Sneakers today are not like your grandparents Keds as sports apparel companies provide consumers with an array of athletic wear options to suit a variety of tastes and needs. Nike (NYSE:NKE) continues to be the leader in this sector, but Under Armour (NYSE:UAA) and Skechers (NYSE:SKX) are growing fast and gaining market share.

While it's uncertain if Nike's rivals can give the company a run for its money, each apparel maker appeals to different consumers. This provides investors with plenty of opportunities.

Nike: Sustainable growth and innovation
Nike has long been the leading sports apparel manufacturer in the U.S. while continuing to grow its brand internationally through its Converse unit. The company's solid track record of growth and earnings rolls on as evidenced by NIKE's most recent financial report.

The company reported results for the fiscal 2014 third quarter in March that featured revenue growth of 13% to $7.0 billion while diluted EPS also rose 4% to $0.76. It also shored up inventories by 12% to prepare for the spring sales season.

"Our strong Q3 results demonstrate our relentless focus on delivering innovations that resonate with consumers," said company CEO and President Mark Parker.

The report also highlighted increased selling and administrative expenses of 16% percent to $2.2 billion in connection with "demand creation expense" rising 18%. This was driven by marketing costs for product launches, sponsoring the World Cup, and investments in retail product ads.

In short, NIKE continues to invest in growth by developing new products, opening new stores, and building out its e-commerce infrastructure.

NIKE reduces it global footprint
NIKE is not only a growth play, but is one for investors who factor ethics into their calculus. In May, the company announced the release of its Sustainable Business Performance Summary for the 2012-2013 fiscal year. According to NIKE, the company is "making progress across key impact areas of climate and energy, labor, chemistry, water, waste, and community."

"NIKE's success as a growth company is tied directly to our culture of innovation," wrote Mr. Parker in the introduction.

In particular, the company said CO2 emissions at its factories were reduced by 13% by the end of fiscal year 2013 as it intends to reduce these emissions by 20% through fiscal year 2015. The company also strives for water efficiency, with a goal of 15% reduction in water usage by that time at its contract factories that make footwear.

"We believe business has a critical role to play in meeting the challenges of a changing world – addressing climate change, preserving the earth's constrained resources, enhancing global economic opportunity – not by reducing growth but by redefining it," Parker said.

NIKE's share price is currently hovering at the $75 mark, about $5 off of the company's 52-week high. The company's forward price earnings ratio is 22.27, a few points lower than the current P/E of 25.65. Investors should mark their calendars for June 26 when NIKE announces third-quarter results to determine if there is a better price entry point.

Under Armour on the rise
Under Armour has expanded its consumer base so that its products are used by professional athletes as well as "weekend warriors." The company intends to continue with its growth plan by opening new stores and signing up with professional sports teams.

In April, Under Armour opened its latest apparel shop on Broadway in the SoHo neighborhood of New York City. The specialty location flies under the chic name of the SoHo Brand House. It is Under Armour's largest retail outlet so far.

The company is also embarking on new ventures with professional sports teams. In May, for example, Under Armour announced a multi-year deal with Rugby Canada. The deal calls for the company to outfit all senior Rugby Canada teams as well as Men's and Women's Under 20 and Men's Under 17 teams. 

These sponsorship deals are obviously far smaller than NIKE's which is representing at the World Cup in Brazil big time. But Under Armour's new alliances coupled with its "Brand House" openings will allow the business to grow its brand across the global village and gain market share.

Skechers is reinvigorated by walking shoes
Skechers is known for its multiple lines of shoes, particularly children's shoes adorned with colors and lights. The company is also a leader in the walking shoe segment.

In April, Skechers announced financial results for the first-quarter ended March 31, 2014 which highlighted net sales of $546.5 million compared to $451.6 million in the first quarter of 2013.

Investors reaped rewards in the past year as well as Skecker's share price has made a significant advance from about $21/share to its current price point hovering at $45. The question remains as to whether the company can continue this momentum, even though the forward P/E of 16.5 bodes well for continued share price growth.

The Foolish long run
NIKE, Under Armour, and Skechers serve the needs of different customers. While Skechers is a smaller player, the company remains a good growth story. The future also looks bright for Under Armour as it executes a solid strategy to grow its brand.

In the final analysis, how can you bet against a company like NIKE that comes up with a snarky slogan like Just do it and boasts a solid track record of financial performance to boot?