The Knowledge: Stella McCartney on how to do sportswear with style Fashion and sportswear designer Stella McCartney gives her style tips for a good-looking work-out Feel good Most people hide behind their black leggings for exercise and think the less people see of their work-out gear the better, but I find that a great kit encourages and inspires me to exercise. When you are wearing something stylish or cool you feel better when you are performing, and I have spoken to athletes who agree. It can give women the confidence to be themselves when they work-out, too, and why not? Your gym kit should be afforded the same emotional and physical freedom as the rest of your wardrobe. You shouldn't have to sacrifice anything for your sport: you should feel 100 per cent yourself. Get the whole look I'm a bit of an all-rounder in terms of exercise. I run, horse-ride, do dance aerobics in my front room and practise yoga, though not as much as I should. I often cycle to work too, on top of running after four kids, which is probably my main form of exercise! I always go for the head-to-toe gym look. Colour-blocked running leggings bring a bit of energy to your work-out environment, plus they look equally good with a pair of heels. You need a great cover-up piece in case you get caught in the rain. A printed bomber jacket is versatile and looks good on all body types. Stella McCartney with the synchronised swimming team Acrobatix, modelling her S/S '14 collection Invest in your feet A quality pair of trainers is key if you work-out regularly. I know it is easy to get used to your old pair and to buy a new pair seems a pain, but there are so many cool trainers out there using exciting technology that it is worth upgrading. Trainers can transform the way your body responds to exercise. I can't stop talking about the Energy Boost Shoe by Adidas (£110, adidas.co.uk) - and not because I designed it! They give you a real bounce when you are running. McCartney's ADIDAS Boost trainer Choose pack-aways Look out for lightweight, wind-resistant kit that easily folds up. I run home from work and need leggings and shoes that are light enough and small enough to stick in my day bag. Pack-away items that transform clothing into a parcel that you can just hold in your hand are also really useful. I love that idea of making sport really accessible. If you feel like going for a jog you can pull your shoes out and go. Aerial yoga at Stella McCartney's Spring/Summer '14 presentation for ADIDAS Embrace technology Many fashion designers take inspiration for their runway collections from sportswear, but I get to do the opposite. I'm learning about new sports all the time, such as aerial yoga, and am designing kit specifically for them. Bringing sports performance clothes and fashion together encourages you to take your exercise clothes outside the gym. I feel that women are sometimes unaware of the brilliant technology available in sportswear. Look out for the materials ClimaLite, ClimaCool and thermoplastic polyurethane (TPU). ClimaLite (made of a cotton blend) and ClimaCool (made from synthetic fibres) encourage quick moisture evaporation and reduce skin temperature during exercise. TPU is breathable, supportive and durable and is used in sportswear, from shoes to anoraks. For an environmentally friendly kit you can buy pieces that are 95 per cent waste free or made from recycled materials or organic cotton, such as my Low Waste range for Adidas .