My ladder hasn't pulled loose but I was very hesitant about putting my big butt on it as it seemed like it would collapse. My solution was to get one of those ratcheting truck bed cargo bars from Wally World. I had to modify the bar since it was too long to fit under the bottom horizontal support tubes. This was a simple modification, disassembling the bar was removal of one machine bolt and nut and the two sections of the bar came apart. I then shortened each section a similar amount and reassembled. I use a short piece of 2x2 to span both horizontal tubes as close to the step as possible, place the fixed end of the cargo bar on the ground and ratchet the other end of the bar up until there a slight amount of upward pressure on the ladder and climb on. No sagging and, most importantly, no strain on ladder supporting points. Cheap, simple, adaptable for any ground level, and "solid as a rock."