So it's kind of interesting that I'm now running into shanking shots. I'm thankfully not a serial shanker but it can be debilitating and ruin my confidence.
So after shanking an 8 iron approach shot today, I wondered why I would shank an 8 iron. I can see shanking a wedge but an 8 iron??? Anyway, and maybe Tom can shed some light on this subject, but after some thinking, it occurred to me that my left shoulder was tense, or "up" at address, similar to the same position if reaching for a computer keyboard.
So I ran through the motions after the shank and discovered that my left shoulder was "up and forward" or tense at address. As such, from that position, my left shoulder will rise up on the backswing and flatten my shoulders at the top. So my next thought was "SHOULDER DOWN" at address, then MORE DOWN upon takeaway. I can't explain why but that ended my shanks.
Tom, do you have any insight on why someone like me who is moving down to a 4 hcp would suddenly start shanking? Is the tense left shoulder the "true" issue or are their other movements that create the shank? The head pro at my club said (today) that it was amazing that I could fix a shank so quickly which is why I think my left shoulder is the culprit.
@GolfLivesMatter - It can happen to anyone at anytime. You'll even see one occasionally on Tour. Tension can definitely be a culprit, as can a flattening of the shoulders, which may or may not occur as a result of rolling the hands in the takeaway and sucking the club to the inside. Combine both of these and it's a ticking time bomb for when - not if - the "S" is going to happen.
Here is a member video I did on the "laterals". However, since you were able to astutely self-diagnose and resolve the issue (well done, by the way!), I would not spend too much time thinking about this.