What are the benefits of stiff-legged deadlifts, leg curls, good mornings, and lunges?

Firstly, stiff-legged deadlifts are a hip hinge movement, they train the hamstrings, erector spinae and glutes mainly.

To hold and maintain the bar close to your body, you will also activate your traps, lats and forearms to a lesser degree.

Having your legs almost straight will allow you to stretch your hamstrings even more and benefit from a nasty weighted stretch.

Why is this important? A recent study by Pedroso et al. (2021) found that in some situations, partial ROM training may actually be superior to full ROM training.

The researchers had 4 groups of untrained women perform leg extensions in different ways.

1. The end-range ROM group performed only the top 30° of movement near full knee extension.
2. The stretch ROM group performed only 35° of movement in the bottom.
3. The ‘full’ ROM group performed both of the above ROMs, reaching 100° of movement.
4. The varied ROM group alternated between the initial stretch ROM and the final end-range ROM workouts.

The group that performed the movement only in the stretched position gained more muscle that the group that trained in the shortened position.

“This would seem to indicate that mechanical stress alone was not responsible for the observed differences; rather, muscular development appears to be driven via an interaction between mechanical stress and muscle length”

As a result, from a bodybuilding point of view, stiff-legged deadlifts are really effective!

The hip hinge movement is also really important for sports such as sprinting for instance.

Secondly, leg curls are wonderful when done in addition to deadlifts.

The reason is simple, the hamstrings contribute to both hip extension and knee flexion.

If you want optimal growth in this region, you need to do your leg curls.

Furthermore, leg curls are often done with higher reps than deadlifts which allows you to hit other types of muscle fibres.

Thirdly, the good morning is a hip hinge movement too, but the position of the bar changes some aspects of the exercise.

Due to having the bar on your back, your traps, lats and forearms won’t have to work as much to stabilise the bar which means that the limiting factor during the movement has to be your lower body.

They also have a better stimulus-to-fatigue ratio due to the alteration in muscle activation.

This means that compared to stiff-legged deadlifts, your recovery between sets and workouts will be faster.

Finally, lunges are some kind of a hybrid movement, they put a lot of tension on both knee extension and hip extension.

Your quadriceps, glutes and hamstrings are all going to get worked during the movement.

However, you can emphasize either knee extension or hip extension!

By keeping your torso more upright, you will reduce the movement at the hips and consequently, increase it at the knee joint which means that your quads will work more.

And by having your knees going far beyond your toes, the degree will depend on your mobility, more movement is going to occur at the hips leading to more glutes and hamstrings growth.