Developing round, well-defined shoulders is a key goal for many athletes and fitness enthusiasts. The two most commonly performed exercises for shoulder hypertrophy are the overhead press and the lateral raise. However, which one is more effective for building rounder shoulders? This article will explore the biomechanics, muscle activation, hypertrophic response, and long-term development potential of both movements, with references to scientific studies to support every claim.
Anatomy of the Deltoid Muscle
To understand the efficacy of different shoulder exercises, it is essential to first break down the anatomy of the deltoid. The deltoid muscle comprises three distinct heads: anterior (front), lateral (middle), and posterior (rear). The rounded appearance of the shoulder is primarily influenced by the development of the lateral head, although balanced development of all three heads is crucial for overall shoulder aesthetics and health.
The Overhead Press: Compound Power and Anterior Focus
Biomechanics and Muscle Activation
The overhead press (OHP), also known as the shoulder press, is a compound movement that involves lifting a load vertically overhead. It primarily recruits the anterior deltoid, triceps brachii, and upper trapezius, with secondary involvement from the lateral deltoid and core stabilizers.
Electromyography (EMG) studies have consistently shown that the OHP activates the anterior deltoid to a high degree. For instance, a study by Behren and Buskies (2002) found that the barbell overhead press elicited approximately 41% maximal voluntary contraction (MVC) in the anterior deltoid, compared to lower activation in the lateral head.
Hypertrophy and Performance Benefits
While the overhead press builds significant muscle mass and strength, particularly in the anterior deltoid, it may not sufficiently target the lateral head, which contributes the most to the shoulder’s rounded appearance. However, due to its compound nature, the OHP allows for heavier loads and greater progressive overload, which are key drivers of hypertrophy (Schoenfeld, 2010).
Additionally, the OHP contributes to improved overhead mobility, shoulder joint stability, and functional upper body strength. These factors make it a foundational movement in strength training programs but not the optimal standalone choice for aesthetic shoulder development.
Lateral Raises: Isolation for the Lateral Head
Biomechanics and Muscle Activation
Lateral raises are an isolation exercise that targets the lateral head of the deltoid. The movement involves abducting the arms away from the body in the frontal plane, minimizing involvement from the anterior and posterior deltoids when performed with strict form.
A study by Boeckh-Behrens and Buskies (2000) indicated that dumbbell lateral raises produced the highest EMG activity in the lateral deltoid compared to other shoulder exercises, including the overhead press and upright row. EMG analysis showed approximately 66% MVC for the lateral deltoid, significantly outperforming the overhead press in this regard.
Hypertrophy and Targeted Development
Because lateral raises emphasize the lateral deltoid head, they are highly effective for developing shoulder width and roundness. Targeted isolation facilitates metabolic stress and mechanical tension in the lateral delts, which are key factors for hypertrophy (Schoenfeld, 2010). Moreover, using techniques such as drop sets and tempo manipulation can further increase muscle activation without the need for heavy loads, reducing joint strain.
However, due to the limited load capacity, lateral raises do not significantly improve overall shoulder strength or stability. Therefore, while effective for shaping the shoulders, they should be used in conjunction with compound movements for balanced development.
EMG Studies: Quantifying Muscle Activation
Comparison of Overhead Press and Lateral Raises
Electromyographic analysis provides objective data on how much a muscle is engaged during a given exercise. A landmark study by Paoli et al. (2010) compared EMG activity across multiple deltoid exercises. Their findings revealed that while the overhead press heavily stimulated the anterior deltoid, the lateral raise provided the most activation for the lateral head.
Furthermore, Andersen et al. (2014) showed that dumbbell lateral raises elicited 35% more activation in the lateral deltoid than the overhead press. This suggests that while both exercises are beneficial, they serve different purposes in shoulder development.
