In the NFL during the 1970s, were workouts mostly push ups, sit ups, pull ups, calisthenics?

Because weightlifting was still a fairly foreign concept as opposed to now where it is highly popular among all sorts of people. Plus, I would think they would not have the fitness machines we have today. This, and I guess there were not as many trainers or nutritionists igned to each time as there are today. This and the limited number of people on the medical staff