Muscle-specific hypertrophy: chest, triceps and shoulders

Unfortunately, building a massive body requires a more thoughtful approach than simply trying to move as much weight as humanly possible.

To know how to best train a muscle, you must first understand its physical structure and, in particular, its biomechanics and muscle fiber composition. This information will help you choose the correct repetition ranges, weekly volume and rest intervals for optimal results.

But many exercisers do not customize these load parameters to the specific muscle being trained. For example, they will dedicate 4 to 6 weeks of their training to hypertrophy and perform each exercise with a repetition range of 8 to 12 repetitions.

This is a mistake. Optimal hypertrophy training is muscle specific.

In this two-part article, I will give you the necessary information on these two topics for each major muscle - biomechanics and muscle fiber composition. Today's article will cover the pecs, triceps and shoulders and will begin with a brief summary on muscle fibers.

The different types of muscle fibers

There are at least three different types of muscle fibers. To increase contraction speed, increase force production and increase resistance to fatigue, you have type I, type IIa and type IIb muscle fibers.

Type I muscle fibers are slow-contracting muscle fibers and type II muscle fibers are fast-contracting fibers. The following table lists the most important characteristics of each of these muscle fiber types.

Type I fibers are slow-twitch and type II fibers are fast-twitch. The following table lists the main characteristics of each muscle fiber type.

	Type I fibers	Type IIa fibers	Type IIb fibers
Contraction time	Slow	Moderately fast	Very fast
Size of motor neurons	Small	Medium sized	Very large
Resistance to fatigue	High	Quite high	Low
Activity	Aerobic	Long duration anaerobic	Short duration anaerobic
Maximum duration of use	Hours	<30 minutes	<1 minute
Power produced	Low	Medium	Very high
Mitochondrial density	High	High	Low
Capillary density	High	Medium	Low
Oxidative capacity	High	High	Low
Glycolytic capacity	Low	High	High
Primary stored energy source	Triglycerides	Creatine phosphate, glycogen	Creatine phosphate, glycogen

Each muscle has a different muscle fiber composition. Some muscles are dominated by fast contracting fibers, while others are dominated by slow contracting fibers.

Muscle fiber composition is largely genetically predetermined and has very important muscle-specific training implications. Fast contracting fibers respond best to low volume, long rest intervals, high intensity and low frequency. Slow contracting fibers, on the other hand, respond best to high volume, short rest intervals, low intensity and high frequency.

Perhaps most importantly, fast-contracting muscle fibers have a significantly higher growth potential than slow-contracting muscle fibers. Even in untrained individuals, they are typically more than 20% larger and it is not uncommon for them to be over twice as large.

The muscle fiber composition of each muscle varies from person to person, but as with most physiological characteristics, the individual differences are not that great. In the general population, differences in the percentage of slowly contracting muscle fibers are usually between 5% and 10%. So you are probably not special in this respect, even if your mother told you that you are.

As for the change in muscle fibers from one type to another, age seems to be a factor (the percentage of fast contracting muscle fibers starts to decrease after the age of 30), although some studies have shown that high intensity resistance training helps to prevent this. Bodybuilding-style training with weights in the 6 to 12RM range can convert both type I and type IIb muscle fibers into type IIa muscle fibers.

However, since weightlifters, powerlifters, bodybuilders and physically inactive people differ by less than 5% in terms of the percentage of slowly contracting fibers in their muscles, it is unlikely that you need to consider muscle fiber conversion in your training.

Also, the theory that high intensity (>90% of 1RM) is optimal for hypertrophy because it helps you get more fast contracting fibers and these fibers have the greatest growth potential is probably wrong. Yes, getting stronger will help you become more muscular as it enables you to expose your muscles to more stress, but it is also important that you don't neglect your slow contracting fibers.

In bodybuilders, unlike powerlifters and Olympic weightlifters who show preferential hypertrophy of type II fibers, hypertrophy of both muscle fiber types can be observed.

As a conclusion from this, you should always try to achieve a balance between volume and intensity for maximum hypertrophy.

This is basically all useless if you don't know the muscle fiber composition of your muscles.

To solve this problem, some smart trainers - who for whatever reason seem to be French Canadians - have developed a test to help you figure out how fast contracting a muscle is. This test is commonly known as the 80% test.

