Training for mountain hunting is like composing a good meal. You want all the right types of food on your plate to get solid nutrition. And it ought to taste decent so you don’t mind eating it. But sometimes you put a type of food on your plate just because you know it’s good for you, and you choke it down to get what you need. (Mom was right about eating your veggies.) 

A meal must also have balance to get the most out of it. That requires eating the right amounts of the right types of foods. Otherwise, you end up over or undereating one type of food while sacrificing the others. Recovery, performance, and body composition suffer because of the sacrifice. You have to compose your mountain fitness “plate” in the same way you’d compose a good meal if you want to perform and recover while hunting.

Muscular endurance is the main dish we build our mountain training meal around. It’s what keeps our legs pumping on uphills; and without it, our legs turn to goo on downhills. Forget about carrying heavy loads or hunting back to back to back days without it. You will have no stamina; you will bonk; you will have a very bad time.

The problem is, developing muscular endurance is confusing. It’s tough for hunters to sort through all the ingredients to create the training meal that truly feeds muscular endurance. And when it’s improperly trained, you lose your legs early and never get them back. The first few uphills and downhills destroy your quads, smoke your hamstrings, and leave your calves screaming. You lose your stamina and miss opportunities, and enjoyment, because you can’t go to where you want, or need, to go. Each hill becomes a bowl of broccoli instead of a fat steak to be savored. 

Read on and you will learn how to compose your training meal to develop muscular endurance the right way for mountain hunting. If you follow the advice, and consistently train, you’ll develop the confidence to go wherever you want, whenever you want. Your legs will never be the limiting factor.

What is Muscular Endurance?

To develop your mountain muscular endurance, you must first understand it. That requires a sound definition.

Muscular endurance is the ability to contract your muscles with repeated effort over time without fatigue. 

Two things are necessary for you to earn that ability. You need your muscles to be efficient at utilizing fuel while clearing and recycling metabolic byproducts. And you need your nervous system to continually send strong contraction signals to your muscles. 

Before we dig deeper into all of that, we need to talk about how muscles contract.

The Science of Muscular Contractions

Back in the 1950s, The Sliding Filament model of muscular contraction was introduced. Although we’ve done a lot of learning since then, the theory still mostly holds. However, it’s been updated to the Three Filament Model. Here’s the gist.

The three filaments are the proteins actin, myosin, and titin. Titin binds to actin, creating stiffness and alignment. Myosin binds to actin and the two proteins slide past each other in what’s called cross-bridge cycling. This contracts your muscles.

Now, none of this happens without energy. Adenosine triphosphate (ATP) is the source of that energy. Your body makes it by breaking down fats, carbs, and sometimes protein. 

Calcium is also released into the muscle cell to regulate the whole show. It essentially moves blockers out of the way so myosin can bind to actin, create the cross-bridge, slide, and contract your muscles.

BUT, none of this happens without your brain sending a contraction signal. Your motor cortex sends a signal which travels down your spinal cord to a motor neuron. That motor neuron is part of a motor unit, which is made up of the neuron and all of the muscle fibers it innervates. The motor cortex sends the signal, then all of the stuff we talked about above happens.

Okay. You have the general picture. Let’s move on.

Metabolism + Nervous System: How Muscular Endurance Works

Metabolic byproducts result from the reactions necessary to make your muscles contract. Muscular contraction creates quite a few byproducts, the majors are lactate, phosphate, and hydrogen ions. That’s why measuring your blood lactate level is the most effective way to determine your training intensity. Muscular endurance training improves your muscles’ ability to recycle lactate for fuel. This happens mostly in your slow-twitch fibers (more on that in a bit). It also improves your muscles’ ability to buffer phosphate and hydrogen ions. They are the culprit behind the burn you feel in your muscles (It’s not lactic acid. That’s a myth.). They also signal fatigue, limiting your muscles’ ability to contract. 

Then the nervous system again enters the picture. We train it to fight fatigue in two ways to improve muscular endurance. There’s central fatigue and peripheral fatigue.

Central fatigue comes from the brain and is caused by a few things—neurotransmitter changes, perception of effort, and a built-in governor you have to protect you from damaging your body. They combine to make you feel like you’re working harder even when your muscles still have more stamina. So, it stops sending contraction signals with the same frequency and intensity. It’s part of the brain-quits-before-the-body conundrum.

Peripheral fatigue happens at the other end of the nervous system, and it’s caused by the build up of metabolic byproducts in muscle cells. This signals fatigue to your nerves. That feedback goes up the chain, and the brain decreases contraction signals.

Sustained Firing: The Crux of Muscular Endurance

Sustained firing means sustained contractions. That’s what we want. 

We get it by improving all the things which contribute to developing muscular endurance:

• Improving how efficiently our muscles use fuel (carbs and fat), meaning we have better stores and we use less to create movement

• Improving our ability to buffer and recycle metabolic byproducts

• Improving our nervous system’s ability to recruit the right motor units without fatigue

• Improving the function of our cardiorespiratory system to deliver oxygen and nutrients while aiding in clearing and recycling metabolic byproducts

We know what we want and we know the big picture of how we get it. We’ll talk specifics. And to talk specifics, we have to make a quick pit stop to chat about muscle fiber types. Otherwise, the specifics won’t carry the necessary weight.

