Grenades are not as effective as many people here seem to think, for example the grenade being used by the Axis is the model 24, this was NOT a fragmentation grenade, it relied solely upon blast radius damage. It's stick handle and weight meant it could be thrown a good distance, 30 - 40 yards
The Russian F1 grenade is actually a defensive grenade, and is a fragmentation grenade, it was designed to break into 36 smaller pieces upon detonation (although there would be other smaller less lethal fragments) the range was designated to reach 200 meters, effective to 30 meters and could be thrown an average of 35 meters. As such there we only meant to be thrown from behind cover.
Now there are some other things to take into consideration when thinking about grenades, firstly, the fragments and blast will always raise at about a 15 degree angle from the point of explosion, to explain this simply it is because when the grenade explodes the force of the explosion goes in EVERY direction, including downwards with of course hits the ground (or what ever it may be laying on) and pushes back upward, this then pushes all the other explosive force upwards, this effect means that the explosive force and fragments will always raise upwards getting higher the further out it goes from the grenade.
If you actually lay down 5 or 6 feet away from a grenade on level ground, it wont kill you (you may be injured slightly from blast damage and for sure you will be scared witless)
Grenades are far more effective in enclosed spaces, because the pressure wave from the grenade cannot dissipate and does a lot more damage, in open spaces the pressure wave is not effective at all.
The grenades are underpowered, but not by as much as people think, and before anyone asks I am an ex soldier and yes have thrown grenades and know full well how they work)