Target muscle: Erector Spinae (or hamstrings. See ‘Comments and tips’ section)
Synergists: Hamstrings, Gluteus Maximus, Adductor Magnus
Holding a pair of dumbbells, stand with your feet shoulder-width or narrower apart.
Position the dumbbells in front of your hips, holding them side by side, with an overhand (pronated) grip.
Keeping your arms and knees straight (though not locked), inhale as you flex your hips and waist to lower the dumbbells until you feel a mild stretch in your hamstrings.
Exhale as you extend your hips and waist to return the dumbbells to the starting position.
Repeat for the prescribed number of repetitions.
Comments and tips
The dumbbell straight-leg deadlift is a compound hip-hinge exercise that targets the erector spinae if there is waist flexion/extension. Without waist flexion/extension (i.e. if the back is kept neutral), the hamstrings will be the target and the exercise will become an isolation exercise. However, the erector spinae will still be significantly activated, albeit isometrically, especially if the dumbbells are heavy.
Keeping your knees straight emphasizes the hamstrings over the glutes. The reason is that, when the knees are kept straight, the hamstrings get stretched. The more stretched the hamstrings are, the more they can contribute to the deadlift movement. In contrast, the dumbbell deadlift limits the contribution of the hamstrings because the knees are allowed to bend.
Do not lock your knees out.
For the safety of your back, begin with a light weight. Gradually add weight to allow for adequate lower-back adaptation.
Do not pause or bounce at the bottom of the movement.
Be aware that straight-leg deadlifts are different from stiff-leg deadlifts. In straight-leg deadlifts, the knees are kept straight (though not locked), whereas in stiff-leg deadlifts, the knees are either kept a little flexed or are allowed to flex a little during the descent.