Muscle Fiber Types and Their Contributions to Muscular Endurance

You have three types of muscle fibers: Type I (slow-twitch), Type IIa (fast-twitch with intermediate fatigue), Type IIx (fast-twitch with fast fatigue). Each of your muscles contains all three types of fibers. However, each motor unit innervates only one type of fiber. The goal is to train our body to recruit Type I and Type IIa motor units for as long as possible.

There are a handful of reasons why we want our slow-twitch fibers doing most of the work. The short of it is, they’re better at developing all of the things that contribute to muscular endurance. They’re set up for aerobic metabolism, meaning they use fat for fuel. They get the best blood supply. That means more oxygen and nutrient delivery and more byproduct clearing. Slow-twitch fibers are also better at managing calcium, which leads to more sustained contractions. Their cross-bridging is also slower and more efficient, making it more sustainable. On top of all that, they’re better at utilizing recycled lactate for fuel, and they fire at a much lower threshold, which limits nervous system fatigue.

Then we want Type IIa fibers well-developed in support. This improves muscular endurance and staves off fatigue in several important ways for mountain hunting. 

First, they save you from recruiting the much more fatigueable Type IIx fibers. There are times when hiking uphill under load that you’ll be forced to recruit higher threshold motor units. You’ll just need more force than slow-twitch motor units can provide. If your Type IIa fibers aren’t conditioned, you’ll bypass the in favor of Type IIx motor units. Fatigue follows soon after.

Type IIa fibers also have slow-twitch fiber qualities, although to a lesser degree. They adapt well to endurance training because they can be developed aerobically by increasing capillary density, mitochondrial density and quality, and by utilizing fat for fuel. They can also produce and use lactate for fuel, and have better calcium channels than Type IIx fibers. Type IIa fibers can also handle more tension in comparison with slow-twitch fibers, making them the perfect uphill companion. 

Our Type IIx fibers don’t greatly contribute to mountain hunting muscular endurance. But they do play a role. Improving our strength raises their recruitment threshold. So does high-intensity conditioning. Raising those thresholds increases the amount of neural drive necessary to recruit them. In turn, we stave off their use because each step we take becomes relatively easier in comparison to what we’re able to produce. When we get stronger, we become less reliant on Type IIx fibers at lower intensities, while also delaying our need for them.

On top of considering how our muscle fibers generally function in relation to muscular endurance, we also have to think about how they practically function during mountain movement.

How We Use Our Muscles for Mountain Muscular Endurance

We need our muscles to perform three main functions while we’re humping it up and down hills. We need them to create drive; we need them to maintain control; we need them to maintain posture.

Drive is for uphill movement and stepping up onto boulders, logs, and the like. Control is for downhill movement and maintaining stability on variable terrain. Posture is to keep us upright and breathing well under the load of our pack. If we miss out on training any of these functions we fail to maximize our mountain muscular endurance.

Now that you have a solid understanding of muscular endurance, let’s carry it forward and talk about how to train for it.

Developing Slow-Twitch Muscular Endurance for Mountain Hunting

Since the slow-twitch fibers are mostly aerobic, we train them in the aerobic zones with a few different aerobic training methods. However, there’s also a great strength training method that increases the size of your slow-twitch fibers so you can fit more aerobic machinery inside of them.

Before we get into the methods, let’s cover what happens when you train for slow-twitch muscular endurance.

Adaptations to Slow-Twitch Muscular Endurance Training

Slow-twitch endurance development is mostly aerobic development. So, we'll kick this little shindig off with general aerobic adaptations, because they build the “highway” that allows all of the metabolic good stuff to take place in our muscles. 

Central and Peripheral Adaptations to Aerobic Training: Heart, Blood, Vessels, and Fueling

First up are central adaptations. These are the improvements in your heart. Some great things happen to your heart when you consistently train Zones 1 and 2 with enough volume. Your stroke volume and your cardiac output increase. Stroke volume is the amount of blood your heart pumps out with each beat. Cardiac output is the amount of blood your heart pumps each minute. Each improves because blood pools in your heart’s left ventricle. This stretches the muscles of the ventricle, allowing it to pump harder and send out more blood with each beat. Your heart muscles get stronger.

They also get more efficient. This is in part due to the strength gain, but it’s also because you gain more mitochondria in your heart muscles and they get better at producing energy.

As a result, your resting heart rate decreases and your HRV (the variability in space between heart beats) increases. This increases the size of your aerobic window, which is the distance between your resting heart rate and your aerobic threshold (the top of your Zone 2). We want that distance to be as large as possible to increase overall aerobic energy contribution. The HRV increase is a product of better “communication” between your heart and your vagus nerve, which controls your autonomic nervous system. This essentially improves your ability to manage stress—training or otherwise. 

Your total blood volume also increases. Your body makes more blood. This means your working muscles get more oxygen and nutrients, and you’re better able to remove and recycle metabolic byproducts. 

