Under Armour Inc. (NYSE:UAA) just reported stellar fourth-quarter results and two new acquisitions -- but the market isn't quite sure what to think.

Under Armour stock fell slightly in Wednesday's after-hours trading after the performance apparel specialist said quarterly revenue jumped 31% year over year to $895 million, which translated to a 35% increase in earnings to $0.40 per diluted share. That brought Under Armour's full-year 2014 sales to $3.08 billion, a 32% increase over 2013 and well ahead of Under Armour's previously raised guidance for net revenue of $3.03 billion. Both quarterly figures also easily exceeded Wall Street's expectations for sales and earnings of $849 million and $0.39 per share, respectively.

Within that, quarterly apparel revenue climbed 30% to $708 million, helped in the cold season primarily by new products in training, hunting, and studio, and including new innovations in its Storm, ColdGear Infrared, and Charged Cotton lines. Footwear revenue jumped 55% to $86 million, thanks to new offerings in running and basketball. Accessories revenue also rose 22% to $79 million.

Under Armour's higher-margin direct-to-consumer revenue also grew 27% year over year to comprise 38% of total sales. And despite growing 123% over the same year-ago period, international sales still comprise a paltry 9% of Under Armour's total.

A $560 million bet on connected fitness
In addition, Under Armour announced two new acquisitions in the connected fitness space. It completed the first early last month, purchasing Denmark-based Endomondo for $85 million. Endomondo, for its part, boasts a respectable connected fitness community with roughly 20 million registered users concentrated primarily in Europe. According to Under Armour, those users are a perfect complement to its existing connected fitness platform.

Speaking of which, that's also roughly the same size user base as app maker MapMyFitness had when Under Armour acquired it for $150 million in late 2013. Since then, Under Armour says it has grown MapMyFitness' base to 31 million registered users and in the process "gained further insight and validation into the power of the data generated by this community." At the time of the MapMyFitness acquisition, Under Armour CEO Kevin Plank insisted that he "wouldn't consider this an app company rather than a community first and foremost."

The second acquisition comes in the much larger form of a $475 million agreement to buy San Francisco-based MyFitnessPal, which has built a gigantic 80 million registered user base, given its focus on healthy living and nutrition. This acquisition is expected to close sometime in the current quarter and will expand Under Armour's connected fitness offerings with MyFitnessPal's vastly popular nutritional resources, including a calorie counter and nutrition and exercise trackers. Keeping in mind Under Armour ended the year with debt of $284 million and cash and equivalents of $593 million, this acquisition will be funded through a combination of cash on hand, an expanded term loan, and a revolving credit facility. 

Altogether, considering any overlap and combined with Under Armour's launch of the new UA Record app last month, Under Armour is poised to enjoy the largest digital health and fitness community in the world, with over 120 million unique global consumers.

What to expect in 2015
Finally, Under Armour expects 2015 net revenue of roughly $3.76 billion, good for 22% growth over last year and in line with Wall Street's estimates. In addition, 2015 operating income should be in the range of $397 million to $407 million, representing 12% to 15% growth. To explain the discrepancy, note that that range includes the dilutive impact of Under Armour's acquisitions, one-time deal costs, and the anticipated negative impact of a strong dollar on foreign exchange rates.

Even so, it seems safe to assume Under Armour knows all too well the long-term value of the insight and rapport it can gain with its massive connected fitness community. All things considered, as a longtime Under Armour shareholder myself, this was a terribly impressive quarter that bodes well for the future.