* Q2 net profit 418 mln vs consensus 386 mln
* N.America sales up 16 pct, greater China up 27 pct
* Reebok impairment of several hundred million euros
* 2018-2020 targets confirmed
* Shares indicated up 2 pct (Adds detail, background)
BERLIN, Aug 9 (Reuters) - German sportswear firm Adidas has taken an impairment charge on its struggling Reebok brand, but said the retrospective accounting move would have no impact on its 2018 results as it reported a better-than-expected second quarter.
Sales rose 10 percent to 5.26 billion euros ($6.11 billion) after currency effects, beating the 8 percent expected by analysts.
Net profit from continuing operations rose 20 percent to 418 million euros, also beating analyst forecasts for 386 million.
Adidas shares, already up 14 percent this year, were indicated up 2.1 percent in pre-market trade.
It said higher prices and sales through more profitable channels such as ecommerce helped the bottom line
Marketing spending rose to 13.5 percent of sales from 12.3 percent due to the soccer World Cup.
Adidas, which has been taking market share from rivals Nike and Under Armour in North America, saw sales growth in the region slow slightly to 16 percent, but accelerate to 27 percent in greater China.
As Adidas had previously cautioned, sales were flat in western Europe, where Nike has been growing faster.
Nike teams dominated the final rounds of the World Cup, meaning Adidas missed out on an extra boost from jersey sales.
In June, Nike beat profit and revenue estimates as new launches and a focus on direct-to-customer sales helped reverse declining sales in North America for the first time in a year.
Adidas said it was taking a medium triple-digit million euro impairment related to the Reebok trademark in 2016 after the German Financial Reporting Enforcement Panel disagreed with how it calculated historical book value.
But it said the restatement had no impact on its cash position and reiterated its guidance for 2018 and beyond, adding that Reebok's prospects were unchanged, even as the brand reported a 3 percent fall in second-quarter sales.
Adidas bought the Reebok brand in 2005, but it has performed poorly since. Chief Executive Kasper Rorsted announced plans in 2016 to overhaul Reebok, including opening a new headquarters in Boston and speeding up store closures.
$1 = 0.8616 euros Reporting by Emma Thomasson; editing by Douglas Busvine and Jason Neely