Core
29 pieces
- Exercise28 October 2026Side hyperextensionA side bend done on the back extension bench. You lie on your side with your hip on the pad and your feet locked in, lower your upper body toward the floor, then lift it back in line with your legs. It trains your obliques and the quadratus lumborum, a deep muscle on each side of the lower back, which is why it also goes by the QL raise.
- Exercise28 October 2026GHD sit-upA sit-up on the glute ham developer. Your hips sit on the pad and your feet are locked in, so you can lean back past where the floor would stop you. It works your abs and your hip flexors together[1], and that long range makes it the hardest sit-up Reckoner knows, so build into it slowly.
- Exercise26 October 2026Plank with alternating leg liftsA plank with one foot off the floor at a time. Taking a foot away narrows the base you balance on, so your trunk has to stop your hips turning as well as sagging, and the glute on the lifted side works to hold the leg up[1]. It is the next step for somebody whose plank is already solid, not a first hold.
- Exercise19 October 2026Hanging leg raiseThe hanging knee raise with the legs straight. The longer lever makes it one of the hardest things you can ask of your abs: in one lab study it challenged the abdominal wall more than the other whole body exercises tested[1]. It earns its place once the knee raise is still and easy.
- Exercise19 October 2026CrunchThe plain floor crunch: lie down, curl your shoulders toward your hips, come back down. It is small, it needs no kit, and measured against a row of ab machines it was among the best for the abs[1]. What it asks for is a curl of the spine, not a pull on the head.
- Exercise14 October 2026Decline sit-upThe sit-up on a bench tipped head down, with your feet hooked under a pad. The slope makes each rep harder than one on the floor[3], and the hooked feet let the hip flexors pull harder too[2]. So it is a hard abdominal exercise that is also a hard hip flexor exercise, and a fine way to make a sit-up heavier without holding a weight.
- Exercise14 October 2026Decline crunchThe crunch on a decline bench: feet hooked, shoulders curling up toward your hips, lower back staying on the pad. It is the short version of the decline sit-up, and the shortness is the point. Keeping the movement in the spine and out of the hips is the first thing a synthesis of abdominal research names in choosing an exercise, and it names a slope as a way to make one harder[2].
- Exercise13 October 2026Machine torso rotationSeated with your hips held, you turn the upper body against a stack. The library lists the obliques as the prime mover and the abs as the helpers. That is close to everything that can responsibly be said about it: no study of this exact machine was found, so this page stays nearer to technique than most.
- Exercise5 October 2026Russian twistSit back with your torso leaned off vertical, feet on the floor, hands together at your chest, and turn your ribcage from one side to the other. Done well it is a small, slow rotation that works the obliques and the abs. Done badly it is an arm swing over a rounded back, which is what most people picture.
- Exercise2 September 2026Weighted V-upFlat on the floor, a weight held overhead, and then the arms and the legs come up to meet over your hips. It is the hardest of the loaded floor movements in this library to do cleanly, because you have to coordinate two halves of your body while nothing is anchored.
- Exercise2 September 2026Vest hanging knee raiseThe hanging knee raise with a weight vest on. It exists because abdominal work that stays at bodyweight forever eventually stops asking for anything, and a vest is the cleanest way to keep making the same movement harder without changing what it trains.
- Exercise2 September 2026Suitcase carryOne dumbbell, one hand, and a walk in a straight line. Everything about the load wants to bend you toward it, and the muscles down your other side spend the whole walk refusing. It is the most useful one-sided trunk exercise there is, and the one to be most deliberate about loading.
- Exercise2 September 2026Standing cable side bendOne handle, one hand, and a bend straight out to the side against the pull. It is the most direct way to load the muscles down the side of your trunk, and it is also the exercise most often bought for a reason it cannot deliver.
- Exercise2 September 2026Sit-upThe sit-up is the oldest abdominal exercise there is and the one with the most argued-about reputation. It trains the abs, it also asks a great deal of the hip flexors, and the case against it is more interesting than either side usually admits.
- Exercise2 September 2026Side plankOn one elbow, hips stacked and lifted, body in one line from the ear to the ankle. It is the plainest way to load the side of your trunk, and one of the few bodyweight holds that has been measured producing enough activity to count as strengthening work[1].
- Exercise2 September 2026Reverse crunchA crunch curls the top of the torso toward the hips. A reverse crunch curls the hips toward the torso. Same muscle, opposite end, and the difference on the floor is whether your backside actually leaves it or whether you only swing your knees.
- Exercise2 September 2026Pallof pressStand side on to a cable, hold the handle at your chest, and press it straight out in front of you. The cable spends the whole set trying to rotate you toward the stack, and refusing that rotation is the entire exercise. Nothing visible happens, which is why it is so often done wrong.
- Exercise2 September 2026Machine crunchThe ab machine is the least fashionable way to train the abs and one of the most useful, because it lets you load a crunch precisely and add to it week after week. What it demands is that the spine does the moving, which the seat and the pad will happily do for you if you set them wrong.
- Exercise2 September 2026Lying leg raiseFlat on the floor, legs straight, lift them and lower them. Most of the movement here belongs to the hip flexors, and the abdominal work is the part nobody watches: stopping the lower back arching off the floor as the legs go down.
- Exercise2 September 2026Hollow holdFlat on your back, arms overhead, legs straight and low, and the whole of your lower back pressed into the floor. It is the hardest of the bracing holds in this library for most people, and the position collapses the instant you stop paying attention to it.
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