In a nutshell, given an exercise that targets a specific muscle, determine your 1RM weight and then test how many reps you can perform with 80% of that weight. If you can perform less than 8 reps, then the fast-twitch muscle fibers dominate that muscle. If you can perform more than 8 repetitions, the slow-contracting muscle fibers will dominate.

There are more sophisticated variations of this test, such as using 85% for 5 repetitions, but the principle is always the same.

The advantage of this test is that it is individualized. The disadvantage is that it is impractical. I don't know anyone who uses this test systematically because you have to find an exercise for each muscle that really isolates that muscle, which means it's probably hard to perform that exercise with the 1RM weight (have you ever done one repetition of flying movements with the 1RM weight?).

You also can't overcome neural factors. Poor technique or an inefficient nervous system will cause you to underestimate your 1RM and give you the impression that your muscles are contracting slower than they actually are. You can use exercises like front squats and dumbbell bench presses to get a general idea of your muscle fiber composition, but this is far from perfect.

The good news is that there is plenty of research on muscle fiber composition.

Now that we've got the introductory notes out of the way, let's get to the good stuff!

Chest

The pectoralis major consists of two muscle heads - the muscle head that attaches to the sternum (lower chest) and the muscle head that attaches to the clavicle (the upper chest).

The primary functions of the pectoral muscles are diagonal shoulder flexion and adduction, as used in flying movements. So to target the pecs, you should choose exercises that involve diagonal shoulder flexion or adduction.

Note: It is flexion when the shoulders are internally rotated and adduction when the shoulders are externally rotated. If you have trouble seeing the rotation of your shoulders, look at your elbows when your arms are raised in front of your body. If your elbows are pointing outwards to the side, it means your shoulders are rotated inwards and if your elbows are pointing towards the floor, it means your shoulders are rotated outwards. Remember this because you will need it in a minute.

In addition to this, the angle between your arms and your body will determine which head of the pectoralis will be trained the most - incline bench for the upper chest and reverse incline bench for the lower chest.

One problem that many exercisers have when training their pecs is that the front shoulder muscles take over. The anterior shoulder muscles are also involved in diagonal shoulder flexion, but their role in adduction is minor.

Therefore, if you want to isolate the pectorals from the anterior shoulder muscles, you should perform exercises where the shoulder is externally rotated. The most obvious choice would be standard flying movements where you actively try to rotate your hand slightly outwards.

However, although the pectorals are best isolated by exercises that involve external rotation of the shoulders, the pectoralis major is biomechanically more efficient, and therefore stronger, when the shoulders are internally rotated.

This means that you cannot maximally stimulate your chest without training the front shoulders and you should take this into account when putting together your training program. However, it is a common mistake to overemphasize the front shoulder muscles.

Which exercises are best for stimulating the chest?

For pressing exercises, the further out to the side you place your elbows, the better.

This causes an internal rotation of your shoulders and results in the exercise involving more diagonal shoulder flexion and less off-diagonal shoulder flexion, which is the movement performed during the front lift.

I agree with Vince Gironda that the bench press to the neck or guillotine bench press is undoubtedly the best exercise for the pecs.

Bench pressing in this way has been known to cause shoulder pain in some - not to mention that bench presses to the neck are not entirely safe when performed without a training partner, so you might prefer to use dumbbells or not take the risk at all.

An underrated exercise that protects your shoulders while still training your pecs is the flying underhand grip (https://www.youtube.com/watch?v=8OSGl8qtZKI). Most exercisers perform flying movements exclusively with a neutral grip, but the pectoralis major is stronger when the shoulders are internally rotated, which is why an underhand grip is superior for stimulating the chest.

You can perform this exercise with dumbbells, but flying movements with dumbbells have a resistance curve that doesn't match the strength curve (no tension at the highest point of the movement) and going too low can overload the shoulders. For these reasons, I prefer to do them on the cable pulley.

If there is no equipment in your gym that allows an underhand grip, such as straight handles or short ropes, you can simply grab the carabiners (handles are for pussies, right?) or pull straps through the carabiners and grab the straps.

As for the optimal number of repetitions for chest exercises, you should use a medium repetition range. The pectoralis major is a performance muscle and both of its muscle heads are primarily made up of fast contracting fibers in almost everyone, with 60% Type II fibers being the average.

The bottom line:

• The pectoralis major is made up of about 60% fast-contracting fibers.
• It is strongest when the shoulders are internally rotated (elbows pointing away from each other during the press) and is best isolated by maximizing the lateral extension of the elbows.
• Try flying repetitions with an underhand grip and a medium repetition range.

