Cosmonaut Valentin Bondarenko after a swim. No sound. 

Valentin Bondarenko (1937-1961) was a Ukrainian pilot, selected for the first cosmonaut group, which included Yuri Gagarin. He died in an accidental fire in a high-pressure oxygen environment in a soundproofed altitude chamber during testing/training. The incident and his existence was hushed up and not publicly revealed until the 1980s.
I think that's Pavel Belyayev behind him. Part of footage of cosmonauts playing sports and running through the woods in their swim briefs.