Complex sentence: Netherland has trained in martial arts since he was a child, and holds a 7th Dan in Aiki-jujutsu, 5th Dan in Kempo, and 5th Dan in Judo.
Split into simpler sentences: Netherland has trained in martial arts since he was a child. Netherland holds a 7th Dan in Aiki-jujutsu, 5th Dan in Kempo, and 5th Dan in Judo.