The 5 Factors of Muscle Growth
Since I was in my early teens I remember the desire to get bigger and stronger. I was even designing workout programs for people in my early college days way before becoming an official strength coach. I remember also in the late 70’s that the weight room at the local YMCA was down in the facilities basement. Now, the main selling point of any YMCA is their weight room/fitness facility. The fitness industry has come a long way. But why is there a gym on every street corner in town? I think it really took growth in the Golden Age of Body building (the 70’s and 80’s). During that time people were learning and enjoying all the health benefits of working especially how they looked and felt. Even athletes were beginning to get into the weight training movement in the 1970’s. Of course there were still many around who thought like my old high school football coach who told me not to lift weights; he didn’t want us getting too stiff and bulky.
My thoughts: “The heck with that, I’m lifting anyway!” Watching individuals for the last 40 years in high schools, universities, and gyms perform some type of resistance style training, the question that I always pondered were simply this, “just how does muscle grow and what is the best way to achieve that growth through resistance training?” Now that is the Holy Grail question! If we are going to spend all this time in the gym, what is the best way to put on muscle? Whenever I hear someone say, I don’t want to add muscle (I’ve heard this a few times over my years), I would reply, “Then why in the heck are you in the gym?” Adding or maintaining the muscle you have can lead to so many health benefits like getting stronger, more fit, and a better body shape! Muscle has shape, fat does not! Muscle is a metabolic active tissue that loves to burn calories, something that fat is too lazy to do.
During my long career in the strength and conditioning field, I have had the pleasure of being around some great minds in the exercise science field. The first person who drew my attention toward muscle growth capability was Dr. Vaughn Christian. I was a junior at Appalachian State University and was really into bodybuilding. During that time Dr. Christian was one of my exercise science professors. I could learn so much in the classroom from him and go apply it to what I did in the gym the very same day, and this was in the late 1970’s! Two other men that I had the pleasure of knowing plus great friendships were Dr. Harold O’Bryant and Dr. Michael Stone. Both were and still are world renowned exercise science professors and co-authors of the book “The Science of Weight Training” which I still keep in my office for further guidance to this day. This is all leading to our question of “How does muscle grow”?” or more scientifically looking at different ways one can activate muscle fiber to get a favorable response to growth or hypertrophy and along with that comes strength. Let me state from the out-set that when we talk about muscle growth, we’re talking about hypertrophy. However while strength training, speed training, and training for hypertrophy are all different, there is much carryover. Let’s look at our five techniques for muscle growth.
1. Progressive Overload:
I remember asking Dr. Stone while I was the Strength & Conditioning Coach at ASU what the best way to get our athletes bigger and stronger was and without hesitation he said “progressive overload.” Progressive overload is simply adding weight to the bar each set or workout. However there’s a ceiling to how much weight we are able to lift during a particular exercise. When that threshold is reached during that phase of one’s training, then that individual may want to progressively overload to a different rep scheme. You might choose more reps, which would mean lighter loads, or fewer reps, which would mean the intensity (or weight used) would be able to progressively go up. It’s important to note that just because the weight used would naturally go down because of higher reps being implemented, that does not mean sub-max intensity. I stress that as much weight as possible should be used for the reps on a particular set being performed IS of the upmost importance (unless percentages are being used to get to a certain max or the workout being performed is a sub-max speed/explosive training session). At some point one may get to a stage in your training where adding weight after weight and rep after rep gets old and you get that “burned out feeling” or even joint issues. That’s when you can turn to another type of training that will also activate muscle for the pathway to growth; and that is Metabolic Tension. Metabolic tension or stress is so important and the other 3 factors of muscular growth as well.
2. Metabolic Tension (MT):
Let’s back up and talk some exercise physiology so we may have a better understanding of MT. I often wondered as a young bodybuilding why bodybuilders looked one way and powerlifters looked another. Besides the obvious using more weight, less volume or reps, and of course diet, there had to be something else and from an exercise science standpoint, and there most certainly is! You see, there are two types of muscular hypertrophy: contractile and non-contractile. The first contractile (as Dr. Brad Schoenfield states) is when hypertrophy manifest itself in the muscle as the fiber or sarcomeres becomes longer or in parallel. Another way to put it, the muscle is trying to adapt by becoming much thicker to lift the heavy weight that is being forced upon it. The second type of muscular hypertrophy is called non-contractile sarcoplasmic. This is where there is an increase in non-contractile elements in the muscle such as collagen or glycogen. This is caused by mainly high volume high rep training and hydration within the fiber. Some people might say this is non-functional muscle….”just big muscles,” however there is research that suggest that the increased hypertrophy due to high volume training and hydration of the cell associated with sarcoplasmic hypertrophy can mediate a hypertrophic response, and because of this type of response then the chances are good that this can lead to contractile hypertrophy, meaning the muscle becomes more dense, and when more dense the potential for strength. Research also suggests that high volume training increases levels of human growth hormones (HGH) which will help greatly in adding on muscle.
