One-Sided Training

Unilateral training is your one-way ticket to the next level.


Independence­ – of thought, of movement, and of choice – often proves to be a deciding factor in whether you’re on the road to building the physique of your dreams or not. In the gym, one form of independence can come via unilateral training, which is the practice of training one side of your body independently from the other.

When we train, we often fail to consider that virtually any muscle group in the body can be isolated. We squat, we bench and we deadlift with both hands on the bar and both feet on the floor, but it’s possible — necessary, even — to effectively work one side without involving the other.

If you can perform a movement with two hands gripping a barbell, chances are you can do the same movement with one arm or leg. This ability to isolate is a critical element to muscle growth and strength.


Unilateral training can lead to greater muscle growth. Research shows that when you work one arm, it is significantly stronger than it is during bilateral exercises. Scientists theorize that you are stronger unilaterally, because you use more fast-twitch muscle fibers in each muscle of the limb being trained than you do when using both limbs together. Being able to lift more weight with one side means that you place more overload on that muscle, which can result in greater gains in strength and growth over the long run. Plus, greater muscle activity means using more fibers within your muscles. More of those fibers are going to grow bigger, which will add up to greater mass gains.

>> A study from Iowa State (Ames) compared strength during unilateral and bilateral exercises. They had males do a biceps curl exercise with 1) the left arm only, 2) the right arm only, and 3) both arms at the same time. They measured the amount of force (strength) produced during each trial and measured the amount of muscle fiber activity with electromyography. To determine the strength deficit with bilateral training, they added the force measures from the left-arm-only and right-arm-only trials and compared the sums to the amount of force applied during the bilateral trials. Not only did the unilateral training allow more force to be applied by each arm (about 20% stronger; i.e., each arm was 10% stronger during unilateral training), but the activity of the muscle fibers in each arm was greater when trained unilaterally.

Unilateral training will make you stronger. Training one side of your body at a time significantly strengthens your core. And building a stronger core makes you stronger on almost every exercise.

>> Scientists from the Memorial University of Newfoundland (St. John’s) wanted to confirm which exercises were best for strengthening the core muscles. They tested the activity of three major core muscle groups — upper-lumbar muscles, erector spinae muscles and lower-abdominal muscles (including the deep transverse abdominis and internal obliques) — during several core exercises (bridge, pelvic tilt, alternate arm and leg extension, parallel hold, side bridge and superman on an exercise ball and on a stable platform, as well as during unilateral and bilateral dumbbell chest presses and shoulder presses. The unilateral shoulder press significantly activated the upper-lumbar and erector spinae core muscles, and the unilateral chest press significantly activated all three core muscle groups, compared to the bilateral versions of those exercises.


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