Unilateral training—exercises performed one side at a time—is a highly effective strategy for building bigger, stronger, and more symmetrical arms. Unlike bilateral movements, which engage both limbs simultaneously, unilateral exercises isolate each arm, forcing it to work independently.
This approach not only corrects muscular imbalances but also enhances motor control, joint stability, and total-arm hypertrophy.
[wpcode id=”229888″]Backed by scientific research and practical gym wisdom, this article outlines the three most effective unilateral exercises for arm growth, explaining why they work and how to incorporate them into your training. Whether you’re overcoming a strength imbalance or chasing aesthetic perfection, these three exercises deliver unmatched results.
Why Unilateral Arm Training Works
Muscle Imbalance Correction
Muscle asymmetries are common in bilateral training due to limb dominance. For instance, during barbell curls or bench presses, the stronger arm often compensates for the weaker side, leading to chronic imbalances. Unilateral training ensures each arm does its fair share, reducing discrepancies in size and strength. According to research published in the Journal of Strength and Conditioning Research (JSCR), unilateral resistance training significantly improves strength balance between limbs when compared to bilateral training (Baechle & Earle, 2008).
Greater Neural Activation
Unilateral exercises increase neural drive to the working limb. The phenomenon known as “cross-education” or interlimb transfer describes how training one limb can result in strength gains in the untrained opposite limb (Lee & Carroll, 2007). This neural adaptation is beneficial in rehabilitation settings but also supports strength development in healthy individuals. It’s a testament to how focused, one-arm training stimulates the central nervous system more intensely.
Enhanced Range of Motion and Joint Stability
When using unilateral movements, athletes can typically move through a fuller range of motion. This enhances muscle activation and leads to greater hypertrophy. Moreover, stabilizing the body with one limb working at a time requires greater recruitment of stabilizer muscles around the shoulder, elbow, and wrist joints, which builds durability and control (Behm et al., 2005).
The 3 Best Unilateral Arm Exercises
1. Single-Arm Dumbbell Preacher Curl
Why It’s Effective
The single-arm preacher curl isolates the biceps brachii, particularly the long head. With the arm braced on a pad, momentum is eliminated, forcing the biceps to carry the entire load. This controlled environment enhances the mind-muscle connection and promotes mechanical tension—both critical for hypertrophy.
Scientific Backing
Research has shown that the preacher curl elicits higher EMG activity in the biceps than standard curls due to the stretched position and strict form (Oliveira et al., 2009). Performing this unilaterally increases focus and reduces compensatory movement, which further boosts muscle recruitment.
How to Perform It
- Sit on a preacher curl bench with a dumbbell in one hand.
- Rest your upper arm flat against the pad, keeping your shoulder stationary.
- Slowly curl the weight, contracting the biceps at the top.
- Lower it under control to the start position.
- Perform 3–4 sets of 8–12 reps per arm.
Programming Tips
Use a moderate weight and controlled tempo (e.g., 2 seconds up, 3 seconds down). The stretch under load at the bottom position is particularly beneficial for stimulating muscle growth due to increased time under tension.
2. Unilateral Cable Triceps Pushdown
Why It’s Effective
Unlike bar pushdowns, the unilateral version ensures each triceps muscle—particularly the lateral and long heads—is trained independently. This removes the ability to compensate with the dominant side and allows for precise wrist positioning, optimizing tension on the triceps throughout the full range of motion.
Scientific Backing
A study in The Journal of Sports Science and Medicine found that cable-based triceps pushdowns generated high triceps activation, especially when performed with strict form and individualized angles (Saeterbakken et al., 2014). Unilateral variations further enhance this by allowing full elbow extension and better muscle recruitment.
How to Perform It
- Attach a single handle to a high cable pulley.
- Stand facing the machine and grip the handle with one hand.
- Keep your elbow tucked to your side and push the handle down until the arm is fully extended.
- Pause, then return to the start position slowly.
