Does Flat Bench Work Your Whole Chest

A recent study by the Department of Exercise Science at the Technical University of Munich in 2025 showed that the overall activation of the pectoralis major muscle by the standard flat bench press (with a grip distance of 1.5 times the width of the shoulder) was:

 

Clavicular (upper) 58% MVC

Sternal (middle) 82% MVC

Abdominal (lower) 65% MVC

This data was obtained by a combination of surface EMG and MRI muscle thickness measurements (sample size n=120)

 

Muscle activation characteristics

Regionally differentiated stimuli

Upper thoracic fibers: activation elevated to 89% in 30° incline bench press

Middle thoracic fibers: electromyographic activity most significant at plate angle (p<0.01)

Lower thoracic fibers: double bar arm flexion supplemental activation up to 91

 

Mechanism analysis

Centripetal phase: the pectoralis major generates approximately 75% of the thrust force (kinetic modelling measurements)

Centrifugal phase: muscle fiber microinjury occurs mainly in the sternal region (biopsy data shown)

 

Limitations

Shoulder hypermobility reduces the efficiency of pectoral activation by 37%

Grip spacing of more than 1.6 times the shoulder width leads to an increase in deltoid compensations

Optimization of the training programmer

 

Movement combination recommendations (2 workouts per week):

- Flatbed bench press 4×8 (main focus on mid-chest)

- Low pulley cleat 3×12 (strengthens lower chest)

- Reverse-grip upper incline push-up 3×10 (stimulates upper chest)

 

Technical points:

- Barbell contact should be 2cm below the nipple line

- Centrifugal phase of controlled 3-second descent (enhances muscle fibre recruitment)

 

INDUSTRY APPLICATION DATA

The National Strength and Conditioning Association (NSCA) 2025 Annual Report states that trainers who combine the flat bench press with the machine flyer have a 28% higher increase in pectoral muscle thickness than a single training group (12-week tracking data).