Injuries in the U.S. Army Infantry.  Among infantry Soldiers, marching has been reported to be the second highest activity associated with injuries ranging from 17% to 22%, exceeded only by running injuries which ranged from 27%–30%...

Load Weight ... of 30% to 45% of body weight previously identified for optimal Soldier performance in combat conditions...

good practice guidelines:

Use the equipment appropriately...

Limit frequency of foot-march training... Because exceeding four marches a month may unnecessarily increase risk, training regimens should not exceed one distance march a week...

Progress gradually.  Gradual progression of activity has been shown to reduce the occurrence of injuries in populations not used to new physical demand levels, such as IET or newly arrived Soldiers not acclimated to the environment or running regimen. For runners, a common progression “rule of thumb”is to increase frequency, distance, or speed by no more than 10% to avoid injury or re-injury.36 This same concept can be applied to load weight, distance, and speed in foot marching programs.

..while maintaining 3-mph speed, load weights for uninitiated trainees might begin at 20 pounds(~18 pounds would increase the energy cost of an average 180lbs Soldier 10%) and progress to 40, then to 60, and higher if needed.  Progression target distances increasing speed, frequency and loads progressively between targets might be 2, 5,10, up to 12 miles depending on unit mission.  Alternate days for increasing load weight(intensity) and distance/duration(e.g., increase in distance accompanied by a decrease on load weight).

Originally Posted By Greenspan:
I'm gonna go with no shit, but a lot of people dont get it. I always want to tell fat people to stop running which is basically the same thing overloaded  untrained.

Originally Posted By R_S:


Yep!  

Seems like more people are out hiking/rucking this year but don't know where to start.  Then you've got SF guys like John Mosby who say everyone should be able to haul 80lb+ packs.  

Truth is that rucking a 20lb pack at a 3mph pace is a good start.  I've seen little guys try to start out with 50lb packs which is way over the 30% body weight guideline and asking for big trouble.