Complex sentence: Mike Kipruto Kigen (born 15 January 1986) is a Kenyan (until 2015) and Turkish (since 2015) long-distance runner who specializes in the 5000 metres and 10,000 metres.
Split into simpler sentences: Mike Kipruto Kigen (born 15 January 1986) is a Kenyan long-distance runner who represents Turkey (since 2015). He specializes in the 5000 metres and 10,000 metres.