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March 29, 2021 at 1:42 pm
All news  |  Brighton Half Marathon 2021
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All about the Long Slow Run (LSR)

Mike Bannister, founder of our training partner RunBrighton, explains the long slow run (LSR). Find out why this session is crucial in a half-marathon training programme.

Why is the long, slow run important for half-marathon training?

By ‘slow’, we mean slower than half-marathon race pace.

When we run, we use different energy systems. A long-distance race, such as a half marathon, mainly uses our aerobic system (as opposed to, say, sprinting over a short distance like 100m, which is predominantly anaerobic).

In fact, running a half marathon is approximately 97% aerobic. It’s therefore really important that we train our aerobic capacity, and gradually increasing the duration of the long run will help you achieve this. This is typically the Sunday run in most half-marathon training schedules.

A common error, with many runners, is to run too hard on the long, Sunday run – maybe training at half-marathon race pace for most of the run. Don’t forget, this long training run is principally about developing your aerobic capacity, gradually increasing time on feet, and building endurance. It’s not about improving your speed.

From time to time, half-marathon race pace is incorporated into the long run. But certainly not for the whole of every long run.

Sessions to improve speed are done differently, and they typically form part of your midweek training.

One of the problems with running too hard on the long, Sunday run, is that you’re unlikely to recover sufficiently to properly execute your midweek speed-training sessions. There can then become an imbalance, as regards your whole week’s training. The long run is essential for half-marathon training and, if it is done too fast, not only can it be an inefficient way to train, you also increase the risk of developing an injury.

As a rough guide, the long run should normally be done at approximately 10-15% slower than half-marathon race-day pace (circa 1 minute-per-mile slower than race pace).

As an example, if a realistic target time for your half marathon is 2 hours (an average pace of approximately 9 minutes-per-mile), the pace of your long run should be approximately 10 minutes-per-mile. A tip, to ensure your long run is done at the correct pace, is to keep it conversational. You should be capable of holding a fluid conversation throughout your training run. If you find yourself becoming breathless and you struggle to string a sentence together, you’re probably training too hard.

So, keep it easy, have a nice chat, enjoy the scenery, improve your endurance and develop your aerobic capacity!

Membership with RunBrighton

You can now sign up for membership with our training partner, RunBrighton, for their build-up to the Brighton Half Marathon. But be quick as places are limited. Membership revolves around a group run every Sunday, alongside a range of associated benefits. Find out more at RunBrighton.com.