Then we move to the far end of the system and the peripheral adaptations.

The increase in blood volume also increases capillary density. Capillaries are the smallest blood vessels in the body. They transfer oxygen and nutrients into muscles while extracting metabolic byproducts. This makes your aerobic metabolism more efficient, allowing your muscles to rely more on aerobic energy production. Increased capillary density—and better blood vessels in general, along with greater blood volume—increases venous return, or the efficiency of blood returning to the heart. This allows the entire system to work faster and with more efficiency.

V02max also increases to a degree because your blood has greater oxygen carrying capacity, your increased capillary beds offer more surface area for oxygen transfer into muscles, and your mitochondria get better at utilizing oxygen because you get an increase in aerobic enzyme activity. 

There is also the fueling aspect of the equation.

Aerobic training improves your fueling capacity and efficiency. You get more intramuscular fat stores, giving your muscles more readily available fuel so it doesn’t have to rely as much on free fatty acids in your blood. Carbs are also spared, meaning you use them less. You leave them “in the tank” for when you really need them. Your Type I fibers also get better at recycling lactate and using it for fuel. It’s a nice little metabolic blend that allows your slow-twitch fibers to sustain contraction without fatigue.

In addition, your slow-twitch fibers get better at buffering the hydrogen ions that signal fatigue. And calcium sensitivity, reuptake, and reuse improves.

Now that we understand how aerobic training improves slow-twitch muscular endurance systemically and in the muscles, let’s move on to the training methods.

Slow-Twitch Muscular Endurance Training Methods for Mountain Hunters

General aerobic training has its place in developing slow-twitch muscular endurance for mountain hunters. However, we’re focusing on the specific training methods that have the greatest impact on mountain endurance, starting with a specific strength training method and moving on to hiking and rucking.

Tempo Strength Training and 1 x 20 Training for Slow-Twitch Development

Listen, I don’t like Russia anymore than you do. But the commie bastards were ahead of the training curve for a long time in the 20th Century. They produced great training methods like tempo strength training.

It’s a method that uses constant muscular tension and constant movement with limited rest between sets. This creates hypoxia (lack of oxygen) in your muscles, which causes your slow-twitch fibers to grow. Bigger slow-twitch fibers means more room for mitochondria, aerobic enzymes, and their aerobic engine brethren. 

Performing the reps properly is super important. You use a 2-second down, no rest in the bottom, 2-second up, no lockout at the top, tempo. And you maintain it for 30- seconds to 60 seconds. You rest for 30- to 60-seconds between sets, completing between 3 and 6 sets of an exercise during a workout.

Doing tempo strength with front squats, rear-foot elevated split squats, RDLs, bent over rows, calf raises, and push-ups have the most carry-over to mountain hunting, with rear-foot elevated split squats and calf raises having the greatest impact.

We typically program them during our Early Offseason training block or when a hunter is early on in their aerobic development. This makes sense because we are creating the “space” within the muscle fibers to fit more aerobic machinery as, and before, we do all of the work to develop that machinery. But we also include tempo calf training in Late Offseason and Preseason training blocks.

The 1 x 20 method, developed and made popular by Dr. Michael Yessis, is also a solid, general slow-twitch muscular endurance method. We apply it by doing 1 set of 20 reps with up to 20 different exercises, while resting 60 seconds between exercises. The loads are light enough to recruit slow-twitch fibers, and the rest is long enough to keep the workout from becoming too glycolytic or carb heavy. We space these workouts throughout the year.

Uphill and Load Carriage Slow-Twitch Muscular Endurance Training

If you want your slow-twitch fibers to do most of the work carrying you uphill, you must train on inclines. You must also get efficient under the load of your pack. It begins with the combination of unloaded hiking and flat-ground rucking.

Unloaded hiking, whether on terrain, incline treadmill, or stairclimber, in Zones 1 and 2 recruits your slow-twitch fibers and trains them aerobically for uphill movement. You get the specific contractions necessary for climbing grades while ensuring that you’re recruiting slow-twitch muscle fibers. It’s important to accrue volume of unloaded hiking before adding weight so your slow-twitch fibers are trained to do their job before you introduce your pack. Adding load too early can bypass your slow-twitch fibers in favor of your fast-twitch fibers, causing you to miss out on developing slow-twitch muscular endurance. It’s best to start on about a 10% incline and progress up to a 15% incline. This also ensures that you recruit Type I fibers as you build training volume. 

As you unloaded hiking volume, start rucking on flat ground. This builds efficiency underload and prepares your slow-twitch fibers for the increased tension of uphill hiking while carrying weight. Start with about 10% to 15% of your body weight, and progress on flat ground until it’s easy to carry 20% of your body weight for miles while moving at a good clip. You can test your progress by doing our 3-Mile Rucking assessment. You’ll ruck for three miles on flat ground with 20% of your body weight in your pack. If you can finish in 45 minutes or less with your heart rate average in Zone 2, you’re definitely ready for incline rucking.

(If you want the full scope of your current hunting fitness, download The Hunter’s Field Test and put yourself through it. It tests your mobility, strength, efficiency under load, and uphill muscular endurance.)