- Do 3–4 sets of 10–15 reps per arm.
Programming Tips
Maintain a neutral wrist position and emphasize the end-range contraction. Slow eccentrics and peak contractions will make the movement more effective, especially for hypertrophy goals.
3. Zottman Curl (Unilateral Variation)
Why It’s Effective
The Zottman curl is a hybrid movement that targets both the biceps and brachialis during the curl, and the brachioradialis and forearm extensors during the eccentric phase. The unilateral version enhances control, ensuring consistent form and balanced strength development between arms.
Scientific Backing
The brachialis plays a crucial role in arm thickness and elbow flexion strength. EMG studies show that neutral and reverse grips emphasize the brachialis more than supinated grips alone (Rutherford et al., 2010). Since Zottman curls blend supination and pronation in a single movement, they maximize overall arm engagement.
How to Perform It
- Hold a dumbbell in one hand with a supinated grip (palm up).
- Curl the weight up, squeezing the biceps.
- At the top, rotate your wrist to a pronated grip (palm down) and slowly lower the dumbbell.
- Rotate back to supinated at the bottom.
- Perform 3–4 sets of 10–12 reps per side.
Programming Tips
Use moderate weight and focus on a controlled eccentric phase. Avoid swinging the torso or using momentum. This exercise is especially good as a finisher in your arm day routine due to its metabolic and mechanical load.
Implementation Strategies for Maximum Growth
Frequency and Volume
For muscle hypertrophy, training arms twice per week with a mix of unilateral and bilateral exercises is optimal. Aim for 10–14 sets per week per muscle group (biceps and triceps), distributed over 2–3 sessions. These three unilateral exercises can replace or complement your existing arm work.
Progressive Overload
Regardless of the exercise, progression must occur—whether through increased resistance, more reps, slower tempo, or better range of motion. Log your lifts and aim for small weekly improvements.
Mind-Muscle Connection
Unilateral training allows for better focus on contraction quality. Research supports that consciously focusing on muscle contraction increases EMG activity and muscle growth over time (Snyder & Fry, 2012). Use this to your advantage with each rep.
Rest and Recovery
Muscle growth happens during recovery. Allow at least 48 hours between direct arm sessions and ensure proper nutrition and sleep to support recovery and adaptation.
Bibliography
Baechle, T.R. and Earle, R.W., 2008. Essentials of Strength Training and Conditioning. 3rd ed. Champaign, IL: Human Kinetics.
Behm, D.G., Leonard, A.M., Young, W.B., Bonsey, W.A.C. and MacKinnon, S.N., 2005. Trunk muscle electromyographic activity with unstable and unilateral exercises. Journal of Strength and Conditioning Research, 19(1), pp.193–201.
Lee, M. and Carroll, T.J., 2007. Cross education: possible mechanisms for the contralateral effects of unilateral resistance training. Sports Medicine, 37(1), pp.1–14.
Oliveira, L.F., Matta, T.T., Alves, D.S., Garcia, M.A. and Vieira, T.M.M., 2009. Electromyographic analysis of biceps brachii and brachioradialis muscles during curl exercise variations. Journal of Strength and Conditioning Research, 23(8), pp.2303–2310.
Rutherford, O.M., Jones, D.A. and Newham, D.J., 2010. Clinical and functional significance of muscle strength. In: M. Cardinale, R. Newton and K. Nosaka, eds. Strength and Conditioning: Biological Principles and Practical Applications. Chichester: Wiley-Blackwell, pp.55–71.
Saeterbakken, A.H., Andersen, V., van den Tillaar, R., & Fimland, M.S., 2014. Comparison of muscle activation and force output during bilateral and unilateral bench press. Journal of Sports Science and Medicine, 13(4), pp.746–751.
Snyder, B.J. and Fry, W.R., 2012. Effect of verbal instruction on muscle activity during the bench press exercise. Journal of Strength and Conditioning Research, 26(9), pp.2394–2400.
