From a younger Arnold Schwarzenegger's "Education of a Bodybuilder" --
"Already, since my experiences at the lake, I was a strong believer in training partners. I needed someone not only to teach me but to inspire me. I trained better, harder, if I was around someone whose enthusiasm was as strong as mine and who would be impressed by my enthusiasm. That first winter, I trained with Karl Gerstl, the doctor who had helped me with my initial program. Aside from his usefulness as a translator, it was especially helpful to be around Karl. He knew everything about the body. He was serious and worked hard. We trained the same way, except our goals and our diets were different: I wanted to gain weight, to bulk up; Karl wanted to lose it. But Karl gave me the boost I needed.
There were certain days when something held me back and I didn't train as hard as on other days. That was inexplicable to me. Some days nothing could hold me back. Other days I'd be down. On the down days I couldn't handle anywhere near my normal amount of weight. It puzzled me. Karl and I discussed it. He had read a great deal of psychology (at fifteen I barely knew the word, though his argument made good sense and in fact helped lay the foundation for my later thinking). "It's not your body, Arnold. Your body can't change that much from one day to the next. It's in your mind. On some days your goals are just clearer. On the bad days you need someone to help get you going. It's like when you ride a bicycle behind a bus and get caught up in the slipstream. The wind sucks you along with it. You just need some prodding, some challenge."
Karl was right. Every month, I had at least a week when I didn't really want to train and I questioned myself: Why should I train hard if I don't feel like it? These were the days Karl pulled me out of it. He'd say, "Man, I feel great today! I want to do bench presses. Let's do twenty-five instead of twenty. How about a contest? Ten shillings to the one who does the most bench presses."
It worked perfectly. He forced me to get off my butt, to get my sluggish body moving. It became extremely important to have somebody standing behind me saying, "Let's do more, Arnold. Come on—another set, one more rep." And it was just as important for me to help somebody else. Watching him work out, encouraging him, somehow drove me on to do an even tougher set."