Once you’re efficient under load and have accrued a solid amount of unloaded Zone 2 hiking, it’s time to blend the two. Start with about 15% of your body weight on a 10% incline while keeping your heart rate in Zone 2. Increase the total volume of this work by doing more sessions or doing longer sessions before you add weight or increase the incline. 

The goal is to progress up to carrying 20% of your body weight in your pack while moving at 1.5- to 2-miles per hour on a 15% incline while staying in Zone 2. If you can do that, your aerobic system, your efficiency under load, and your slow-twitch muscular endurance are at a superior level. This can take a while. Keep progressing until you get there. Then maintain it. 

Zone 3 for Slow-Twitch Fibers

It’s important to note that you do recruit slow-twitch fibers in Zone 3, especially at the lower end of the zone. So, while we’ll talk more about Zone 3 in the section on fast-twitch fibers, it is important for developing slow-twitch muscular endurance. Even in Zone 3, your slow-twitch fibers are recruited first, and your Type IIa fibers kick in as slow-twitch motor units fatigue. Zone 2 training makes up the bulk of slow-twitch muscular endurance work, but Zone 3 training contributes and is important for developing your slow-twitch fibers at higher intensities. 

Developing Fast-Twitch Muscular Endurance for Mountain Hunting

In this context, when we say fast-twitch, we mostly mean Type IIa fibers. They have much more oxidative capacity than Type IIx fibers—although, Type IIx fibers do have some. We develop the endurance of our Type IIa fibers to reduce the reliance on Type IIx fibers and delay their recruitment. This is a very big deal for mountain muscular endurance. If you rely on Type IIx fibers, you fatigue much faster because they are reliant on carbs, they don’t buffer byproducts as well, and they can’t recycle lactate for fuel. They also signal fatigue to your nervous system much faster. Type IIa fibers are our mid-range heroes, especially during uphill climbs. 

Let’s talk about adaptations. Then we’ll discuss training methods.

Adaptations to Fast-Twitch Muscular Endurance Training

One of the biggies is increasing oxidative capacity, or using fat for fuel. This spares us from using stored carbs for mid-range to harder efforts. And it means that they can be trained for sustainable output without fatigue. It happens because, similar to Type I fibers, Type IIa fibers can develop better capillary beds and greater aerobic mitochondrial density and quality—just not quite to the degree that slow-twitch fibers can. 

Type IIa fibers can also produce and use lactate for fuel more efficiently and with greater capacity than Type IIx fibers. This offers another fueling source to keep them working. At the same time, improving Type IIa fibers endurance reduces their reliance on lactate for fuel because they burn less carbs—lactate being a product of glycolysis, or burning carbs for fuel. Their ability to buffer lactate and shuttle it into slow-twitch fibers for use also improves, as does their ability to buffer the hydrogen ions that create muscle burn and signal fatigue.

All of this contributes to delaying recruitment of Type IIx fibers even as intensity and muscle tension increases. You can do more, and harder, work without fatigue.

Fast-Twitch Muscular Endurance Training Methods for Mountain Hunters

Type IIa fibers do respond to Zone 2 training. However, to get the most out of them for mountain hunting, they must be trained at higher intensities—mostly Zone 3 and some lactate threshold work at the edge of Zone 3 and Zone 4.

We keep most of the Zone 3 work specific to mountain movement. However, we do use some general methods. Our lactate threshold work is often general, but we do apply it specifically in some circumstances. We’ll start with some general strength training methods for improving muscular endurance, talk about general and specific Zone 3 work, then we’ll cover lactate threshold work.

General Fast-Twitch Muscular Endurance Training (Strength Training, Zone 3, and Aerobic Plyometrics)

We’ll kick this off with the strength training methods. Then we’ll chat about Zone 3 training.

1 x 20 Training

Yes, it appears again. 

While 1 x 20 training is mild enough to recruit slow-twitch fibers, it also recruits Type IIa fibers. That makes it a decent training method for developing general fast-twitch muscular endurance. This is about recruitment and repeated strength output, and less about training your muscles to deal with acidity. Our next method does that.

Interval-Based Strength Training

Think of HIIT intervals applied to strength training. You’ll do 20- to 30-seconds of work, then rest for 30- to 60-seconds. You can do this circuit style or by doing one exercise at a time. For most folks, progressing from circuit training to single-exercise intervals is a good call. Circuits spread out the stress, making the overall workout less intense. The single-exercise setup increases intensity because it continually applies stress to the same muscles. The pinnacle is progressing to doing this unilaterally (single-limb) and doing all of the sets on one leg or arm before moving on to the next leg or arm. For example, 5 sets of 30-seconds work, 30-seconds rest of rear-foot elevated split squats on your right leg, followed by the same amount of intervals on your left leg. This setup offers you a cordial invitation to burn land. 

Interval-based strength training builds your Type IIa fibers’ ability to buffer acidity, repeatedly produce force under fatigue, and repeatedly contract without oxygen. This all contributes to allowing you to do more work with less burn.

High-Volume Calf Training

The calves are too often neglected in hunting fitness programs. They play a huge role in driving you uphill, giving you control on downhills, and maintaining your stability on varied terrain. We train the heck out of them in multiple ways.

