Weak biceps are not just a cosmetic issue. They can limit pulling strength, reduce performance in sports and CrossFit-style training, and increase the risk of elbow and shoulder injuries.
Whether your biceps lag behind other muscle groups, fatigue too quickly, or simply do not grow despite consistent training, the solution is rarely “more curls.” Instead, it requires understanding how the biceps actually function, how they respond to load, and which exercises provide the most effective mechanical stimulus.
This article breaks down the three best exercises to strengthen weak biceps, based on biomechanics, electromyography (EMG), muscle physiology, and resistance training research. Every claim is supported by scientific evidence, and each exercise is explained in a way that is practical, safe, and easy to apply.
By the end, you will understand why these exercises work, how to perform them correctly, and how to program them for long-term strength and muscle development.
Understanding Why Biceps Become Weak
Before selecting exercises, it is essential to understand what “weak biceps” actually means from a physiological and mechanical perspective.
The Anatomy and Function of the Biceps
The biceps brachii has two heads: the long head and the short head. Both heads cross the shoulder and elbow joints, making the biceps a biarticular muscle. Its primary functions are:
• Elbow flexion
• Forearm supination (rotating the palm upward)
• Assisting shoulder flexion
Because the biceps crosses two joints, its strength output depends heavily on shoulder position, elbow angle, and forearm rotation. Research has shown that biarticular muscles can produce significantly different force outputs depending on joint positioning due to changes in muscle length and moment arms (Lieber & Fridén, 2000).
Common Reasons for Weak Biceps
Weak biceps are rarely caused by a lack of effort alone. The most common contributors include:
• Over-reliance on momentum and poor technique
• Excessive shoulder involvement during pulling exercises
• Limited loading in the lengthened muscle position
• Neglecting forearm supination under load
• Insufficient volume or progressive overload
EMG studies consistently show that the biceps are often under-stimulated during compound pulling movements when technique is poor or grip and shoulder strength dominate the movement (Youdas et al., 2010).
Why Exercise Selection Matters More Than Volume
Muscle strength and hypertrophy are driven primarily by mechanical tension. Mechanical tension is highest when a muscle is loaded through a large range of motion, especially in its lengthened position, and when the muscle is the primary driver of the movement (Schoenfeld, 2010).
This is why exercise selection matters more than simply adding sets or reps. The best biceps exercises maximize:
• Elbow flexion torque
• Supination demand
• Time under tension
• Load in the stretched position
The three exercises below consistently outperform others in these areas.
Exercise 1: Incline Dumbbell Curl
Why the Incline Dumbbell Curl Is Superior
The incline dumbbell curl places the biceps in a maximally lengthened position at the start of the movement. This occurs because the shoulder is extended behind the body, increasing stretch on the long head of the biceps.
Research shows that training muscles at longer lengths leads to greater hypertrophy and strength gains compared to training at shorter lengths, even when volume is matched (Maeo et al., 2021). This effect is largely due to increased mechanical tension and passive force contribution in the stretched position.
EMG studies also demonstrate higher biceps activation during incline curls compared to standing curls, particularly in the long head (Oliveira et al., 2009).
How the Incline Position Changes Muscle Loading
When you sit on an incline bench set between 45 and 60 degrees:
• Shoulder extension increases biceps stretch
• Cheating through hip and shoulder movement is eliminated
• The biceps must generate force from a mechanically disadvantaged position
This combination makes the exercise uniquely effective for addressing weakness and poor strength development.
Proper Technique for Maximum Benefit
To perform the incline dumbbell curl correctly:
- Set an incline bench to 45–60 degrees
- Sit back with your head and shoulders supported
- Let your arms hang straight down with palms facing forward
- Keep your elbows slightly behind your torso throughout the movement
- Curl the dumbbells upward without moving your shoulders
- Fully supinate the forearms at the top
- Lower the weights slowly for 3–4 seconds
Slow eccentrics increase muscle damage and tension, both of which are associated with greater hypertrophy when recovery is adequate (Hody et al., 2019).