Triceps

If you understand the range across the chest, then you know why bench pressing like a powerlifter is not optimal for chest development. Powerlifters often don't have the biggest pecs, but their triceps are usually monstrous (look at Dave Tate as an example of this).

This is not only due to the biomechanics (bent back, elbows closer to the body, J-curve) of the powerlifting bench press, which emphasizes the triceps more than the chest, but also due to the muscle fiber composition of the triceps.

In addition to this, the triceps brachii is even more of a performance muscle than the pectoralis major. Its proportion of fast-contracting muscle fibers is about twice as high as the proportion of slow-contracting muscle fibers, which corresponds to a proportion of 67% type II muscle fibers.

Accordingly, you should not worry about kickbacks with high repetitions. Instead, ramp up the intensity on lockouts(https://www.youtube.com/watch?v=mH-S0bmUyPA), dips and close bench presses on the reverse incline bench. It's best to use low reps most of the time. High reps won't do much for most people.

There's something else you should know about the triceps - they are made up of three muscle heads (long, lateral and middle), with the long muscle head crossing the elbow joint and the shoulder joint, helping to extend and adduct the shoulder (moving the arm down and towards the body).

This means that it is insufficiently trained when it has to act as an elbow extensor while the shoulder is adducted or extended. This means that it cannot muster enough tension to be active on both joints at the same time. Basically, all horizontal pressing exercises including dips (you may say dips are vertical, but I say "who cares") inadequately stimulate the long head of the shoulder. You need to do overhead work to train the entire triceps.

The bottom line

• The triceps are made up of 67% fast contracting fibers. So train them according to the motto "train heavy or go home."
• The long muscle head must be trained with overhead work.

Shoulders

As you probably know, there are three shoulder muscles - the anterior, lateral/side and posterior muscle head of the shoulders.

As a side note, there is no such thing as a "medial/middle shoulder muscle head". In anatomy, medial refers to "near the center of the body", while the correct term lateral refers to the "outside of the body". These terms are often confused with each other for understandable reasons, but they are actually opposing terms and not synonyms.

Terminology is not the only thing that is misunderstood about shoulder training. Many people use a completely unbalanced shoulder program. One study showed that bodybuilders have anterior shoulder muscles that are on average five times larger than those of physically inactive people. But their lateral shoulder muscles are only three times larger and their posterior shoulder muscles are only 10 to 15 percent larger. (Gundill, 2002)

This is not surprising when you consider that many exercisers primarily perform horizontal and vertical presses for their shoulders and their shoulder training is not balanced to begin with. This is partly due to the misconception that side raises are a good isolation exercise for the lateral shoulder muscles.

This is not the case as long as you do not modify this exercise.

If you take the force generated by the lateral shoulder muscles during the abduction performed in side raises as 100%, the force generated by the anterior shoulder muscles is about 75% and the supraspinatus force is 25%. This means that the supraspinatus (another rotator cuff muscle) and the anterior shoulder muscles together generate as much force as the primary muscle in this movement, the lateral shoulder muscle.

Furthermore, these studies were primarily conducted with physically inactive people, so athletes with dominant anterior shoulder muscles can expect even worse results. The same applies to overhead pressing exercises. Performing these towards the neck or with dumbbells helps a little, but they still don't produce balanced shoulder development on their own.

How can you train the lateral shoulder muscles without involving the front shoulder muscles?

Reduce the amount of shoulder flexion (raising the arm as in front raises). You may have heard that it is safer to perform side raises at the scapular level, which is about 30 degrees forward. This statement is correct, but it also means that the exercise becomes a kind of front lift.

The same applies to not fully extending the elbow. Yes, this puts less stress on the elbow joint, but you should still aim for a 99% extension. This should be enough to keep the load on the muscles rather than the elbow.

The weight should be on a line that continues straight from the lateral shoulder muscles to the side. This means that it is better to perform this exercise on an incline bench. Try an angle between 15 and 60 degrees incline. The lower the angle, the more you involve the rear shoulder muscles.

Performing side raises on an incline bench brings me to another factor of increasing the activity and range of motion of the lateral shoulder muscles. The first 30 degrees of abduction are primarily performed by the supraspinatus, after which the lateral shoulder muscle head becomes the primary performing muscle. This is not a bad thing, as the supraspinatus also needs training, but it means that you need to control the movement at the top.