For muscular endurance, we do high-volume density sets. Density, in the training world, means you try to increase the amount of work you do in a given time period. For example, we’ll set a 3-minute timer and do as many single-leg calve raises as possible before the timer goes off, alternating legs every 5 to 10 reps. 

General Zone 3 Training

Zone 3 is an even split between producing energy aerobically and anaerobically, making it perfect for Type IIa development.

When we say general, we mean methods that aren’t directly related to loaded mountain hiking. It includes things like running, rowing, and biking. We typically use this kind of training in the mid- to late-offseason with relatively shorter intervals in the 10- to 15-minute range. This allows for a nice blend of Type I and Type IIa fiber recruitment while building Zone 3 capacity in preparation for longer, more specific training.

Aerobic Plyometric Training

It’s those pesky Russians again. Val Nsedkin, a Russian sport scientist, developed aerobic plyometric training. Joel Jamieson made it popular in the U.S. when he published his book Ultimate MMA Conditioning in early 2009. (I’ve read it cover to cover more times than I can count. And I took his in-person conditioning course back in 2015.)

Aerobic plyometrics are low-impact, repetitive movements done for extended periods. Here’s an example from our training:

1-minute of 2-foot hops, immediately followed by 1-minute of lateral line hops, immediately followed by 1-minute of low split squat jumps, immediately followed 1-minute by lateral scissor hops, immediately followed by 1-minute of forward and backward skipping.

Aerobic plyometrics do a few important things for us as mountain hunters. First, they increase the strength and resilience of our feet and lower legs, which helps us manage long hikes on unstable terrain. Second, they increase the aerobic capacity of the Type IIa fibers in our feet and calves, improving their muscular endurance.

They also improve the reactivity of those muscles, meaning they get more spring. When you have more spring, each step costs you less energy.

Aerobic plyometrics pair nicely with high-volume calf training. We’ll do aerobic plyometrics at the beginning of a session, and high-volume calf training at the end.

Mountain-Specific Fast-Twitch Muscular Endurance Training

We use two main methods to build mountain-specific fast-twitch muscular endurance. Sustained uphills under load and high-intensity continuous training (HICT) step-ups. We’ll start with HICT then talk about the sustained uphills.

HICT Step-ups

Once again, we must talk about the Russians. Val Ndeskin is back. He developed HICT to improve the aerobic capacity of Type IIa fast-twitch fibers in Russian athletes. It’s great in all sorts of applications, from training field sport athletes to prepping special operations candidates for selection courses. We use it to develop sustained uphill drive and to acclimate to heavy packs in a safe environment.

HICT requires the right combination of pace and weight. The pace must be fast enough to aerobically challenge fast-twitch fibers, but not so fast that it becomes a carb-burning acid bath. And the weight must be heavy enough to recruit Type IIa fibers. When doing HICT step-ups, we use a pace anywhere from 1 rep per side every 15-seconds to alternating 1 rep per side every 4- to 5-seconds. We utilize the slower pace in the early offseason and the faster pace in the late offseason and pre-season. It’s important that each rep is done with maximal intent, meaning you’re attempting to step up with as much force and speed as possible. You know you’ve hit the sweet spot of pace and weight when you maintain a heart rate in high Zone 2 / low Zone 3, you can put maximal effort into each rep, and you don’t struggle to maintain the pace.

Sets might look like 2 x 8-minutes of 1 rep per side every 15-seconds with 3-minutes rest between sets, or 1 x 20-minutes of alternating 1 rep per side every 5 seconds.

Sustained Uphills Under Load 

This is the most mountain hunting-specific muscular endurance training. You wear your pack and move at a steady pace on an incline while maintaining your heart rate in low- to mid-Zone 3. Sessions last anywhere from 20- to 60-minutes. Pack weight is typically around 20% of body weight, but exceptionally conditioned hunters might use anywhere between 30% to 40% of body weight. (Important note: Folks training in the heavier weight range will only do a few sessions with that much load. Doing more than that can lead to diminishing returns.) It can be done on terrain that’s long enough and has an appropriate grade. This works well for hunters who live in the West and have ready access to big mountains. Most often, however, it’s done on an incline treadmill or stairclimber. 

Here’s an example workout:

2 x 20-minutes in low Zone 3 with 20% of body weight loaded into your pack, with 3- to 5-minutes rest between work intervals.

The long intervals are great because they offer enough time for Type I fibers to fatigue so that Type IIa fibers get more conditioning. 

Lactate Threshold Training

Your lactate threshold is the line between your Zone 3 and your Zone 4. It’s the point at which you switch from an even split of aerobic and anaerobic energy production to primarily anaerobic energy production. More Type IIx fibers are recruited and more carbs are burned for fuel. We train it to push it back just a bit and to improve how well we buffer and recycle metabolic byproducts. This allows us to stay in Zone 3 for longer, recruiting more Type I and Type IIa fibers while sparing carbs and using more fat for fuel.

