The Elusive Inner Chest Workout... 
When it comes to building an impressive chest the majority of guys start with the usual flat barbell bench press before spending a substantial portion of their workout focusing on hitting the 'inner chest' with exercises that promise to develop the thickness of the middle of the chest.
From holding and pressing a 45lb plate in front of their inner chest (known as Svend press) to hitting machine chest presses and push-ups with odd angles and hand placement.
Pick up a bodybuilding magazine and browse through the chest workouts within and you'll see the same thing repeated again and again when it comes to building a well-rounded chest.
"Hit your bench press and incline press, then move onto some dumbbell or pec deck flyes to build the width of your chest before finishing up with some extreme isolation movements for the inner chest"
Like most things you'll read in bodybuilding magazines that simply isn't true.
Hell, I'd say by following that specific advice to 'hone in' on the different portions of the chest you're going to end up with pretty lacklustre results...
You Won't Get Build Your Inner Chest If You're Focusing On 'Inner Chest Exercises'
The easiest way to dispell the myth and importance of the inner chest workout and exercises for 'outer chest width' and 'inner chest thickness' is by looking at the anatomy of the chest.
As you can see above the chest is comprised of the pectoralis major and pectoralis minor, the pectoralis major being the muscle we're working 99% of the time when we're hitting our pressing and fly movements.
The chest does not have 'heads' like the deltoids, biceps or triceps.
When it comes to shoulders if you're lacking size on the side of your shoulders this can be targeted easily enough by spending more time on exercises that primarily utilize the medial deltoid.
By hitting different variations of side lateral raises you will be able to specifically focus on this weak point.
The chest, however is a different story.
There are no inner or outer heads.
When we're performing a chest exercise, be it weighted dips or incline dumbbell press we're either contracting the pectoralis major or we're not.
We can't place more focus on contracting the inner portion or the outer portion of the pectoralis major...
A muscle fiber either contracts or does not contract, utilizing a close grip on an exercise claimed to smash the inner chest (such ass the Svend press) makes no difference as the entire muscle fiber is firing.
The 'inner' portion of the muscle fiber isn't going into overdrive while the 'outer' portion of the muscle fiber takes it easy.
It just doesn't work like that.
You'll likely see little to no chest growth at all if you're purposely targeting these isolation based 'inner chest exercises' as they're simply not enough to force growth.
In order for your chest to grow you must focus on lifting heavy and applying a large amount of tension to the chest via progressive overload.
The Hard Truth About Chest Genetics
Your ability to build an impressive inner chest comes down to genetics.
Just like bulging bicep peaks, some people can build 'em and others cant - this comes down to the shape of your muscle bellies and the insertion points of the muscle.
The key to the inner chest is a small gap between your pectoral muscles.
A 'lagging inner chest' is 99% of the time the result of a large gap between your pectoral muscles.
Many would say the two chests above are lagging, however this is a case of poor chest insertions (large sternum gap).
Concentrate Your Forces On These Chest Exercises...
The Flat Barbell Bench Press
The barbell bench press is often used as a benchmark of strength and an overall measure of progress – there’s no doubt about the fact that an increased load can be lifted when utilizing the barbell bench press as opposed to the dumbbell bench press, however as you begin to lift heavier and heavier weight on your bench this is the time when muscular imbalances reveal themselves - be sure you don't neglect unilateral exercises such as the dumbbell press to counter this,
The Tension on the chest when working with a barbell is dependent on the hand placement utilized – a wider hand placement will be placing greater emphasis on the chest, meanwhile a shoulder width or narrower grip will place the load on your triceps.
When performing heavy sets of your barbell bench press a spotter is required as getting stuck under the bar is a concern
Movement: Compound
Targets: Chest & Triceps
Required: Barbell + Bench
Lay on a flat bench.
Grip the barbell with thumbs wrapped around the bar at a slightly wider than shoulder width grip.
Assume a slight arch with your back (you should be able to just fit a fist between your lower back and the bench), plant your heels firmly on the ground and squeeze your shoulder blades down and back.
Unrack the barbell and slowly lower it down in a controlled manner to the middle of your chest, stopping just shy of the barbell touching your chest.
Drive through your chest to power the barbell back up to the starting position, with arms fully extended.
The Incline Barbell Bench Press
Movement: Compound
Targets: Chest & Triceps
Required: Barbell + Incline Bench
Lay on an incline bench (45 degree angle).
Grip the barbell with thumbs wrapped around the bar at a slightly wider than shoulder width grip.
Assume a slight arch with your back (you should be able to just fit a fist between your lower back and the bench), plant your heels firmly on the ground and squeeze your shoulder blades down and back.
Unrack the barbell and slowly lower it down in a controlled manner to the middle of your chest, stopping just shy of the barbell touching your chest.
Drive through your chest to power the barbell back up to the starting position, with arms fully extended.
The Weighted Chest Dip
Movement: Compound
Targets: Chest & Triceps
Required: Parallel Bars
Optional: Weight Belt/Dumbbell
Raise yourself up onto a pair of parallel bars.
With your elbows slightly outward tilt your torso forward by looking ahead and bringing your legs up behind you.
From this position contract your arms while maintaining this slight angle in your torso, this ensures we're targeting the chest and not the triceps as our primary muscle group.
Lower yourself down as far as possible, hold this contraction for 1 second.
Driving through your chest explode upward and extend your arms to return yourself to the starting position above your parallel bars.
Repeat for the desired number of repetitions, add a dumbbell between your legs or strap on a weight belt when possible.
Dumbbell Flies
dumbbell flies are an excellent exercise for adding both size and strength to the chest.
There's a fine line between good form, poor form and a potential injury when it comes to performing dumbbell flies, as strict form is near impossible to maintain with heavy weight, often resulting in shoulder and rotator cuff related issues.
If you take one thing from this paragraph on dumbbell flies let it be this:
Forget the weight, focus on your form, a nice slow tempo and hold that contraction at the top of bottom of each repetition momentarily - save the heavy lifting for your pressing movements.
Movement: Isolation
Targets: Chest
Required: Dumbbells + Bench
Sit on a flat bench with a dumbbell in each hand. Rest the dumbbells on your thighs with your palms facing each other.
Using your thighs kick the dumbbells up one at a time.
Once the dumbbells have been loaded into place ensure your palms are facing towards each other.
Maintain a slight bend in your arms as you proceed to slowly lower the dumbbells down to your sides, keep your arms as straight as possible without having them locked out.
Squeeze and contract your chest at the bottom of the repetition for 1 second.
Maintaining the same slight bend in your arms proceed to fly the dumbbells back up to the starting position. The best analogy I have heard (which helped me finally get the right form!) for dumbbell flies is to imagine you're hugging a tree - practising this movement standing up without weights and familiarise yourself, then take it to the bench with your dumbbells.
