Musician Sandra Riley Tang of home-grown band The Sam Willows has not worn a normal bra for almost 1 1/2 years. Instead, she dons a sports bra most of the time.

The 25-year-old says: "I wear sport bras that are for light workouts and which have nice designs at the back. They are much more comfortable and they match my style."

She also wears crop tops and tights to attend meetings and run errands, a look she describes as "smart casual".

Tang, who is also creative director and co-founder of yoga studio The Yoga Co., is among people who are incorporating sportswear into their everyday wardrobe, as the athleisure trend catches on.

Hitting the sweet spot between function and fashion, athleisure broadly describes clothing that can be worn for working out and as casual wear. Think patterned tights or jogger pants in place of skinny jeans, and crop tops instead of shirts, styled with sneakers.

Athleisure is big business. United States sports apparel giant Nike's fiscal 2016 income statement review reports that revenues rose by 6 per cent to US$32.4 billion (S$43.4 billion).

The influence of pop culture has also bolstered the trend. Mr Gabriel Yap, 38, head of marketing for Puma South-east Asia, says that after American pop singer Rihanna and reality television star Kylie Jenner were seen endorsing Puma's Pwrshape Control sports bra and tights ($89 and $99 each), sales of those items "easily tripled".

It is not just sport brands that are offering a wider variety of colourful and stylish sportswear. Fast-fashion brands such as Swedish label H&M has its own sports department and British high-street retailer Topshop recently launched an activewear line, Ivy Park, with American pop star Beyonce.

A spokesman for Wing Tai Retail, distributor for Topshop here, says: "Our customers are in their 20s to 30s who want to stay in shape and stay in fashion. And there is another group of teens who are fans of Beyonce."

Brands are responding to the demand. H&M opened a sportsfocused store at Kallang Wave Mall in June 2014, just six months after introducing its sport concept to the Singapore market, and home- grown multi-label sportswear store MissFit and MrFit opened its first two outlets at 313@Somerset in May.

American sportswear company Under Armour will open a store at VivoCity in the middle of this month. Later this year, it will launch fashion-driven lifestyle line Under Armour Sportswear in the United States, but it will not be available in Singapore yet.

Mr Mandeep Chopra, 40, owner of MissFit and MrFit, says the stores were set up to take advantage of the healthy-lifestyle trend. They stock apparel and shoes from brands such as Adidas, Under Armour and Puma.

He says: "The athleisure trend has been around for some time and it is a key selling point for us. People want to look good even when they are working out."

Mr Chopra, who also owns sneaker company Limited Edt, has customers buying shoes for their "aesthetic value and coolness factor" instead of just functionality.

It is the same at Puma, with Mr Yap saying that running-style leisure footwear accounts for at least 60 per cent of the brand's product offerings, compared with 30 per cent in the past.

At multi-label sneaker store Leftfoot, business has improved because of the athleisure trend.

Co-founder Kevin Low, 41, says: "Sales have increased by 20 per cent and we see more women coming to the stores dressed in sporty cropped tops and joggers and the latest runners from Adidas or New Balance."

The popularity of athleisure wear is not only because it looks good, but also because it feels good. People who wear sports clothing in and out of the gym say that comfort is the main draw.

Carla Dunareanu, 27, an actress and television presenter with Fly Entertainment, says she will "always choose comfort over style".

"And the fact that the clothes are Dri-Fit is fantastic because I perspire a lot. Wearing clothes that dry easily makes me feel a lot more comfortable," she says, referring to Nike's fast-drying fabric.

Dunareanu, who runs and does Brazilian jiu-jitsu, estimates that at least half her wardrobe is sportswear, most pieces are from Nike. She has about 100 pieces of sportswear, including sports bras, tops and tights, and at least 60 pairs of running shoes and sneakers, which she wears with jogger pants and crop tops.

Aside from the gym, she also wears sportswear to work and to cafes and restaurants.

Recruiter Michelle Wong, who goes to the gym every day, likes to wear her Under Armour or Nike sports tops with casual cotton shorts. For tops that are a combination of a sports bra and blouse, she pairs them with jeans or skirts.

She has about 50 pieces of sportswear, including sports bras, tops and tights.

The 31-year-old does not go to work in sports clothing, but pairs tights with a tank top when she goes to the movies or brunch.

She says: "My gym clothes make me feel fit, healthy and sexy. It's also economical to wear them more often anyway."

Sportswear has also become the outfit of choice for musicians such as Sara Wee of pop-rock band 53A and Tang when they perform on stage. For The Sam Willows' concert last month, Tang wore a pair of Nike short tights customised with sewn-on sequins.