Typically, we take a general approach to lactate threshold training, utilizing cardio equipment such as the air bike or by doing incline running on a slight incline (for those who run a lot and are well-adapted to it). However, we’ll also do lactate threshold intervals on the stairclimber with a light- to moderate-weight pack.

You’ll see some ultra endurance athletes perform lactate threshold intervals that last up to 60-minutes. That’s not necessary for us. You only need about 20 total minutes in a workout to improve work around lactate threshold, so we’ll use intervals anywhere from 4- to 15-minutes to accrue the necessary time in the zone. 

We only use lactate threshold training for those hunters who are well-conditioned enough to take advantage of it. When we do use it, we program it somewhere between the late stages of early offseason training and early preseason training.

Eccentric Muscular Endurance: Control for Downhills

That ol’ fella Newton proved that what goes up must come down. Hunters worry so much about uphills, that they forget to train for downhills. But downhills get your legs just as bad as uphills, sometimes worse.

Downhill hiking relies mostly on eccentric muscle contractions. This means that the muscles lengthen as they contract. It causes more muscle damage than the concentric contractions that carry you uphill. So, if you don’t train for repeated eccentric contractions, you’ll fry your legs on downhills and end up walking like a baby giraffe running a jackhammer. Worse, you’ll cook your legs so badly that you struggle on uphills and downhills on each hike during the following days.

The best in-the-gym training downhill training is done by doing exercises that target your quads with eccentric contractions at varying speeds. For example, front squats and rear-foot elevated split squats with a 3- to 5-second lowering phase. These build the strength and capacity of eccentric contractions in your quads. Holding isometrics in the bottom position of a lift also helps to build your muscles’ ability to contract while elongated. Instead of lowering for 3- to 5-seconds, you’ll drop into the bottom of the lift and hold there for the same amount of time. You can also do extended isometric holds for 30- to 60-seconds. 

But you also have to train fast eccentric contractions. You can do this with repeated jumps, quarter squats done rapidly, and drop-and-catch plyometric exercises. Aerobic plyometrics also help here. They aren’t as intense, but the repeated contractions are helpful in building eccentric stamina for downhills.

Slow step-downs from a high box and single-leg goblet squats to a box are also staples in our programs. They isolate one leg at a time to keep eccentric stress on the quads. 

You need to do these exercises for a fair amount of reps or time to build endurance with eccentric control. For example, a set of 5 rear-foot elevated split squats with a 5-second lowering phase keeps your leg under eccentric tension for a total of 25 seconds. That’s the kind of time and tension necessary to build eccentric muscular endurance in your quads.

Work eccentric control training into your program during the late offseason (April + May) and during the preseason (June through September). Do some slow eccentrics with your main lifts, repeated jumps and drop-and-catch exercises during power training, and slow step-downs and single-leg goblet box squats during assistance training. 

It’s also important to do loaded hikes on undulating terrain. This specifically trains your downhill muscular endurance because it’s what we do in the mountains. If you’re a flat lander without access to undulating terrain, I’ve outlined what you can do in the “specific mountain hunting muscular endurance strategies” section towards the end of the article.

Isometric Muscular Endurance: Strength and Posture Under Your Pack

Staying tall and strong under your pack is monumentally important for your stamina and endurance. When your posture breaks down, you move inefficiently, your breathing mechanics go to shit, and your back takes more stress than it should. Inefficient movement leads to faster fatigue because each step wastes energy. Poor breathing mechanics also lead to faster fatigue while also potentially leading to feelings of panic and poor core stability that stresses your back. The fatigue and feelings of panic come from decreased oxygen delivery. Less oxygen equals poor aerobic function. It also increases CO2 levels in the blood, which causes the panicked feeling. Decreased core stability arises because you can’t use your deep breathing muscles, which are your first line of defense in protecting your spine. Posture failures cause you to lean too far forward and hunch over, stressing your spine. 

You must train to overcome all of it. We’ll talk about how, starting with breathing, progress to building endurance to maintain posture under load, and finish with core training that keeps you upright.

Training Your Breathing Mechanics

While this isn’t necessarily isometric work, it fits in this section because we’re training our breathing mechanics to stay strong under our pack, which is the goal we’re aiming at in this section.

Before we get into the work, it’s important to understand what muscles you use to breathe and how they work.

The Breathing Muscles and How They Work

Your breathing muscles function in layers—primary, secondary, and tertiary. The goal is to create and control internal pressure to efficiently inflate and deflate your lungs. These muscles stretch to create internal pressure that allows you to inhale. And they shorten to decrease pressure, allowing you to exhale. You want your primary and secondary breathing muscles to do this work. If your tertiary muscles get invited to the party, you’re stressed and your breathing has gone to hell.

The primary breathing muscles are the diaphragm and external intercostals (outside rib muscles). The diaphragm presses down to create space for the lungs to expand during inhalation. It rises to move air out of the lungs during exhalation. The external intercostals lift the rib cage for the lungs to expand during inhalation, and they contract to compress the rib cage during exhalation. They work together to create 360-degree rib cage expansion. When they function well to do this job, you get the best possible gas exchange in your lungs.

