Muscular Endurance: All You Need to Know

[vc_row][vc_column width=”1/1″][vc_column_text text_color=”color-jevc” uncode_shortcode_id=”341540″ text_color_type=”uncode-palette”]Over the past 20 years, I’ve written and spoken many thousands of words about Muscular Endurance training. Both Training for the New Alpinism and Training for the Uphill Athlete have entire sections of the book devoted to the topic. Articles like Vertical Beast Mode that remain on UphillAthlete.com explain it as it relates to Mountaineers and Alpinists.

Having had to explain ME training hundreds of times, in this article, I pull together all that experience to produce my current thinking on the subject in one article. Careful readers will even notice some differences between this and earlier writings I’ve done on this subject.

There are two key components to the training methods I have developed

Build a big aerobic base

Layer Muscular Endurance on top of that

Boom, there you have it! Do those things, and you are 90% of the way toward having some of your best mountain performances. If you grasp these concepts well, you can stop reading right here.

I didn’t invent either of these ideas, and I didn’t invent the combination of them. What I have done is develop protocols for their use in different forms with alpinists, mountaineers, mountain runners, ski mountaineers, and Olympic Cross Country skiers.  While some specifics change depending on the sport, these two underlying principles are applicable across this range, and in fact, the full range, of endurance sports.

What is Muscular Endurance?

Legendary Russian coach and exercise scientist Yuri Verkhoshansky’s definition is widely accepted:

The ability of a muscle to exert a relatively high percentage of its maximum force for many repetitions of the propelling movement.

How high a percentage, and for how many repetitions are relative terms? The higher the percentage of the muscles’ maximum force, the fewer repetitions that the muscle will be able to make before it fatigues. So, the muscular endurance needed by a rock climber to power through a 10-move crux is going to be different than the muscular endurance a mountain runner out for many hours at a time will need. They’re the same quality, just differing in intensity. They’re trained using the same principle. From that italicized sentence above, you might infer the following:

Increase the muscle’s max strength and you have a greater strength reserve and potential to increase the muscular endurance.

Why Just Being Stronger is Not The Answer

If the above holds true and it was really that simple, Olympic weight lifters or Power Lifters would have the greatest muscular endurance. Real-world observation easily dispels that notion. What’s up with that?

It comes down to muscle fiber type. The largest cross-section, most forceful (i.e., strongest) Fast Twitch fibers called FTb need to be recruited to generate maximum muscle force and do not have good endurance. They have poor endurance due to much lower mitochondrial (the aerobic or endurance engine of a cell) density than the endurance disposed Slow Twitch fibers. Their thicker cross section means oxygen has farther to perfuse to reach those fewer mitochondria. While training for max strength improves the contractile force of all the muscle’s fibers, both ST and FT, it is the FTb fibers that get the biggest training stimuli, and they respond by becoming even thicker in cross-section. This is the property called hypertrophy sought by bodybuilders.  Hypertrophy is a negative adaptation for an endurance athlete who has to not only carry that extra muscle mass around but also has to use valuable oxygen to keep those muscle cells alive. These are two very big reasons why the best endurance athletes in sports that require the athlete to support and carry his or her body weight against gravity tend to be smaller/lighter framed and not built like Power Lifters. Two endurance sports where extra muscle mass is less of a detriment are swimming and rowing/paddling.

Once again, as with all endurance, it comes down to those unglamorous ST fibers. They have a smaller cross-section (generate lower force and are much less likely to thicken with hypertrophy training). They are surrounded by more dense capillary beds, along with a much higher mitochondrial mass. These attributes allow them to provide the crucial base of aerobic support for higher-intensity work done by FTa fibers. Those fibers inhabit the range between the ST and FTb and are where this muscular endurance training effect takes place. These Goldilocks fibers have some of the strength characteristics of FTb fibers while being endowed with some of the ST fibers’ endurance qualities.

Here is the big secret to this training

The ST fibers provide the aerobic vacuum cleaner to suck up and utilize the lactate by-product of the hard-working FTa fibers nearby.

Hopefully, you can see now how inextricably linked are those two bullet points at the start of the article.  They go hand in hand, and each needs to be maximized for top performance.  I’ve covered aerobic base training in many other places. So, let’s stick to talking about ME here.

If we can find ways of isolating and loading those FTa fibers right to the point of their endurance limit, we can increase their endurance. This is where we come back to the word relative again. The relative level of strength and muscular endurance desired by the rock climber will be quite a different balance than that needed by the mountaineer.

• To target those limiting FTa fibers, we need to first use a training modality that engages those muscles responsible for the kind of locomotion in the event being trained for.
• Next, increase the load on them to the point where after a number of repetitions, you induce local muscular fatigue felt as a light burn in the working muscle group. This is done by adding resistance/weight.
• Once again, the load and the number of repetitions  relative to the duration of the event you are training for.

