Back muscles
Teres Major: the small muscle that widens the top of the V
It spans blade to arm and nothing more, which is why it does all its work in the first third of a pull-up and none of it at the top.
What is the teres major?
Teres major is the short, thick muscle running from the lower outer corner of the shoulder blade to the front of the upper arm bone, visible as the bulge under the armpit. It pulls the arm down and back like a shorter lat, so wide-grip pulling and straight-arm work load it hardest. Developing it starts the V-taper higher up.
| Anatomical name | Teres major |
|---|---|
| BackMaxx zone | Lat Width |
| What it changes | The small bulge under the armpit that makes the V look wider than it is. |
| How it responds | Hit by wide-grip pulling and straight-arm work — anything that drives the elbow down and back. |
| Exercises tagged | 17 of 77 |
Teres major, and the strip of back it owns
Teres major is a short, thick muscle running from the lower outer corner of the shoulder blade to the front of the upper arm bone. On a back photo it occupies one specific piece of real estate: the small bulge directly under the armpit, above the top border of the lat and below the flat of the blade.
Its line of pull is nearly identical to the lat’s, over a much shorter distance. Both bring the upper arm down and back toward the ribs. What differs is where each one starts, and how far it has to travel to finish the job.
That is why nothing in BackMaxx trains one without the other. All 17 movements in the corpus that tag teres major tag the lats as well. There is no isolation exercise for it, and it does not need one.
The one thing it changes in a back silhouette
The widest point of a back seen from behind is not the middle of the lat. It is the armpit line, and teres major is the muscle sitting there.
Fill it and two things move in the outline. The taper begins higher up, so the V reads longer for the same lat spread. And the top corner of the silhouette goes from a straight drop off the shoulder to a distinct step out, then in — the shape that photographs as width even through a shirt.
Up close it also cuts the notch between the rear delt and the lat. A back with a developed teres major shows three separate masses stacked from shoulder to ribs. A back without one shows two and a gap where the third belongs.
Teres major vs the lats, side by side
| Teres major | Lats | |
|---|---|---|
| Starts on | Lower outer corner of the shoulder blade | Spine, lower ribs and pelvis |
| Ends on | Front of the upper arm bone | Front of the upper arm bone |
| Range where it dominates | Overhead down to arm-at-your-side | Overhead all the way in to the ribs |
| What it adds to the look | The bulge under the armpit, and a higher taper | The outline itself, armpit down to the waist |
| Movements tagging it in the corpus | 17 | 38 |
| Best single pick | Straight-arm pulling | Full-range vertical pulling |
Same insertion, different anchor. That one row of the table is the whole story: because teres major starts on the blade rather than the pelvis, it runs out of range early, and the latissimus dorsi keeps working long after it has finished.
Where in a pull it actually works
BackMaxx notes that it is hit by wide-grip pulling and straight-arm work, anything that drives the elbow down and back. The mechanism behind that is range, not grip.
Spanning only blade to arm, teres major does its work early: from a dead hang, or from a fully stretched pulldown, up to roughly the point where the upper arm reaches your side. Past that the elbow travels behind the torso and the job passes to the rhomboids and mid traps. The top-half squeeze people chase is largely not this muscle.
Two consequences follow. The bottom of every pull is the part that counts, so a dead-hang start and a full stretch overhead are not optional. And straight-arm work loads it out of proportion to how easy it looks: with the elbow angle locked, the whole movement is the arm sweeping down from overhead, which is precisely the arc teres major owns. The straight-arm pulldown is the closest thing to a direct set it ever gets.
The movements that load it hardest
Seventeen of the 77 movements tag teres major, and every single one scores into Lat Width. It is the only BackMaxx muscle whose entire exercise list sits inside one zone.
| Family | Movements in the corpus | Reps | Why it reaches teres major |
|---|---|---|---|
| Straight-arm pulling | Straight-Arm Pulldown, Banded Straight-Arm Pulldown | 3 x 12–15 | Locked elbow means every degree of the arc is shoulder extension |
| Overhead pulldowns | Wide-Grip Lat Pulldown, Lat Pulldown, Close-Grip Lat Pulldown, Banded Lat Pulldown | 3 x 10–15 | The stretch at the top puts it under tension before the pull starts |
| Bodyweight bar work | Pull-up, Chin-up, Neutral-Grip Pull-up | 3 x 6–10 | A dead-hang start loads the bottom third, where it is strongest |
| Slow and heavy bar work | Negative Pull-up, Weighted Pull-up, Weighted Chin-up, L-Sit Pull-up, Commando Pull-up, Towel Pull-up | 3 x 4–8 | Long time under tension across the same bottom range |
| Assisted machine work | Assisted Pull-up, Assisted Chin-up | 3 x 8–12 | Keeps the full range available when bodyweight cuts the set short |
Notice what is missing. Not one barbell, dumbbell or kettlebell movement in the corpus tags teres major. The list runs on bodyweight (5), cable (4), pull-up bar (3), machine (2), resistance band (2) and towel (1), because this muscle wants the arm starting overhead and free weights rarely put it there. Nine of the 17 work at home.
