I am not a physician or bio-mechanics expert just a common joe who has ridden a bicycle for many decades for ungodly hours per day on occasion. Proper Cycling "Form" has always been a big thing with me. For proper form I submit:
A picture of Zakelj in a climbing position.
A picture of Eva Lechner and Maya Wloszczowska descending on the same nasty course.
In cycling handlebar width is critical. From Looking at the proportion of the handlebar to these elite X-Country mountain bike racers it looks like your "monster" example has far to wide a handlebar that is forcing her into a wide "push-up" form. Shortening the bar on the Monster by 5 to 10 cm would also help her positioning.
I've always been very picky on the width of handlebars for each type of bicycle (track, road, cross, x-country mountain, downhill mountain) as one of the main elements of proper form.
Bar width as well as bar reach are necessary adjustments that most people don't seem to make on motorcycles. All of my bicycles have specific reach/width bars that also very by riding type and I have boxes of old bars/stems along with untold cut-offs of handlebars from making those changes.
Maybe riders should start having their motorcycles fitted.
Riding a motorcycle and comparing it to mountain biking is apples and oranges. Motorcycling is an isometric activity: very little movement unless of course one is a racer. Otherwise most of us expend all our energy with our bodies pretty much locked into one position.
Those mountain bikes are set up to take advantage of the powerful foot/ankle, knee and hips muscles. It seems obvious the handlebar design has only one purpose and that is to provide maximum leverage so the rider has maximum input and control of the front end.
The poor sport rider suffers severely from leaning far to forward with her short body to reach the handle bars. The width of the bars, although important is 3rd behind the height and reach of the bar. Additionally this women has to reach so far forward that she has to hyperextend her lower back in order to keep her trunk off the tank (and I am not talking about her breasts as a guy could have the same issue). And the there is seat height which she would benefit from raising up to increase trunk clearance over the tank but then she may need to lower the suspension to get her feet on the ground. And on and on it goes. Peg placement height and forward/backward.
