Why Strength Training?

-WARNING: SCIENTIFIC CONTENT!-

Have you ever picked up an object you expected to be heavy such as a box and picked it up so fast that you almost fell over? Have you ever underestimated an objects weight and failed to lift it on your first attempt? Why is that? Well this is where it gets super cool! Right now in your seat, if you lift your arm up, only a very small number of the muscle fibers within your bicep are being recruited to do the job! All of the other fibers are just hanging out! This has huge implications when it comes to exercise! Understanding how it is that your muscles are activated is vital to choosing the right exercises and how much resistance to use.

Size principal

First, let us discuss a few neuromuscular terms. The word “muscle” is a very broad term referring to all muscle fibers within a group such as the biceps or quadriceps. Within each muscle are a vast number of fibers that are called upon in varying numbers to perform tasks of varying levels of difficulty. If I want to move a table from one side of the house to the other, I don’t need to recruit twenty burly men to assist me; I probably just need one or two. What if I decide to put a couple boxes of books on there too? I might recruit someone else to help. What if I remembered that I wanted my old school-300lb-flatscreen to go too? I would recruit two or three more! Muscles work roughly the same way.

The size principle states that motor units are recruited from the smallest to the largest based on the force demands placed on the muscle. A motor unit consists of a motor neuron and all of the muscle fibers it innervates. There are typically several hundred muscle fibers in a single motor unit.

The smaller or low threshold motor units are recruited first. Then motor units with progressively higher thresholds are recruited based on the increasing demands of the activity (think of the table). This selective activation of motor units and the difference in size of the motor units allow for graded force-production, and therefore, more precise control of the amount of force that the whole muscle can generate. The only exception to this rule is power (high velocity) training. When trying to move an object with a higher velocity, the high-threshold motor units containing type II fibers are activated first, skipping over the low-threshold motor units containing type I fibers.

The All-or-None Law

This law states that when a motor unit reaches its threshold for activation, all of the muscle fibers in that motor unit are activated fully. If the threshold is not reached, then none of the muscle fibers in that motor unit are activated.

Application

Now let us relate this to the gym. What if you decide you want larger biceps? What if your one-rep max (maximum weight that can be lifted one time) for a dumbbell curl is 100lbs (go you!) but you stick with 40lb dumbbell and rep it out twelve times every time you hit the gym? If you’re new to the gym, no doubt you will get some results, but if you can perform the lift twelve times, you are only strengthening a small portion of the muscle fibers in your bicep (let’s just say 40%). That means that 60% of your muscle fibers aren’t being developed AT ALL!! They are just sitting on the couch playing xbox!

This is where strength training comes in to play. Strength is defined and measured by the one-rep max (1RM). Strength training, according to the National Strength and Conditioning Association, involves training loads of approximately (it will vary greatly depending on training status) 85-100% of your 1RM for 1-6 reps per set with between 2-5 minutes of rest in between. Performing lifts with this kind of weight will recruit those high threshold fibers and lead to stronger, larger muscles. As an added bonus, loading your body with heavy weights increases bone mineral density! This is why women, especially postmenopausal women, can benefit greatly from a well-designed strength training program.

This is why many professional bodybuilders participate in powerlifting during off season when they are trying to build mass. The squat, bench and deadlift are best lifts for loading the wagon and developing those large muscles of the legs, chest and back.

Periodization

Without any variation in your program, you will likely end up overtraining or undertraining. By varying your training with light, moderate and heavy days, you allow your body to rest. On the light days, the muscle fibers activated on the heavy day get to rest!

While strength training isn’t rocket science, doing it the right way takes careful planning and strategy.

Thanks for reading! Stay tuned for more posts!