Muscle balance and lateral imbalance

Understand the depth of muscular balance and lateral imbalance, essential for optimal performance and injury prevention. This article examines why one side might be stronger and how unilateral exercises can correct these discrepancies.

Muscle balance and lateral imbalance is a condition where the strength, size, or function of muscles is not equal between the two sides of the body (left vs. right) or between antagonistic muscle groups (e.g., biceps vs. triceps). Often, the dominant side is stronger and more developed, which, if excessively pronounced, can lead to a number of problems.

Why is the dominant side stronger?

💬 Simply put: Muscle imbalance is when the muscles on one side of your body are stronger or larger than those on the other, which can lead to problems if the difference is significant.

Most people have a dominant side (right or left) that we use for most daily activities like writing, throwing, or carrying objects. This constant use leads to greater stimulation and adaptation of the muscles on that side. The brain sends stronger and more frequent nerve impulses to the dominant muscles, contributing to their better development of strength and coordination. Additionally, some sports and professions can also amplify this imbalance, for example, tennis players who primarily use one arm, or workers performing repetitive movements with one limb.

Consequences of significant lateral imbalance

While a slight imbalance is normal, a large difference in strength or size between the two sides of the body can have negative consequences. According to research by Brad Schoenfeld, an asymmetry of over 10-15% between the limbs can increase the risk of injuries, especially in sports requiring explosive or repetitive movements. This includes pain in the back, knees, or shoulders. Furthermore, imbalance can limit athletic performance, as the weaker side becomes a limiting factor for overall strength and power. For example, if one side is weaker during a squat, it may collapse first, compromising technique and limiting the weight you can lift.

💬 From practice: I often observe my clients slightly tilting the barbell towards their stronger side when performing exercises like the barbell bench press or overhead press. This is a clear indicator of muscle imbalance. Correction requires not just increasing the strength of the weaker side, but also retraining the neuromuscular connection for proper activation.

The role of unilateral exercises

Unilateral exercises are a key element in a program to correct muscle imbalance. They involve performing movements with one limb at a time, thereby isolating and loading each side individually. Examples of such exercises include lunges, Bulgarian split squats, single-arm rows, single-arm overhead presses, and others. Through them, we can specifically address the weaker side, allowing it to catch up without the dominance of the stronger side.

✅ Pros

Correct muscle imbalances
Improve coordination and stabilization
Reduce the risk of injuries
Increase overall strength and endurance
Activate more stabilizing muscles

⚠️ Cons/Risks

Require more time to perform
Can be more difficult to balance initially
Lower overall lifting weight compared to bilateral exercises
Require greater concentration on technique

Integrating unilateral exercises into your training

For effective correction, it is important to include 1-2 unilateral exercises for each muscle group that exhibits imbalance. Start with the weaker side to ensure you get maximum stimulation when you are fresh. If you notice that the weaker side is significantly weaker, you can do 1-2 more reps or one more set for it. The goal is not to exhaust the stronger side, but to 'catch up' the weaker side. Progressive overload should be individualized for each side. According to research by Israetel, hypertrophy programs should include 10-20 working sets per muscle group per week, with some of these sets being unilateral.

Examples of effective unilateral exercises

Muscle group	Unilateral exercises	Benefits
Legs/Glutes	Bulgarian split squat, Lunges (various variations), Single-leg Romanian deficit	Improve balance, correct asymmetries in legs and glutes
Back	Single-arm dumbbell row, Single-arm cable row	Develop back strength without compensation from the stronger side
Chest	Single-arm dumbbell press, Single-arm cable crossover	Increase shoulder stability, stimulate individual chest muscle strength
Shoulders	Single-arm dumbbell shoulder press, Single-arm lateral raise	Correct imbalances in shoulder girdle strength, improve stability

When to consult a specialist?

If lateral muscle imbalance is causing chronic pain, significantly limiting movement, or not improving with training, it is advisable to seek consultation with a physical therapist or sports doctor. They can perform a movement assessment, identify the underlying causes of the imbalance (which may be related to nerve issues or structural abnormalities), and provide an individualized rehabilitation and training plan.

🎯 Key takeaway: Actively addressing muscle balance through unilateral exercises is not just for aesthetics, but for long-term health, functionality, and optimal athletic performance. Don't neglect your weaker side – it's the key to unlocking your full potential.

See more in the fitness guides of Sport Zona Academy.

📚 Scientific sources

🔬 Expert note from Sport Zona

From my observation over the years, most athletes who come to me with pain or injury have a visible lateral muscle imbalance that has been neglected. Often, this manifests as one side being less developed or poor movement patterns when the body is under stress. Correcting these imbalances is often key to long-term health and performance, especially in asymmetrical sports.

See more in the fitness guides of Sport Zona Academy.