Maximum lat hypertrophy requires the use of both shoulder extension and adduction. As with the chest, shoulder rotation influences the muscle’s biomechanical efficiency. For shoulder adduction, the lats are strongest when the shoulders are somewhat externally rotated (lat pull downs). For shoulder extension, the lats are strongest when the shoulders are in neutral position.(straight bar pull down).
During straight-arm pulldowns, you should use a slightly V-shaped handle instead of a straight bar to maximally recruit your lats.
The lats have an equal amount of slow and fast twitch fibers, so they respond best to medium reps.
Take home messages:
• Include both shoulder extension and adduction in your programs.
• Think about your grip and shoulder rotation for your exercises.
• The lats respond best to medium volume.
The Traps
As only the upper traps are visible in the mirror, the middle and lower traps often get left out (mirror muscle effect).
However training the traps is pretty basic – worked out mostly by shrugs or uprights rows.
The traps are a muscle which is slow twitch dominant, so you should do relatively high reps.
For those training their necks, the sternocleidomastoid, is about 65% fast twitch.
Take home message:
• Your traps are important. Train them fully, and train them more than your pecs.
Lower Back
Besides extending the spine, the erector spinae also laterally flex and rotate the spine.
The erector spinae (lower back) are 56% slow twitch dominant meaning they would respond best to medium to high rep exercises.
