What is an Antagonist Muscle?
An antagonist muscle has an opposite function to another. For example, the hamstrings and quadriceps are antagonistic because they have opposite functions. When the quadricep shortens (contracts concentrically) and causes knee extension, the hamstring lengthens, and vice versa.
Antagonist vs. Agonist vs. Synergist Muscle (With Examples)
To fully understand how an antagonist muscle functions during movement, we must first look at agonists––the prime movers during an activity.
An agonist muscle is the one that does most of the work during an exercise––for example, the quadriceps during a squat or the chest during a bench press.
Antagonist muscles are those with an opposite function to prime movers. For instance, those would be the lats, rear deltoids, and biceps during a bench press. These muscles lengthen as the chest, triceps, and front deltoids shorten.
Finally, we have synergist muscles, which assist agonist muscles. To use the bench press as an example again, the chest is the agonist, whereas the triceps and front deltoids serve as synergists.
Antagonist Muscle Examples
- Bench press – antagonists: lats, rear deltoids, and biceps
- Pull-up – antagonists: chest, front deltoids, and triceps
- Bicep curl – antagonist: tricep
- Tricep extension – antagonist: bicep
FAQ
1. What is an example of an antagonist muscle pair?
The quadriceps and hamstrings are examples of antagonist muscle groups with opposite functions.
2. How is an antagonist muscle different from an agonist?
An antagonist has the opposite role to an agonist, which is the prime mover during an activity. For instance, when the agonist shortens, the antagonist lengthens, and vice versa.
