Understanding Bi-Articulate Muscles

I already know what you’re thinking . The author just wanted to have an excuse to flex his muscles and used the article cover for it. Fair enough, hey theres nothing wrong with wanting to flex your muscles. Hey we work hard for this right? And its the beginning of the year. So I lot of people are looking to join gyms with them right to flex those muscles ( as they should).

Most newcomers will do 1 of 2 things:

• Grab a set of dumbbells and hammer out a bunch of bicep curls
• Decide that they have no clue as to what they’re doing and head over to the treadmills

Hey thats where you have folks like me. We’re here to help you get the most out of those workouts. Nerds like me study anatomy to help the masses. Lets go over some briefly. For every muscle theres an :

• origin ( what bone the muscle is “On”)
• Insertion Point (which joint connects to and “pulls against”)
• Action( what the muscle actually does)

Dr Brad Schoenfeld’s article , “ Accentuating Muscular Development Through Active Insufficiency and Passive Tension” explains how a 2 joint muscle is is shortened at 1 joint while the muscular contraction starts at they other. This is referred to as “active insufficiency” in his article. Passive tension, on the other hand is when that 2 joint muscle is fully stretched from both ends, creating optimal tension.

Think about a rubber band. Is there more tension in the rubber band if if its folded up in our pocket? Or is there more tension if we’re stretching out out with both hands? Our muscles are the same way. Referring up above to muscles “insertion” point, most of our muscles “pull” against 1 joint. For example, our pecs, and lats work along the shoulder joint. Our glutes work along the hip joint. But some muscles work along 2 joints.

The above photos are from the anatomy book that I study from, “Sieg and Adams, Illustrated Essentials of Musculoskeletal Anatomy”. Our bicep and tricep are muscles are referred to as bi-articulate because they work across 2 joints.

The bicep muscle (our guns 💪) do more than bicep curls. The bicep flexes the elbow joint, and turn our hand from palm down to palm up(also referred to as supination). But one of the 2 heads also flexes the upper arm(when we put our arm out to give a handshake. Thats also the short head of the bicep working). So that muscle works along both our elbow and shoulder joint.

Our triceps (the other side of our arm) muscles extend the elbow. Think about sitting in a chair, and using the chair’s arm rest to help yourself up. The tricep muscles are straightening out our arm/ extending the elbow. But one of the 3 tricep muscles( long head) also extends the upper arm. Think about a runner running at full speed. One arm will be in front of the body, the other arm will be behind the torso. The arm behind the torso is , in part, being extended by the Tricep(along with other muscles, 2 of the 4 rotator cuff muscles=infraspinatus, & teres minor), teres major, pec major, lats and posterior part of the deltoid). Like the bicep muscle, the tricep also works along both the elbow and shoulder joint.

Other examples of bi-articulate muscles are amongst the lower leg musculature, the big calf muscle,the gastrocnemius, and 1 of the 4quad muscle at the rectus femoris.

Fitness professionals help our clients understand the exercise programming. IT ALL STARTS WITH ANATOMY. Don’t wing it, hire a fitness professional.