Conventional Deadlifts vs. Stiff-legged Deadlifts

So I’ve been getting a lot of positive feedback on reviewing research studies which compare exercises to head to head. That being said, here’s one that compares conventional deadlifts to stiff-legged deadlifts (SLDL). Also, keep in mind that this is a head-to-head comparison and one exercise may be better suited then the other depending on how it‘s programmed into a training plan.

Researchers took 14 men and attached electrodes to their biceps femoris (one of the hamstring muscles), vastus lateralis (one of the muscles in the quad), medial gastrocnemius (one of the calf muscles) and lumbar multifidus (lower back) to measure muscle activation during each exercise. The men then performed conventional deadlifts and SLDL using 70% of their one-rep max for each exercise.

The results showed no significant difference in muscle activation in the biceps femoris during either exercise. Nor was there any difference in the lumbar multifidus or medial gastrocnemius. There was, however, a significant difference in the vastus lateralis with the conventional deadlift causing greater activation.

Therefore, if you’re looking to build your hamstrings then you can’t go wrong with either exercise.

With the above in mind, the LBC crew doesn’t program stiff-legged deadlifts into workouts. Instead, we program Romanian deadlifts (RDL), which we feel are a superior movement to SLDL. One of the primary differences between the RDL and SLDL is that the RDL only works the spinal erector muscles statically whereas the SLDL does so dynamically (given the flexion and extension that occurs during the movement’s execution). This creates additional low back stress on the ligaments and disks which is one of the reasons we use RDLs instead.