Lionheart (1990)

Léon Gaultier (Jean-Claude Van Damme) is a soldier in the French Foreign Legion, serving abroad in East Africa. But after his brother is cruelly murdered, Gaultier deserts his assignment and travels to the United States to help his widowed sister-in-law (Lisa Pelikan), who is now struggling to care for her children. But the job market is tough, so Gaultier takes his hand-to-hand combat skills into the brutal world of bare-knuckle fighting, where the paydays are nearly as big as the risks.