Reciprocal Inhibition or Opposing Muscle Groups?

What is reciprocal inhibition? Why should you care? What can you learn from it?

(Spoiler, they're the same thing.)

The nerd definition is:

"Reciprocal inhibition is a neuromuscular process in which muscles on one side of a joint relax to allow the contraction of muscles on the opposite side, enabling smooth and coordinated movement... Observed that when the central nervous system signals an agonist muscle to contract, inhibitory signals are sent to the antagonist muscle, encouraging it to relax and reduce resistance. This mechanism, known as reciprocal inhibition, is essential for efficient movement and helps prevent muscle strain by balancing forces around a joint."

Now to explain it to you more simply:

When one muscle contracts, the opposing muscle relaxes.

Let's go through some of the most common examples:

• biceps and triceps

• quads and hamstrings

• chest and back

• Lats and shoulders

Doesn't that look familiar? It's because it is! It's just the fancy name for opposing muscle groups. This is why working opposing muscle groups makes sense from a weightlifting perspective.

Why is this important?

This is a part of how we program and to help you further understand why we do what we do.

Biceps and Triceps:

The common theme here is going to be if one muscle is fully contracted, the opposing muscle will be fully relaxed. For example, when we do a bicep curl, when we have the maximum amount of tension of the bicep, in order of the joints to not tear off the other connecting muscle(s), the triceps needs to be fully relaxed. Then, when we bring the arm/bicep all the way down at the bottom of the curl, the bicep is now fully stretched. the triceps is fully contracted. Thats why triceps extensions are the opposite motion of a bicep curl.

Remember: To some this may seem like common knowledge, others may find this brand new. Whichever side you are on, let's keep learning!

Quads and Hamstrings:

Same principle as above, but with the quads and hamstrings now. An example of this would be squats. As you bring your body down into the bottom of a squat, your hamstrings "loading" and getting your quads ready to spring up. Then, once your hamstrings have loaded, your quads take over and shoot you up, using the full contraction of your quads to bring you to the top of the squat. Finally, leaving your hamstrings fully stretched at the top of the squat.

Tip: With some of my clients, I will say "your biceps and hamstrings are similar, and your triceps and quads are the same". And to simply put it, your hamstrings and biceps are "pulling muscles" while your triceps and quads are "pushing muscles".

Chest and Back:

With the chest and back. There is controversy as to whether or not we should be doing all chest exercises, all back exercises, or a combination of both. Personally, doing a combination of both has shown the most benefit. However, everybody is different. See what I did there... Moving on. Looking at the chest and back from a reciprocal inhibition standpoint, let's look at the bench press. As your unload the barbell and lower the bar closer to your chest, your chest is stretching (relaxing), and your back is loading the weight. Once you have hit depth and bring the bar back up, your chest fires and pushes the weight all the way back up. The opposing lift to this would be the seated cable row or the barbell bent over row. As you're bring the bar/cable handle closer to your chest, it is completely stretching your back and then the chest supports the weight at the "bottom" of the row.

Tip: Your opposing muscles are also supporting muscles. In case someone says that instead of opposing muscle groups.

Shoulders and Lats:

Here's a fun trick to try yourself. Put your arm above your head and try to flex your chest muscles. you might get a little contraction but not a full contraction. Thats because your shoulders are the pushing muscle in order to lift your arm above your head, and it is your lats that support your shoulders. Now grab your lats with your arm above your head. Should be the same thing as your chest. A small contraction but not a full one. That is your lat supporting the weight of your arm. I hope this little demo helped you visualize what reciprocal inhibition and opposing muscle groups does and how it feels. A good example of these two would be the overhead press and the lat pull down.

Fun Fact: Nothing in your body technically "pushes". It's all one giant pulley system. We will dive into that in another blog.

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