Metabolic Tension is simply different pathways of tension to activate muscle fiber so it will respond in a manner that is right for muscular growth. They don’t call it tension for nothing! There will be some pain involved when in this phase of your training. One has to go beyond and even fight through the burn and pain that creates metabolites that produces Hydrogen-Ions and Lactic Acid. Yep – it’s called stress! That hypertrophy that is created with that “burn” is simply time under tension or (TUT). And that time comes from high amounts of volume with certain amounts of load. There are many different rep schemes to help create and help one fight through this “Burn.” Needless to say those loads need to be decreased because of the higher reps that are associated this type of training. And the good thing is, research indicates that one can still gain muscle (hypertrophy) by using lighter loads.
And yes, there may be lighter weights because of all the volume used, however Darren Candow PhD. and professor at the University of Regina in Saskatchewan, Canada, just recently did a presentation for the ISSN (International Society of Sports Nutrition) where he presented evidence in a study to where light weights performed to muscular failure are just as effective as using heavy weights for hypertrophy.
Here are a few schemes for hypertrophy. Forced Reps: This is where your workout partner helped you with 2 or even 3 more reps even though you had reached failure. The draw-back, you need a workout partner, someone you can trust to give that perfect forced rep. Cluster Sets: Let’s say my rep scheme this workout is 8-10 reps on any particular set. Perform an exercise with a weight that will allow you those reps, rest 5-8 seconds then perform what reps you can with the same weight to failure while fighting through the burn. Partials: Partials are simply half or even quarter reps at the end of a set. Let’s say for instance you are performing “preacher curls” with a barbell and you have gone to failure with 6-8 reps. With partials you would simply perform more reps to extend the work (and pain) by performing half or quarter reps from the extended position or from the full flexion position. Whatever repetition scheme you use to continue the work, be able to create that all important Metabolic Tension or Stress. Perform your 10 reps that you were set out to perform then bang out 3 to even 10 more reps (depending on the exercise) while fighting through that incredible burn knowing that each rep brings about more muscular growth. Rest Intervals: Your rest intervals between sets are important during “metabolic tension” and training for solely hypertrophy. Too little rest between sets and you’re training for more muscular endurance. Too much rest time and you can lose those all-important metabolites (Hydrogen-Ion’s and Lactic acid).
3. Eccentric Resistance:
Technically, this type of training could have been lumped in with Metabolic Tension. However because of all the studies showing how Eccentric Resistance helps increase muscle size, strength of muscle fiber and recovery time reduction for certain types of injuries, this type gets its own section.
When you lower a weight on a particular exercise it lengthens the prime mover muscles. This is the Eccentric phase of the movement. When you lift the weight being used it shortens the prime mover muscles that are being used. This is called the concentric phase of the movement. One reason that one can become stronger and build muscle using eccentric overload is that more weight can be used and force production is greater when lengthening muscles. Other reasons one may want to focus on eccentric overload at certain phases of one’s training is that studies have also shown that protein synthesis (and thus more muscle growth) is greater following accentuated-eccentric training. Plus with more muscle fiber recruitment there’s a greater release of Insulin Growth Factor-1 (IGF-1). Eccentric load training was not meant to stand alone. Evidence points clearly to where a combination of concentric and eccentric training is much more likely to be superior. Unfortunately today, I still see many general fitness people and even some bodybuilders who don’t take full advantage of the eccentric part of a particular exercise by letting the weight just fall and thus not feeling the weight as it descends. These folks are missing out on some good growth time. It’s important to note that tempo is always important on different phases of your training.
