Plain and simple: belly putters provide an added degree of accuracy and consistency. Because the grip end of the belly putter anchors to a fixed position (1"-2" above the belly button), players are much less likely to rotate their hands in an open or closed fashion - eliminating tendencies to push or pull putts. If you find yourself constantly pushing or pulling putts and feel like stability would enhance your putting game, why not give the belly a try?
Accuracy and consistency can also be achieved with a long putter. Long putters offer an even higher degree of stability as only one arm is required to be in motion. Like the belly putter, long putters anchor to a fixed position, commonly on the golfer's chest or lower chin area. When properly gripped, the long putter takes virtually all wrist action out of the equation - a very common tendency among many players. Because the left arm (right arm for a lefty) remains motionless, most long putter users take on a "claw" type grip - similar to holding a pencil. This allows the golfer's fingers to guide the direction of the putt, rather than the wrist.
What to consider when finding the right fit for a belly or long putter
2011 PGA Champion, Keegan Bradley
Belly & Long Putter Length
Finding a comfortable belly putter length will vary based upon body type, but the chart below provides a healthy approximation according to height:
6'0" and Taller
5'8" and Under
Recommended Shaft Length
For an even closer measurement, simply hold a string against a comfortable anchor point on your mid-section (1"-2" above belly button) and measure from the anchor point to the top end of your conventional putter grip. That measurement + the length of your conventional putter will provide you with an even closer belly putter length fitting.
Like the belly putter, long putter length does vary based upon body type, posture, and comfortability in your own unique stance. But, to gain some insights into what a healthy approximation would be, there are a couple factors to consider in general. First, figuring out if it's more comfortable to have the end of the putter closer to your chest or your chin. Many players with back problems prefer a longer putter (closer to the chin), as this length requires very little bend in the spine. Second, once a comfortable anchor point has been reached, players should make sure that their eyes are over the ball, about 2" out from the toe. Long putters typically range from 46" to 53".
Belly & Long Putter Lie Angle
When the toe of the putter head is up at the point of impact, there is a tendency to pull the putt. Conversely, if the toe of the putter head is down at impact, there is a tendency to push the putt. A belly putter provides a stable lie angle when anchored properly 1"-2" above the belly button and this added stability promotes a better lie angle, as the sole of the putter is parallel with the putting surface.
The U.S.G.A allows a maximum 80° lie angle, which is typically what long putters are designed with. Again, like the belly putter, this can vary - but a greater lie angle is very common in long putters and will offer the highest percentage of success when it comes to maintaining a level and stable angle to the putting surface.
Belly & Long Putter Head Weight
Belly and long putters maintain consistently heavier head weights in comparison to a conventional putter head weight. This heavier weight serves as a balanced counterpoint to the stable anchor point on your mid-section, chest, or chin area. The heavier clubheads promote a straight back and straight through swingpath, coupled with face angle consistency.
Center Shafted vs. End Shafted
Center shafted belly and long putters generally have very little offset, while end shafted belly putters generally have more offset built into the hosel. Hosel-less end shafted belly and long putters are typically designed with a double bend shaft to compensate, again providing more offset.