Single-leg Romanian deadlift with a dumbbell: how to learn balance and hip hinge, which side the dumbbell goes on, and what studies show for hamstrings.
The single-leg Romanian deadlift (single-leg RDL) is a hip hinge on one leg: you bend forward from the hips, the free leg extends backward, and you come back up. Glutes and the back of the thigh keep you balanced.
The honest answer to "How hard is it for glutes and hamstrings?": very. In a study with 12 active men with at least two years of strength training, activity of the upper gluteus maximus reached 105 to 169 % and that of the biceps femoris 70 to 122 % of the activity measured in a maximal voluntary contraction [1]. Anchor: both muscles were as busy in this exercise as in a maximal test, or more. There was no significant difference between dumbbell and flywheel.
A hint from the field adds to this: in a study with 77 high-school runners, adding 3 × 3 single-leg Romanian deadlifts to the warm-up lowered the risk of mild to moderate hamstring strains (risk ratio 0.34), with no effect on severe injuries [2]. The study was not randomised (level of evidence 3), so the results are a hint, not proof.
Stand on one leg, standing knee slightly bent, the other leg relaxed. Hold the balance for 20 seconds per side.
Milestone: 3 × 20 seconds per side without support.
Hold a wall with one hand. Bend from the hips forward, the free leg extends backward, the back stays straight. Gently touch the floor with the other hand and come back up.
Milestone: 3 × 6 per side with support, back neutral, hips stay square.
Let go of the wall. The free leg stays straight, the hips point to the floor, not to the side. Go only as deep as the back stays straight.
Milestone: 3 × 6 per side without the wall, without putting the foot down.
Take a dumbbell in one hand. In the study with 12 men, on the flywheel device activity in the gluteus medius, lower gluteus maximus and erector spinae (standing-leg side) rose when the load switched to the opposite side of the standing leg ("contralateral", as the study puts it). There was no significant difference between flywheel and dumbbell, and the authors recommend the opposite side for the dumbbell too [1]. Start light and progress in small steps.
Milestone: 3 × 8 per side with dumbbell, neutral back and stable hips.
Take 3 seconds down, 1 second pause, 2 seconds up (practice). That makes balance a task, not a coincidence.
Milestone: 3 × 8 with a 3-second lowering, without the hips opening up.
How to track progress: Progress when you manage 3 × 8 per side with a straight back line, a quiet standing leg and square hips. Compare both sides: the weaker side decides the load. Film yourself from behind and from the side. That is a rule of practice, not a study figure.
Where does it fit in training? The single-leg Romanian deadlift fits as an accessory exercise after squat or deadlift or, in a small dose, in the warm-up [2]. 2 to 3 sets of 6 to 10 reps per side is a practice value. Plan rests of 1 to 2 minutes, because balance slips with fatigue.
Warm-up: Do 1 to 2 sets of 6 reps without weight, with wall contact, and check balance and hip position. Then follow light sets with the dumbbell. If balance already wobbles during the warm-up, it is not a good day for heavy loads. This is practical advice, not a study statement.
The exercise is a balance test. At first do it at a wall or rack so you can hold on. Only increase the load when technique sits without weight. Stop with a pull in the back of the thigh or in the lower back. This guide explains and motivates, it does not replace supervised training or a coach.
Imagine balancing a spirit level on your pelvis. Whoever keeps the level horizontal does not open the hips. This is a coaching image, not a study finding. One more trick: grip the floor with the foot like a claw and keep three points in contact (big toe ball, little toe, heel).
Yes. In one study, biceps femoris activity reached 70 to 122 % of the maximal reference activity [1]. In another measurement with four hamstring exercises (including the Romanian deadlift), the semitendinosus was more active than the biceps femoris [3].
In a study with 77 runners, the risk of mild to moderate strains was lower with the exercise in the warm-up (risk ratio 0.34), with no effect on severe injuries [2]. That is a hint, not proof.
On the flywheel device, the study found more glute and erector activity when the load was on the opposite side of the standing leg; the authors recommend this for the dumbbell too [1].
3 × 6 to 10 per side is a practice value.
No. It is a complement for balance and side differences.
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