Maximizing Muscle Activation: A Comprehensive Guide to Exercise Selection

Muscle activation plays a vital role in strength training and hypertrophy. It refers to the number of muscle fibers recruited during an exercise, which directly impacts muscle growth and strength gains. Selecting exercises that elicit high muscle activation is essential for maximizing workout efficiency and achieving fitness goals. This article offers a comprehensive guide to exercise selection based on muscle activation rates, drawing on data from peer-reviewed journals to provide evidence-based recommendations.

Methodology

To gather information for this article, a comprehensive review of peer-reviewed journals was conducted. The research focused on studies that compared muscle activation rates for different exercises across various muscle groups. The primary aim was to identify exercises that elicit the highest levels of muscle activation, thereby providing practitioners with evidence-based recommendations for exercise selection ¹.

Types of Muscle Fibers

Muscle fibers can be broadly classified into two types: Type I and Type II. Type I fibers, also known as slow-twitch fibers, are more resistant to fatigue and are primarily involved in endurance activities. Type II fibers, also known as fast-twitch fibers, are responsible for generating force and power and are primarily involved in strength and power activities. Different exercises may recruit different types of muscle fibers, and understanding these differences can help optimize training programs for specific goals ².

Types of Muscle Contractions

Muscle contractions can be classified into two main types: concentric and eccentric. Concentric contractions occur when the muscle shortens while generating force, such as during the lifting phase of a bicep curl. Eccentric contractions occur when the muscle lengthens while generating force, such as during the lowering phase of a bicep curl. Research suggests that different types of muscle contractions may result in varying levels of muscle activation and should be considered when designing training programs ³.

The Role of the Nervous System in Muscle Activation

The nervous system plays a crucial role in muscle activation by coordinating muscle contractions. When we perform an exercise, the nervous system sends signals to the muscles, initiating the contraction process. The efficiency of this process can affect the number of muscle fibers recruited and, consequently, the level of muscle activation. Factors such as training experience and fatigue can influence the nervous system's ability to activate muscles effectively ³.

Quadriceps

The quadriceps femoris is a group of four muscles located on the front of the thigh. These muscles are responsible for knee extension and hip flexion. Several studies have investigated muscle activation during various quadriceps exercises, and the findings reveal some interesting insights.

The barbell back squat is a highly effective exercise for overall leg development, eliciting high activation across the quadriceps, hamstrings, and glutes. Studies have shown that squats produce up to 74 percent maximum voluntary contraction (MVC) in the quadriceps, 52 percent in the glutes, and 43 percent in the hamstrings during the ascent phase ⁴.

A study published in the Journal of Physical Therapy Science found that the front-rack squat is another extremely effective way to develop bigger and stronger quads ⁵. This exercise involves holding a barbell or dumbbell under the chin, resting on the shoulders, and performing a squat.

Another study compared muscle activation during various quadriceps exercises in patients who had undergone total knee arthroplasty (TKA) ⁶. The researchers found that knee extensions with an elastic band showed significantly higher voluntary peak quadriceps muscle activity (93.3% MVIC) than knee extensions performed on a machine (74.9% MVIC). Similarly, the one-legged squat (86.7% MVIC) and sit-to-stand (80.7% MVIC) exercises elicited higher voluntary peak quadriceps muscle activity than the leg press performed on a machine (66.8% MVIC). This finding highlights a key insight: simpler forms of strength training can be just as effective as machine-based exercises, particularly for individuals new to strength training or those who do not have access to gym equipment.

A systematic review analyzed muscle activation on the lower limbs with five different variations of the squat exercise ⁷. The review found that low-bar squats, which involve a greater hip hinge, provoke major activation on the hip extensors (including the quadriceps) than other squat variations. It is worth highlighting that similar activation patterns were observed between the front squat and the high-bar squat.

Furthermore, research has shown that muscle activation is not always linear and that other factors, such as the velocity of the movement, can affect muscle activation ⁸. This is why it is important to consider all factors when selecting exercises, not just the weight being lifted.