Lat Width is where it scores
Teres major rolls into Lat Width — the V-taper, width from the armpit down — and it is the most literal muscle-to-zone match in the app. The zone is named for the armpit line. This is the muscle at the armpit line.
In practice that means your Lat Width score moves on the back of the same sets that build your lats. When the score stalls while Upper Back climbs, the fix is usually range rather than volume: more work starting from overhead, fewer heavy rows. Both the Lat Width exercise list and the four-week V-Taper Sprint are built on that assumption.
Spotting a lagging teres major in a photo
Arms down at your sides hides it, as it hides anything living under the armpit. Bring the elbows up toward shoulder height, or spread the lats, and the area opens.
Then trace the line from the rear delt down to the ribs:
- Delt, then a straight drop into the lat with no bump in between — behind.
- A small rounded mass that shows up only with the arm raised — coming.
- A bulge that holds its shape with the arms down, cleanly split from the delt above and the lat below — developed.
The silhouette tell is faster than any of that. Find the widest point of your back in the photo. If it sits down at rib level instead of up near the armpit, teres major and the upper lat are the reason, and the taper will read short no matter how lean the waist gets.
How much pulling it takes
Nobody programs teres major on its own. You program Lat Width and make sure the range is there.
- Twelve to twenty hard pulling sets a week for the zone is where most people see it move.
- Keep at least two of those as straight-arm sets at 12–15 reps, which is the only work that biases it over the lats.
- Run one vertical pull in the 4–8 rep range and one in the 8–12 range. It sees both, provided every rep starts from a stretch.
- Two sessions beat one long one, because on high-rep pulling your grip gives out before this muscle does.
Five ways people leave it behind
Leaning back and rowing the pulldown. Once the torso passes about 30 degrees the elbow finishes behind the ribs and the set is a row. Teres major stopped working somewhere around ear height.
Going as wide as the bar allows. Extra-wide cuts range at the top, which is the only part of the rep this muscle cares about. The corpus prescribes just outside shoulder width on the wide-grip pulldown for that reason.
Skipping the stretch at the bottom. Pull-ups from a bent-arm hang delete exactly the inches you are trying to train. Full extension every rep, even if the set ends three reps early.
Bending the elbows on straight-arm work. The moment the elbow flexes, the triceps take over and the sweep becomes a pressdown. Set a slight bend and keep it there for the whole set.
Rowing and nothing else. A back built on barbell rows gets thick without getting wide, because no part of that pattern starts overhead.
Best teres major exercises
All 17 movements in the BackMaxx library that load the teres major, grouped as the library groups them.
Browse the full 77-exercise library →
Frequently asked questions
What does the teres major do?
It brings the upper arm down and back toward the ribs, and turns it inward on the way. Running only from the lower corner of the shoulder blade to the front of the upper arm bone, it covers that path over a short distance, which is why it finishes its work by the time the arm reaches your side.
What is the difference between the teres major and the lats?
They finish in the same place on the arm but start in different places. The lat sheets off the spine, lower ribs and pelvis; teres major starts on the corner of the shoulder blade. So the lat keeps pulling all the way in to the ribs, while teres major dominates only the overhead portion, and adds the bulge right under the armpit.
What are the best teres major exercises?
Straight-arm pulldowns first, because the locked elbow makes the whole arc shoulder extension. Then full-range overhead pulling: wide-grip and standard lat pulldowns, pull-ups and chin-ups from a dead hang. Seventeen of the 77 BackMaxx movements tag it, split across bodyweight, cable, pull-up bar, machine, band and towel work.
Can you isolate the teres major?
No, and no app should claim otherwise. Every one of the 17 movements in the corpus that tags teres major also tags the lats, because the two share a line of pull and an insertion. The closest you get to biasing it is straight-arm work, which keeps the elbow out of the equation and stays in the overhead range.
How do you know if your teres major is lagging?
Look at a rear photo and find the widest point of your back. If it sits at rib level rather than up near the armpit, this muscle and the upper lat are behind. Closer in, the tell is a straight drop from the rear delt into the lat with no separate rounded mass between them.
Do pull-ups work the teres major?
Heavily, but only through the bottom half. From a dead hang up to the point where the upper arm reaches your side, teres major is doing a large share of the work. Above that the elbow travels behind the torso and the load shifts to the rhomboids and mid traps, so half-reps from a bent-arm hang miss the muscle entirely.
Is your teres major the problem?
BackMaxx scores eight back muscles individually from one photo, so you find out whether the teres major is actually what is holding your back back — or whether it is something else.
Download on theApp Store Download on the App StoreFree to download. iPhone, iOS 26 or later.