Chin-ups, pull-ups hand position and muscles used.

[synonymous]

I use an assisted chin-ups machine. One of my goals is to get through a set without the machine.

There are 2 separate places for hand placement. The first, about shoulder width apart pulling up. The second has the hands almost directly above your head, pulling yourself up, palms facing each other. It's almost like doing a row only UP (Sorry if this sounds confusing).

I asked the gym trainer what differences there would be. He said that with shoulder width apart and palms facing away from you, you use more of your back muscles and less of your arms (Biceps). Whereas with the palms facing each other style grip, closer together, you don't hit your lats as much and using more arms than back for the movement than you would otherwise.

Any of this make sense?

[Alex.V]

Nope. Biomechanically speaking, the arms and back are doing the exact same relative work in both positions, the leverages are simply worse for both muscle groups in the palms away/wider grip position (more torque needed to generate the same vertical force vector), so it "feels' harder.

[FearFactory]

Neutral grip FTW. Easiest on my shoulders and I can take sets further.

[Matthew Bryduck]

The wide grip chin will widen the upper back and create a full sweep in the lats. The close grip chin will widen the lower lat and develop the serratus. If you really want to strengthen your lats you need to learn how to pull with you elbows, which helps take some of the stress off the bicep.

Matt

[synonymous]

Nope. Biomechanically speaking, the arms and back are doing the exact same relative work in both positions, the leverages are simply worse for both muscle groups in the palms away/wider grip position (more torque needed to generate the same vertical force vector), so it "feels' harder.

So, in your opinion, it doesn't matter which grip I use, so long as I'm pushing myself to lift/pull hard each time?