* Sales up 28 pct in China, 26 pct in North America
* Running and fashion shoes grow at double-digit rates
* Nike and Under Armour both cutting jobs (Adds details, background)
BERLIN, Aug 3 (Reuters) - German sportswear firm Adidas AG reported another quarter of bumper sales growth in North America and China on Thursday as it took market share from rivals Nike and Under Armour with its retro styles and running sneakers.
Adidas, which had already announced preliminary second-quarter results and raised its 2017 guidance last week, said sales grew 28 percent in China and 26 percent in North America, although they fell 11 percent in the tough Russian market.
Overall, sales rose a currency-neutral 19 percent to 5.038 billion euros ($5.97 billion), with the core Adidas brand growing 21 percent while sales at the Reebok fitness brand were up 5 percent.
Adidas said sales were driven by double-digit increases in the running category, where it has been unable to keep up with demand for its springy Boost shoes, as well as for its Originals and Neo fashion lines.
Adidas doubled its share in the U.S. sport footwear market to 12.7 percent in April, while Nike slipped 2 percentage points to 52.7, market intelligence firm NPD said, with Adidas taking three of the top spots in the 10 best-selling shoes.
The Adidas retro basketball shoe Superstar was the top selling sneaker in the United States in 2016. While sales of that model have slowed somewhat, Adidas has two new blockbuster shoes - the NMD Runner and the Tubular Shadow, NPD says.
On Tuesday, Under Armour shares slumped to a record-low after the company trimmed its sales forecast and said it would cut jobs and close stores as it struggles in a fast-changing and fiercely competitive U.S. sportswear market.
Nike also announced in June that it would cut about 2 percent of its global workforce and eliminate a quarter of its shoe styles, to better compete in a slowing market.
($1 = 0.8440 euros) (Reporting by Emma Thomasson; Editing by Maria Sheahan)