I Trained One Side HEAVY vs LIGHT For 60 Days (Bad Idea)

Summary

This 60-day experiment explored whether lifting light weights for high reps or heavy weights for low reps is more effective for muscle growth. Training each side of the body unilaterally, the experimenter and beginner Dennis tracked strength, endurance, and muscle gains using MRI, DEXA, and EMG measurements. Heavy weights increased strength, while light weights boosted endurance and produced a bigger pump. Surprisingly, muscle growth was similar on both sides, with only minor differences. The experiment highlighted the importance of effort, proper form, and recovery over absolute weight, showing that moderate rep ranges, nutrition, and training variation can optimize growth while minimizing injury.

Takeaways

• 😀 The experiment focused on comparing the effects of training one side of the body with heavier weights versus lighter weights with more reps.
• 😀 Results showed that both sides of the body became stronger, but muscle growth was slightly more noticeable on the lighter side.
• 😀 Training with lighter weights and higher reps (15-25) led to more muscle growth in some areas, especially the chest, but the difference was minimal.
• 😀 Both participants experienced small but measurable muscle growth, with one participant gaining 2 lbs and the other gaining 3 lbs of muscle.
• 😀 A slight muscle imbalance occurred in the iliosoas muscle, which helps stabilize the hips and back, due to heavy one-sided exercises.
• 😀 Despite the imbalance in muscle growth, the imbalances were small and did not cause significant differences in overall muscle development.
• 😀 Form, effort, and consistency were shown to be more important for muscle growth than the amount of weight lifted.
• 😀 The heavy side showed better strength for fewer reps, while the light side allowed for more volume and higher endurance.
• 😀 MRI scans confirmed muscle growth, but only a tiny difference was observed between the heavy and light sides, with some areas growing slightly more on the lighter side.
• 😀 After the experiment, both participants were encouraged to shift to a balanced rep range (6-15 reps) to avoid potential strain from extreme training approaches.
• 😀 The key takeaway from the experiment is that the quality of the training (effort and form) is far more important than the amount of weight used in achieving muscle growth.

Q & A

What was the main goal of the experiment in the video?

The main goal of the experiment was to explore how training one side of the body with lighter weights and the other side with heavier weights impacts muscle growth, strength, and endurance.

What did the participants experience when training their weaker side with lighter weights?

When training the weaker side with lighter weights, participants generally experienced better endurance, as the lighter side allowed for more reps, but it didn’t necessarily lead to greater strength gains compared to the heavier side.

Did training with lighter weights result in more muscle growth on the lighter side?

Surprisingly, the lighter side did grow slightly more in most muscles, but the difference was minimal, and it wasn’t statistically significant. For example, the chest on the lighter side grew more, but only by a small amount.

Why did the iliossoas muscle grow more on the left side during the experiment?

The iliossoas muscle, which helps stabilize the hips and back, grew more on the left side because of the heavy one-sided leg exercises. The muscle worked harder to stabilize the heavy weight, leading to more growth on that side.

What were the results of the MRI scans and how did they impact the findings?

The MRI scans confirmed that the muscle growth was relatively small, with the light side seeing slightly more growth overall. However, there was a notable imbalance in the iliossoas muscle, which caused back problems after the experiment.

How did the participants’ body composition change after the 60-day experiment?

Dennis gained 3 lbs, all of which was muscle, while the other participant gained 2 lbs, with half a pound being muscle. The body fat percentage dropped slightly for both participants without significant cardio training.

What did the participants think about the differences between the lighter and heavier sides in terms of muscle growth?

Both participants noted slight differences in growth between the two sides, but the changes were minimal. The heavier side was generally stronger, while the lighter side had more endurance, but neither side showed a clear advantage in terms of overall growth.

What did the experiment reveal about the effectiveness of training with light vs. heavy weights?

The experiment showed that both light and heavy weight training have their benefits. While heavy weights may lead to more strength, lighter weights allow for higher volume and better endurance, which can lead to slight increases in muscle growth, but both sides saw some form of improvement.

What were the primary takeaways for how to train effectively for muscle growth?

The main takeaway is that effort and form are more important than the amount of weight used. A moderate rep range (6-15 reps) tends to be the sweet spot for muscle growth, balancing load with volume, while heavy and light training can still offer benefits when included strategically.

How did the experiment affect the participants' preference for training in the future?

After the experiment, the participants seemed to appreciate the idea of using a moderate rep range for most of their training, as it provided a balance between challenge and joint safety. However, they also expressed interest in incorporating a mix of both light and heavy sets for variety and additional benefits.