It is really that simple. There are a multitude of ways to do this, but before we discuss some of those means, I feel compelled to recognize the heritage of these ideas. When it comes to muscular endurance, I am evoking the legacy of one of the greats.

The Roots of ME Training Theory

While I had heard the term muscular endurance tossed around in the strength training literature, it was not until I picked up a copy of Verkhoshansky’s Block Training System in Endurance that the pieces really started to fall into place for me.

Verkhoshansky’s research showed that ME is the main determinant of an athlete’s maximum sustainable speed in efforts lasting more than a few minutes. A more complete picture is that the endurance limit is set by the balance of Aerobic Capacity of the ST fibers and the Muscular Endurance of the FTa fibers. This endurance limit has a confusing number of names (thanks to exercise science): Old school, it is called Anaerobic Threshold (AnT); medium old school is Lactate Threshold; if you want to sound like an exercise scientist, you call it Maximum Lactate Steady State; more recently with the advent of power meters it has gotten called Critical Power or Functional Power. It is what essentially amounts to the quality we call endurance: the ability to maintain the highest high power outputs for prolonged periods, from minutes to hours.

Why You Don’t Read More About ME Training in Endurance Sports

Conventional endurance training, as practiced widely, does not normally contain a training block with a ME focus.  In fact, when you mention that concept to most endurance coaches and athletes, you get blank stares. Traditional endurance training practice derives the ME training effect by doing high-intensity (Z3 and Z4) interval training. When exercising in these high-intensity zones for many minutes, the muscles’ FTa fibers are getting a similar training stimulus as they receive when we isolate them and induce local muscular fatigue. The difference is that traditional interval training carries with it a high global fatigue cost. Whereas the Local Muscular training stimulus carries only a local fatigue cost. So, recovery is quicker, and a higher volume of Z1-2 training can be maintained.

Why I Advocate  for the Special ME Block

While a ski coach, I often noticed that the skiers would get progressively slower in each repetition during an interval workout after the first couple. Not only did they slow, but they were not able to get their heart rate as high in the later repetitions. It is then that Verkhoshansky’s admonition that local muscular fatigue was the principal limitation to endurance. The progressively decreasing heart rate was the giveaway. As the legs became fatigued and the skier slowed, the heart was not being called upon to provide more blood/oxygen because the legs couldn’t use it. Remember that the heart responds to the demand of the muscles (via the brain). If the muscles do less work, the heart doesn’t need to supply as much oxygen.

What if I had the skiers improve that local muscular endurance with a special block of ME training BEFORE they engaged in a traditional interval training block? Well, I tried it, and the results were immediate and impressive. After even a few ME workouts, the skiers could complete more repetitions at a higher speed and heart rate before fatiguing.  This meant that those traditional intervals were now much more effective at producing the desired global training effect.

Since those days over 20 years ago, I have personally implemented this training approach with hundreds of athletes in Cross Country Skiing, Mountaineering, Alpinism, Mountain Running, and Ski Mountaineering with consistent stellar results.

Now on to the applications of this theory

Over the past 30 years, I’ve not been shy about experimenting with variations of ME training, starting while training with our very own coach Ben Husaby as he prepared for the 1992 Olympics. I perfected the water jug carry method I later used extensively with Steve House while training for my own K2 expedition in 1995. Our coach Maya Seckinger was a willing guinea pig as a young skier. Another of my former skiers, Sam Naney was also a test monkey for different versions of it. More recently, super alpinist David Goettler willingly participated in a few variations.

The most important thing I have learned is that there are a multitude of ways to achieve this effect, and your imagination can run wild. There are some simple guidelines we use with all our athletes. But first, this important warning:

ME Caveats

• ME training works, and it works quickly. If you are doing the workouts as I prescribe and do not see improvements in performance from week to week, it is not because you are doing too little ME. It is because you are doing too little recovery. The excitement of seeing rapid gains when using these ME workouts often leads many folks to overemphasize them in their training program by replacing time spent training at easier aerobic paces (Recovery and Zones 1 and 2) with these “money” workouts.
• The higher your basic aerobic capacity, (your Aerobic Threshold) (AeT), the bigger and longer lasting the gains will be from this training.
• You MUST maintain the Z1-2 aerobic volume and add this training on top of that. If you don’t, the gains you see will be quick (10–20 percent in only a few workouts), followed at first by a plateau and later a decline in performance.
• You must induce a distinct local muscle burning sensation in the propelling muscles to reap the benefits of this training

When to Implement ME

Ideally, you will have your AeT be within 10 percent of your AnT as measured by heart rate before you begin an ME training block. However, even if you are aerobically deficient, you must add higher-intensity training to your program to be best prepared.