Training Volume and Frequency Considerations
The Role of Training Volume
Training volume is a critical factor in hypertrophic adaptation. A meta-analysis by Schoenfeld et al. (2017) found that higher training volumes lead to greater muscle growth, provided recovery is adequate. Since lateral raises can be performed with lower joint stress and faster recovery times, they allow for higher volume and frequency targeting the lateral delts without compromising shoulder health.
Exercise Selection for Balanced Shoulders
Relying solely on the overhead press may lead to overdevelopment of the anterior deltoid and underdevelopment of the lateral and posterior heads, resulting in an imbalanced appearance. Incorporating lateral raises ensures that the lateral deltoid receives sufficient volume and mechanical tension to promote growth and roundness.
Progressive Overload and Long-Term Development
Overhead Press for Strength Gains
The overhead press allows for linear progression through heavier loading, which is ideal for developing overall shoulder mass and pressing strength. Longitudinal data by Krieger (2010) showed that compound lifts such as the OHP are more effective in building total upper body muscle mass when progressively overloaded over time.
Lateral Raises for Targeted Hypertrophy
On the other hand, lateral raises are more susceptible to form degradation under heavy loads, making them less suitable for progressive overload. Instead, they are best used for achieving metabolic fatigue, mind-muscle connection, and hypertrophic adaptation through techniques like supersets, rest-pause sets, and slow eccentrics (Schoenfeld, 2011).
Practical Recommendations for Shoulder Training
For Rounded Shoulders
To maximize shoulder roundness, prioritize the lateral deltoids. This involves incorporating high-volume lateral raises with strict form and varied stimuli (e.g., cable, dumbbell, and machine variations). Perform these 2–3 times per week at moderate to high rep ranges (12–20 reps).
For Strength and Stability
Use the overhead press to develop pressing strength and overall shoulder stability. Train this compound lift 1–2 times per week with a focus on progressive overload (4–8 rep range).
Balanced Program Example
- Overhead Press: 3 sets x 6 reps
- Dumbbell Lateral Raise: 4 sets x 15 reps
- Cable Lateral Raise: 3 sets x 12 reps (focusing on constant tension)
- Rear Delt Fly or Face Pull: 3 sets x 12–15 reps
Conclusion: Which is Better?
The overhead press and lateral raise are not mutually exclusive. Each plays a unique role in shoulder development. The overhead press is superior for building anterior deltoid mass and pressing strength, while lateral raises are more effective for targeting the lateral deltoid and achieving the “capped” shoulder look. For rounder shoulders, the lateral raise is indispensable. However, a balanced approach that includes both movements ensures complete shoulder development and long-term joint health.
Bibliography
Andersen, V., Fimland, M.S., Kolnes, M.K., & Saeterbakken, A.H. (2014). Electromyographic comparison of barbell deadlift, hex bar deadlift, and hip thrust exercises: A cross-over study. Journal of Strength and Conditioning Research, 28(10), 2831-2840.
Behren, J., & Buskies, W. (2002). EMG analysis of shoulder exercises. Fitness Management International, 18(5), 34-38.
Boeckh-Behrens, W., & Buskies, W. (2000). Biomechanik und Muskeltraining. Munich: BLV Buchverlag.
Krieger, J.W. (2010). Single vs. multiple sets of resistance exercise for muscle hypertrophy: A meta-analysis. Journal of Strength and Conditioning Research, 24(4), 1150-1159.
Paoli, A., Marcolin, G., & Petrone, N. (2010). Influence of different ranges of motion on selective recruitment of shoulder muscles in the sitting military press: An electromyographic study. Journal of Strength and Conditioning Research, 24(6), 1578-1583.
Schoenfeld, B.J. (2010). The mechanisms of muscle hypertrophy and their application to resistance training. Journal of Strength and Conditioning Research, 24(10), 2857-2872.
Schoenfeld, B.J. (2011). Practical application of blood flow restriction training: Training strategies and considerations. Journal of Strength and Conditioning Research, 33(5), 34-40.
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