In addition to the exercises mentioned above, step-ups and their variations have been shown to elicit very high levels of gluteus maximus (GMax) activation, which can also contribute to quadriceps development. For example, the step-up exercise showed an average GMax activation of 169.22% MVIC, followed by the lateral step-up (114.25% MVIC) and diagonal step-up (113.21% MVIC) ³.

Based on these findings, the top 5 exercises for quadriceps activation are:

1. Knee extensions with elastic band ⁶
2. One-legged squat ⁶
3. Front-rack squat ⁵
4. Low-bar squat ⁷
5. Front squat/High-bar squat ⁷

It is important to note that squat jumps are an explosive power-focused exercise that activates fast-twitch muscle fibers, which can contribute to hypertrophy and improved speed of muscle contraction ⁵.

Hamstrings

Moving on from the quadriceps, let's now explore the hamstrings, a group of three muscles located on the back of the thigh. These muscles are responsible for knee flexion and hip extension. Several studies have examined muscle activation during various hamstring exercises, and the findings suggest that exercise selection plays a crucial role in maximizing hamstring activation.

A study published in the International Journal of Sports Physical Therapy compared three hip-dominant hamstring exercises: the rocker, Perpetuum mobile fast (PMfast), Perpetuum mobile slow (PMslow), and the Nordic hamstring exercise (NHE) ⁹. The researchers found that the explosive exercises (rocker and PMfast) showed greater hamstring activity than the NHE and PMslow. The rocker showed the greatest hamstring and gluteus maximus activity.

Another study compared maximal electromyography (EMG) activity for the hamstring muscle group during a maximal sprint with several types of hamstring strength exercises ². The researchers found that the laying kick, along with the Nordic hamstring exercise and its variations, had the highest muscle activations. Specifically, the Nordic hamstring exercise showed an average activation of 63% MVIC for the semitendinosus, 33% MVIC for the biceps femoris, and 64% MVIC for the semimembranosus. The laying kick showed similar activation levels, with 65% MVIC for the semitendinosus, 40% MVIC for the biceps femoris, and 75% MVIC for the semimembranosus. In contrast, the cranes showed the lowest muscle activation (in all muscles) together with the standing kick for the semimembranosus.

A study published in the Journal of Strength and Conditioning Research investigated the relative muscle activity of the hamstring group and selected surrounding musculature during the leg curl, good morning, glute-ham raise, and Romanian deadlift (RDL) ¹⁰. The researchers found that the RDL showed significantly greater biceps femoris activation than the other exercises.

The prone leg curl elicited the highest muscle activation compared to other hamstring exercises, including the seated leg curl, glute-ham raise, Romanian deadlift, stability ball hamstring curl, reverse hip raise, and glute-ham developer ¹¹.

A key insight from these studies is that the Nordic hamstring exercise and its variations are highly effective for hamstring activation ^{2 12}. This is because these exercises closely mimic the demands placed on the hamstrings during sprinting, which is a common mechanism for hamstring injuries.

Based on these findings, the top 5 exercises for hamstring activation are:

1. Rocker ⁹
2. Laying kick ²
3. Nordic hamstring exercise ^{2 9}
4. Perpetuum mobile fast ⁹
5. Romanian deadlift ¹⁰

Note: C = Concentric phase, E = Eccentric phase, ST = Semitendinosus, BF = Biceps Femoris, SM = Semimembranosus

Chest

Moving on from the lower body, let's now delve into the best exercises for chest activation. The chest muscles, primarily the pectoralis major, are responsible for shoulder horizontal adduction and flexion. Several studies have investigated muscle activation during various chest exercises, and the findings highlight the importance of exercise selection for maximizing chest muscle activation.

A study published in the ACE Certified News compared muscle activation during nine common chest exercises ¹³. The researchers found that the barbell bench press elicited the highest pectoral muscle activation compared to other chest exercises like the dumbbell fly or push-up. The pec deck and bent-forward cable crossovers also elicited nearly equivalent muscle activation as the barbell bench press.

Another study compared the barbell bench press (BBP) to dumbbell flyes (DF) ¹. The results showed higher muscle activation in the whole movement and the majority of the lifting phases for the pectoralis major for the BBP compared to the DF.

