Why the Walk Down Under a Pack Is Harder Than the Climb

The climb is not what breaks you. The walk down is.

Going uphill under a pack is hard work and it feels like the hard part. So you train the climb, and you treat the walk out as the free half of the trip. But the muscle damage, the strength you lose and the soreness that arrives two days later are all produced on the descent, where your legs make force while they lengthen, braking you and the load down the hill.

If you are hunting elk in Colorado this fall, that direction is not optional. In this state, failing to reasonably dress, care for, prepare and provide edible wildlife meat for human consumption is a violation, and at a minimum the four quarters, the tenderloins and the backstraps are edible meat. The meat comes out with you, on your back, and the way out is usually down.

Why does hiking downhill hurt more than hiking uphill?

A descent does two things to you at once.

The first is the muscle action. Going up, your legs shorten as they produce force. Going down, they produce force while they are being lengthened, because they are braking you instead of lifting you. Those eccentric contractions are what produce muscle damage and neuromuscular fatigue. Same vertical feet, different bill.

The second is momentum. Every step down adds some, and the braking force that controls it is eccentric as well. The NSCA's review of loaded marching is direct about the cost: high cumulative deceleration loading over a two to four week period leads to an increased risk of overuse injury.

The PLOS ONE researchers set out from a documented problem: prolonged downhill walking damages leg muscles, reducing force generating ability and muscle coordination, and those losses increase the risk of more serious injuries and accidents in mountain trekking. Sore is the least of it. You get worse at moving, on the ground where being worse at moving costs the most.

What happens to your legs on a loaded descent?

One study put numbers on it. Untrained young men walked downhill for forty minutes at a 28 percent grade, at 5 km/h, carrying 10 percent of their body mass. Peak knee extension strength dropped about 19 percent. Creatine kinase peaked around 636 U/L. Soreness peaked at about 81 on a 100 mm scale.

None of it showed up during the walk. It was measured at 24, 48 and 72 hours afterwards. The day you feel worst is rarely the day you worked hardest. Walk in on Monday and your legs file their report on Wednesday.

The pack rewrites your mechanics before fatigue gets involved. Vertical ground reaction force rises by roughly 10 newtons for every kilogram of external load you add. The load pulls your center of mass back and up, so you lean forward to compensate, your steps get shorter and your step rate goes up. That is your gait changing to carry the weight. Then you point it downhill.

What does the load itself cost you?

The energy cost of walking with a backpack rises with the weight carried, your body mass, your walking speed and the grade. The type of terrain moves it again.

Where the weight sits matters more than most people expect. Each kilogram added at the foot raises energy expenditure by 7 to 10 percent. Each kilogram at the thigh raises it about 4 percent. Boot choice is a load decision. So is anything you strap to your legs.

A pack carries best when its center of mass sits close to your own, and a hip belt moves pressure off the shoulders.

The injuries that come with carrying loads are documented and specific: foot blisters, stress fractures, back strains, metatarsalgia, rucksack palsy and knee pain. Bone stress injuries turn up in the metatarsals, the tibia and the femur, and it is the rapid jump in volume that raises the risk. I am naming those, not treating them. If something hurts past soreness, that is a medical question, and we send anything clinical to our partner Redbud Medical Spa.

Can you train for the descent, or do you just suffer through it?

You can train for it, and the most useful finding in this area costs five minutes.

In that same study, one group did five minutes of easy, non-damaging downhill walking a week before the forty minute bout. Every damage marker came down by 47 to 64 percent: strength loss, creatine kinase, soreness. A second group did five minutes of level walking instead and came out no better than the group that did nothing at all.

The authors put their conclusion in one line:

Performing small volume of downhill walking is crucial in preparation for trekking.

The study has limits, and they cut toward caution. Untrained young men, a treadmill, a fixed grade, and a pack at 10 percent of body mass, which is light. You on real ground under real weight is the harder case, not the easier one, and those percentages are not a promise to you. What transfers is the direction of the finding: the descent is trainable in advance, and it takes downhill to train it.

What should you be training before elk season?

Strength sits underneath all of it. Squat strength and vertical jump performance both correlate with marching capacity under load. And it is the combination that carries it: aerobic exercise, resistance training targeted at the specific muscles involved, and regular loaded marching, run together, considerably improve marching speed and efficiency.

The last recommendation is the one that decides whether the rest of it works: progress the workload to the individual rather than by a fixed percentage rule. Two hunters with the same season and the same pack still need different work, and a template cannot tell them apart.

How much time do you have before the season?

Do the light downhill session one to fourteen days before the hard descent. The study above used a week because that was its protocol, not because a week is the requirement, and the American College of Sports Medicine gives the wider range. Four or five days out still counts. A short runway costs you room to work unhurried. It does not cost you the protection.

Count the rest of the build in loaded carries, one every 7 to 14 days, rather than in weeks on a calendar. That gives you the honest measure of what is left: how many carries fit before you go, and one light downhill session inside the last two weeks.

If you are hunting the September archery season, that is a short build and it is still worth doing. Understand what one light session buys you: it is one session against one hard day, and it takes the edge off the damage rather than removing it. If you are hunting one of the October or November rifle seasons, you have room for several carries and time to raise the terrain gradually.

What this looks like when I coach it

I coach standards, not workouts. On a hunting build that means putting the descent in your legs before the season does.

I put step-downs and split squats in on purpose, because they are the braking pattern. I land a loaded carry every 7 to 14 days. I run resistance and aerobic work alongside each other roughly three days a week, and I add terrain gradually. I write the progression for the person in front of me.

I run your programming through TrainHeroic, with the videos, the metrics and the tracking in one place. I coach in person in downtown Golden and remotely, with clients as far out as Florida and Hawaii.

Train the direction that costs you

You train the climb because it hurts while you are doing it. The descent takes strength away from you, and it takes it two days later, on the morning you needed it. Put that direction in before the season.

If you want it built around your season, your pack and your ground, start here.