Last Updated on April 2, 2022 by Heather Hart, ACSM EP, CSCS
The 3 Minute Mountain Legs workout, along with similar high repetition/low or no weight workouts, have become highly popular among the trail and ultrarunning community as a way to supposedly build strength to help with both climbing and descending hills while running.
I love seeing athletes show interest in wanting to improve their performance through strength training and cross training modalities. But I also love exercise science, and as a coach and fitness professional, it is important to me that I help athletes better understand WHY they do what they do.
Therefore, I’m going to dive into a post explaining why the 3 minute Mountain Legs workout, and other similar high repetition exercise workouts, don’t actually do what most runners think when it comes to building strength.
What is the 3 Minute Mountain Legs Workout?
The 3 minute Mountain Leg workout includes 20-50 repetitions of reverse lunges on the left leg, 20-50 repetitions of reverse lunges on the right leg, followed by 30-100 single leg step ups on the left leg, and 30-100 single leg step ups on the right leg.
In the YouTube video explaining the workout, David Roche, elite trail runner, coach, and creator of Mountain Legs Workout, explains that the goal of the workout is to help runners gain strength to help with climbing and descending hills while running. Further, he suggests you should repeat this workout 3-4 times a week at the end of a run.
Now, to be fully transparent, Roche mentions both in his video and the accompanying post on Trail Runner Magazine that if you already have a good strength routine that you do without fail, you should stick with that.
But Roche believes that many trail and ultrarunners don’t stick with traditional strength training routines because of the time commitment, so Mountain Legs is a good substitute for building strength for both uphill and downhill running.
And while I mention Mountain Legs often in this post, I’m also referring to other workouts that involve high repetitions of exercise, with little or no weight, that runners frequently use believing that it will help them build muscular strength. This is not a personal attack on just one workout, however I name it frequently simply because that workout is so well known among the community.
Let’s dive into why this might not actually be the case, by first understanding the difference between muscular strength and muscular endurance, and how we improve each.
What Is Muscular Strength?
Muscular strength is defined as the maximal force that a muscle or muscle group can generate.
(I know I tend to go overboard with this stuff, so I promise to keep the science as concise and easy to understand as possible in this post.)
Building muscular strength increases the capacity of a muscle to generate higher forces, and for a runner, this may reduce the energy needed to actually run.
For the long version, check out the entire post I’ve written about the benefits of strength training for trail and ultra runners.
How Do We Build Muscular Strength?
In order to build strength, your muscles must be overloaded under a stimulus greater than what they are currently adapted to. This is known as the Principle of Overload.
According to the National Strength and Conditioning Association, heavier loads at approximately 85% or greater than that of your 1RM (the maximum amount of weight you can lift for that particular exercise for one single repetition), with lower repetitions (less than or equal to 6 reps) are associated with gains in strength.
Adaptations to lifting heavier weights include:
- Increased cross-sectional size of muscle fibers (hypertrophy – your muscles get “bigger”)
- Greater recruitment of muscle fibers (your brain calls more muscle fibers in to do the work)
- Increased rate of firing (your muscle fibers are able to contract faster)
…all of which increases the force generating capabilities of muscle.
But that’s not all! True strength training workouts elicit structural changes and improved function in bone, tendons, ligaments, fascia, and cartilage, which can not only aid your body in continued strength gains, but helps with injury prevention as well.
What Is Muscular Endurance?
Muscular endurance is the ability of a muscle to resist fatigue while performing repeated muscle contractions under submaximal forces. This often gets confused with cardiorespiratory endurance, which is the ability of the heart and lungs to deliver oxygen to the body’s tissues during sustained physical activity.
More simply put: muscular endurance refers to a specific muscle group’s ability to “keep going” during exercise (think: how long can I run up this hill before my quads get tired), while cardiorespiratory endurance refers to your whole body’s ability to “keep going” (think: how long can I run at this pace before I start to feel tired).
How Do We Build Muscular Endurance?
Lighter loads (less than or equal to about 67% of 1RM) over a higher number of repetitions (greater than 12 reps) will increase muscular endurance.
Adaptations to lighter loads over higher repetitions include:
- Strengthening Type 1 muscle fibers (“slow twitch”) that are endurance based and slow to fatigue.
- Improving the aerobic capacity of muscles by increasing mitochondrial density .
- Improving cardiovascular and cardiorespiratory responses.
- Improves cellular respiration (your body’s ability to create “energy” for exercise)
…all of which allows your body to be able to run for longer.
Muscular Endurance Misconceptions Among Runners
So many runners see “endurance” and assume that’s what they need to train for in the weight room. I mean, it’s the Principle of Specificity, right? Hell, I often made this mistake when I first got into this industry, and likely incorrectly wrote about it on this very site.
Well here’s the thing: do you want to know a far more specific exercise that includes lighter weight bearing loads over high repetitions that elicits awesome muscular endurance gains? It’s running. Running does that.
And I’m guessing if you’re reading this post, you’re already running.
Does the 3 Minute Mountain Legs Workout Build Strength?
If you are already an active trail or ultrarunner, chances are very high that the 3 Minute Mountain Legs workout is not going to help you build any strength. And that’s because you are simply not presenting a force heavy enough to elicit any strength gains (Principle of Overload).
Any movement that can be repeated for more than around 12-15 repetitions simply does not include a large enough load stimulus to elicit any gains in strength.
