How to Harden Muscles Naturally (and Keep Muscles Hard Permanently)

Workout Plans | Written by Nathan Petitpas | Updated on 6 April 2023

A man performs a slow eccentric to harden muscles while doing a bicep curl with his shirt off inside an industrial building with concrete walls.

Many weight lifters, newbies, and seasoned pros alike strive to harden muscles and keep them hard permanently.

Believe it or not, it is possible to naturally achieve rock-hard, dense muscles and hang onto them for the long run by following the right training regimen that incorporates the right styles of training, lifting modalities, in addition to proper diet and nutrition.

What Causes Muscles to Harden While Flexing?

To better understand how to get hard muscles while flexing, it’s important to first learn why muscles harden at all. Our muscles are made of blocks of protein called myofibrils. These blocks join together to form fibers that can fold together when active (or flexed). This contraction makes the muscle bigger and harder while flexing or during flexion.

Of course, most lifters don’t want muscle fibers that only harden when they flex. They want to look ripped 24/7 or as they say, suns out, guns out. The best way to achieve hard muscles permanently is to build muscle mass and lift weights in a manner that promotes harder muscles at rest, and while flexing.

Why Do Muscles Harden After Lifting Weights? Harden Muscles Cause After Gym

There are a few different theories behind why muscles harden after lifting weights. Some bodybuilders believe that testosterone levels are a key factor behind hard muscle mass.1 Other weightlifters claim that getting hard muscles is all about decreasing body fat and that a body fat percentage of 10% or less is critical to hardening muscles.2

Some fitness experts insist that eccentric exercise (exercise that focuses on stretching the muscle) is the key to developing hard muscles. The eccentric exercise involves exaggerating movements that lengthen the muscle, like the sitting motion in a squat or lowering the arms during a curl.3 This type of motion offers many benefits during training, including an increase in muscle mass.

According to research in the British Journal of Sports Medicine, weight lifters who perform eccentric exercises at a higher intensity than concentric exercises — those who elongate the “sit” in their squat instead of the “stand” — see greater strength and muscle increases. This suggests that the technique a lifter uses when he or she trains is essential to getting desired results.

Other researchers and fitness experts claim that the secret to gains and muscle hardness lies not with the way you train, but the weight you train. Lifting heavier weight at lower reps (ideally seven reps or fewer) activates the high-threshold motor units (HTMUs), which are the strongest muscle fibers in your body. HTMUs have serious growth potential, which means they can help you look harder and more ripped.4 Heavy lifting also helps improve neurogenic tone (muscle tone when flexing or moving). However, this type of training also enhances myogenic tone, which is muscle density that comes from the muscle itself rather than flexing (aka hard muscles).

Research from the European Journal of Applied Physiology and Occupational Physiology compared bodybuilders to a group of healthy, yet average, volunteers and discovered that the bodybuilders had more overall muscle fibers than the control group. This is likely because heavy lifting helps the body produce contractile proteins called myosin and actin. As contractile proteins are the densest parts of muscle fibers, a lifter who has more of these proteins in his or her muscles will appear harder even at rest.5

A man with a mustache wearing a grey shorts, without a shirt on showing his rock hard muscles in a dark gym.

Source: bondarkchik via Canva.com23

At the end of the day, proper training is the ultimate key to getting and keeping hardened muscle. Metabolic stress (through eccentric exercise, for example) is the best way for lifters to activate those satellite cells. Exercise helps lifters decrease their body fat percentage — it’s even an essential weight loss rule. And when it comes to testosterone levels, a 2010 study in Sports Medicine even found that resistance exercise can increase testosterone levels in both men and women!

This is why it’s so important for weight lifters to focus on their training technique if they want to create lasting hard muscles.

How Do You Get Rock Hard Body Muscles?

Weight lifters can use a wide range of training techniques to achieve hypertrophy in the gym. Some of the best methods to harden muscles are the following:

  • Eccentric Exercises: One of the great things about eccentric exercise is that you can incorporate it into typical parts of most workout sessions. Exercises like squats, deadlifts, push-ups, and rows can all become eccentric exercises; just slow down the movement so that the lengthening phase (for example, the sitting in a squat or the downward motion in a push-up) takes three seconds and the shortening phase (the stand in a squat or the upward push in a push up) takes only one.6 This will put more tension on the muscles and help improve muscle density. And as an added bonus, these slow movements offer a little extra stretch that is great for stiff muscles!
  • Supersets: A superset involves doing two exercises back to back, followed by a short rest. To build muscle during a superset, aim to do 8-12 reps of each exercise for a total of 16-24 reps before each rest period.7
  • Drop sets: In a drop set, a weight lifter will do one exercise until failure, then deload by 10-30% and lift until failure again.8 This process allows lifters to maximize their potential for muscle growth by forcing both slow-twitch (fibers that sustain force for long periods) and fast-twitch muscle fibers (fibers that offer a more powerful force for short bursts) to activate in the exercise.

