Over the Top is a 1987 drama film starring Sylvester Stallone, and produced and directed by Menahem Golan about a long haul truck driver who tries to win back his alienated son while becoming a champion arm wrestler. The screenplay was written by Stirling Silliphant and Sylvester Stallone.

Lincoln Hawk is a struggling trucker who arm wrestles on the side to make extra cash while trying to rebuild his life. Hawk’s wife Christina is very ill and asks that Hawk pick up their son Michael from military school so that he may get to know him; Hawk left them 10 years earlier. His controlling father-in-law Jason Cutler, a wealthy man who hates Hawk and disapproved of his daughters relationship with him, believes that Hawk has no right to be in his grandson’s life. Mike is very distrusting and bitter towards Hawk and treats him with contempt at every turn.

Over the course of a cross country trip, Mike comes to trust his father until learning about his mother’s death. Feeling he would have been there with her if not for Hawk, he leaves for his grandfather’s estate. An attempt to retrieve Mike ends with Hawk being arrested.

Eventually, Lincoln competes in the World Arm Wrestling Competition, held at the Las Vegas Hilton. His hope is to win the grand prize of $100,000 and an expensive, new semi-truck and thus be able to start his own independent trucking business. Mike, stunned by his grandfather’s deceptions, goes to the Hilton and finds Hawk. Apologizing for misjudging him, Mike gives Hawk the emotional support he needs to compete.

Summary via Wikipedia.