For mountaineers, I’ve had the best luck using an ME block for the last 8-12 weeks (minimum of 6 weeks) before they begin their taper. Ski mountaineers can follow this advice.

For mountain runners, I typically use the ME block early in the base period as volume begins to build and have implemented as long as a 16-week ME block when I had plenty of time. Then, I shift to traditional uphill and rolling intervals for a final 8-week block before the taper. Skimo racers can use this approach.

How to Implement ME

Weighted Carries

The simplest way to create an ME training effect is to add resistance while doing some endurance training sessions. A well-proven way of doing this is to put water jugs in a backpack so the water can be dumped out at the top. Stronger athletes will find additional benefits from carrying the weight back down the hill. The hill will need to be very steep: typically 30% grade or more. A normal US Forest Service trail will rarely exceed 10-12%. This steepness requirement will eliminate the outside/natural terrain for most people.

For the terrain challenged, look for fire stairs in a tall building.  Skyscrapers are best, although even six stories can do the job.

For those without the tall building option, find a gym with a Stairmaster machine. These are like escalators, and you are climbing up them as the stairs fall away. While not as exhausting as real stairs or a very steep hill, they can get the job done well enough. We have used this method with hundreds of mountaineers to great effect.

How Much Weight?

Remember, The load you carry must be heavy enough that the local fatigue in your legs is the limitation, NOT your breathing. Disregard heart rate in these ME workouts. If your legs are not feeling a low-level burn for the full climb, you’re not getting maximum benefit. It will take some experimentation to find the right weight for you. In small buildings or short hills you will be doing these as an interval style workout. That’s OK. It works. Try for laps that are at least 5 minutes long.

For those without any of these options, standing on a bike in a very high gear can accomplish a very similar effect.  Sound farfetched? Olympic silver medalist Cross Country skier Bill Koch used this training method after removing the bike seat to avoid the temptation to sit before he won the overall World Cup title in 1983.

The point of adding the extra weight or riding in a big gear is to increase the recruitment of those FTa fibers. Recall from Training for the New Alpinism that if you can’t recruit them, you can’t train them. Due to these fibers’ relatively poor endurance (aerobic) capacity, they will be what determines your AnT heart rate for this type of work. If it is done correctly, that heart rate will be lower than your unweighted AnT heart rate.

How Much Vertical?

I’ve found that if these weighted carry workouts are done with enough weight to create that low-grade muscle burn for no more than one hour of total climbing time, even elite alpinist David Goettler gets plenty of training stimulus. Don’t start with an hour if you have never done this before. Thirty minutes will be plenty for the first time

The Verkhoshansky ME Method

Earlier, I mentioned that there are a multitude of ways to achieve a muscular endurance training effect. What I’m about to explain might appear to violate or at least confuse some of the principles explained above. Set aside any preconceived notions, keep an open mind, and read on.

What I’ve done in this instance is to take a page (actually several) right out of Yuri Verkhoshansky’s books and added a slight twist to them to produce what we’ve referred to for years as a Gym ME progression. It is a progression of ever-increasingly challenging workouts, meant to be completed once per week for between 8 and 14 weeks. We used this very successfully to increase the fatigue resistance in the legs of mountain runners primarily but also in mountaineers and alpinists.

Gym Based Muscular Endurance Workout:

This Muscular Endurance workout is appropriate for Mountaineers, Mountain Runners, and Ski Mountaineers. Anyone who needs to go steeply uphill faster for longer will see gains from this workout. The beginning workout is shown here. If this is the first time you have been through this ME progression, you should use bodyweight only for the first 2-3 workouts to learn the movements and avoid severe muscle soreness.

Absorbing the impact of the jumping exercises in this routine through eccentric muscle contractions builds good fatigue resistance for downhill running. Downhill running extracts a heavy toll on mountain running that is hard to prepare for without doing a high volume of downhill running, which carries with it a huge global fatigue cost. While the ME program will make your legs tired, the global fatigue load is much lower than that which comes from a high volume of running. We’ve proven the efficacy of this routine with hundreds of mountain runners. If you are limited on time or access to mountain terrain or want to try a different approach than the high volume method, give this a try.

While I generally encourage the use of weighted carries for mountaineers, I’ve used this as a base period preparation block before moving to the weighted carries with a number of high-level mountaineers and alpinists with great results.

The progression shown below is a suggestion that should work well for most people. However, variations in individual starting strength will mean that some people will progress faster than others. We find that most people will get mildly stiff and sore for two days after doing this workout. Attacking the first few workouts too aggressively can leave you wondering what happened to your legs and glutes. Ease into this program. Allow some easy recovery workouts after this. We typically recommend doing this workout one time/week to see significant gains if the remaining training load is high. If the training load is otherwise low, then do this 2x/week. It is easy to overdo this kind of work. Start slowly and progress at your own rate.

