Hip Holds Are Finger Friendly
The very first climbing holds were rocks glued to cement walls using auto body resin. Training on the holds was tough, the chunks of rock tend to be clunky and sharp, and the glue holding the rocks blew at about every third use of the hold.
The first commercial walls were built in France in the 1970s and gradually climbers gravitated toward making cast holds out of ceramic and fired clay. Early on though, the hip thing was to make either single-digit pockets or ridges the diameter of a bread knife.
Completing a route made up of these early holds could be pretty miserable.
In the 1980s, the climbing hold company Entreprise starting marketing prefabricated panels that could be fit together to create walls. Huge outdoor Entreprise walls, with their natural-looking features and cool insets, have played host to international climbing comps for three decades. But their walls limit options for adding holds, and climbers favored walls allowing for complete route changes using a growing variety of cast holds.
On home walls, climbers extended training sessions by creating smooth, tendon-friendly wooden insets using jig saws, routers, and sand paper.
Today, companies like Voodoo, Climb It, Stone Age, and Nicros offer holds of all sizes shapes and colors, with perfect texture for maximum grip and minimum skin damage. For examples check out http://www.stoneageclimbing.com/