If you're one of those guys who moves the weight up laterally with momentum and then ducks under the weight, then you're only loading your supraspinatus and barely training your lateral shoulder muscles. If you perform the exercise on an incline bench, you cannot duck under the weight during the upward movement and can concentrate on the muscle activity instead.

There is another very important factor that determines shoulder muscle activity - shoulder rotation (just like the chest muscles).

The more you internally rotate your shoulder during shoulder flexion and abduction, the more you engage the lateral and posterior head of the shoulder muscle and the less you engage the anterior head of the shoulder muscle. During a horizontal shoulder abduction, as in reverse flying movements - rotating your arm outwards increases the activity of the lateral shoulder muscles at the expense of the posterior shoulder muscles.

When training the lateral and posterior shoulder muscles, I therefore recommend that you extend your elbows almost fully, that you do not use the scapular plane and that you rotate your shoulders inwards.

These technical adjustments increase the stimulation of the middle shoulders, but also reduce the width of the subacromial space and increase the risk of impingement syndrome, which is why you should be careful if you are already struggling with shoulder problems. You can also counteract these problems by retracting your shoulder blades.

The fact is that shoulder impingement is primarily a concern if your shoulders are not structurally balanced in the first place and these exercises improve this situation, making it a bit of a chicken and egg scenario. In addition to this, I recommend shoulder isolation training on an incline bench, which is generally gentler on the shoulder.

As for the posterior shoulder muscles, in addition to rotating the shoulders inward during reverse flyes or side raises on a flat incline bench, you can also train these muscles with any type of pulling movement such as rowing or face pulls (https://www.youtube.com/watch?v=u9TvW5bvXxE) that hyperextends the shoulder (meaning that the elbows are moved behind the body). The latissimus and pecs cannot stretch the shoulder beyond the anatomical position, so the posterior shoulder muscles become the primary active muscles.

For the anterior shoulder muscles, front raises in the scapular plane with the shoulders rotated outwards is a good, risk-free exercise. Unless you're not doing overhead presses, I don't think you need isolation training for the anterior shoulder muscles - especially not as long as your shoulders are structurally balanced.

Speaking of structurally balanced development, I recommend face pulls with an underhand grip for training the external rotators. Contract the muscles hard at the highest point of the movement and pull the rope up to your face. If you want to isolate the infraspinatus and teres minor, you can perform external rotations lying on your side. These produce the most EMG activity of most external rotation exercises.

Remember, however, that reverse flying movements also train the external rotators. So unless you are having trouble activating the infraspinatus and teres minor, it is generally sufficient to only perform reverse flying movements and face pulls.

In terms of the number of repetitions, all the muscles of the humerus and scapula are actively involved in posture and stabilizing the shoulders in virtually every upper body movement. It can therefore be expected that these muscles have a high work capacity and that the slowly contracting muscle fibers dominate with a share of 60%.

This is true for the entire shoulder girdle with one odd exception - the infraspinatus provides some momentum for the external rotators and has a slight dominance of fast contracting fibers.

The bottom line

• Traditional shoulder training emphasizes the anterior shoulder muscles at the expense of the rest of the shoulder girdle muscles.
• Overhead presses generally include plenty of work for your front shoulder muscles.
• Add side raises on an incline bench and reverse flying movements with inwardly rotated shoulders to your program to make it more balanced and complete your shoulder development.
• Use a medium to high repetition range.

I hope this article has given you some new ideas for optimizing your training. In the next part, I will look at the rest of the primary muscles of the human body.

