There are two ways to hold the bar during squats.

a. with your thumbs wrapped around the bar {standard}
b. with your thumbs over the bar {thumbless grip}

Benefits of the thumbless grip

The main benefit of the thumbless grip is that it allows your wrist to be straight (in line with the fingers and knuckles). Conversely, when you wrap your thumb around the bar and squeeze hard during squats, your wrist has no choice but to buckle a little bit. Usually, that’s not a problem because during a proper squat execution the bar is never supported by your wrists or elbows – it’s the torso that holds it. However, even if you do everything correctly, you may still experience wrist pain during squats. That’s why some people prefer to use the thumbless grip.

High bar squats

The high bar squat requires less shoulder flexibility and takes less energy to hold the bar. Therefore, you are less likely to suffer from wrist pain regardless of your grip type. The general consensus is that high bar squatters should use a regular grip for additional support and tension.

Low-bar squats

The thumbless grip is more popular among low-bar squatters because the movement requires more flexibility to hold the bar and places more tension on the wrist, elbow and shoulder joints.

In the picture below, you see the famous powerlifter Kirk Karwovski. He holds the bar with a regular grip. As a result, his wrist is tilted to one side.

In the next picture, the powerlifter relies on a thumbless grip that keeps his wrist in a straight line.

Additional notes:

A thumbless grip does not equal a proper alignment by default. You can still tilt your wrist to the side or even put it directly under the bar. To avoid this problem, you have to develop position awareness. Practice is your best friend.