the lactate threshold, to help develop a sense of “race pace”.

  3. High-intensity interval training (at or greater than Vo2 Max for 30-90 seconds) can be used to increase running economy and speed.

  4. Fartlek training incorporates steady-state runs with short bursts/sprints, to improve fuel utilisation.


Finally, running is a high impact sport and overuse injuries are common. For this reason, avoid large spikes in weekly load and don’t increase frequency, duration or intensity by more than 10% each week. Allow your client time to recover before the event, by maintaining intensity, but decreasing load. Fatigue will dissipate faster than their fitness, so this will increase their “preparedness”.

To conclude, there are a whole host of things that you can do to prepare your client for an endurance event, but how detailed their training programme is will largely depend on two things. Firstly, their motivation. If they want to do it for fun and aren’t too concerned with their time, you should try to make their experience enjoyable and may not need to focus on all of the above. Secondly, the type of event. Training for a park run vs an ultra-marathon will look very different. Tailor your training to the individual, their abilities, the event and what they want to get out of it.

About the author: Matt Hancock, Sports Scientist

Matt Hancock is a Sports Scientist, Strength and Conditioning Coach and Co-Founder of the UKPTA. He is currently working alongside England Rugby and completing a PhD in Injury Epidemiology and Performance Analysis. To find out more, visit our “About Us” page.