A stiff leg deadlift is a movement whereby we do a deadlift, but with straighter knees, and this is to stimulate the hamstrings, which are muscles of the back of the leg.
It is ideal to start with a light weight and build up, this is because we are also targeting the area of the lower back, where people often strain themselves too much and cause injuries, such as sciatica.
When starting the exercise, it is important to squeeze the hamstrings to engage them, which means the force is more likely to be produced by these same muscles, instead of the lower or mid back.
In the picture above, you will see a group of muscles in pink, with a name next to them. The muscles that are labelled are the muscles directly associated with the stiff leg deadlift.
If you look closely, the area which most people associate with the inner thigh, is labelled as the adductor magnus, and the adductor magnus is a muscle responsible for helping extend the hips (thrust forward).
When this muscle develops, the inner thigh appears more toned and there is a smaller gap.
Why Do I Love Stiff Leg Deadlifts So Much?
The main reason is because they target more muscle because they are a compound exercise, this means that more muscles are targeting in one single movement, as opposed to an isolation exercise such as using the adductor/abductor machine, which only targets single muscles.