 NOTES:

You can and should modulate the intensity of this workout and the resultant fatigue and soreness in the following ways:

The height of your jumps and the extent of the range of motion in the more ballistic movements should be moderated if you have never done this type of training before or have gotten very sore and stiff from it in the past. Do this at about 80% range of motion 80% effort the first couple of times to see how your body responds.

The number of sets will also affect fatigue and soreness. If you are new to this or got very sore when you did it before, start with 4 sets for the first 2-3 workouts rather than start with the suggested 6 sets below.You have been warned. These initial ME workouts have a way of feeling very easy when you are doing them but coming back to bite you for the next few days. Go easier than you think you need to.

Workout:

Immediately below is the general makeup of the workout with exercises explained.  Below that is the laid out in the 14-week progression of this series.

Warm up

10-15 min light aerobic exercise building to Z3 effort for the final 2 min.

10 get ups. Just get up off the floor from a supine position

10 burpees

Complete all sets of each exercise before moving on to the next exercise. Do not speed through these. Shoot for the recommended tempos with the various exercise.

Exercises

6 sets of 10 reps on each leg of Split Jump Squat. (SJS) Tempo of about 1 jump per second. Video here

6 sets of 10 Squat Jumps (SJ) tempo pf about 1 jump/1/2-1 second. Video here

6 sets of 10 reps on each leg of Box Step Ups (BSU). Use a box that is about 75% the height to the bottom of your knee cap. Do 10 reps on R leg then switch to 10 reps on L leg. Tempo about 1 rep/sec. Video here

6 sets of 10 reps each leg Front Lunge (FL). Do 10 reps on R before switching to L leg.  Tempo about 1 rep/sec.  This is one that hits the glutes the hardest so start with a gentle lunge of 40-60cm (16-24inches). Video here

10min aerobic cool down.

Workout Progression

WO #1 and 2 Start with Body Weight only. Rest 60sec after each set of an exercise. Rest 60sec between exercises. On Box Step ups and Front Lunge exercises do all R leg then all L leg and rest 30 seconds between sets. Do 1 time through circuit.

WO #3 Still body weight and 6 sets of 10 reps of each exercise. Drop rest/set to 45 sec/set. On BSU and FL stay with 30sec between sets. Rest 60 sec between exercises.

WO #4: 5 Sets of 10 reps. Add weight. Using a weight vest is ideal way. Start with no more than 10% of body weight. Same rest/set. Rest 60sec/set and between exercises. If you have done this ME progression before and feel you need added challenge (I rarely use this unless the athlete is very strong)

Add the following new exercises from here on through the progression:

5 sets of 10 reps of Goblet Squat/Overhead Press.

5 sets of 10 reps of 2 hand Kettle Bell Swing

WO#5: +10% BW. Do 6 Sets of 10 reps. Cut rest/set to 45 seconds except Box Steps and Lunges, stay with 30 seconds Rest 90sec between exercises.

WO#6: +10% BW. Do 6 sets of 10 reps. Rest 40sec/set and 30 sec for BSU and FL. Rest 60 sec/exercise.

WO#7: +10% BW. Do 6 sets of 10 reps. Rest 30sec/set and 30 sec for BSU and FL

Rest 60 sec/exercise

WO#8: +10% BW. Do 8 sets of 10 reps. Rest 45sec/set and 30sec for BSU and FL Rest 60sec/exercise.

WO#9: +15% BW. Do 6 sets of 10 reps. Back to 40 sec rest/set. 30 sec rest/set for BSU and FL.

 Rest 45sec/exercise

WO#10: +15% BW. Do 8 sets of 10 reps. 45 sec rest/set. 30 sec rest/set for BSU and FL Rest 30 sec between exercises.

WO#11: +15% BW. 8 Sets of 10reps. 30sec rest/set. 20sec rest/set for BSU and FL. Rest 30sec between exercises.

WO#12: +15% BW. 8 Sets of 10reps. 15sec rest/set. 15sec rest/set for BSU and FL. Rest 20sec between exercises.

WO#13: +15% BW. 8 Sets of 10reps. 10sec rest/set. 10sec rest/set for BSU and FL. Rest 10sec between exercises.

WO#14: +15% BW. 8 Sets of 10reps. 10sec rest/set. 10sec rest/set for BSU and FL. Rest 10sec between exercises.

To get the benefits of this progression, you need to do it for at least eight sessions.  Try for one session/week. For every session or week you miss, drop back two workouts in the progression and start over.

Prepare to be amazed at your strength, muscular endurance, fatigue resistance, and durability.

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