Very common is the downward shoulder tilt from non-dominant side to hitting side at preparation and right up to contact on the modern tennis forehand. You will see this with many advanced players and at varying incoming ball heights. This shoulder tilt provides a foundation to swing in an upward and across path to generate top spin and confidently accelerate into the shot.
Examples include stand out Stanford college player Axel Geller:

Example of the forehand tilt with another top Stanford college player, Tom Fawcett:

Here are a few more examples of Martin Redlicki of UCLA, Brandon Holt of USC and Aleks Vukic of University of Illinois:
One would assume, a similar but mirrored tilt would be present on the two handed backhand. Many tennis coaches refer to the two handed backhand as being technically the same as a lefty forehand. (RH dominant player) However, almost the opposite is often observed. Many players tilt their shoulders from the hitting side to the dominant side or stay relatively level at contact. This is also grip dependent, but for the most common grips, this is consistently observed.
Often I see recreational players in a baseball swing set up for the two handed backhand. See Jim Courier (however his extreme grip contributes to this) In most cases this is due to the incorrect shoulder tilt that mirrors the forehand shoulder tilt. It would seem natural to tilt in the same way that you do on the forehand…from right shoulder to left shoulder hitting side for a right handed player. However, as you can see from the many pics attached below from high level college players and true for ATP players the shoulder tilt on the backhand does not mirror their shoulder tilt they have on the forehand, it is very similar, right shoulder up, left shoulder down on most groundstrokes regardless of forehand or backhand.
Here are examples that were not cherry picked, just routine, often first backhand frame that was captured.
Tom Fawcett Two handed backhand:

Oliver Frank jumping two hand backhand:

Oliver Frank Backhand return:

NCAA singles D1 Singles champion 2016 Nuno Borges

So to really make this as controlled as possible, I just Googled Pro two handed backhand images, and as you can see, the general theme is the shoulder tilt from hitting side to the dominate which is not mirrored of the forehand technique.

Why do we observe this? There are a few reasons. The more neutral grip with the non-dominant hand partly contributes to this and because there are two hands on the racquet, dropping the dominant side shoulder to a certain extent helps open up the shoulders and give freedom to the forward swing. This common shoulder tilt, which is rarely discussed in private lessons or group clinics, is also important to help pull the core into the court and across to help make the cross court shot more coordinated. There are possibly other bio-mechanical factors that contribute and I would be interested in hearing your comments on this subject.
KW Tennis Nation