Drop sets are particularly useful for building muscle mass (and therefore creating hard muscles). A 2018 study in the Journal of Sports Medicine and Physical Fitness reported that participants who practiced drop sets saw a 5.8% increase in muscle thickness versus participants who used normal resistance training.

  • Reps in Reserve (RIR): A lifter’s reps in reserve (RIR) are the number of reps after a set that he or she would be able to do with good form.9 For example, if a lifter completes 10 bench presses, but could do 12 before technical failure (the point at which good form is impossible), he or she has an RIR of 2. Training with RIR helps lifters minimize fatigue, which means they can keep training and building strength (and muscle) each time they hit the gym.
  • Periodization: Periodization is a training technique that breaks up your routine into periods (hence the name). A typical periodization cycle is a four- to six-week period of intense workouts, followed by a shorter period of lighter workouts.10 This method delivers great results because it gives your body time to heal between hypertrophy periods. It also gives you time to focus on decreasing body fat through a cutting/dieting period (like a 1,000 calorie deficit diet)./li>
  • Powerlifting or Lifting Heavy: Powerlifting is known as “the strongest sport in the world”.11 This technique requires you to produce as much force as possible on your muscles during exercises like squats, deadlifts, or bench presses. Just remember that powerlifting is a very intense workout program. If you want to harden muscles with this technique, make sure to start with a powerlifting program for beginners to avoid injury.
  • Getting Lean: As we mentioned earlier, losing body fat and getting leaner can help a lifter’s muscles appear harder and denser. However, if a lifter decides to focus on losing fat (known as a “cutting phase”), he or she needs to keep training to maintain the muscle gains they’ve already earned. Luckily, MV training is often enough to keep muscles hard as a lifter cuts weight.

Of course, it is also important to emphasize the value of rest when building hard muscles. Lifters who don’t give their muscles enough rest can actually decrease the time their body has to metabolize proteins, which results in fewer gains and softer muscles.12

Should I Do Anything Different to Harden Certain Muscles LIke Chest, Arms, Legs, Back, Shoulder, and Abs?

We’ve mentioned that the key to hard muscles is proper training, but there are certain things you can do to harden certain muscles. What does that really mean? It means not just working harder, but working smarter — training the optimal rep ranges for each muscle group, and giving your muscles enough time to recover.

Use the following training guides to better understand your ideal training volume:

  • Arms: Your arm muscles can be trained nearly every day and with high volume because they recover quickly. For biceps, aim for at least eight sets per week (at least four sets per session if you train 2x a week), but do not exceed 12 sets in a single session. For triceps, aim for at least six sets per week of direct tricep work (in addition to any chest pressing you do). For forearms, aim for at least two weekly sessions with at least four sets.
  • Legs: For both calf muscles and quad muscles, you need at least eight sets of direct work each week to harden those muscles. You can spread those sets across your week (4 sets per session at 2x a week, 2-3 sets at 3x training, etc.) and even increase the number of sets, but do not exceed 12 sets per session. Hamstrings only need four sets of direct work to make gains — and because of the significant fatigue and risk of damage that comes with training hamstrings, it’s recommended not to train them more than 4x a week (one set a session).
  • Back: There are 40 different back muscles to train on your body. Therefore, the back requires a little extra work to grow and maintain. Most lifters need at least 10 sets of back work each week to harden their back muscles, ideally split into five sets 2x weekly. In some cases (for example, in the case of an experienced lifter), it may be beneficial to up your training volume to as much as 30-35 sets per week; however, remember that that figure includes all back work — both vertical and horizontal exercises.
  • Chest: The minimum effective volume (MEV) — the minimum amount of work you can do to make gains — for chest muscles is at least six sets per week. Obviously, the number of sets in each session varies based on how often the lifter trains each week (three sets for 2x training, 1-2 sets for 4x, etc.). Experienced lifters will require more sets, but do not exceed 12 sets per session.
  • Shoulders: Many lifters manage to train their shoulder muscles through the pulling and pressing exercises they do for the back and chest. However, if a lifter really wants to develop these muscles, it’s best to do it by training the rear delts with at least six sets per week. Ideally, this should take place over at least two weekly sessions (three sets per session), but you can get faster results from graining 3-5 times per week.
  • Abs: Everyone knows that abs like granite are the gold standard for hard muscles. But here’s what’s great about them: you can grow your stomach muscles and harden those abs with zero sets of direct work. This is because other exercises like squats and deadlifts actually provide your abs with enough stimulus to harden muscles and keep them looking great.13

How Long Does it Take Until You See Soft Muscles Harden Up?

