A little semantics in question. By definition, "non-dominant" implies lesser role, not greater, and "dominant" implies greater role.
Check Mauro Marcos two-hand backhand video, which describes (for right-handers) the left-hand is dominant and right-hand less so, i.e. 70/30, 60/40.
https://www.youtube.com/watch?&v=IGlkvPal99A
and a second Marcos video with Coach Kyril, which describes the role of the dominant arm in two-handed backhand ("left-hand is clearly dominant for right-handers").
https://www.youtube.com/watch?v=7sN1F5_3TtI
The non-dominant is the "Stabilizer", which maintains the racquet face alignment for proper stroke and follow through.
I used the two-hander for tennis elbow. It was never satisfying, and required high muscular effort to achieve any power, and lacking the whip one gets with a good one-hand backhand. Without thinking about hand dominance, I began playing around with the grip. In stages, I moved the left-hand (for righty's) toward the racquet butt. Obviously, some right-hand fingers would drop off the butt. I'd just tuck them into the palm.
Once left with only the right-hand thumb and index fingers on the racquet, I achieved my ideal stroke for power and control. In this condition, the two right-hand fingers are a true "Stabilizer", and allows swinging away with confidence. Most if not all coaches and top players will pooh-pooh the concept, but it really works.
Hence, my left_hand is perhaps 98%, and right-hand 2%
I've posted last year on this forum, with the usual doubters saying they could knock the racquet out of my hand. Absolutely not true! Its become my go to shot, or killer shot for max power and control, baseline or approach. Since my elbow finally healed, I mix in one-hand backhands depending on the approaching ball trajectory, or ball spin or pace I wish to achieve.
Why does this work? Longer moment arm (left-hand to sweet spot), combined with longer stroke and follow-through, results in much higher racquet face velocity at impact. Muscular effort is used only to achieve max swing speed, not to muscle the ball at impact. Its essentially a left-hand forehand with usual modified eastern forehand grip (ignoring the right-hand two fingers for the moment, which you can even drop on the run for left-hand topspin returns). Grip change can be extremely quick, instinctive after awhile.
I call is the Extended Two-Hand Backhand (E2HBH).
E2HBH Web Page
The site gets ~30-40 hits a month from around the world for last several years, literally everywhere. Three years ago, one 30-something player in Texas tried the stroke and noticed his stroke seemed so much smoother and started to improve -- and thanked heartily. Since then, he has honed the stroke and coincidentally moved up from 4.0 to 4.5, so the E2HBH is not limited to mobility/flexibility impaired >40 crowd (like I used to say). I'm well beyond that point, and still improving the shot. Age seems no limit.
