À maintenir le corps je pense. Sinon on glisse vers l’avant.
I first tried it with only a handlebar and it was very comfortable on the butt however it required quite a bit of force pushing back on the handlebar to stay on the seat. Overall on a 2 mile road test it was not that comfortable to ride because of the strength required to stay in position.
Next I added a « Groin Support Bar » to hold me back on the saddle. I rode about a mile with no padding on the groin support and is worked quite well. I then added some padding on the groin support and adjusted some so it fits correctly. On an 8 mile road test on the 29" uni it preformed very well with no adverse effects and no need to « rest » my butt as needed on my normal unicycle saddle. (Actually my normal saddle on my 36er is quite comfortable but just have to take a minute or two break or peddle standing up for awhile ever few miles on longer rides.)