Strength training is a powerful performance-enhancing activity. Strong runners are faster, more efficient, and injury resistant.

When designing a strength plan for running you need to consider many variables. Stability is one of those variables. Stable strength training exercises such as two-legged (bilateral) squats, deadlifts, and overhead presses are distinctly different from unstable versions such as single-leg (unilateral) versions of these exercises.

Each version conveys unique benefits and limitations. The best strategy to enhance your running includes both stable and unstable weight training exercises.

The Benefits of Stable and Unstable Lifting

Stable lifting has two advantages that improve your running. First, a stable exercise allows you to generate more force and lift more weight—and one of the main reasons to lift weights is to train the muscles to impart more force into the ground. Tendons also respond favorably to heavy loads, becoming stronger, more injury resistant, stiffer and thus more springlike. Strong muscles along with strong, stiff tendons increase your running economy. Better running economy allows you to conserve energy while running.

Second, a stable exercise allows you to move through a full range of motion (ROM.) Several studies show that full-ROM training is superior to partial-ROM for building strength. Further, strength is position-dependent, meaning you gain strength only through the range in which the limbs and muscles move, not beyond that range. You don’t need to lift through a full ROM every time you lift, but some of your training should definitely involve full ROM.

unilateral squat
photo: courtesy Kyle Norman

While unstable lifting doesn’t allow for as much weight or range of motion, it too has an advantage—it enhances motor control. Motor control is defined as “the process of initiating, directing, and grading purposeful voluntary movement.” Think of motor control as movement skill.

Running is a series of alternating single-leg hops that require both stability and power. Your nervous system must reflexively coordinate the stabilizer muscles (gluteus minimus, gluteus medius, adductors, and muscles in the lower legs and feet) with the prime movers (quads, hamstrings, gluteus maximus, gastrocnemius) to drive you forward without injury. If you can’t stabilize your joints and limbs while running then you’ll waste energy and increase your chance of injury.

The Spectrum of Stability

You can take many tiny steps to increase or decrease stability of a lift. Here’s a spectrum of sample exercises, from most to least stable:

  • Machine exercises such as the leg press, leg extension, and Smith machine
  • Bilateral (both feet on the ground) barbell exercises such as squats, deadlifts, rows, and presses.
  • Bilateral dumbbell versions of the above
  • Unilateral (one foot on the ground) barbell exercises
  • Unilateral dumbbell exercises
  • Asymmetrically loaded bilateral exercises using barbells, dumbbells, and/or bands and tubing
  • Asymmetrically loaded unilateral exercises

At the extreme is lifting on an unstable-surface training aka UST (lifting weights while standing on inflated rubber disks, balls, or foam mats). Research on UST is limited, what data there is indicates that it may be useful in the rehab setting but has limited use for healthy athletes. You can get all the instability you need from single-leg and asymmetrically loaded exercises.

Loads

The best way to get strong is to lift heavy: 3-6 reps for 2-5 sets is ideal. When lifting, you should work to a high level of exertion. The final reps of all sets should be just shy of failure. Use excellent form when lifting. Don’t sacrifice good technique for more reps or weight.

If you’ve never performed barbell lifts such as squats, deadlifts, presses, and Romanian deadlifts then you should consult with a personal trainer or strength coach.

You’ll use less weight on unstable exercises. Technique will be harder to maintain compared to stable exercises. Use the same rep range as described above for some workouts. You can use lighter weights and a higher rep range (8-15 reps for 2-3 sets) for other workouts. Using a higher rep range with more unstable lifts helps ingrain good motor control.

Exercises

Here are several examples of stable exercises and their less-stable counterparts. Many exercises can be made more or less stable in numerous ways, these are only examples.

Squats

Stable: Bilateral back squat

Unstable: Unilateral back squat

More Unstable: Unilateral dumbbell asymmetric squat

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Stable vs. unstable lifting: Which is best? The answer is both. Both come with different benefits. Stable lifting allows you to both lift more weight and move through a greater range of motion (ROM.) Unstable lifting demands precise neuromuscular coordination and strengthens stabilizer muscles. Use both strategies. Here are three #squat variations: 1. Bilateral back squat 2. Unilateral back squat 3. Unilateral asymmetrically loaded squat #unstableloadtraining #movementvariability #functionalfitness #functionalstrength #cyclistswholift #runnerswholift #strengthtrainingforrunners #strengthtrainingforcyclists #injuryprevention #getstrong #getstronger #strengthtraining

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Romanian Deadlift (RDL)

Stable: Bilateral barbell

Unstable: Unilateral barbell

More Unstable: Unilateral asymmetric

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Stable vs. unstable lifting. Both are good. Neither is better. They're different. Runners, cyclists, and other athletes should work along the stability spectrum when lifting weights. More stable exercises allow you to produce more force and work through a full range of motion. Unstable lifts develop motor control and strengthen stabilizer muscles. Here are three versions of the Romanian Deadlift: 1. Bilateral with a barbell 2. Unilateral with a barbell 3. Unilateral asymmetrically loaded with a dumbbell #doyouevenrunstrong #romaniandeadlift #functionalstrengthtraining #functionalstrength #singlelegrdl #unstableloadtraining #movementvariability #functionalfitnss #cyclistswholift #runnerswholift #strengthtrainingforrunners #strengthtrainingforcyclists #injuryprevention #singlelegdeadlift #singlelegtraining #rdl #rdls

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Overhead press

Stable: Bilateral dumbbell

Unstable: Unilateral dumbbell

More Unstable: Unilateral asymmetric

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Stable vs. unstable lifting: Which is best? Both types convey benefits. The best strategy is to train along a spectrum from highly stabilized lifts to highly unstable lifts. There are many ways to vary the level of stability in a lift. Here are three versions of the overhead press with dumbbells. 1. Bilateral 2-arm press 2. Unilateral 2-arm press 3. Unilateral 1-arm asymmetrically loaded press #unstableloadtraining #movementvariability #functionalfitness #functionalstrength #cyclistswholift #runnerswholift #strengthtrainingforrunners #strengthtrainingforcyclists #injuryprevention #getstrong #getstronger #strengthtraining #overheadpress #overheadpresses

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Sample workout

Here’s one way to structure a workout using both stable and unstable weight exercises:

Jump rope for several minutes.

Go through your favorite mobility routine to prepare for lifting.

Bilateral back squat: 5 reps x 3 sets

Unilateral dumbbell press: 5 reps x 3 sets

Unilateral asymmetric RDL: 10 reps x 2 sets

In sum: Stable exercises build the greatest amount of strength. Unstable exercises build both strength and motor control. Your weight training plan should include both heavy, stabilized exercises along with unstable exercises.