And on a Side Note: Can you perform all three techniques listed above at one time? The answer is Yes and No. Yes, Bodybuilder might attempt using all but a Power-Lifter could only in the off- season. Example: let’s say on a set of Dumbbell bench presses you decide to progress to 5 pounds more than you have ever done for a set of 5-6 reps. So you pound-out 5 reps, then someone helps you in the concentric phase of the movement by helping you up under your elbows for 2 more reps, then you focus on lowering the weight for 3-4 seconds for 1-2 reps. Now that would be going to an extreme, but that would be one way to perform all 3 pathways to muscular growth all in one set! Stay with the Basics, and then go to Variations. Athletes, Bodybuilders and Power lifters, some individuals when just starting out want to try everything under the sun and want to burn-out with every set, thinking “the more the better.” Working smarter will pay huge dividends later in your training! Always be smart with “progression overload.” Get strong on your major lifts such as the bench press, back squat (whether it is low bar or high bar), the dead lift, and a simply overhead military press and the power clean. I would suggest perfecting those particular lifts before going to other free weight variations. Once you hit a ceiling of strength when you’re first starting out, then start varying your lifts and different ways to activate muscle fiber.
4. Exercise Variations:
As I stated above, when you get to a point where you’re not a beginner anymore have mastered the major lifts, venture out to the many variations of the bench press, squat, dead lift, and the overhead press. These variations will create different levers that will activate muscle fiber in different ways to create strength and growth. As a strength coach and former bodybuilder, I have found anywhere from 4 to 5 different variations of each of the major lifts works best for me. There are some power lifters I know who’s variations of certain lifts are much more, finding which variations works best for you takes time. Different variations include using different machines also. Have you ever gone to a different gym and performed an exercise such as a leg press that you have done hundreds of times at your gym but using this slightly different leg press machine creates a different feel and even soreness? And yes, muscle soreness is related to muscular growth, (but I’ll save that for another time, place, and article). This occurs because using that different piece of equipment created a different lever and a different angle that the muscle or muscles just weren’t use to performing.
5. Speed of the Movement:
I remember listening to Jeff Conner (Strength & Conditioning coach for East Carolina University) in an interview say that the only thing that he was interested in was progressive overload plus the speed of the bar or movement. As a strength coach Jeff is not worried about how big the muscles are but getting players strong and explosive is his main objective. However the speed in which the weight is being moved simply creates more motor units being recruited or activated. A simple example is walking. Walking recruits very little muscle fiber but walk fast and the legs, hips and glutes start to burn and fatigue. Now start to go even faster, even sprint and wow, what a transformation of the body! Why? The more speed involved, the more motor unit recruitment. Accelerating the concentric phase of your lift will heighten strength gains and help add muscle as well, but as for building muscle one should lift at least 60% of one’s 1 rep max. This would be the minimal percentage one should use when trying to build muscle. Even when the bar is heavy (anything that is over 90% of one’s 1 rep max)) you should lift and accelerate the bar as fast as possible. In the 1980’s Dr. Fred Hatfield (aka Dr. Squat) popularized the term “Compensatory Acceleration.” Compensatory acceleration simply means lifting the bar as fast as possible, regardless of the weight. Tension on the body is caused by the load or speed of the movement. That force that the athlete is able to create is a combination of mass X acceleration which = force. So when the load is heavy and you’re putting as much muscular tension on the bar as possible, force and power production increases. The result: a greater number of motor units in the muscle fiber are being activated and when that happens there’s a greater chance for building muscle.
In conclusion: Being in this industry for decades, I have tried a lot of programs when training my athletes and clients. In more recent years, I’ve adapted power lifter Matt Wenning’s program in which a combination of linear and conjugated periodization is used. Another successful program for me that I have used with many of my athletes is from my good friend and Strength and Conditioning Coach for the Carolina Panthers, Joe Kenn’s “Tier System”. We have serious lifters at Europa Sports Products (where we have a 3,000 sq. foot weight training facility) that use everything from Jim Wendler’s 5-3- 1 program to a simple and straight linear periodization model. What I’m saying is that there are many different to go about getting strong and putting on muscle, and finding the right program for you takes time and wisdom. Competing in bodybuilding in the late 70’s and early 80’s and being in the profession of strength and conditioning for over 35 years, I would say that “I’m still learning, still experimenting — and still training.” So when your goal is wanting to adding more muscle, choosing one of the five methods above should do the trick. Neurologically you would want to mix these five methods at different times during your training program. One can’t simply stay on one of these methods indefinitely because at some point the Central Nervous System (CNS) would simply burn-out or as in the Method #1, there’s a ceiling. Lucky for all of who want to add muscle no matter the reason or what our goals happen to be, there are many ways!
Chip Sigmon CSCS*D, CISSN, USAW, RSCC*E
Strength & Conditioning, Wellness Coordinator, Europa Sports Products
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Candow, Darren, “In Search of the Holy Grail: Muscle Growth” Presented at the ISSN Conference at the University of Regina, Sept. 2017. www.sportsnutritionsociety.org.
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