The scalenes, sternocleidomastoids (SCM), and internal intercostals are your secondary breathing muscles. The scalenes elevate your first and second ribs; the SCMs elevate your sternum, and the intercostal muscles assist in forced exhalation. These muscles are supposed to kick in when intensity increases and the primary breathing muscles need back up. However, folks with poor breathing mechanics often use them as primary breathing muscles, even at rest.

The upper traps, pec minor, lats, and abs are the tertiary breathing muscles. The upper traps elevate the shoulders and collar bone. The pec minor elevates the ribs when your arms are fixed. The lats can help expand the rib cage when your torso is rigid, for example, when you’re wearing your pack. The abs can help with forceful exhalation and creating intra-abdominal pressure when the diaphragm is fatigued. It’s important to remember that we don’t want these muscles to do this work.

How to Improve Your Breathing Mechanics

360-Degree Breath Training

The first step is training yourself to breathe with 360-degree rib cage expansion. Start by learning in the least stressful environment and progress by adding stress. You add stress by exposing more of your body to gravity and by adding movement and tension.

Gravity has the least effect on your body when you’re lying on the ground. So, start by lying on your back with your knees bent and your feet flat on the floor so that your entire spine is in contact with the floor. You can also elevate your heels onto a box, bench, or chair while keeping your hips and knees bent to 90-degrees to help keep your spine flat on the floor. Place a hand on your belly, and calmly breathe in so that you feel your belly rise into your hand and your low back press into the floor. Once you have that down, move your hands to your sides and press the index fingers into the soft spaces between the top of your hips and the bottom of your ribs. Calmly inhale through your nose so that you feel those soft spots press into your index fingers. Once you have that down, place a hand on your chest and breathe in so you feel your chest rise into your hand and your upper back press into the ground. Once you’ve accomplished that, rest your arms on the floor at your sides, and breathe in to expand all of the areas we just discussed, starting by sending air low into your belly and letting it rise into your chest.

After nailing that process on the ground, repeat it in the kneeling position with your heels resting on your butt. Then do it with one knee up and one knee down, switching knees as it sinks in. Then stand and repeat the process.

Once you have it down while standing still, do it while walking slowly. Then walk faster. Then do it at a slow jog.

Now, you should be able to utilize it while doing core exercises, while lifting, and while rucking.

Strengthening Your Diaphragm and Intercostals

There are a ton of drills you can use to strengthen your diaphragm. I’ll include one in this article for the sake of brevity (Don’t wanna get too long winded. See what I did there?). It’s the physiological sigh, as made popular by Dr. Andrew Huberman. 

Take a deep, nearly full breath in. Then, without exhaling, take another sharp, fast inhale to fully expand the lungs. Then exhale fully through your mouth, getting all of your air out. Do this three to five times in succession. 

You’re getting a double whammy here. It’s a great technique for managing stress and focus. And the full inhales and exhales strengthen your diaphragm and intercostal muscles. Do this a handful of times throughout the day.

(If you want to use this to tone down before bed, do a bunch of cycles while lying in bed.)

Isometrically Strengthening Your Shoulder Girdle, Core, and Hips

Your shoulder girdle, core, and hips support you under your pack. Each must be strong, stable, and have good isometric endurance. We build that endurance with sustained recruitment. That means either holding isometrics for increasingly longer periods, and by increasing the number of isometric holds done during a workout and a training week. Here are the methods we use to train them.

Carry Variations + Dumbbell/Kettlebell Loaded Lower Body Exercises

Carries are kind of like rucking by proxy. They train all of the muscles used to move with your pack on without wearing your pack. Carries keep the shoulder girdle under tension, train the core to remain stable, and train your hips to stabilize as you move under load. 

All carry variations are productive for building isometric muscular endurance under your pack. We utilize farmers carries, suitcase carries (single-arm farmers carry), rack carries, single-arm rack carries, waiters carries (overhead), and single-arm waiters carries. We also do farmers and suitcase marching, which is holding one or two weights at your sides and marching in place. Not only does this train your shoulder girdle, it also trains your hips and core to remain strong and stable as your pack shifts on your body.

Carries are best programmed for time. We do them for sets anywhere from 30-seconds up to suitcase carries for a mile without putting the weight down. We also use the 6-point carry made popular by physical therapist and performance coach, Gray Cook. Using one, light- to moderate-weight kettlebell, you carry for 6- to 12-minutes without putting it down while moving it to one of the 6 carry positions—suitcase in each hand, rack in each hand, and waiters in each hand. As you start to fatigue in one position, you transfer the weight to another position, working up, down, and across your body.

It’s best to do carries with kettlebells because the weight is concentrated at one pole and it’s easier to get them into a natural position when doing rack and waiters carries.

Holding dumbbells or kettlebells to load exercises like lunges, step-ups, and single-leg RDLs is also a form of carry. They’re great for all rep ranges, but have a greater effect on the isometric endurance of your shoulder girdle, core, and hips when you use them for higher-rep sets.

Bonus: Carries build your grip strength, which is important in general and for longevity.

