This is the moment Terminator star Arnold Schwarzenegger's son Joseph Baena shows fans just what he is made of as he runs a triathlon in skin-tight Speedos. https://filedn.eu/lhVNGNsizwl5t7THnzzJ2c8/CEN-SchwarzeneggerSonBaena-01.mp4 Bodybuilder Joseph was clearly struggling to keep his bulges under control as he jogged along a beach to the finish line in…