UB-SHOULDERS-DELTOIDS-X


DELTOIDS – STRENGTH & MUSCLE MASS


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TRAINING


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DELTOIDS – REVIEW
– Including Moment Arm Data


Deltoids – Beardsley


The leverages of the deltoid regions change with joint angle 


A. Shoulder Ab-duction Angle – Middle or Lateral Deltoid – Lateral Raises
The internal moment arm lengths of the anterior and middle deltoids both increase with increasing shoulder ab-duction angle.
The middle deltoid is the best shoulder ab-ductor until approx 90º shoulder elevation, after which the anterior deltoid becomes similarly effective, or perhaps even slightly better.
– Thus, when using lateral raises to train the middle deltoid, it is not necessary to use large ranges of motion.
B. Shoulder Flexion Angle – Anterior Deltoid – Pressing and Front Raises
The internal moment arm lengths of the anterior and middle deltoids both increase with increasing shoulder flexion angle
– Yet, the clavicular head of the pectoralis major is the best shoulder flexor until approximately 120º of shoulder elevation. Only after this point does the anterior deltoid become similarly effective, or perhaps slightly better.
– Therefore, when identifying shoulder flexion exercises to train the anterior deltoid, it is probably best to work substantially above shoulder height, such as with overhead press variations.
C. Shoulder Elevation Angle Posterior Deltoid
– The internal moment arm lengths of the posterior deltoid decrease with increasing shoulder elevation angle, in the sagittal plane when performing shoulder extension – close grip pulls and rows
– Also in the frontal plane when performing shoulder ad-duction – wide grip pulls
– Even so, the inferior and superior regions of the latissimus dorsi and the inferior region of the pectoralis major also contribute much more substantially to shoulder ad-duction at almost all joint angles, making it unlikely that the posterior deltoid can
be trained very effectively in this movement.
– Shoulder Extensor – Posterior Deltoid – Close grip Rows and Pulls
– Yet, as a shoulder extensor, the posterior deltoid has the best leverage at all joint angles, and is likely the prime mover when the shoulder is elevated above 90º, and certainly when the shoulder is elevated above 120º.
– Thus, overhead shoulder extension (close grip pulling) exercises likely develop this part of the deltoid.
– Horizontal Extension – Posterior Deltoid – Rows with Elbows Up
– The posterior deltoid also has excellent leverage for shoulder horizontal extension
– Even so, the latissimus dorsi and the teres major also have some leverage, but only when the arms are positioned in front of the body.

– Therefore, in practice we can treat the posterior deltoid as the primary shoulder horizontal extensor for the entire range of motion.


There are 7 regions of the deltoid and not just three


– For many years, it was assumed that the deltoid had three main functional regions (anterior, middle, and posterior) but more recent research has identified that there are in fact seven functional regions.
– Importantly, research has shown that each of the seven regions are activated to a greater extent when they have better leverages (owing to the principle of neuromechanical matching).
This suggests that exercise variety is very important for the deltoid, and simply targeting the three main regions may not be sufficient to maximize muscle growth in all individuals.


Pressing variations can be altered to target the deltoid


– For many years, we have known that different pressing variations can be used to target either the anterior deltoid, pectoralis major, or triceps brachii.
– Research has now shown that the following can all increase the relative contributions of the anterior deltoid during pressing variations.
[1] increasing bench incline
[2] training with peak forces closer to full elbow extension (as when using elastic resistance or partial ranges of motion,
[3] increasing grip width
[4] using a reverse grip
[5] using a barbell instead of machines or dumbbells 


During the (overrated) lateral raise elbow angle affects middle deltoid activation


– Lateral raises are a common exercise for training the middle deltoid.
– Even so, there is relatively little difference in middle deltoid activation between the overhead press and the lateral raise.
– Since most bodybuilders will use an overhead (or steep incline) press for training the anterior deltoid, this does suggest that the lateral raise may not be a necessary addition to most bodybuilding programs, despite its popularity. 
When doing the lateral raise, the elbow angle affects the activation of the middle deltoid. Using a straight arm allows a greater level of middle deltoid activation (irrespective of the shoulder rotation angle), while using a bent arm reduces the activation of the middle deltoid.

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The deltoid regions vary in their fiber type, which affects fatigue


– Since upper body muscles tend to display higher levels of voluntary activation and a more fast twitch fiber proportion, they are usually more easily-fatigued (and damaged) than lower body muscles.
– Nevertheless, there are variations between the three regions of the deltoid. The posterior deltoid is way more slow twitch than the other two regions, which means that it will tolerate both a higher volume and regular training.


EMG STUDIES


ANTERIOR, MIDDLE & POSTERIOR DELTOID
– DB Overhead Press, DB Lateral Raise, Low Cable Lateral Raise, Reverse Fly, 45º Incline Row

ACE Research – Top Shoulder Exercises – 2015 – Sweeney – PDF Thesis .
Procedure
– all of the subjects were required to have some weight-lifting experience and attended one mandatory practice session
Exercises
DB Overhead Press
Bent Arm DB Lateral Raise thumbs neutral . Straight Arm Cable Lateral Raise

Seated Rear Lateral Raise – Reverse Fly .
45º Incline Row elbows out
Results
Anterior Deltoid: DB OHP 75% . DB Front Raise 55%
Lateral Deltoid: Incline Row 85% . DB Lateral Raise 80% . Cable Lateral Raise 75% . BB Upright Row 70% . Seated Rev Fly 70% . DB OHP 60%
Posterior Deltoid: Seated Reverse Fly 75% . Incline Row 70%

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ANTERIOR, MIDDLE & POSTERIOR DELTOID
– Lateral Raises, Reverse Pec Deck, Incline Lat Pulldown, Seated Machine Row
– Shoulder Press, Bench Press, Pec Deck

EMG of the Deltoid Between Different Strength Training Exercises – 2013 – Botton, Wilhelm, Pinto, Ugjni, Lima
Subjects
– at least six months strength training
Exercises
Smith Machine Shoulder Press; Bench Press; Pec Deck
DB and Cable Crossover Lateral Raises
Seated Row elbows up – seated upright; pronated grip; shoulders abducted to 90°; horizontal shoulder extension
Reverse Pec Deck – neutral grip and elbows straight, performing horizontal shoulder extension
Incline Lat Pull elbows up – posterior tilt position so that the cable of the machine was perpendicular to the body. 
Results
Anterior Deltoid: Smith Shoulder Press 70% . Bench Press 55% . Pec Deck 50%
Lateral Deltoid: DB Lateral Raise 55% . Cable Lateral Raise 55% . Reverse Pec Deck 50% . Seated Row 40% . Smith Shoulder Press 25%
Posterior Deltoid: Reverse Pec Deck 90% · Inclined Lat Pulldown 55% · Seated Row 50% . DB Lateral Raises 35% . Cable Lateral Raise 35%


ANTERIOR, MIDDLE & POSTERIOR DELTOID
– Reverse Pec Deck, Incline Lat Pulldown, Seated Machine Row

Analysis of anterior, middle and posterior deltoid activation during single and multijoint exercises – 2015 – Franke, Botton, Rodriques, Pinto, Lima
Procedure
– 12 males with at least one year of strength training experience; MVIC 10RM
Results
Anterior Deltoid: low numbers
Lateral Deltoid: Reverse Pec Deck 50% · Inclined Lat Pulldown 40%  ·  Seated Row 20%
Posterior Deltoid: Reverse Pec Deck 90% · Inclined Lat Pulldown 55% · Seated Row 50%

 

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