Beginner lifters might be desperate to see real gains and have that rock-hard muscle. They’ll get it — but only after several weeks of consistent and effective training. Most lifters start to see results like increased muscle mass, greater strength, and hard muscle after approximately 12 weeks of training.14

What Should I Eat or What Supplements Help to Harden Muscles?

When it comes to supplements, most people wonder what vitamins help with weight loss but bodybuilders know that supplements can also be hugely influential in their quest to harden muscles. Weight lifters who want to harden their muscles can benefit from certain supplements that encourage satellite cell activation (and remember, satellite cells are an important part of muscle development).

Some supplements you’ll want to add to your fitness regimen include:

  • Creatine: This supplement helps the body regenerate a molecule called adenosine 5′-triphosphate (ATP) ATP plays a critical role in muscle size and strength, as well as recovery.15 You can add creatine into your diet by eating more foods like red meat, salmon, pumpkin seeds, and seaweed.16
  • Whey protein powder: Protein is always essential for muscle growth, and studies show that whey protein powder can deliver stellar results. According to the Journal of Exercise Nutrition and Biochemistry, people who consume 40g of whey protein before and after workouts can see greater muscle circumference and strength, as well as an increase in exercise volume. Note, casein protein powder is better before bedtime since it digests slower. While the simplest way to eat more whey protein is to mix the powder into your pre- or post-workout shake, you can also get whey protein from dairy products like cows milk, yogurt, and ricotta cheese.17
Three bottles of whey protein powder are next to each other; each is a different color (red, green, and blue), and each has a different flavor (vanilla, chocolate, and strawberry).

Source: farakos via Canva.com24

  • Vitamin K: Some research suggests that insulin can help increase the density of satellite cells. Vitamin K helps improve insulin sensitivity, which can ultimately benefit muscle development in the long run.18 Vitamin K is present in leafy greens like spinach, kale, and collard greens, but foods like mayonnaise and soybean oil are also rich in this vitamin.19
  • Glutamine: This supplement helps increase the levels of leucine (an amino acid used to synthesize proteins) in muscle fibers. This can help decrease fatigue and muscle breakdown, so lifers can recover more quickly and maximize their training.20 Lifters can get more glutamine in their diet by eating more beef, chicken, eggs, and fish (specifically cod).21

The supplements listed above can be influential in helping your muscle development, but they are just one part of a muscle-building diet. It’s also important to be in a caloric surplus as you build muscle. Up your protein intake to at least 0.25g per kilogram of body weight at each meal.22

How to Ensure Your Harden Muscles Stay Dense Permanently

Doing the work to get hard muscles is one thing — keeping them is another. Luckily, it requires minimal effort to ensure that muscles stay hard and dense once they get there. Once a lifter has built up hard, strong muscles, he or she can maintain them simply by sticking to their maintenance volume (MV) during each session.

MVs tend to be very low effort (four sets a week for biceps, eight sets a week for quads, and no direct work for muscles like the delts and abs). With just one or two hours per week, it’s easy to maintain that muscle you worked so hard to develop and strengthen.

It may take work, commitment, and a lot of sweat to harden muscles, but with the right training, you can enjoy the fruits of your labor forever.

FAQ About Hardening Muscles

Can Hiking Harden Your Leg Muscles?

Advanced weightlifters probably will not achieve hypertrophy on the average weekend hike. But new lifters or hikers can see hardened leg muscles if they frequent the trails often.


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About the Author

Nathan Petitpas

Nathan has been a fitness enthusiast for the past 12 years and jumps between several types of training such as bodybuilding, powerlifting, cycling, gymnastics, and backcountry hiking. Due to the varying caloric needs of numerous sports, he has cycled between all types of diets and currently eats a whole food diet. In addition, Nathan lives with several injuries such as hip impingement, spondylolisthesis, and scoliosis, so he underwent self-rehabilitation and no longer lives with debilitating pain.