If you fancy a change from running that will actually help your main sport, try open-water swimming (OWS). With some essential kit and a bit of work on technique, swimming can complement your running in all sorts of ways, whether you want to do more cross training, and her advice on how to dip your toe in the world of open-water swimming or are maybe thinking about your first triathlon.

Naturally there are more opportunities for the less hardy to do it in the summer months, in this country at least, but at any time of year it’s worth researching your nearest OWS centre or lake and finding out when they’re accessible.

We asked Fenella Langridge, a professional middle-distance triathlete (who's usually based in Salisbury when she’s not competing around the world), to talk about the benefits of swimming or are maybe thinking about your first.

Summer’s best, at an official centre

‘Even I’m not comfortable swimming in open water on my own,’ says Langridge. ‘It’s always sensible to have someone with you, or someone spotting you from shore in case you get into difficulty.’ She recommends newbies book into a supervised open-water swimming centre, where you will often be given an introduction to the centre and the basics of OWS. There will also be a marked-out course and a team of lifeguards, often patrolling the water in kayaks or small boats. Langridge trains at Vobster Quay near Froome and New Forest Water Park; Outdoor Swimmer has a list of supervised outdoor-swimming centres in the UK. Expect to follow a circuit (anything from 100m up), which will be marked out with buoys, with a clear entry and exit point.

In the UK, open-water swimming centres are usually open between May and October, which is the smartest part of the year to get going as a newbie, as you won’t be used to the much colder winter temperatures. It’s easier to commit to training in the warmer months, when the water can be around 17-20C, as swimming becomes much more appealing. ‘Some people swim in winter, but remember: those people do it week in, week out, and year-round,’ warns Langridge. ‘It would be quite dangerous to jump into open water in December if you’d never done it before.’ If you do decide to swim independently, ‘tell someone where you’re going, make sure you’re confident with your surroundings and know what you will do if you get in trouble’.

OWS is a different kettle of fish from pool swimming

‘You can be phenomenal in the pool but useless at open-water swimming,’ laughs Langridge. ‘That’s because your strength and skill set are not suited to OWS, but you can learn it – you just have to practise.’ The most important skill in OWS (apart from the swimming itself) is to be adaptable. ‘Strong open-water swimmers have the ability to change their stroke depending on the conditions – for example, a change in current, being hit by a wave or if they are swimming alongside someone,’ says Langridge.

If you’re a strong enough swimmer that you can keep going for 30 minutes in a pool without stopping, expect to be able to go for half that time in open-water conditions before you start to tire. ‘Wetsuits offer buoyancy, but that’s very different to pushing off from the end of the pool, or stopping on the side for a rest or a drink.’

How to improve your technique for open-water swimming

Most open-water swimmers use front crawl because it is the best stroke for energy efficiency, but if you’re not in a rush, Langridge suggests you just use whatever stroke makes you feel most comfortable. But not backstroke. ‘It will be hard to navigate and floating on your back is often a signal of distress in OWS’. Swimming with a high stroke rate and bilateral strength (ie. equal power in both arms and even kicks) will help you to stay on course and cope with conditions that can change quickly. Sometimes visibility can be low and there may be more distractions than in the pool, whether that’s other water users, avian life or whatever’s in the murk down below.

‘In order to swim as straight as you can, imagine train tracks underneath you and encourage your arms to follow them,’ recommends Langridge. ‘Keep your head still and smooth because once that moves, your whole body moves.’

When it comes to sighting – following buoys to stay on course – Langridge suggests you look every third stroke until you find your rhythm. ‘You don’t need to lift your head too high unless it’s really choppy,’ she advises. ‘In still water, act like a crocodile – have your eye out of the water but your nose and mouth in. This will keep your head still and help you stay on course.’

The pool is good training for OWS

Pool swimming is much calmer and feels more safe, without wind or currents to fight against. That makes it a better place to practise before heading out into the big water. Langridge uses her local pool three or four times a week for training, where she perfects her technique and builds her endurance.

For newbies, she recommends practising sighting in the pool: ‘Have someone stand at the end of the lane and hold up fingers – your goal is to look every other stroke and count the fingers,’ she says. She also recommends tying a band around your ankles (or using a pull buoy) to immobilise your legs, which, in turn, helps increase your arm turnover. If she doesn't have a band or buoy, Langridge improvises with an old inner tube that was once part of her Parcours bike wheels. ‘You use your legs less in OWS – they are mostly for balance and efficiency,’ she says. ‘An increased arm turnover makes you stronger, straighter and more resilient in currents and chop.’

Don’t forget the wetsuit

Most supervised open-water swimming centres stipulate wetsuits when the temperature drops below 16C. However, Langridge advises you wear a long-sleeve suit regardless because ‘you will glide through the water and they give you buoyancy, which is helpful if you get tired and want to float’. You can often hire wetsuits from swimming centres, or brands such as Zone 3 will rent you a wetsuit from one month to an entire season; if you’re committed, it’s more cost-effective to Open-water swimming: a beginners guide.

‘It’s essential your wetsuit fits properly, or it will impede your swimming,’ says Langridge. ‘Every suit is made differently – there’s usually detailed guides on their websites. Make sure you pull it up enough around your shoulders and hips so you have room to move, and flexibility in your shoulders – you should feel comfortable to do 10 arm turns without it feeling too draggy.’ Langridge recommends a 3mm thickness for summer swimming and triathlons. To help get into her suit, Langridge keeps her socks on to help slide her legs in and she often wears gloves to protect the material from her nails. When you get in the water, splash some water inside the suit to help ‘sucker’ it to your body and acclimatise yourself to the temperature.

What other kit do I need for outdoor swimming?

‘I’d suggest buying two pairs of goggles,’ says Langridge. ‘One pair that are clear and a pair that block out the sun. If it’s a dark day, you don’t want to be wearing tinted goggles that stop you seeing where you’re going.’ She recommends larger-coverage goggles for open-water swimming and tests them out by sticking them to her face without the straps. ‘If they stay in place, that’s the sign of good, water-tight goggles.’

Langridge also uses a standard swimming cap for two reasons: the bright colour makes her more visible in the large open space, and if it’s particularly cold, she can increase her warmth by putting a second one on. Thermal hats, booties and gloves will also help the extremities when the temperature drops. Another way to be more visible in the sea to boats and jet-skiers is to attach a bright tow float to yourself. And if you are at risk of ear infections in the water, ear plugs or a bottle of Swim Seal will help.

What to do when the fear strikes

It can feel surprisingly lonely when you’re far from shore, and we all know what happened in Jaws. It’s not unusual to feel frightened and vulnerable. According to Langridge, focusing your mind on numbered or visual targets can stop you from imagining the worst. ‘Break your swim into blocks of, say, 50 strokes, or tell yourself you will commit to swimming to a certain buoy before your turn around. Focusing on small goals will help you relax and – hopefully – the experience will start to become more enjoyable.’