You are looking at rugby league, a northern British alternative to rugby union which uses short but not quite as short shorts as rugby league shorts.
http://www.englandrugby.com/
I had to play rugby union at school in the 1970's when our shorts were even shorter.
For even shorter shorts look to Australian rules football.
https://www.bing.com/videos/search?q...48&FORM=VRDGAR