A study published in the Journal of Sports Sciences compared 1-RM strength and EMG activity in the chest press using a free barbell (conventional bench press), a Smith machine, and dumbbells ¹⁴. The researchers found that electrical activity in the pectoralis major did not differ between the barbell and Smith machine bench press.

According to research from ACE Certified News, the barbell bench press, pec deck machine, and bent-forward cable crossovers are equally effective for chest activation ¹⁵. This allows for flexibility in exercise selection based on individual preferences and equipment availability.

The 15-degree incline dumbbell press was found to be the most effective for upper chest activation ¹⁶.

Based on these findings, the top 5 exercises for chest activation are:

1. Barbell bench press ^{13 1}
2. Pec deck machine ¹³
3. Bent-forward cable crossovers ¹³
4. Smith machine bench press ¹⁴
5. 15-degree incline dumbbell press ¹⁶

Back

Shifting our focus to the back, we encounter a complex group of muscles responsible for various movements, including pulling, extending, and rotating the spine. Several studies have investigated muscle activation during various back exercises, and the findings suggest that exercise selection is crucial for maximizing back muscle activation.

A study published in the Journal of Strength and Conditioning Research compared muscle activation during six different back exercises ¹⁷. The researchers found that the pull-up elicited the highest latissimus dorsi activation, followed by the bent-over row and chin-up. Specifically, the pull-up showed 96.9% MVIC for the latissimus dorsi, while the bent-over row showed 84.7% MVIC and the chin-up showed 79.6% MVIC.

Another study investigated the muscle activation level of the latissimus dorsi, biceps brachii, and middle trapezius/rhomboids muscle groups during a series of different exercises ¹⁸. The researchers found that the highest latissimus dorsi activation occurred during the seated row with retracted shoulder blades.

Deadlifts and bent-over rows proved to be the best overall back exercises, activating multiple muscle groups effectively for maximum strength and growth ¹⁹. The barbell deadlift consistently ranks as one of the most effective back exercises according to EMG studies ²⁰. This compound movement targets the erector spinae, latissimus dorsi, and other muscles in the posterior chain.

Based on these findings, the top 5 exercises for back activation are:

1. Pull-up ¹⁷
2. Seated row (retracted shoulder blades) ¹⁸
3. Barbell deadlift ²⁰
4. Bent-over row ¹⁷
5. Chin-up ¹⁷

Shoulders

Now, let's turn our attention to the shoulders. The shoulder muscles, primarily the deltoids, are responsible for shoulder abduction, flexion, and extension. Several studies have investigated muscle activation during various shoulder exercises, and the findings suggest that exercise selection is crucial for maximizing shoulder muscle activation.

A study published in the ACE ProSource compared muscle activation during 10 different shoulder exercises ²¹. The researchers found that the dumbbell shoulder press was the most effective exercise for the anterior deltoid, while the seated rear lateral raise was the most effective for the posterior deltoid.

Another study compared muscle activity of the anterior, medial, and posterior deltoid in the bench press, dumbbell fly, shoulder press, and lateral raise exercises ²². The researchers found that the shoulder press and lateral raise exercises showed a higher level of muscle activation in the anterior and medial deltoid compared to the bench press and dumbbell fly exercises. Specifically, the shoulder press showed 33.3% MVIC for the anterior deltoid and 27.9% MVIC for the medial deltoid, while the lateral raise showed 21.2% MVIC for the anterior deltoid and 30.3% MVIC for the medial deltoid.

A study published in the Journal of Human Kinetics investigated the effects of different shoulder exercises on the activation of deltoid portions in resistance-trained individuals ²³. The researchers found that the shoulder press presented a significantly higher level of activation for the anterior deltoid when compared to other exercises. For the medial deltoid, the lateral raise and shoulder press presented a significantly higher level of activity than the bench press and dumbbell fly.

A key insight from these studies is that the shoulder press and lateral raise are highly effective for overall shoulder development ^{22 23}. This is because these exercises target all three heads of the deltoid muscle.

For the upper trapezius, the shoulder press showed significantly greater activation than the incline press, which in turn was significantly greater than the bench press ²⁴.