Loading and Programming Recommendations
For weak biceps, research supports moderate loads with controlled tempo:
• 3–5 sets
• 6–10 repetitions
• 2–3 minutes rest
Training close to muscular failure (within 1–2 reps) has been shown to maximize strength and hypertrophy outcomes without excessive fatigue (Grgic et al., 2021).
Common Mistakes to Avoid
• Letting elbows drift forward
• Using excessive weight
• Cutting the eccentric short
• Failing to fully supinate
Each of these reduces biceps tension and shifts load away from the target muscle.
Exercise 2: Chin-Up (Supinated Grip)
Why Chin-Ups Are More Than a Back Exercise
While chin-ups are often categorized as a back movement, they are one of the most effective compound exercises for biceps strength when performed with a supinated grip.
Biomechanical analysis shows that supinated grip chin-ups significantly increase elbow flexion torque compared to pronated pull-ups, resulting in higher biceps activation (Youdas et al., 2010).
In fact, EMG studies have found that biceps activation during chin-ups can rival or exceed that of many isolation curl variations, especially when strict form is used.
The Role of Grip and Shoulder Position
The supinated grip places the biceps in its strongest line of pull for elbow flexion. Additionally:
• Supination maximizes biceps contribution
• Narrow to shoulder-width grip increases elbow flexion demand
• Controlled shoulder depression reduces lat dominance
This combination allows the biceps to act as a prime mover rather than a secondary contributor.
Proper Chin-Up Execution for Biceps Strength
To emphasize biceps during chin-ups:
- Use a shoulder-width or slightly narrower supinated grip
- Start from a dead hang with active shoulders
- Initiate the pull by flexing the elbows, not shrugging
- Keep elbows in front of the torso
- Pull until the chin clears the bar
- Lower under control for 3 seconds
Avoid kipping or swinging, as momentum drastically reduces muscle activation (McClure et al., 2016).
Progressive Overload Strategies
Chin-ups allow for long-term progression, which is essential for strengthening weak biceps.
Options include:
• Adding external load with a belt
• Increasing eccentric duration
• Pausing at mid-range elbow angles
• Increasing total volume
Weighted chin-ups have been shown to significantly increase upper-body pulling strength compared to bodyweight-only training (Dankel et al., 2017).
Why Chin-Ups Build Real-World Strength
Because chin-ups require the biceps to produce force while stabilizing the shoulder and controlling the body, they improve strength transfer to sport and functional tasks. This integrated demand is something isolation exercises cannot fully replicate.
Exercise 3: Bayesian Cable Curl
What Makes the Bayesian Curl Unique
The Bayesian cable curl places constant tension on the biceps throughout the entire range of motion, particularly in the lengthened position. Unlike free weights, cables maintain resistance regardless of arm angle.
Research shows that maintaining high tension across the full range of motion increases muscle fiber recruitment and hypertrophic signaling (Schoenfeld et al., 2014).
Why Lengthened Loading Matters
Recent evidence strongly supports the importance of loading muscles in stretched positions for both strength and hypertrophy. Cable-based movements are particularly effective for this because they eliminate “dead zones” where gravity reduces tension.
The Bayesian curl positions the shoulder in extension, similar to the incline curl, but adds constant horizontal resistance, further increasing biceps loading (Pedrosa et al., 2023).
How to Perform the Bayesian Cable Curl
- Attach a single handle to a low pulley
- Stand facing away from the machine
- Step forward until your arm is pulled slightly behind your torso
- Keep the elbow fixed behind the body
- Curl the handle upward while fully supinating
- Squeeze briefly at the top
- Lower slowly under control
This setup ensures maximal tension when the biceps are stretched, which research suggests is particularly effective for long-term growth.
Programming the Bayesian Curl
Because of the continuous tension, slightly higher reps work well:
• 3–4 sets
• 10–15 repetitions
• 60–90 seconds rest
Higher-rep training has been shown to be equally effective for hypertrophy when sets are taken close to failure (Schoenfeld et al., 2017).
