Interesting!
Charlie and/or PJ, does this look like something DDR athletes would have done in the 60s and early 70s? In her book, she said the program she started Evelyn on was based on what the East Germans did.
The book also talked about sand workouts, but nothing more than they went to beach at one period of the year for workouts.
Seeing she used speed during competitions, I see why there are so many 100m in August.