The Single Worst Exercise
Dr. Joel Seedman, PhD
This is the full-length version of Dr. Seedman's article that was originally featured on T-Nation
The straight-leg or stiff-legged deadlift (SLD) is not only one of the most useless exercises in existence but it’s also one of the most dangerous and counterproductive movements you can perform.
The straight-leg deadlift represent a flawed and bastardized variation of a proper hip hinge movement such as a Romanian Deadlift (RDL). Besides placing enormous strain on the vertebral column due to faulty mechanics in the lumbo-pelvic-hip complex, the SLD can lead to tears and avulsions in the hamstrings.
Many individuals believe simply because they feel a large stretching sensation in the hamstrings they’re actually stimulating significant strength and hypertrophy gains in the targeted musculature. This couldn’t be further from the truth. In reality they’re placing limited tension on the actual muscle fibers of the hamstrings and posterior chain. Instead this exaggerated and unnatural stretch is creating excessive trauma and micro ruptures to the hamstring tendon-insertion, which is highly vulnerable to tears and avulsions.
In fact I’ve witnessed a strong correlation with straight-leg deadlifts and hamstrings tears amongst athletes and bodybuilders I’ve worked with over the years. When we eliminate this movement and teach them to hinge correctly by replacing the SLD with a properly performed RDL (with soft knees), not only do their hamstrings and gluteal muscles gain exponentially greater strength and size but tweaks and injuries to their posterior chain and low back become almost non-existent
It should also be noted that a straight-leg deadlift reinforces faulty hip hinge mechanics into the central nervous system. In fact the technique involved for an SLD represents a highly dysfunctional method for bending at the hips and waist while the RDL or any other proper hip hinge represents a highly functional method for producing the same movement.
Because movement transfers beyond the weight room and into our everyday life, grooving faulty hip hinge mechanics during training transfers to improper hip mechanics in real world scenarios. Instead of picking up heavy objects with correct biomechanics, individuals begin to incorporate the same flawed hip technique employed on the SLD. This increases the vulnerability of low back and sciatic issues not to mention tweaks and pulls to the posterior chain. In fact nearly every low back-related issue I’ve ever witnessed can be traced back to faulty hip hinge mechanics. Unfortunately straight-leg and stiff-leg deadlifts only contribute to this.
In essence, if you’re cool with hamstring tears, low back pain, sciatic issues, and faulty hip mechanics, then stick with the stiff leg deadlift. On the other hand if the goal to gain functional strength and size in the posterior chain while reinforcing proper hip mechanics into your CNS then you would do best to replace the SLD with an RDL or any other properly performed hip hinge movement.