"Wide grip for width, close grip for thickness." Every gym repeats it. Almost nobody has measured it. We put electrodes on the latissimus dorsi and ran three grips.
Left against right, rep against rep, week against week.
The test
One lifter, one cable stack, three grips: wide overhand, shoulder-width neutral, and underhand. Load and rep count matched. Both lats instrumented so we could watch symmetry as well as raw activation. Each grip returns a Muscle Score — normalised to the lifter's own maximum.
The result
What it says
The neutral grip edged it. It let this lifter drive the elbow down and back through the longest range with the least help from the biceps. Underhand followed close behind. The wide overhand grip — the one the truism crowns for lats — placed last here, shortening the range at the top and handing work to the teres and rear delt.
The symmetry bar told a second story: on the wide grip the right lat ran 9% ahead of the left. A gap you would never feel, and would never fix, without measuring it.
The catch
Grip mechanics are personal — limb lengths and shoulder structure move the ranking. The truism is a starting guess. Your lats have the real answer, and they will only give it to a sensor.
Run it yourself
Repsense compares grips side by side and flags the imbalance while you train.
Repsense is a training-analytics tool, not a medical device. Results are relative indicators for training.