How Arnold Schwarzenegger's workouts have evolved in his 70s

At 71, Arnold Schwarzenegger is still pumping iron — although not as he once did.

"My knees are shot," the Hollywood strongman told US Men's Health magazine in an interview explaining how his workouts have changed as he's aged.

"Squatting and all those kind of like heavy leg exercises, I can't do anymore," the actor said. "I have to protect my knees because I want to go skiing. I do mostly bicycling."

While Schwarzenegger remains a "big believer" in free weights — think things like dumbbells and barbells — he's also incorporated more machines into his strength workouts.

"The machines that you have today, I wish that I could have used them in addition to what I did [when I was younger], because they're really amazing," he said.

"A guy like myself who had shoulder surgery, hip surgery, knee surgery—they can always find an exercise around the injury that I could do," he said. "So I cannot do dumbbell lateral raises anymore, but I can go and find the machine that does exactly the same thing and I have no pain."