Based on these findings, the top 5 exercises for shoulder activation are:

1. Dumbbell shoulder press ²¹
2. Shoulder press ^{22 23}
3. Lateral raise ^{22 23}
4. Seated rear lateral raise ²¹
5. 45-degree incline row ²¹

Note: C = Concentric phase, E = Eccentric phase, ST = Semitendinosus, BF = Biceps Femoris, SM = Semimembranosus

Biceps

Next, we'll examine the biceps brachii, a two-headed muscle located on the front of the upper arm. This muscle is responsible for elbow flexion and forearm supination. Several studies have investigated muscle activation during various biceps exercises, and the findings suggest that exercise selection is crucial for maximizing biceps muscle activation.

A study published in the ACE ProSource compared muscle activation during eight different biceps exercises ²⁵. The researchers found that the concentration curl elicited significantly higher muscle activation of the biceps than any other exercise tested.

Another study measured how much each exercise worked the biceps and ranked them in the following order ²⁶:

1. Concentration curl (~98% activation)
2. Cable curl (~81% activation)
3. Chin-up (~80% activation)
4. Barbell curl (~76% activation)
5. EZ curl (wide grip) (~75% activation)

Chin-ups are one of the best exercises to grow your biceps ²⁷.

A study published in the Journal of Strength and Conditioning Research compared muscle activation during the EZ-bar curl, barbell curl, and dumbbell curl ²⁸. The researchers found that the EZ-bar curl elicited higher activation of both the biceps brachii and brachioradialis compared to the dumbbell curl.

During the ascending phase of a bicep curl, biceps brachii excitation was greater with the supinated handgrip compared to the pronated and neutral handgrips ²⁹.

A key insight from these studies is that the concentration curl is the most effective exercise for biceps activation ²⁵. This is because it isolates the biceps muscle and minimizes the involvement of other muscle groups.

Based on these findings, the top 5 exercises for biceps activation are:

1. Concentration curl ^{25 26}
2. Cable curl ²⁶
3. Chin-up ²⁶
4. EZ-bar curl ²⁸
5. Barbell curl ²⁶

Triceps

Finally, let's explore the triceps brachii, a three-headed muscle located on the back of the upper arm. This muscle is responsible for elbow extension. Several studies have investigated muscle activation during various triceps exercises, and the findings suggest that exercise selection is crucial for maximizing triceps muscle activation.

A study published in the ACE Certified News compared muscle activation during eight different triceps exercises ³⁰. The researchers found that triangle push-ups elicited the most muscle activity in the triceps, followed by triceps kickbacks and dips.

Another study investigated the best triceps workout to hit every triceps head based on current scientific literature ³¹. The researchers found that the close-grip bench press and weighted dips are heavy exercises that stimulate type II muscle fibers and are great overall triceps developers. The close grip bench press enables us to easily overload it and lift very heavy weights ³¹. For the lateral head, the cable push-down with either a straight bar or V-bar elicited the highest activation.

A study published in the Journal of Electromyography and Kinesiology investigated the influence of exercise intensity and speed on muscle activation during the triceps push-down exercise ³². The researchers found that the rate of force development (ROF) increases with an increase in intensity and speed.

The long head of the triceps showed higher EMG activity with the supinated handgrip compared to all other conditions during the triceps push-down exercise ³³.

A key insight from these studies is that triangle push-ups, triceps kickbacks, and dips are highly effective for triceps activation ³⁰. These exercises can be performed with minimal equipment, making them accessible to a wide range of individuals.

Based on these findings, the top 5 exercises for triceps activation are:

1. Triangle push-ups ³⁰
2. Triceps kickbacks ³⁰
3. Dips ³⁰
4. Close-grip bench press ³¹
5. Weighted dips ³¹

Conclusion

Selecting exercises that elicit high muscle activation is crucial for maximizing workout efficiency and achieving fitness goals. This article has provided a comprehensive guide to exercise selection based on muscle activation rates, drawing on data from peer-reviewed journals to provide evidence-based recommendations. You can optimize muscle growth and strength gains by incorporating these exercises into your training program.

While muscle activation is often considered a predictor of strength gains, this relationship has not been scientifically proven ³⁴. It is essential to consider individual needs and goals, the role of different muscle fiber types, and the importance of progressive overload when designing training programs ⁸.

