the balancing muscles are the limiting factor.
Stabilizer Muscle Training
A One Leg Deadlift primarily works the Stabilizer Muscles, as it does with One Leg Step Up; which has been addressed in previous post.
If increasing Stabilize Muscle is the objective, Stabilizer Movement are very effective.
However, Stabilizer Movement are not effective in Overloading the...
Primary Muscles
The Primary Muscle are more effective Overloaded when the Stabilizer Muscle are taken out of the equation.
Machines like the Leg Press, Smith Machine, etc. are more effective with increasing mass and strength in the Primary Muscles; since they take the Stabilizer Muscle out of the equation.
Barbell Exercise such as the Squat, Pressing, Deadlifts fall somewhere in between.
Thus, it come down to the Training Objective.
One Leg Deadlift Stabilization Training
One method that allows allows increasing the workload in Primary Muscle in a One Leg Deadlift is to perform them holding on to a Kettlebell or Dumbbell with one hand. With the other hand, hold on to something like a Power Rack, Chair, etc.
This method shifts more of the workload to the Primary Muscle in a One Leg Deadlift. This method is the same as with Step Up, noted in previous posts.
Training The Stabilizer and Primary Muscles
One approach would be to include both One Leg In-Stability Deadlift Training as well as One Leg Stability Deadlift Training into a Training Program. There are various way that could be used.
If a rep starts to go south, I just put the other foot down,
One Leg Barbell Deadlift Assisted Overload
Actually, this is a very effective method of performing an Assisted Overload.
It essentially the same as let's say performing a Bench Press with a Spotter. When you being to fail with the Concentric Part of the Bench Press, the Spotter provide some Assistance when you hit the the Sticking Point.
The Assisted Bench Press Training with a Spotter allow a lifter increase the Overloading in the movement.
The same is true by putting your other foot down to assist in the One Leg Deadlift that performing the work.
The beauty of it is it's simplicity.
Once the Stabilizer Muscle are fatigued (have been Overload) performing the One Leg Deadlift, placing the other foot down continuing the exercise, take the take the fatigued Stabilize Muscles out of the equation. The load is shifted to the Primary Muscle in the Movement.
Increasing The Stability Training
Attaching Band to an Ascending Strength Curve Movement (Squat, Press, Deadlift, One Leg Deadlift, One Leg Step Up, etc.) allows muscles to be Overloaded through a greater range of the movement.
One of the additional benefits of Attaching Bands is that it provide some additional Overloading on the Stabilizer Muscles.