The bicep curl is one of the most popular exercises in resistance training, yet few lifters execute it optimally for maximal growth. Despite its apparent simplicity, the curl is often performed incorrectly, compromising effectiveness and increasing injury risk. To get the most out of your training, refining your technique is non-negotiable. Below are five science-backed principles to elevate your bicep curl performance and accelerate muscle hypertrophy.
Secret 1: Use a Full Range of Motion
Why Partial Reps Sabotage Gains
One of the most common mistakes in curling technique is limiting the range of motion. A full range of motion (ROM) involves extending the arm completely at the bottom of the curl and bringing the hand up until the biceps are fully contracted, ideally touching the shoulder with the dumbbell or bar. Incomplete reps reduce muscle fiber recruitment, particularly in the long head of the biceps, which is heavily activated during the fully lengthened and fully shortened phases.
A study by Pinto et al. (2012) compared the effects of partial versus full ROM on muscle hypertrophy in resistance-trained men. Subjects who used a full ROM exhibited significantly greater muscle growth in the elbow flexors over 10 weeks, suggesting that maximizing ROM enhances mechanical tension and metabolic stress—two primary drivers of hypertrophy.
Stretch-Mediated Hypertrophy
Stretching a muscle under load—a concept known as stretch-mediated hypertrophy—is also crucial. According to a study by Pedrosa et al. (2023), training at longer muscle lengths can stimulate greater hypertrophy than at shorter lengths. By fully extending the arm at the bottom of the curl, you place the biceps in a stretched position under tension, thereby enhancing the hypertrophic response.
Secret 2: Control the Eccentric and Concentric Phases
The Power of Slow Eccentrics
Muscle hypertrophy is not just about lifting weight; it’s about controlling it. The eccentric (lowering) phase of the lift causes more muscle damage and creates a greater hypertrophic stimulus than the concentric (lifting) phase. According to Schoenfeld et al. (2017), eccentric contractions result in higher levels of muscle protein synthesis and structural damage, both of which are essential for growth.
To optimize results, aim to curl the weight up over 1–2 seconds and lower it over 3–4 seconds. This increases time under tension, another critical factor in stimulating muscle growth.
Concentric Quality Matters Too
While the eccentric phase is dominant in terms of mechanical stress, the concentric portion shouldn’t be rushed or mindless. A study by Tanimoto and Ishii (2006) found that slow lifting speeds, even during the concentric phase, increased muscle activation and hypertrophy. Thus, rather than aggressively curling the weight, lift it with control and intent to maintain continuous muscle tension.
Secret 3: Eliminate Momentum to Isolate the Biceps
Why Cheating Reduces Efficiency
Using momentum, such as swinging the torso or using the legs to initiate the movement, drastically reduces the effectiveness of the exercise by shifting the load away from the biceps. This not only minimizes tension on the target muscle but also introduces the risk of injury to the lower back and shoulders.
Research by Oliveira et al. (2009) shows that when improper form is used, secondary muscles like the anterior deltoid and brachialis dominate, reducing the workload on the biceps brachii. This diminishes both the quality of the stimulus and the hypertrophic response.
Techniques to Minimize Momentum
To eliminate momentum, perform curls standing with your back against a wall or use a preacher bench. Additionally, reduce the load to a manageable weight that allows complete control throughout the rep. Using these methods forces the biceps to perform the majority of the work and increases muscle activation.
Secret 4: Focus on Tension, Not Just Load
Mind-Muscle Connection
Muscle growth is influenced more by the quality of tension than by the absolute weight used. This is where the mind-muscle connection becomes essential. A study by Calatayud et al. (2016) demonstrated that subjects who focused on contracting the biceps during curls achieved higher EMG activation than those who did not consciously engage the muscle.
Instead of thinking about moving the weight, think about squeezing the biceps throughout the entire movement. Visualizing the muscle contracting can enhance intramuscular coordination, improve form, and lead to better hypertrophic outcomes.
Appropriate Load Selection
Using a load that is too heavy often leads to poor form and decreased time under tension. According to research by Schoenfeld et al. (2016), hypertrophy can be achieved across a wide range of loading schemes (30–85% of 1RM), provided sets are taken close to failure. This suggests that moderate weights with excellent form are not inferior to heavy weights, and in many cases, may be superior for muscle growth.
Focus on using a weight that allows 8–15 reps with strict form. Stop sets 1–2 reps shy of failure for volume accumulation, but occasionally train to failure for maximal recruitment.
Secret 5: Program for Optimal Frequency and Volume
Training Frequency for Growth
Training frequency directly affects total volume and recovery. For the biceps, 2–3 sessions per week is ideal for most lifters. A meta-analysis by Schoenfeld et al. (2016) found that higher training frequencies lead to better hypertrophy when volume is equated, likely due to more frequent stimulation of muscle protein synthesis.
Split your weekly volume over multiple sessions to avoid fatigue-related form breakdown and to maintain high-quality reps.
Volume Targets and Progression
For hypertrophy, 10–20 total weekly sets for the biceps is a widely accepted range. However, more isn’t always better. Overtraining the biceps, especially in conjunction with back training, can lead to diminishing returns. Monitor recovery, soreness, and performance trends to determine if volume needs to be adjusted.
Progressive overload remains critical. Track reps, sets, and loads, aiming to gradually increase one or more variables over time. But always prioritize form and tension over simply adding weight to the bar.
Exercise Selection and Variation
While the standard barbell or dumbbell curl is effective, incorporating variety can enhance muscle development and prevent plateaus. Include:
- Incline dumbbell curls for stretched long head emphasis
- Concentration curls for peak contraction
- Hammer curls for brachialis and forearm recruitment
Changing the angle, grip, or tempo periodically challenges the muscle differently and promotes balanced growth.
References
Calatayud, J., Borreani, S., Colado, J. C., Martin, F., Rogers, M. E., & Andersen, L. L. (2016). Muscle activation during push-ups with different suspension training systems. Journal of Sports Science & Medicine, 15(3), 494–501.
Oliveira, L. F., Matta, T. T., Alves, D. S., Garcia, M. A., & Vieira, T. M. (2009). Effect of the hip position on electromyographic activity of trunk and thigh muscles during the abdominal crunch exercise. Journal of Strength and Conditioning Research, 23(9), 2443–2449.
Pedrosa, G. F., Clemente, F. M., Vilaça-Alves, J., & Barbosa, T. M. (2023). Effects of training at long vs. short muscle lengths on muscle hypertrophy: A systematic review and meta-analysis. Sports Medicine, 53(2), 297–316.
Pinto, R. S., Gomes, N., Radaelli, R., Botton, C. E., Brown, L. E., & Bottaro, M. (2012). Effect of range of motion on muscle strength and thickness. Journal of Strength and Conditioning Research, 26(8), 2140–2145.
Schoenfeld, B. J., Grgic, J., Ogborn, D., & Krieger, J. W. (2016). Strength and hypertrophy adaptations between low- vs. high-load resistance training: A meta-analysis. Journal of Strength and Conditioning Research, 31(12), 3508–3523.
Schoenfeld, B. J., Ogborn, D., & Krieger, J. W. (2017). Effects of resistance training frequency on measures of muscle hypertrophy: A systematic review and meta-analysis. Sports Medicine, 46(11), 1689–1697.
Tanimoto, M., & Ishii, N. (2006). Effects of low-intensity resistance training with slow movement and tonic force generation on muscular function in young men. Journal of Applied Physiology, 100(4), 1150–1157.
