When it comes to speed control, there are two mechanisms we can use: length of the stroke with a constant energy, or we can keep the same length of the stroke and vary the energy.
The key to good putting is making sure the ball comes off the putter with the same velocity every time. That’s a lot more predictable with the same overall tempo.
A good way to figure that is to create a speed ladder. Really focus on allowing the length of the stroke control the speed instead of making shorter, pop strokes.
