Under Armour (UA - Get Report) (UAA - Get Report) is back in play in 2018.

After a rough performance in 2017, shares of Under Armour are looking positive again, thanks in large part to a big fourth-quarter earnings beat earlier this month that sent shares rallying more than 16% same-day.

"We are getting incrementally better every single day, and we are feeling that right now," CEO Kevin Plank told TheStreet in an interview following the earnings win.

Plank reiterated that bullishness on 'Mad Money' with TheStreet's founder Jim Cramer on Wednesday.

Fundamentals are only part of the turnaround story in Under Armour here. The technical picture in Under Armour is another force to be reckoned with. Under Armour is carving out a pretty textbook example of a bottom as we round the corner to March. And while shares were under pressure back at the end of 2017, that price action actually set the stage for the outperformance we're seeing now.

So, to figure out how to trade Under Armour from here, we're turning to the chart.

Under Armour made its ultimate low back at the start of November, following third-quarter earnings. From there, shares have managed to make higher lows, an indication that buyers are finally back in control of things again.

Resistance up at $16 helped Under Armour form an ascending triangle pattern off of its lows, a bullish price setup that was triggered with February's earnings beat. That breakout signal makes more upside in the high-probability trade for shares of Under Armour from here.

Short term, shares have been consolidating just above newfound support at their $16 breakout level. That's a pretty common thing to see, particularly after such a big gap higher. It makes sense to aim to buy as close to that $16 level as possible.

Relative strength, the indicator down at the bottom of Under Armour's price chart, adds some extra upside confidence to shares right now. The higher lows in relative strength signal that Under Armour isn't just making higher lows in its own price action right now, it's also systematically outperforming the broader S&P 500 since last fall. As long as that relative strength uptrend stays intact, Under Armour is statistically predisposed to keep on beating the rest of the market.

From a risk-management standpoint, Under Armour could fall quite a bit without invalidating its uptrend. Prior lows around $13 are a logical place for intermediate-term longs to park a protective stop.

Under Armour's recent outperformance doesn't look like a flash in the pan -- shares are carving out a pretty textbook example of a long-term price reversal. It now looks like as good a time as any to be a buyer.

This article is commentary by an independent contributor. At the time of publication, the author held no positions in the stocks mentioned.