I have been bouldering outdoors for 3+ years, many times alone and often with friends. This incident occurred on Portland where I've spent many weekends climbing, this precise wall was actually new to me but I focused on some of the moves closer to the ground and only attempted topping out on boulders where the moves were well within my grasp. I was using one large bouldering pad but a few steps in the rock on the ground meant it was difficult to sufficiently protect a large fall which formed part of my reason for only trying routes well within my capabilities. Whilst topping out the boulder I grabbed to holds on top of the crag (I couldn't see these), as I went to rock over both of the holds came off in my hands and I fell towards the floor from approx 4m. I landed mostly on my crash pad but my right heel came off the back and the force of it crashing into limestone slab below fracturing my heel (calcaneus) and a couple of the joints in the area.