this applies to all players, but receivers in particular.
imo, the coaches and trainers need to be careful about the amount of daily sprinting they're putting these guys through.
high-strung sprinters--like most of these receivers are--can't handle an huge workload on their legs, and this is a particularly troublesome problem in a training-camp situation. niners staff would do well to consult with an experienced track and field sprint coach about ways to avoid injury. it's much better in the long run to keep race horses healthy. if you're a sprinter, you can't run hard, fast high-volume, grueling workouts every day and stay healthy. that's common knowledge. i hope niner's staff realize that they can't run the receivers on the same same play count as other positions--they end up with way too much work volume on their legs because of the amount of play-to-play distance they cover a an high rate of speed.
if multiple hammies, hips, and groins are going gimpy, there's a simple reason: overwork. that's reality. i know it doesn't fit training-camp mentality to dial back stuff, but it's needed for the WR group.