The short answer is, well… no, not really. Despite what you’ve been told, strength training and bodybuilding is one in the same. Probably, the reason behind why people believe there is a difference is due to the phenotypes athletes possess within a particular sport. Bodybuilders possess heavily muscled bodies and train within different rep ranges (usually higher reps, high volume) and with difference exercises compared power lifters; which causes people to think that their training is the cause of the resulted physique. This is called selection bias. Many people fail to realize that people with genetic predispositions tend to gravitate towards the sport or activity which favors his or her genetic advantage. What is going to dictate which category trumps the others in regards to displaying the largest improvements is genetics and diet.
I don’t like to call it strength training or bodybuilding. I prefer to call it “resistance training”. This explains the approach we are using to simulate the muscle to adapt. The other two names just categorize the results that follow the stimulation.
In order for muscle fibers to grow larger or become stronger, they must be placed under a significant amount of stress; stress that the muscle tissue and nervous system is not used to. When the muscle is placed under significant stress and deeply fatigued, the body responds by producing an adaptation which will help it handle the stress better if the stress is re-introduced in the future.
For instance, say you are capable of producing 100 units of force with a given muscle and you perform an exercise using 70 units of resistance (70% of your 1 rep max). As you lift and lower the weight , motor units (groups of muscle fiber) will continuously fatigue. Once you reach the point where you have fatigued so many motor units that you are only capable of providing 69 units of force versus the 70 units of resistance you are using, you have reached what is called momentary muscle failure and have tapped into the body’s beloved energy reserves. The human body does not want to continuously tap into its reserve resources as they are there to assist the body in life threatening situations. A stimulus is produced to tell the body to make the necessary improvements so that it can better resist the stress (resistance) from tapping into its reserves if the stress is re-introduced in the future. The body will partition resources and up-regulate certain bodily processes to develop additional strength; say, 110 units of capable force production so it will take a bit longer to tap into its reserves. This is what a strength increase is and is referred to as overcompensation.
Throughout the set of exercise, you will recruit (in sequential order) slow, intermediate and fast twitch motor units. The first few repetitions recruit slow twitch motor units which fatigue slowly and recover quickly but are not capable of proving much force output. By the end of the set, the last rep or two, you are recruiting fast twitch muscle fiber. Fast twitch muscle fiber is capable of producing the most force output and is capable of the most myofibril expansion and proliferation within the muscle cell. More myofibrils result in more contractile force within a muscle fiber which results in more strength. That simple!
So, now we can see that strength and hypertrophy go hand in hand. But, why do some trainees get so strong without displaying a lot of muscle growth, and vice versa? The answer is due to the difference in individual expression of certian genes.
One genotype that plays a role in determining the response the resistance training is Interlukin-15. There are three types; Type AA, Type CA and Type CC. Those who possess the Type AA genotype will show large improvements in muscle size but will not demonstrate that much strength in the gym. Those who possess the Type CC genotype will display great improvements in strength, but not as much muscle growth to go along with it. Trainees who possess the Type AA genotype will tend to gravitate towards body building since they have a natural advantage for building muscle. Those who possess a Type CC genotype will gravitate towards strength sports like power lifting. Most people will possess the Type CA genotype which will provide responses with a more reasonable ratio of size to strength improvements from resistance training; somewhere in the middle.
Myostatin expression is also very important in determining muscle growth potential. Myostatin is a protein that limits muscle growth in the body. Evolutionarily, having too much muscle mass would make it more difficult to survive since it requires a lot of calories to feed and difficult to lug around. Organisms evolved in a food scarce environment over millions of years. Those who developed the most efficient and optimal amount of muscle passed those genes on. That is why it is very rare to encounter someone who is capable of building excessive amounts of muscle mass. Those with a higher expression of myostatin in his or her body will have a harder time adding muscle mass. Those with lower levels of myostatin have the ability to build more muscle. Pretty simple. There are actually some animals which don’t possess the myostain protein and as a result have ridiculously large muscles. Simply google “myostatin bull” and see for yourself. Certain approaches to diet and lifestyle can minimize myostatin expression; this is a topic for a later post.
Now, a little more about strength. What do we mean by strength? Most people refer to your one rep max bench press or squat as a measurement of strength. One thing we must realize is that the body is a very adaptive organism and will find ways to handle a stress in the most efficient way possible if it is consistently exposed to it. If you consistently train in a power lifting rep range (2-5 reps), your body will become more neurologically efficient in that rep range. Take that same individual and have them compete with an NFL Combine trainee who is training for completing the maximum number of repetitions on the bench press with 225 pounds. They most likely will not perform as well as the NFL player who is training for that specific test; even though the power lifter may have a much larger max bench press.
As you can see, size and strength are largely dictated by genetic potential. There is no way to train for size or strength specifically, as they go hand in hand. How you wish to use your strength in competition is another story. If your sport or competition requires you to perform well in low rep ranges, train in a lower rep range. If your competition requires the opposite, train in higher rep ranges. Those are only a FEW of the genotypes that influence growth and strength. To learn more, click on the tab Book Recommendations on the BioFit webpage!