Core “Anti” Movements

Your core’s main job is to create stability in your trunk so you can efficiently breathe and transfer through your limbs and into the ground or whatever implement you’re moving. That’s super important for maintaining posture while under your pack for long periods. So, it’s best to train your core to stay still instead of flex and rotate in all directions.

Carries are a form of core anti-movement. But there are a lot of others that you can do in any position. Here are some of the ones we commonly use:

Planks

Plank Walkbacks

Ab Wheel Rollouts

Side planks

Copenhagen Plank Variations

Glute Bridges

Single-Leg Glute Bridges

Tall-Kneeling and Half-Kneeling Lifts and Chops

Tall-Kneeling and Half-Kneeling Pallof Presses and Iso Holds

Standing Lifts and Chops

Standing Pallof Presses and Iso Holds

We do all of these for varying rep ranges and lengths of time. However, it’s important to do some longer duration sets to build isometric endurance. It’s also real damn important that you don’t let your position go to shit during long sets. You have to maintain a good position to train the core to do its job. That means your ribs should be pointed at your hips, and your hips should be pointed at your ribs at all times.

It’s also important to note that any strength exercise done with good form is a core exercise. So, while it’s necessary to add in specific core training to improve your core strength and stability, you’re also getting it when you squat, deadlift, lunge, press, and row well.

We’ve covered a lot of specific ground so far in this article. Let’s tally it up with general muscular endurance training principles for mountain hunting.

General Muscular Endurance Training Principles for Mountain Hunting

We’ll cover these in list form.

1. Accruing aerobic volume is crucial. It builds your delivery and clearance systems while also conditioning your slow-twitch muscle fibers. Progress from general to specific training methods as you lead up to the season, and keep training your aerobic system year-round.

2. Zone 3 incline weighted hiking. It’s necessary for rounding out your aerobic system and conditioning your Type IIa fibers to sustain work so your Type IIx fibers don’t kick in and fatigue you faster. This work is especially important during the preseason.

3. Always increase training volume before increasing training intensity. For example, accrue a lot of Zone 2 general and specific training before progressing up to more Zone 3 training.

4. You must get specific. General muscular endurance training is great and necessary, but you must do the work that specifically transfers to uphill and downhill movement. That means getting on inclines and undulating terrain, or simulating undulating terrain in the gym if you’re a flat lander.

Specific Mountain Hunting Muscular Endurance Strategies

Another simple, digestible list:

1. HICT step-up progression. It trains your Type IIa fibers to sustain work under high tension (weight and incline). Do them at a slower pace in the early offseason, and increase the pace during the late offseason and preseason.

2. Zone 2 → Zone 3 incline loaded hiking progression. This is the most specific work you can do to build your muscular endurance for uphills under load.

3. Loaded hikes on undulating terrain. This is what we do while hunting. We have to do it in training. If you don’t have access to undulating terrain, the next strategy is necessary for you.

4. Hybrid uphill and downhill gym training sessions. Combine incline work, step-ups, step-downs, isometrics, and carries into a training session that simulates undulating terrain.

The Biggest and Most Common Mountain Muscular Endurance Training Mistakes

These mistakes hold a lot of hunters back from maximizing their muscular endurance.

1. Adding intensity before volume. There’s a myth that hunters need to brutalize themselves to improve their mountain fitness and muscular endurance. It isn’t true. This causes them to make sessions hard way too soon. You need to build your training volume before you add intensity. This sets you up to recover and adapt to training in a much better way, while also making it easier to train consistently. It also builds the raw materials necessary for you to take advantage of more intense training.

2. Confusing fatigue with productivity. Any dipshit can make you tired. Feeling spent at the end of a workout is a terrible proxy of progress. It should start to feel easier to do more and harder training. And you do that by gradually increasing volume and intensity while limiting fatigue.

3. Skipping downhill training. Hunters get so intimidated by uphills that they forget that downhills exist. It’s a huge mistake because they miss out on developing the control and endurance that prevents them from frying their legs.

How to Practically Measure Your Muscular Endurance Progress

Here are some easy ways to know you’re improving your mountain muscular endurance:

1. You have a reduced heart rate at the same or greater work load. This means that you’re getting more efficient at each end of the system—your heart and lungs and your muscles.

2. Reduced leg burn. This means you’re getting better at recruiting the right motor units while also improving your muscles’ ability to spare carbs and buffer acidic byproducts such as hydrogen ions and phosphate.

3. Faster recovery. You get your legs and lungs underneath you faster after uphill climbs and you recover faster between workouts.

4. Improved step-up metrics. Take our 10-Minute Step-up Test by either downloading the Pack Capacity Calculator (estimates your proper uphill carry load) or The Hunter’s Field Test (a full menu of tests that assess your fundamental hunting fitness). Re-test every 6 to 13 weeks. If you can achieve more step-ups in 10 minutes, or if you can do the same amount of step-ups in 10 minutes, you’ve improved your uphill muscular endurance under load.

Final Takeaways

Muscular endurance is a complex interaction between your muscle fibers, nervous system, and metabolism. It’s necessary to train all aspects of muscular endurance by building a balanced training plate to be fully prepared for undulating mountain terrain, improving your performance and keeping you safe.