Proper exercise technique is crucial for maximizing muscle activation and preventing injuries ². The most effective exercises for one person may not be the most effective for another person, and exercise selection should be based on individual factors such as training experience, injury history, and fitness goals ².

Remember to prioritize proper form and technique to ensure safe and effective training.

Bibliography

1. A Comparison of Muscle Activation between Barbell Bench Press and Dumbbell Flyes in Resistance-Trained Males - PMC, accessed February 22, 2025, https://pmc.ncbi.nlm.nih.gov/articles/PMC7675616/
2. COMPARISON OF HAMSTRING MUSCLE ACTIVATION DURING HIGH-SPEED RUNNING AND VARIOUS HAMSTRING STRENGTHENING EXERCISES - PMC, accessed February 22, 2025, https://pmc.ncbi.nlm.nih.gov/articles/PMC5685404/
3. Comparison of quadriceps muscle activation in exercises with different duration of concentric and eccentric contractions, accessed February 22, 2025, https://archivosdemedicinadeldeporte.com/articulos/upload/or01_freire.pdf
4. Best Exercises for Each Major Muscle Group Backed EMG Data - JEFIT, accessed February 22, 2025, https://www.jefit.com/wp/exercise-tips/best-exercises-for-each-major-muscle-group-backed-emg-data/
5. The best exercises for quads, according to science, accessed February 22, 2025, https://www.livescience.com/best-exercises-for-quads
6. Quadriceps muscle activity during commonly used strength training exercises shortly after total knee arthroplasty - PubMed Central, accessed February 22, 2025, https://pmc.ncbi.nlm.nih.gov/articles/PMC6606685/
7. (PDF) A systematic review on the muscular activation on the lower limbs with five different variations of the squat exercise - ResearchGate, accessed February 22, 2025, https://www.researchgate.net/publication/348232128_A_systematic_review_on_the_muscular_activation_on_the_lower_limbs_with_five_different_variations_of_the_squat_exercise
8. Comparison of muscle activation and kinematics during free-weight back squats with different loads - PMC, accessed February 22, 2025, https://pmc.ncbi.nlm.nih.gov/articles/PMC6521994/
9. Muscle Activity and Kinematics During Three Hamstring Strengthening Exercises Compared to Sprinting: A Cross-Sectional Study., accessed February 22, 2025, https://ijspt.scholasticahq.com/article/116158-muscle-activity-and-kinematics-during-three-hamstring-strengthening-exercises-compared-to-sprinting-a-cross-sectional-study
10. MUSCLE ACTIVATION DURING VARIOUS HAMSTRING EXERCISES, accessed February 22, 2025, https://www.oliverfinlay.com/assets/pdf/mcallister%20et%20al%20(2014)%20muscle%20activation%20during%20various%20hamstring%20exercises.pdf
11. Best Hamstring Exercises Identified by ACE Research | ACE Fitness, accessed February 22, 2025, https://www.acefitness.org/continuing-education/certified/february-2018/6896/ace-sponsored-research-what-is-the-best-exercise-for-the-hamstrings/
12. Muscle Activation Differences During Eccentric Hamstring Exercises - PMC, accessed February 22, 2025, https://pmc.ncbi.nlm.nih.gov/articles/PMC8167351/
13. ACE-Sponsored Research: Top 3 Most Effective Chest Exercises, accessed February 22, 2025, https://www.acefitness.org/certifiednewsarticle/2884/ace-sponsored-research-top-3-most-effective-chest-exercises/
14. A comparison of muscle activity and 1-RM strength of three chest-press exercises with different stability requirements - ResearchGate, accessed February 22, 2025, https://www.researchgate.net/publication/49746305_A_comparison_of_muscle_activity_and_1-RM_strength_of_three_chest-press_exercises_with_different_stability_requirements
15. TOP 3 MOST EFFECTIVE CHEST EXEDCISES - ACE Fitness, accessed February 22, 2025, https://contentcdn.eacefitness.com/certifiednews/images/article/pdfs/ACE_BestChestExercises.pdf