Yes, your legs may feel tired or burn while performing mountain legs, because those muscles are fatiguing, and likely due to circulating hydrogen ions as a byproduct of metabolism (the “lactic acid vs. lactate” rabbit hole I promise not to go down in this post) .
However, the load is not enough to elicit true physiological hypertrophy and neuromuscular strength gains.
How to Actually Build Leg Strength for Trail Running:
Pick up some heavy weights! A full body workout, twice a week, covering the 7 major complex movement patters – push, pull, squat, hinge, lunge, carry, and anti-rotation, at a weight heavy enough to feel fatigued after about 6-8 repetitions, repeated for 3-6 sets per move, is all you need.
The workout does NOT have to be complicated. But it DOES have to have a load heavy enough to elicit physical adaptations.
Sorry, I don’t make the exercise science rules.
Does the 3 Minute Mountain Legs Workout Build Endurance?
If you are already an active trail or ultrarunner, than chances are very good that the 3 Minute Mountain Legs workout is not going to help you build muscular endurance either.
An athlete who is already able to sustain repetitive muscular movement- like running- for a few to a few hundred miles is not going to see any improvement in endurance from a similar movement at a similar load that only lasts for a few minutes.
Again, we refer back to the Principle of Overload: in order to make adaptations and improvements, the stimulus must be greater than before, and what our body is currently adapted to .
You could argue that because Roche suggests tacking the Mountain Legs onto the end of a running workout, that this is adding to your muscular endurance. While that may be true, again we refer to the principle of specificity and argue that just running would be a better option.
How to Build Muscular Endurance for Trail and Ultra Running:
In order to build muscular endurance for trail and ultrarunning, you need to keep running. It really is as simple as that.
Now, OF COURSE you can do other things to help build muscular endurance. And if you enjoy other things, I highly support doing that. Because I don’t know about you, but I’m not an elite athlete, and I want to spend my precious time here on this earth doing ALL of the things I enjoy.
So, whether it’s the Peloton, or kayaking, or swimming, or WHATEVER other form of exercise that gets your blood pumping and muscles working for long durations of time: great. Keep doing.
BUT, for the purpose of building better muscular endurance for running, the most specific and best thing you can do is to keep running.
But I Don’t Have Hills to Train on, Will Mountain Legs Help Me?
Listen, I get it, I live in flatter than you can even imagine, zero feet above sea level, Myrtle Beach. What’s important to remember here is again the almighty Principle of Specificity. Yes, Mountain Legs mimics the movement of climbing hills, especially the concentric contractions of climbing, and the eccentric contractions of descending.
However, in order to truly build specific endurance for climbing over the course of a trail race or ultramarathon, the workout stimulus absolutely has to last longer than three total minutes at intensity.
A better option would be to somehow work multiple sets of the 3 minute mountain legs routine into a longer run. This would more appropriately simulate the specific demands of a trail or ultra run.
Are There Any Benefits to the 3 Minute Mountain Legs Workout?
Now, I’m not going to be a total buzzkill here, there certainly can be perceived benefits to the Mountain Legs workout, or other similar workouts.
- You enjoy Mountain Legs (etc.). If you enjoy this 3 minute workout, or others like it, and it doesn’t seem to be hindering your training in any way, then hell yeah, stick with it!
- You’re brand new to all of this. If you’ve never done any sort of body weight resistance training before, then Mountain Legs can absolutely be beneficial.
This is because there are a ton of neuromuscular adaptations that happen when you first begin strength training (known as “early phase adaptation”). During this phase, your brain essentially gets better at telling your muscle fibers “hey, we have work do to here!” That’s why you often feel “wobbly” or uncoordinated when you first start lifting weights, but very quickly feel more confident with the movements.
How to Modify the Mountain Legs Workout To Actually Build Strength
If you enjoy the Mountain Legs workout, but want to ensure you’re building strength, be sure to add an appropriate load to each movement, cut back on the number of repetitions (6-8 at most), and increase the number of set (3-6, with at least 2 minutes rest in between).
Repeat the workout 2-3 times per week.
As a bonus, holding the weight on one side of your body (such as a kettlebell) while performing unilateral (single leg) movements, will challenge your balance and help strengthen your core.
Coach Heather’s Final Thoughts:
The bottom line is that ANY movement in the form of improving health is GOOD movement. I will never argue that.
Further, while running performance can be helped by strength training, it can also be HINDERED by it at times. So I’m not insinuating that this workout, or any similar workouts, are WRONG if they help a runner improve their performance.
But it is not strength training.
If you are a trail or ultrarunner looking to truly improve muscular STRENGTH, please know that you need to be lifting heavy weights/moving heavy loads with the goal of progressive overload for adaptation.
And if you are a trail or ultrarunner looking to improve muscular endurance: just keep running.
For more information on this topic, visit the post:
Simplifying Strength Training for Trail & Ultrarunners: 7 Moves to Balance Lifting and Running
Heather Hart is an ACSM certified Exercise Physiologist, NSCA Certified Strength and Conditioning Specialist (CSCS), UESCA certified Ultrarunning Coach, RRCA certified Running Coach, co-founder of Hart Strength and Endurance Coaching, and creator of this site, Relentless Forward Commotion. She is a mom of two teen boys, and has been running and racing distances of 5K to 100+ miles for over a decade. Heather has been writing and encouraging others to find a love for fitness and movement since 2009.