A client in The Snooker Gym Community on Facebook asked this question today and I replied with quite an involved answer with many variables that I thought you may find interesting…
“A question for Nic and group. I understand that the optimum technique is to have the cueing back arm at vertical when addressing the cue ball but is this always possible. A lad I have come across does this but only gets through the cue ball 2-3 inches to the detriment of his game. Have you come across any players who have to hold the cue off vertical to get an adequate follow through. I understand bending the bridge arm can increase follow through but do different body shapes create this vertical backhand problem?”
In fact the bridge arm bending makes zero difference to follow through despite certain TV personalities incorrectly stating otherwise! Their false logic involves 'bending the bridge arm' but actually they are leaning forwards in the stance and keeping the bridge position fixed. Yet it is not even their leaning forwards that increases follow through - it is that they don't keep their cue arm vertical when doing this which causes the cue arm to be backwards of vertical at address.
In effect what the TB pundits are effectively saying is the somewhat obvious: "Move the cue arm backwards of vertical at address and you will get more follow through."
In your client's case, his chest is probably crowding the cue, which can be reduced by:
In addition, many with limited follow through have their shoulders oriented unhelpfully in both planes:
Firstly, some players intuitively feel that their body should be pointing straight ahead (on the line of the cue ball). This false assumption causes the shoulders to point straight ahead, causing the chest to crowd the cue. It also means the cueing shoulder is also outside the line of aim, rather than above it, making it more difficult to cue straight.
Instead, the players should rotate and 'open' their shoulders (clockwise for a right handed player) which will clear the chest from the cue a little. Note I am NOT saying the chest has to be on or off the cue as that depends on what helps the individual from cueing best - and helping a player confirm this choice this is another conversation. Opening the shoulders will give a player the aiming benefit of seeing more cue as the shoulders rotate and open (bridge distance being equal). As the shoulders open, the head should of course stay fixed in relation to the cue (assuming their vision centre has been previously been found).
Secondly, a player will often keep both shoulders horizontal to the table which will keep the bridge shoulder too high for stability, and the cueing shoulder too low - the chest then crowding the cue again. Players have 'Shoulder Induced Cue Crowding (SICC)' in this way because they feel it counterintuitive and wrong to tilt the shoulder line / back by twenty to thirty degrees or so.
Instead, club players with SICC should have a go at emulating the shoulder tilt they see in pros. If the club player is flexible enough to do this it will be easy to get into and usually pays big dividends in cueing freedom and accuracy. All main tour players have their shoulder line very well tilted from horizontal. This anchors the bridge arm onto the table for more stability. It also lifts the cueing shoulder higher above the cue, uncrowding the chest from the cue and allowing more follow through.
Of course, all these variables depend on the physique of the player in concern which means some will need only one or two of the above suggestions to have an adequate follow through that does not restrict their power and comfort on delivery (if the chest crowds the cue too much the grip hand can end up following through into the ribs which will cause the delivery to come off line to avoid that discomfort. We want the grip to follow through into the soft part of the chest that is below the shoulder area.