If you experience pain on the inside of your palm of the bottom hand while swinging there is a good chance the knob of the bat you swing is the culprit. In most instances, this pain is the direct result of a broken hamate.
Most broken hamate injuries in baseball whether it be in the Pros or not - occurs to the players non-dominant hand. Right-handed batters who also throw right, grip the bat with their non-dominant hand against the knob (the left hand). The same goes for Left-handed players who hit lefty. In some cases, players can break both of their hamate bones if they switch hit – like Pablo Sandoval did. This is mostly prevalent where player take a lot of swings.
This can also happen to coaches while using their fungo during infield/outfield practice.
The compression of the hand which causes broken hamate bones happens immediately after the intended moment of contact with the ball.
Since batters are swinging the bat through the zone and ultimately around their body - at some point their hands must roll over the knob of the bat. During that moment, the knob quickly compresses the area of the hand where the hypothenar muscles lie.
The hypothenar muscles are a group of three small muscles of the palm that control the motion of the little finger. Under the hypothenar muscles is the ulnar nerve and the hamate bone.
We are now offering the TB-U10 PRO model, depicted below, aims to reduce the amount of compression a hitter's hand experiences. The big knob gives hitter the ease of mind when swinging. Players are quickly switching to this model - especially if they already experience pain or have had a broken hamate in the past.