i was bored so i thought, why no calculate how much Raids you need to get Strength to lvl 50 and how.
In calculated only the best way(fastest i guess).
If you are wakling 1 Kilometre(overweight) you gain 1.3 Skill Points.
If you are walking another Kilometre in the same Raid you gain 1.0 Skill Point.
Any Kilometre you are walking after that gains you 0.5 Skill Points.
If You throw 7 Grenades (would use F-1 because the are cheap) you gain 1.3 Skill Points.
if you throw 7 more Grenades you gain 1.0 Skill Point.
3.0 Skill Points is the maximum you can get from Grenades.
Best method is i think 14 Nades and 2 Kilometres of walking.
Thats ~4.6 Skill Points in one Raid. 100 Skill Points per Level, thats about 22 Raids per Level.
50 Levels * 22 Raids = ~1100 Raids
So if you Throw 14 Nades and walk 2 Kilometres(overweight) in one raid you will reach lvl 50 in about 1100 Raids.
Did not include Melee Hits, because you will hit someone very rarely.