As strength athletes and bodybuilders, we're always looking for ways to optimize our training and maximize muscle growth. One powerful tool that exercise scientists use to study muscle activation is electromyography (EMG). By measuring the electrical activity in muscles during exercise, EMG gives us valuable insights into which exercises and techniques most effectively target specific muscle groups. Let's dive into some fascinating EMG research and see how we can apply these findings to build more effective workouts.
The Squat vs. Leg Press Debate: What Does the Science Say?
The squat is often hailed as the king of lower body exercises, but how does it actually compare to machine alternatives like the leg press when it comes to quadriceps activation? A study by Machado et al. (2017) used EMG to compare muscle activity during the traditional 45-degree leg press with two variations: one using a physioball between the knees, and another using an elastic band around the knees.
Interestingly, they found that the physioball variation led to significantly higher activation of the vastus medialis oblique (VMO) compared to both the traditional and elastic band techniques. The physioball also increased overall quadriceps activation, particularly in the vastus lateralis [1].
This suggests that adding instability to the leg press with a physioball between the knees could be an effective way to boost quadriceps engagement, especially for the VMO. This may be particularly useful for athletes looking to improve knee stability or address muscle imbalances.
However, it's important to note that this study looked at the leg press, not squats. When it comes to comparing squats and leg presses directly, the research tends to favor squats for overall muscle activation and functional carryover [2]. That said, leg presses can still be a valuable part of a well-rounded program, especially when variations like the physioball technique are employed.
Optimizing Upper Body Pushing Exercises
Push-ups are a staple in many training programs, but how do they compare to newer "functional" variations like suspension training push-ups? Snarr and Esco (2013) compared muscle activity during traditional push-ups and suspension push-ups using TRX-style straps.
Their EMG analysis revealed that suspension push-ups elicited significantly higher activation in the pectoralis major, anterior deltoid, and triceps brachii compared to traditional push-ups. Specifically, suspension push-ups led to [3]:
- 69.5% vs 63.6% activation in the pectoralis major
- 81.1% vs 58.9% activation in the anterior deltoid
- 105.8% vs 74.3% activation in the triceps brachii
These are substantial differences, particularly for the shoulder and triceps. This suggests that incorporating suspension push-ups could be an excellent way to increase the training stimulus on pushing muscles, especially for more advanced trainees who may have plateaued with traditional push-ups.
The Power of Eccentric Overload
Many of us focus primarily on the lifting (concentric) portion of exercises, but research shows that emphasizing the lowering (eccentric) phase can lead to greater strength and muscle gains. A recent study by Zambrano et al. (2023) used EMG to examine muscle activation during various resistance training techniques, including eccentric overload.
They found that using an electromagnetic resistance device to increase the eccentric load by 50% led to greater activation of the anterior deltoid during elbow flexion exercises compared to traditional methods [4]. While the differences in biceps activation were less pronounced, this still highlights the potential of eccentric overload for increasing overall training stimulus.
Practical ways to incorporate eccentric overload include:
1. Using weight releasers on barbell exercises
2. Performing assisted eccentric reps with a training partner
3. Utilizing specialized eccentric overload machines if available
4. Focusing on slow, controlled lowering phases in your regular exercises
Fine-Tuning Exercise Selection with EMG
EMG research can also help us make more informed choices when selecting exercises for specific muscle groups. For example, a study on shoulder exercises by Youdas et al. (2021) found that certain rowing variations using a suspension training system led to high levels of activation in key shoulder stabilizers [5]:
- The upper, middle, and lower trapezius showed >60% of maximal voluntary isometric contraction (MVIC) during high rows and horizontal abduction rows.
- The posterior deltoid also reached >60% MVIC during these exercises.
- The upper erector spinae demonstrated 40-60% MVIC, indicating good core engagement.
This suggests that incorporating suspension rows, particularly high rows and horizontal abduction variations, could be an effective way to target multiple shoulder and upper back muscles simultaneously.
Bringing It All Together: Practical Applications
While EMG research provides valuable insights, it's important to remember that muscle activation is just one piece of the puzzle. Factors like total volume, progressive overload, recovery, and individual biomechanics all play crucial roles in long-term strength and muscle development.
That said, here are some key takeaways we can apply from the EMG research discussed:
1. Consider adding suspension push-ups to your routine for increased chest, shoulder, and triceps activation.
2. Experiment with physioball or band variations on leg presses to boost quadriceps engagement.
3. Incorporate eccentric overload techniques, especially for stubborn muscle groups or to break through plateaus.
4. Use suspension rows, particularly high and horizontal variations, as an efficient way to target multiple upper body pulling muscles.
5. Don't neglect traditional compound movements like squats, as they still tend to provide excellent overall muscle activation and functional benefits.
By thoughtfully applying these EMG-based insights and continuing to prioritize progressive overload and proper recovery, you can optimize your training for maximum strength and muscle growth. Remember, the most effective program is one that you can consistently adhere to and enjoy, so use this information to enhance your current routine rather than completely overhauling it.
References:
1. Machado, W., Paz, G., Mendes, L., Maia, M., Winchester, J. B., Lima, V., ... & Miranda, H. (2017). Myoeletric activity of the quadriceps during leg press exercise performed with differing techniques. Journal of Strength and Conditioning Research, 31(2), 422-429.
2. Ebben, W. P., Feldmann, C. R., Dayne, A., Mitsche, D., Alexander, P., & Knetzger, K. J. (2009). Muscle activation during lower body resistance training. International Journal of Sports Medicine, 30(1), 1-8.
3. Snarr, R. L., & Esco, M. R. (2013). Electromyographic comparison of traditional and suspension push-ups. Journal of Human Kinetics, 39, 75-83.
4. Zambrano, H., Torres, X., Coleman, M., Franchi, M. V., Fisher, J. P., Oberlin, D., ... & Schoenfeld, B. J. (2023). Myoelectric activity during electromagnetic resistance alone and in combination with variable resistance or eccentric overload. Scientific Reports, 13(1), 8212.
5. Youdas, J. W., Kleis, M., Krueger, E. T., Thompson, S., Walker, W. A., & Hollman, J. H. (2021). Recruitment of shoulder complex and torso stabilizer muscles with rowing exercises using a suspension strap training system. Sports Health, 13(1), 85-90.