* First-quarter earnings per share $0.06 vs est $0.04
* Revenue jumps 36 pct to $641.6 mln vs est $598.8 mln
* Apparel sales rise 33 pct
* Shares up 4.7 pct premarket
(Adds details, background, analysts' estimates, shares)
April 24 (Reuters) - Under Armour Inc reported a better-than-expected quarterly profit and raised its 2014 revenue forecast as demand for its hi-tech athletic apparel soars.
Shares of the company, which also makes footwear, rose 4.7 percent in premarket trading.
Under Armour said it now expects revenue of $2.88-$2.91 billion for the year, representing growth of 24-25 percent, up from the $2.84-$2.87 billion it forecast in January.
Analysts on average were expecting revenue of $2.89 billion, according to Thomson Reuters I/B/E/S.
The growing popularity of sportswear, particularly among women, and rising health consciousness among customers have helped to push up demand for Under Armour's athletic apparel.
Revenue from apparel jumped 33 percent to $459 million in the first quarter ended March 31, constituting about 72 percent of total revenue.
Under Armour's clothing lines include HeatGear, which draws moisture away from the body to help the wearer stay cool and dry, and the ColdGear Infrared range that uses a ceramic coating to retain body heat in cold weather.
The company was founded in 1996 by Chief Executive Kevin Plank, then a college footballer.
Under Armour's net income rose to $13.5 million, or 6 cents per share, in the quarter, from $7.8 million, or 4 cents per share, a year earlier.
Revenue increased 36 percent to $641.6 million.
Analysts on average had expected a profit of 4 cents per share on revenue of $598.8 million.
Under Armour's shares closed at $54.44 on the New York Stock Exchange on Wednesday. The stock has risen about 25 percent since January.
(Reporting by Maria Ajit Thomas in Bangalore; Editing by Sriraj Kalluvila and Maju Samuel)