There’s no denying that technology has changed the way we fight wars, but as we take stock of the various ways in which new gear has made it easier to locate, close with, and destroy the enemy, we often lose sight of the ways technology has hindered the modern war fighter as well.

The ever-present technological trade-off of having an effective new tool to add to your combat load is the effect that added weight has on the human anatomy. Soldiers may have better weapons, optics, communications, and body armor than warriors of wars past, but they are still stuck with the same knees. Nowhere is this issue more prevalent, one could argue, than in my own service alma mater, the United States Marine Corps. The required loads for Marine infantry officers are so high that just a few years ago, Army Colonel Ellen Haring wrote an OpEd for the Marine Corps times calling them “unrealistic.”

How much weight are we talking here? The “unofficial” load endurance standard in the Corps for infantry officers is carrying 152 pounds for 9 miles, though that number has been contested by some senior officials. Nonetheless, even in Marine Corps manuals, 100 pound combat loads are considered “standard,” and as Popular Mechanics writer David Hambling recently pointed out, one doesn’t need to look far to find accounts of Marines carrying as much as 200 pounds during combat operations in Afghanistan.

That’s an incredible amount of weight to strap to your back and hoof around, particularly with the possibility of enemy contact. We’re not talking about going for a hike with 200 pounds strapped to your back — we’re talking about looking for a fight. Of course, if and when that fight shows up, the Marines carry a bevy of advanced gear and powerful weapon systems to aid in the battle, but concerns about muscular endurance and load-related injuries permeate the firefight — where limiting risk is often the name of the game.

Where does all that weight come from? Body armor to start with — most American infantry troops now travel in what we used to call “full battle rattle,” wearing a full kit of body armor that includes the familiar Kevlar helmet and jacket (or vest), as well as attachments to cover the neck and groin. The armor itself rings in at around 20 pounds and it’s one of the few elements of a war fighter’s kit that tends to be non-negotiable. Full kit may be inconvenient and cumbersome at times, but because survival rates are much higher among soldiers in full kit, it has become the standard.

From there, you can add weapon systems, the lightest of which would be the M4, which with ammunition adds around 15 pounds. On average, Marines today carry around 20 pounds of batteries for different bits of tech (like the less-than-advanced AN/PRC-117 radio that burns through batteries like a kid’s remote control car on Christmas). Squad weapons, like the M249, weigh 22 pounds loaded, with another six pounds added for each additional belt of ammunition. Mortars or rockets can also add a great deal of weight to a pack — to the tune of around 4 pounds per round.

All of that comes before individual items like food, clothing, night vision, flashlights, an IFAK or medical kit — these all add up to anywhere between 50 and 80 pounds. Imagine walking to work every morning with all that on your back, and then being expected to carry out complex and dangerous tasks once you arrive, all while keeping enough in the tank to make the trek home again once you’re through: that’s the standard expectation for American infantry troops today.

There are a number of initiatives underway that aim to ease the burden on American troops through autonomous robots that can carry gear for them, robotic exoskeletons that can bolster an individual’s strength and endurance, and even programs aimed at using drones or firing empty mortar shells to resupply war fighters rapidly and alleviate the need to carry quite so much on their backs… but to date, all of these efforts remain little more than forward-looking “what ifs,” and the line of veterans at the VA waiting for MRIs on their knees and lower backs isn’t getting any shorter.

Eventually, something has to give, and thus far, it’s been the joints of the men we send into the fight.