Using the very basic principles of leverage PRONGS quickly get into areas where a spade or fork will never perform well.
Wide heel with grip edge to minimise slippage of shoes when penetrating soils and debris also acts as the second fulcrum. Once you have penetrated the soil with the tine "lever up" the heel then rests on the ground and becomes the second lever. Always be careful to never overexert yourself. Levers are wonderful devices and can create a false sense of strength. Just be careful. We want you to enjoy that garden for many years to come.
All Prongs have this "heel". It allows you to penetrate the soil or get into hard to get at places. Ideal when thinning out clumping plants. Also gives you that bit of "extra grunt" when trying to dig out one of those pesky rocks or old bricks. (Yup I have been through all of this myself). The heel has a generous foot area and is serrated to give you some grip. Please wear shoes or boots it makes big indentations on the soles of your feet and makes it difficult to walk for days. So, gentlemen, no "tough guy" stuff, please!