One quick and easy way to evaluate and/or troubleshoot a swing is to look for a number of shapes that you see in a good swing. Those shapes include...

• The Box, The L, and The Parallelogram
• Vertical V
• The Inverted Triangle
• Power L
• The Triangle, Elbow Linkage, and The Triangular Pyramid

While you aren't going to see those shapes in every swing, especially if a hitter gets fooled or has to make a large adjustment, if you never see the hitter make that shape, especially on a well-timed fastball down the middle, then it could be an indication of a problem.