This marriage of form and function was stressed as an important factor in the success of Nike's products, according to the company's president and chief executive officer Mark Parker.

He said during the company's quarterly conference call in June: "We bring performance benefits to sportswear, what we call sports style innovation. We deliver lightweight, breathability and comfort to products for everyday life and it drives a significant business for Nike. We see great potential for innovation and growth ahead with sportswear."

Although the athleisure trend is catching on in Singapore because more people are leading active and healthy lifestyles, some feel the trend is still in its infancy here.

Mr Wilfred Mong, 37, brand communications manager for Under Armour South-east Asia, says: "Singapore is not as developed in this area compared with key cities such as New York and Tokyo. These cities are always at the forefront of innovation and fashion and are often regarded as world trendsetters."

Dunareanu shares his view and thinks women "still have room to be a bit more daring", but finds it encouraging that people here have become "more accepting" of the trend in recent years.

She says: "Many women here wear white caps with denim shorts and probably white or black sneakers. We can afford to be more fun with our choices, such as wearing brighter colours."

While the women are happy to have more styles and options to experiment with, some men are feeling left out. They may have their pick of sneakers and jogger pants, but there is not much else for them.

Gym trainer Muhammad Faiz Arifin, 27, who buys his sportswear mainly from Adidas and H&M Sport, hopes to see more colourful and varied designs for men.

He says: "I wish there were more designs for men. Guys in the gym are still wearing tank tops and shorts or T-shirts and shorts."

Yoga instructor Muhamad Hafiz Sazali, 32, says he has resorted to buying printed leggings from the women's department. He has about 10 pairs from brands such as Lululemon, Base Athletica and Vivre Active, and he goes for monochrome or geometric designs that look more unisex.

He says: "The sportswear apparel available is so one-sided. I wish there were just as many fashionable sportswear options for men as there are for women."

10 sporty pieces for everyday wear

1 Multi-coloured tennis skort, $79, from Adidas

2 Strappy sports bra, $29.90, from H&M Sport

3 Eliofeel women's running shirt with keyhole cut-out at the back, $5, from Decathlon

4 Cropped grey and blue sweater, $76.90, from Ivy Park at Topshop

5 Purple seamless low Streaky Heather sports bra, $59, from Under Armour

6 Adidas x Stella McCartney Pureboost X women's sneakers, $249, from MissFit

7 LunarEpic Flyknit running shoe, $289, from Nike

8 Women's Phoenix Rising yoga pant (above), $109, from Touch The Toes

9 Blue tights with night city scape print (above) from Puma Goldpack, $89, from Puma

10 Men's polyester and cotton sweat pants (above), $39.90, from Uniqlo

STORE LISTINGS

Adidas: Adidas stores, including 313@Somerset, B1-33, 11am to 9.30pm daily, tel: 6735-4959; and Suntec City, 01-323, 11am to 9.30pm daily, tel: 6334-3107

Decathlon: 750A Chai Chee Road, 01-01, 9am to 10pm daily, tel: 6225-4773

H&M Sport: H&M stores, including Orchard Building, 10am to 11pm daily, tel: 6235-1459; and Kallang Wave Mall, 01-74, 10am to 10pm daily, tel: 6702-7170

Ivy Park at Topshop: Ion Orchard, B2-01, 10.30am to 9.30pm (Sunday to Thursday) and 10.30am to 10pm (Friday and Saturday), tel: 6509-8602; and VivoCity, 01-72, 10.30am to 9.30pm daily, tel: 6273-9261

MissFit: 313@Somerset, 03-25, 10.30am to 9.30pm (Sunday to Thursday) and 10.30am to 10.30pm (Friday and Saturday), tel: 6509-8457

Nike: Nike stores, including Paragon, 04-13, 11am to 9pm daily, tel: 6333-8260; and Raffles City, 02-29, 11am to 9pm daily, tel: 6337-0296

Touch The Toes: 31 Arab Street, Level 2, noon to 8pm (weekday), 1 to 7pm (weekend), tel: 6396-5025

Under Armour: Under Armour stores, including Orchard Gateway, B1-05, 11am to 10pm daily, tel: 6702-4918

Uniqlo: Uniqlo stores, including Plaza Singapura, 03-53, 11am to 10pm daily, tel: 6238-0260

Puma: Puma stores, including Tangs Orchard, 11am to 10pm daily, tel: 6737-5500; and Takashimaya, 10am to 9.30pm daily, tel: 6737-5503