Mark Berry and John Grimek
Mark Berry (left) and John Grimek (right.) at the time when Berry was the weightlifting coach for the 1936 Olympic games, held in Berlin, Germany. The Mark Berry Bar Bell Courses, which featured Grimek demonstrating a number of exercises, appeared shortly afterwards. As they had a lot of time on their hands, it's conceivable that Berry and Grimek discussed the details of said courses on the boat trip over to Germany.
Berry was also the weightlifting coach during the 1932 Olympics, held in Los Angeles, California.