Canon L lens that is;
- Non prime
- For action shots
- For portraits
Best choice IMHO is the 70-200 f2.8 IS II. The only downside is $$$, its expensive.
When I first had a 7D I bought my 70-200 for it to do very similar to what your after and found it to be perfect for me.
The only times I found it too long were inside so I also had the 17-55 which was a great combo.