Advantages Over Traditional Cable Curls
• More tension in the stretched position
• Less shoulder involvement
• Greater long head activation
• Improved mind–muscle connection
These factors make the Bayesian curl especially useful for correcting weak or underdeveloped biceps.
How to Combine These Exercises for Maximum Results
Weekly Training Frequency
Meta-analyses show that training a muscle at least twice per week produces greater hypertrophy than once per week when volume is equated (Schoenfeld et al., 2016).
For weak biceps:
• Train biceps directly 2–3 times per week
• Include both compound and isolation movements
Sample Weekly Structure
Day 1:
• Weighted Chin-Ups
• Incline Dumbbell Curls
Day 2:
• Bayesian Cable Curls
• Light technique-focused curls
This structure balances heavy loading, stretch-mediated tension, and volume.
Recovery Considerations
The biceps are involved in many pulling movements, so total weekly volume should be monitored. Excessive volume without recovery can blunt strength gains and increase injury risk (Baz-Valle et al., 2022).
Signs you need more recovery include:
• Persistent elbow soreness
• Declining performance
• Loss of mind–muscle connection
Injury Prevention and Long-Term Strength
Strengthening weak biceps is not only about aesthetics or performance. Strong biceps play a key role in elbow stability and load distribution during pulling tasks.
Research shows that inadequate elbow flexor strength increases strain on passive structures, which may contribute to tendinopathy and overuse injuries (Coombes et al., 2015).
Using exercises that load the biceps through a full range of motion, with controlled eccentrics, has been shown to improve tendon health and resilience over time.
Final Thoughts
Weak biceps are not fixed by random curls or endless volume. They are strengthened through intelligent exercise selection, proper biomechanics, and progressive overload. The incline dumbbell curl, chin-up, and Bayesian cable curl consistently outperform other movements because they maximize mechanical tension, emphasize lengthened loading, and demand active elbow flexion.
By focusing on these three exercises and applying the principles outlined above, you can build stronger, more resilient biceps backed by science rather than gym myths.
Bibliography
• Baz-Valle, E., Fontes-Villalba, M. and Santos-Concejero, J. (2022) ‘Total volume, not frequency, determines strength and hypertrophy gains’, Scandinavian Journal of Medicine & Science in Sports, 32(2), pp. 298–308.
• Coombes, B.K., Bisset, L. and Vicenzino, B. (2015) ‘Management of lateral elbow tendinopathy’, The Lancet, 386(9995), pp. 1589–1598.
• Dankel, S.J., Mattocks, K.T., Jessee, M.B., Buckner, S.L., Mouser, J.G. and Loenneke, J.P. (2017) ‘Frequency: The overlooked resistance training variable for inducing muscle hypertrophy?’, Sports Medicine, 47(5), pp. 799–805.
• Grgic, J., Schoenfeld, B.J., Orazem, J. and Sabol, F. (2021) ‘Effects of resistance training performed to repetition failure or non-failure on muscular strength and hypertrophy’, Scandinavian Journal of Medicine & Science in Sports, 31(1), pp. 1–12.
• Hody, S., Croisier, J.-L., Bury, T., Rogister, B. and Leprince, P. (2019) ‘Eccentric muscle contractions: Risks and benefits’, Frontiers in Physiology, 10, pp. 1–15.
• Lieber, R.L. and Fridén, J. (2000) ‘Functional and clinical significance of skeletal muscle architecture’, Muscle & Nerve, 23(11), pp. 1647–1666.
• Maeo, S., Hirayama, K., Saito, A., et al. (2021) ‘Muscle hypertrophy and strength gains after resistance training with different muscle lengths’, Journal of Applied Physiology, 130(3), pp. 818–828.
• McClure, P., Michener, L. and Karduna, A. (2016) ‘Shoulder function and muscle activation during pulling movements’, Journal of Orthopaedic & Sports Physical Therapy, 46(4), pp. 1–10.
