My intuition would say something similar to
@vosadrian , that you could take pedaling distance away from the feet and kind of increase oedaling frequency with that.
Another thing that could happen on a confentional bike when you go out of the saddle is longitudinal movement. In the power position of the kranks push your own body weight forward to increase force and acceleration, in the weak position pull your bike forward to overcome that position more quickly and get into the next power position. I noticed I made heavy use of lateral movement ot slow speeds in my single speed folding bike. So this technique might be most advantageous on a sprint to start it in a high gear and sit back down, ince you got your cadence up. (And to get up a climb, when your gears are too hard.)
That's why I use oval chainrings now.
On any recumbent I use a riding style for sprints and when I am fatigued, where I lift my butt, spanning an bridge from the shoulder part of the seat to the pedals. Whith this I can also very effectively push a very high gear while raising and lowering the bridge. Maybe the changing body position also changes my angle of attack on the pedals and helps me shrink the weak spot?
Also cranking produces lateral forces and moments that you have to stabilize against. In a saddle you have some lateral support, but it's mainly from the inside if your thigh, that is then rubbing, because you are pedaling ar the same time. So you are supposed to keep your body stiff and derive lateral stability from your hand-handlebar-connection. But that stability travels through a big triangle from your hands around your butt to your feet. When standing up, you "flatten" that triangle, get your butt closer to the line between handlebars and cranks. On a recumbent your handle bar is already closer to your hip, but on most other designs it is not a strong source of stability. On Cruzbikes with their "patented front triangle drive train thingamajig" it actually is and it can give you a great amount of stability on the bike. (Especially if you lost a lot of seat support by lifting up your butt - which is than again closer to the handle bars, flattening the support triangle even more.)
The side to side motion when riding ot of the saddle might rather be to get you in a spot from where you can push the pedal with as little lateral consequences as possible ("straight down" from you center of mass) So steadying the front triangle against sideways motion might very well as much be steadying yourself against pushback from the pedals.
Also there is body angle on a climb. conventional bike riders say, they dont like the feeling if being leaned back on a steep climb and actually lose power because thebforces and dynamics aren't the same anymore (Not the situation the bike geometry is set up for or just not used to that situation?) On a recumbent there is also the hight of feet and heart and head, where on a steep climb your circulation system might have some challenge to distribute the blood ideally. Training in that position surely helps, but also lifting your upper body to sit more upright. This also sharpens the angle between body and legs, which many say increases their pedaling force->torgue->power. For this maneuver a stable handlebar is also highly advantageous, especially when it's also rotationally stable with the cranks.
