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If 26.2 miles just isn't enough, an ultra could be the race for you. Races longer than a marathon, ultras range from 30 miles to hundreds of miles and take place in hundreds of beautiful locations from Sussex to the Sahara.
Although it's possible to approach an ultra from a standing start, most newcomers are marathon runners bitten by the long-distance bug.
Don't worry – you don't have to double your mileage if you double your race distance. The key is to emphasise endurance rather than speed training – so swap time on the track for long runs and hikes on similar terrain to your race.
You'll be running longer, so your body will need more time to recover. Without enough rest days, those crucial long runs will tire you out instead of making you stronger.
Ultras are rarely road races, and they're seldom flat. Avoid problems by incorporating trail, cross-country and hilly sessions into your training. And head to the gym – weight-training will prepare your quads for the hills, while strong core muscles will help you maintain form as the miles tick by.
Of course the element that marks out ultra hero from zero is perfect pace. Even the elite rarely "run" all the way in long ultras, so map out a run-walk strategy and practise until your race pace is second nature. Hiking uses different muscles as well as disrupting the steady rhythm of running, so avoid race-day agony by adding long walks to your training.
It's often said that the most important part of ultra-running is mental, not physical. Long runs, as well as building your physical strength, will give you the mental endurance to stay on your feet for anything from 27 miles to the length of the UK.
Once the going gets tough on race day, you'll need distractions. Start a countdown to the next feed station, strike up a conversation or repeat a mantra through gritted teeth – whatever keeps you occupied.
Ultra-runners burn calories like nobody's business, around 100 calories per mile. Your body can only absorb 240-280 calories an hour, so snack from the start, before you get hungry, and eat carbs little and often to dodge the dreaded ‘wall'.
Even the most sweet-toothed runner would struggle to fuel themselves entirely on energy drinks, bars and gels, so it's important to find "real food" to see you through. Try different combinations on long runs to get the fuel you need – and avoid tummy troubles.
It's just as important to stay hydrated – some ultras even require weigh-ins at feed stations to check runners' hydration. Sip a litre of water an hour to avoid dehydration, and stock up on electrolytes with salty food and drinks.
To avoid heavy water bottles chafing – a real irritation after miles and miles –practise with different bottles and bladder packs.
Small gaiters (garments worn over the shoe) will keep mud, sand and stones out of your shoes, but send a fresh pair of shoes and socks ahead to aid stations if you're able to – there are few things more miserable than running for miles in soggy shoes.
If your race stretches into the night, you'll need to light the way. Invest in an LED headtorch plus another torch for extra depth perception.
If you're on your feet all day – or even all week – you need to stop injuries in their tracks. A sore spot could become a prize-winning blister in minutes, so get used to fixing problems on the hop. Some runners swear by blister plasters or tape, while others coat their feet in a thin layer of lubricant.
Your mileage will be high, so be on red alert for injuries. Get to know your danger areas, and stay on the lookout for incipient injuries.
... but definitely not least, taper training effectively to avoid burnout, exhaustion or injury – you'll never get to the finish if you're tired before you even begin.