Electromyography (EMG) Activity for Pectoralis Major (Chest)

The Pectoralis Major is composed of three different parts:

• pars clavicularis (1)

• descending fibers

• upper part

• pars sternocostalis (2)

• lateral fibers

• middle part

• pars abdominialis (3)

• ascending fibers

• lower part

Regardless of what you have heard or think, each movement/exercise done to focus on the Pectoralis Major, will work each individual muscle fiber in the chest. We are not able to isolate one fiber strand over another, but we can utilize certain movements to target certain fiber stands to a greater degree than other areas of the chest.

Standard weight (load) resistance movements

1. Barbell bench presses

2. Cable crossovers

3. Dumbbell bench presses

4. Seated flys (Pec-Deck)

5. Dumbbell flys

6. Dumbbell pullovers

Body weight movements

1. Dips

2. Push-ups

3. Hard contraction (flexing)

EMG Motor Neuron Firing Activity

Here we are looking at the EMG activity of the Pectoralis Major as a whole:

1. Decline barbell bench press

2. Flat barbell bench press

3. Incline barbell bench press (+25°)

4. Incline barbell bench press (+45°)

When looking at the EMG data, all 4 of the above barbell bench press variations are very effective for hitting the chest. In order, the above movements exhibit the greatest EMG motor neuron activity: pars clavicularis, pars sternocostalis, and pars abdominialis.