Rotary torso (machine)

Core · Machine

The rotary torso machine trains the oblique muscles by rotating the trunk against a weight, with the hips fixed by the seat.

It is easy to learn, but easy to do wrong with too much weight and too much speed.

Sets, reps and RIR

Sets3

Reps10 to 20

RIR1 to 2

Stop the set when position breaks, not when the muscle burns. Quality of position is the whole point.

RIR means reps in reserve: how many you could still have done when you racked it. RIR 2 is two short of failure.

Adjust the seat so the pads sit at the height of the ribs. Put the pelvis firmly against the seat.
Hold the handles lightly and keep the arms relaxed.
Rotate the trunk slowly to one side, until you feel the obliques work, without pushing with the arms.
Pause, then return slowly. Do all reps on one side, then change.
Do 10 to 15 reps per side with a weight you can control.

Too much weight: A weight you cannot control makes you twist from the lower back. Drop the load and keep the hips still.
Pushing with the arms: The arms hold, the trunk turns. If the arms push, the abs get little.
Going too fast: Fast reps let the weight stack carry the movement. Take two seconds each way.

A cable woodchop trains rotation with a free stance and needs more balance. The machine is easier to load and to log.

A plank trains the core to resist rotation. The machine trains it to create rotation.

It suits you if you want a simple way to log rotation work with weights, for example as an end-of-session exercise.

Primary: Obliques.

Secondary: Abs.

Epley's formula, from a set you have actually done. It is an estimate, and it drifts above eight reps, so keep the input between one and twelve.

Weight lifted Reps

Enter a set to see the estimate.

athlate logs this exercise, keeps the numbers, and tells you what you lifted last time.