FiveFrameSwing
Banned
It's a 'tool' in the tool box to be applied to try and 'fix' a flaw a hitter may have,
Sure, it's an over-exaggeration drill that handicaps a 'spinners' spinning action. It isn't what you want. Coincidentally I had two such kids in back-to-back hitting sessions yesterday ... both from the same softball team ... and both taught what you described. The thing is ... some of these girls actually do what they are told .
The drill you describe makes a spinner feel handicapped. Their swing is suddenly shut-off when they can't turn their 'upper' and 'lower' leg as a unit. The hope is that they learn to use their upper leg against their lower leg. Hmmm ... you could simply tell them that .
If an over-exaggeration drill works for your hitters, then fine ... just be clear with them that you don't want them to achieve what you are asking them to do.