There is a tendency for swing analysts on TV, from what I’ve seen, to explain away mechanical flaws in the swing by declaring that the compensations or manipulations in the swing are responsible for power or speed.
That is simply incorrect – if your leading foot jumps or twists in the impact/follow-through phase of the swing, it is nothing more than a compensation for faulty mechanics.
The main culprit is usually the restricted hip back swing, and another culprit is the failure to transfer the body’s weight from the trailing to the leading foot coming down from the top, as you’ll also see classic swingers who have a free hip turn but fail to transfer the weight, as you see below with Jamie Sadlowski:
If you’ve never tried to throw a ball side-arm without transferring the weight to the leading leg, then I wouldn’t advise it, but if you did, you’d see that there is a big problem with trying to swing or throw without transferring that weight and you heard Frank Nobilo’s shout-out to me when looking at that same move last January:
That above move is not a power-producer, but a swing and body-saving move, and you only have to look at Justin Thomas’ right foot firmly anchored through the entire down swing.
It’s like trying to walk or run without letting the weight shift from the trailing to the leading foot – you aren’t going anywhere.
As to the first culprit I mentioned – if the hips are restricted going back, then on the down swing, they reach the impact position before the upper body, arms and club, as they didn’t turn much or at all to begin with.
The swinger then has to violently clear those hips and the left side so that the swing can continue, and you’ll see the compensation of the leading foot twisting or leaving the ground at about here:
But if you’ve performed a proper back swing pivot with a free hip turn, then you have no problem launching that ball by simply transferring that weight as you would when walking, running or throwing:
You shouldn’t see any snapping of the left knee (which would indicate a lack of body weight on the foot to begin with), nor a jumping or twisting left foot through impact or the follow-through.
Pretty basic mechanics there, and it is not amusing at all, but rather depressing to watch faulty mechanics being portrayed on television as something to be desired and emulated.
The jumping foot through impact is not a body-wrecker, but rather a body-saver, but the “snapping” knee through impact is poison.
Combine that harmful move with the lower back crunching of the restricted-hip back swing, and you’re asking for real trouble.
A generation of swingers, still young enough not to care about the damage they are wreaking upon their bodies, will pay the price in the leading knee and lower back, sooner or later, and the past few years have shown that it’s sooner than later for many unfortunate Tour pros.