References

1. Age and sex affect human muscle fiber adaptations to heavy-resistance strength training. G F Martel, S M Roth, F M Ivey, J T Lemmer, B L Tracy, D E Hurlbut, E J Metter, B F Hurley, M A Rogers. Exp Physiol. 2006 March; 91(2): 457-464.
2. Changes in performance, muscle metabolites, enzymes and fiber types after short sprint training. B Dawson, M Fitzsimons, S Green, C Goodman, M Carey, K Cole. Eur JAppl Physiol Occup Physiol. 1998 Jul;78(2):163-9.
3. Comparative effects of high- and low-intensity resistance training on thigh muscle strength, fiber area, and tissue composition in elderly women. D R Taaffe, L Pruitt, G Pyka, D Guido, R Marcus. Clin Physiol. 1996 July; 16(4): 381-392.
4. Data on the distribution of fiber types in five human limb muscles. An autopsy study. F G Jennekens, B E Tomlinson, J N Walton. JNeurol Sci. 1971 November; 14(3): 245-257.
5. Data on the distribution of fiber types in thirty-six human muscles. An autopsy study. M A Johnson, J Polgar, D Weightman, D Appleton. J Neurol Sci. 1973 January; 18(1): 111-129.
6. Effect of strength training on enzyme activities and fiber characteristics in human skeletal muscle. A Thorstensson, B HultŽn, W von Dšbeln, J Karlsson.Acta Physiol Scand. 1976 March; 96(3): 392-398.
7. Effect of training on enzyme activity and fiber composition of human skeletal muscle. P D Gollnick, R B Armstrong, B Saltin, C W Saubert IV, W L Sembrowich, R E Shepherd. JApplied Physiology 1973; 34(1): 107-111.
8. Effects of high intensity canoeing training on fiber area and fiber type in the latissimus dorsi muscle. S J Baker, L Hardy. Br J Sports Med. 1989 March; 23(1): 23-26.
9. Electromyographicanalysis of the rotator cuff and deltoid musculature during common shoulder external rotation exercises. M M Reinold, K E Wilk, G S Fleisig, N Zheng, S W Barrentine, T Chmielewski, R C Cody, G G Jameson, J R Andrews. JOrthop Sports Phys Ther. 2004 July; 34(7): 385-394.
10. Fiber type composition and maximum shortening velocity of muscles crossing the human shoulder. R C Srinivasan, M P Lungren, J E Langenderfer, R E Hughes.ClinAnat. 2007 Mar;20(2):144-9.
11. Muscle fiber types and size in trained and untrained muscles of elite athletes. P A Tesch, J Karlsson. JApplied Physiology 1985; 58(6): 1716-1720.
12. Muscle hypertrophy and fast fiber type conversions in heavy resistance-trained women. R S Staron, E S Malicky, M J Leonardi, J E Falkel, F C Hagerman, G A Dudley. Eur JAppl Physiol Occup Physiol. 1990; 60(1): 71-79.
13. Muscular adaptations in response to three different resistance-training regimens: specificity of repetition maximum training zones. G E R Campos, T J Luecke, H K Wendeln, K Toma, F C Hagerman, T F Murray, K E Ragg, N A Ratamess, W J Kraemer, R S Staron. Eur JAppl Physiol. 2002 November; 88(1-2): 50-60.
14. Performance and fiber characteristics of human skeletal muscle during short sprint training and detraining on a cycle ergometer. M T Linossier, D Dormois, A Geyssant, C Denis. Eur JAppl Physiol Occup Physiol. 1997;75(6):491-8.
15. Pressing Issues: Building better shoulders with overhead presses. M Gundill.Ironman 2002 August; 8: 42.
16. Shoulder muscle activity and function in common shoulder rehabilitation exercises. R F Escamilla, K Yamashiro, L Paulos, J R Andrews. Sports Med. 2009; 39(8): 663-685.
17. Skeletal muscle adaptations during early phase of heavy-resistance training in men and women. R S Staron, D L Karapondo, W J Kraemer, A C Fry, S E Gordon, J E Falkel, F C Hagerman, R S Hikida. JAppl Physiol. 1994 March; 76(3): 1247-1255.
18. The role of resistance exercise intensity on muscle fiber adaptations. A C Fry.Sports Med. 2004; 34(10): 663-679.
19. The upper extremity of the professional tennis player: muscle volumes, fiber-type distribution and muscle strength. J Sanch's-Moysi, F Idoate, H Olmedillas, A Guadalupe-Grau, S Alay-n, A Carreras, C Dorado, J A L Calbet. Scand J Med Sci Sports. 2010 June; 20(3): 524-534.
20. Training induced changes in the subgroups of human type II skeletal muscle fibers. P Anderson, J Hendriksson. Acta Physiologica Scandinavica 1977; 99: 123-135.

By Menno Henselmans | 10/14/11

Source: https://www.t-nation.com/training/muscle-specific-hypertrophy-chest-triceps-and-shoulders

Related blog posts:

>> Muscle-specific hypertrophy: biceps, back and lower body

>> Advanced German Volume Training