Heavier squats target glutes more, leg extensions beat leg presses for quads, cold plunges may hinder growth
Original: 4 Juicy new studies on how to build muscle
TL;DR
Some muscle-building claims are strongly supported by research, while others face contradiction or lack of evidence.
Quick Answer
The four new studies reveal that: (1) heavier squat loads increase glute engagement more than quad engagement; (2) leg extensions are more effective than leg presses for targeting the rectus femoris, a quad muscle undertrained in compound lifts; (3) cold plunges reduce soreness but do not improve strength recovery and may impair muscle growth by blunting protein synthesis; and (4) low starting muscle mass does not predict poor muscle gain, meaning being naturally skinny doesn’t make you a 'hardgainer'.
Claims (10)
1. Taking cold water baths after working out might make your muscles feel less sore, but it won’t help you recover faster and could actually slow muscle growth by blocking the body’s natural healing response.
2. If you're new to lifting weights, how muscular you already are doesn't really predict how much you'll grow from training — it's not a strong clue.
3. When you lift weights, your muscles get a little damaged and inflamed — and that’s actually a good thing. This inflammation helps your muscles heal and get stronger, and usually your body can handle the recovery just fine on its own.
4. Doing leg extensions might grow your front thigh muscle more than leg presses, even though both workouts work the other big thigh muscles just as hard.
5. Even though leg extensions only move one joint, they might work your front thigh muscles better than squats or leg presses because they really target one specific muscle in the quad.
6. Your quads work hard during squats no matter how heavy the weight, but your glutes really kick in only when the weights are heavy or you're almost too tired to keep going.
7. When you squat with heavier weights, your butt muscles (glutes) have to work way harder than your thigh muscles (quads), more than you'd expect just from the added weight.
8. If we use sensors to see which parts of a muscle are working hardest during a workout, those same areas are the ones that will grow the most over time.
9. Leaning back during leg extensions might make your front thigh muscle work harder and grow more because it stretches the muscle more during the move.
10. Even though squats work your legs hard, muscles like the hamstrings and front thigh muscle don't grow much because they get pulled in two directions at once during the movement.
Key Takeaways
- •Problem: Some muscles don’t grow well with regular exercises like squats, recovery tools like cold plunges might actually hurt muscle growth, and people think being skinny means they can’t build muscle.
- •Core methods: Using heavier weights on squats, doing leg extensions for quads, avoiding cold plunges after workouts, and understanding that starting with little muscle doesn’t limit gains.
- •How methods work: Heavier squats make your glutes work harder; leg extensions target the middle quad (rectus femoris) that squats miss; cold plunges reduce soreness but block muscle repair signals; and your starting size doesn’t predict how much muscle you can gain.
- •Expected outcomes: Better muscle balance in legs, full quad development, improved long-term muscle growth, and disproving the myth that skinny people can’t gain muscle.
- •Implementation timeframe: [Not specified in transcript]
Overview
The challenge in resistance training is optimizing muscle growth by targeting specific muscles effectively, selecting appropriate recovery strategies, and understanding individual response variability. This summary presents evidence-based solutions: manipulating exercise intensity to target specific muscles during compound lifts, using isolation exercises like leg extensions to overcome biomechanical limitations, avoiding post-workout cold exposure due to its anabolic interference, and recognizing that low initial muscle mass does not impair hypertrophy potential. Together, these findings refine programming for maximal muscle development.
Key Terms
How to Apply
- 1.Step 1: Perform squats using 70–90% of your 1-rep max, progressively increasing load to emphasize glute activation, especially as you approach failure.
- 2.Step 2: Include leg extensions in your leg routine with a reclined seat position (lean back) to maximize rectus femoris activation and muscle growth.
- 3.Step 3: Avoid cold water immersion (e.g., cold plunges, ice baths) immediately after resistance training to prevent suppression of inflammation-mediated muscle protein synthesis and hypertrophy.
- 4.Step 4: Do not assume low baseline muscle mass limits your potential; follow a progressive resistance training program regardless of starting size, as initial muscle mass does not predict growth rate.
Improved glute and quad development through targeted loading, complete rectus femoris hypertrophy via isolation exercises, preservation of anabolic signaling by avoiding cold exposure, and consistent muscle gains independent of initial physique.
Studies from Description (5)
Additional Links (3)
Claims (10)
1. Taking cold water baths after working out might make your muscles feel less sore, but it won’t help you recover faster and could actually slow muscle growth by blocking the body’s natural healing response.
2. If you're new to lifting weights, how muscular you already are doesn't really predict how much you'll grow from training — it's not a strong clue.
3. When you lift weights, your muscles get a little damaged and inflamed — and that’s actually a good thing. This inflammation helps your muscles heal and get stronger, and usually your body can handle the recovery just fine on its own.
4. Doing leg extensions might grow your front thigh muscle more than leg presses, even though both workouts work the other big thigh muscles just as hard.
5. Even though leg extensions only move one joint, they might work your front thigh muscles better than squats or leg presses because they really target one specific muscle in the quad.
6. Your quads work hard during squats no matter how heavy the weight, but your glutes really kick in only when the weights are heavy or you're almost too tired to keep going.
7. When you squat with heavier weights, your butt muscles (glutes) have to work way harder than your thigh muscles (quads), more than you'd expect just from the added weight.
8. If we use sensors to see which parts of a muscle are working hardest during a workout, those same areas are the ones that will grow the most over time.
9. Leaning back during leg extensions might make your front thigh muscle work harder and grow more because it stretches the muscle more during the move.
10. Even though squats work your legs hard, muscles like the hamstrings and front thigh muscle don't grow much because they get pulled in two directions at once during the movement.
Related Content
Claims (10)
Your quads work hard during squats no matter how heavy the weight, but your glutes really kick in only when the weights are heavy or you're almost too tired to keep going.
When you squat with heavier weights, your butt muscles (glutes) have to work way harder than your thigh muscles (quads), more than you'd expect just from the added weight.
Even though squats work your legs hard, muscles like the hamstrings and front thigh muscle don't grow much because they get pulled in two directions at once during the movement.
When you lift weights, your muscles get a little damaged and inflamed — and that’s actually a good thing. This inflammation helps your muscles heal and get stronger, and usually your body can handle the recovery just fine on its own.
Doing leg extensions might grow your front thigh muscle more than leg presses, even though both workouts work the other big thigh muscles just as hard.
Studies (3)
Hypertrophic Effects of Single- versus Multi-Joint Exercise: A Direct Comparison Between Knee Extension and Leg Press.
DOI: 10.1249/mss.0000000000003957
Effects of cold-water immersion at different body regions on post-exercise muscle damage recovery: a systematic review and meta-analysis
DOI: 10.3389/fspor.2026.1738075
Resistance training-induced appendicular lean tissue mass changes are largely unrelated to pre-training bone characteristics in a larger cohort of untrained adults
DOI: 10.3389/fphys.2025.1681719