16. Best Chest Compound Exercises (Backed by Science), accessed February 22, 2025, https://builtwithscience.com/workouts/compound-chest-exercises/
17. ACE-SPONSORED RESEARCH: What Is the Best Back Exercise? - ACE Fitness, accessed February 22, 2025, https://www.acefitness.org/continuing-education/certified/april-2018/6959/ace-sponsored-research-what-is-the-best-back-exercise/
18. Variations in muscle activation levels during traditional latissimus dorsi weight training exercises: An experimental study - PMC - PubMed Central, accessed February 22, 2025, https://pmc.ncbi.nlm.nih.gov/articles/PMC449729/
19. 10 Best Back Exercises for a Wider, Stronger Frame - Dr. Muscle, accessed February 22, 2025, https://dr-muscle.com/best-back-exercises/
20. Best Back Exercises for Maximum Muscle Activation - JEFIT, accessed February 22, 2025, https://www.jefit.com/wp/exercise-tips/best-back-exercises-for-maximum-muscle-activation/
21. Dynamite Delts: ACE Research Identifies Top Shoulder Exercises, accessed February 22, 2025, https://www.acefitness.org/continuing-education/prosource/september-2014/4972/dynamite-delts-ace-research-identifies-top-shoulder-exercises/
22. Different Shoulder Exercises Affect the Activation of Deltoid Portions in Resistance-Trained Individuals - PMC, accessed February 22, 2025, https://pmc.ncbi.nlm.nih.gov/articles/PMC7706677/
23. (PDF) Different Shoulder Exercises Affect the Activation of Deltoid Portions in Resistance-Trained Individuals - ResearchGate, accessed February 22, 2025, https://www.researchgate.net/publication/343021588_Different_Shoulder_Exercises_Affect_the_Activation_of_Deltoid_Portions_in_Resistance-Trained_Individuals
24. Shoulder Muscle Activation of Novice and Resistance Trained Women during Variations of Dumbbell Press Exercises, accessed February 22, 2025, https://pmc.ncbi.nlm.nih.gov/articles/PMC4590897/
25. ACE Research: Best Biceps Exercises for Strength | ACE Fitness, accessed February 22, 2025, https://www.acefitness.org/continuing-education/prosource/august-2014/4933/ace-study-reveals-best-biceps-exercises/
26. Science: This is the best exercise for biceps growth - Workout Meals, accessed February 22, 2025, https://workoutmeals.com.au/blogs/news/science-this-is-the-best-exercise-for-biceps-growth
27. Bicep Workouts (The 4 Best Exercises To Gain Mass) - Built With Science, accessed February 22, 2025, https://builtwithscience.com/workouts/bicep-workout-science/
28. Differences in electromyographic activity of biceps brachii and brachioradialis while performing three variants of curl - PMC, accessed February 22, 2025, https://pmc.ncbi.nlm.nih.gov/articles/PMC6047503/
29. Biceps Brachii and Brachioradialis Excitation in Biceps Curl Exercise: Different Handgrips, Different Synergy - PMC - PubMed Central, accessed February 22, 2025, https://pmc.ncbi.nlm.nih.gov/articles/PMC10054060/
30. Best Triceps Exercises Identified by ACE Study | ACE Fitness, accessed February 22, 2025, https://www.acefitness.org/certifiednewsarticle/3008/ace-study-identifies-best-triceps-exercises/
31. The Best Science Based Triceps Workout For Growth, accessed February 22, 2025, https://builtwithscience.com/fitness-tips/best-triceps-workout/
32. Muscle Fatigue in the Three Heads of Triceps Brachii During Intensity and Speed Variations of Triceps Push-Down Exercise - PubMed Central, accessed February 22, 2025, https://pmc.ncbi.nlm.nih.gov/articles/PMC7047337/
33. Forearm Position Influences Triceps Brachii Activation During Triceps Push-Down Exercise, accessed February 22, 2025, https://journal.iusca.org/index.php/Journal/article/view/250
34. Biceps Femoris Activation during Hamstring Strength Exercises: A Systematic Review, accessed February 22, 2025, https://www.mdpi.com/1660-4601/18/16/8733