A finger lock is a crack-climbing technique where you slot your fingers into a thin crack and twist or torque them so they lock against the walls. Used in cracks too narrow for a hand jam, finger locks can feel surprisingly secure once trusted, but are strenuous on the fingers and take practice to use well.
A hand jam is the fundamental crack-climbing technique where you insert your hand into a hand-width crack and expand it — cupping the palm and flexing the thumb — so it locks against the crack walls. A solid hand jam is secure enough to hang and even rest on, and is the building block of crack climbing.
A lieback, or layback, is a technique for climbing edges and cracks where you pull sideways on the hold with your hands while pushing your feet against the rock in opposition, leaning your body to one side. It is a powerful way to climb flakes, arete edges, and corner cracks, but can be strenuous and awkward to protect.
A drop knee, also called an Egyptian, is a technique where you turn one knee inward and downward while your foot is on a hold, twisting your hips toward the wall to bring your reach closer and take weight off your arms. It is especially useful on steep, overhanging terrain with opposing footholds.
A toe hook is a technique where you pull with the top of your toes and foot against a hold or feature, using the foot like a hand to maintain tension on steep and overhanging climbing. It's often paired with a heel hook on the other foot to stop the body swinging out on roofs.
An undercling is a hold gripped from underneath, palm up, that you pull up and out on while pushing with your feet to create opposing tension. Underclings feel powerful once you get your body above them and are common under flakes, roofs, and bulges where the rock faces downward.
A pinch is a climbing hold you grip by squeezing between your thumb on one side and your fingers on the other, like pinching a block. Pinches demand thumb and grip strength and range from wide, hard-to-span shapes to narrow ones. Body position that keeps the pinch loaded straight down makes it more secure.
A sidepull is a vertically oriented hold that you pull on sideways, toward your body, leaning away from it to create the opposing force that keeps you on. Sidepulls reward good body positioning — getting your weight on the opposite side of the hold — and are the natural counterpart to the outward-pushing gaston.
An edge is a climbing hold with a defined, flat lip that you grip with your fingertips or stand on with the edge of your shoe. Edges range from generous to razor-thin — where they become crimps — and they are the most common hold type on technical face climbs, rewarding precise edging footwork.
A volume is a large, hollow geometric shape bolted onto an indoor climbing wall, over which smaller holds can be mounted. Volumes change the wall's angle and shape, adding three-dimensional, often slopey climbing that demands body tension and creative footwork. They are a defining feature of modern competition and gym bouldering.