Activating the quadriceps clearly depends on the goal in mind. In this case, we are emphasizing hypertrophy, or muscle fiber enlargement. This blog is based on the most effective, evidence-based ways to efficiently grow your quads!

Yesterday I discussed the best ways to develop strength in the quads. I would like to piggy back off of saying that Closed Kinetic Chain Exercises are prime movements for hypertrophy. Although front squats & back squats (discussed in part 1) are extremely efficient for strength (& good for hypertrophy as well), they are not topping the list when it comes to quad growth emphasis. 

What are the most efficient movements for quad growth?

Heel elevated back squats: 

• Versatility, you can perform this movement with free weight or on machinery. One of the best ways to utilize this movement as a hypertrophy movement is by performing it on a smith machine. The fixed position allows for the focus to be aimed towards concentrated activation & identical movement mechanics each rep, rather than emphasizing stabilization. 
• Knee dominance increases emphasis on the quads by increasing the moment arm. 
• Easy to progressive overload while minimizing risk of injury. 
• You can also narrow your stance & emphasis an upright posture while back squatting (without elevating heels). But, heel elevation preferred for maximal stimulus in the quads (due to plantar flexion position & kinetic/mechanic shift. 
• Study from 2020 investigated how heel elevation influences spinal mechanics during back squats among both novice and experienced lifters. The findings suggest that elevating the heels can lead to a more upright torso position, potentially increasing knee flexion and emphasizing quadriceps engagement. https://www.tandfonline.com/doi/full/10.1080/02640414.2020.1738675?utm_

Hack squat/Leg Press variations:

• Concentrate on quad activation while minimizing balance & stabilization focus. 
• Easy to overload, increase intensity, & prioritize aiming for high mechanical tension.
• Easy to take close to failure or leave reps in reserve (RIR).
• Integrate isometric holds & tempo manipulation safely. 
• Test out different ranges of motion effectively for your liking. 
• Emphasize narrow stances, smaller displacement, & knees traveling over the toes for both movements to ensure quads are the main priority. 
• This study examined how different intensities of leg press training affect the vastus lateralis muscle. Results indicated that higher intensity training led to greater hypertrophy in type II muscle fibers, suggesting that heavy leg press exercises can effectively promote quadriceps muscle growth. https://pubmed.ncbi.nlm.nih.gov/23789443/
• This study compared trunk muscle activation between back squats and hack squats at equivalent relative loads. The findings indicated that while back squats resulted in higher trunk muscle activation, hack squats effectively targeted the quadriceps with reduced trunk involvement, suggesting their utility in focused quadriceps training. https://pubmed.ncbi.nlm.nih.gov/28704312/

Sissy Squats

• Another great movement that can be quite versatile when it comes to modality. Use different ways to integrate load, such as machine or free weight integration. 
• Sissy squats create an immense amount of tension due to the stretch position of the quadriceps. 
• Higher advanced movement. Emphasize body weight & mechanics prior to integrated load.
• Allows for an upright position, which minimizes hip flexion (emphasizes knee flexion). 
• There is a scarcity of peer-reviewed studies specifically examining the effects of sissy squats on quadriceps hypertrophy. Most available information stems from fitness professionals and anecdotal evidence.

Leg Extensions

• The top tier concentrated quad activation movement. 
• Pure quad concentration!
• Single joint movement, I would consider it necessary to integrate for quad growth. 
• Directly focused on knee flexion, no other joint movement responsibilities. 
• This study compared the effects of performing leg extensions at hip flexion angles of 90° versus 40° over a ten-week period. Results indicated that training with a 40° hip flexion angle led to greater hypertrophy in the rectus femoris portion of the quadriceps, suggesting that adjusting the hip angle can optimize muscle growth in specific regions. https://www.researchgate.net/publication/380457955_The_effects_of_hip_flexion_angle_on_quadriceps_femoris_muscle_hypertrophy_in_the_leg_extension_exercise
• This research examined the impact of different ranges of motion during knee extension exercises. The findings revealed that training with partial ranges of motion can still result in significant quadriceps hypertrophy, highlighting the adaptability of muscle growth to various training modalities. https://pubmed.ncbi.nlm.nih.gov/33977835/

Peer review articles

https://www.mdpi.com/2076-3417/15/5/2471?utm_source=chatgpt.com

This comprehensive review examined the impact of different footwear and heel elevations on back squat biomechanics. It concluded that weightlifting shoes with elevated heels decrease trunk lean and increase knee flexion, which may enhance quadriceps activation during squats.

https://pubmed.ncbi.nlm.nih.gov/33844006/

This research focused on how heel lift insoles affect muscle activation and joint mechanics during barbell squats. The study found that heel lifts can alter lower limb biomechanics, potentially increasing quadriceps activation by promoting greater knee flexion angles.

https://www.mdpi.com/2076-3417/15/5/2471

This systematic review analyzed the effects of varying heel heights on squat stability and mechanics. The findings suggest that higher heel elevations can enhance squat stability and may contribute to increased quadriceps engagement due to changes in knee joint angles.

https://pubmed.ncbi.nlm.nih.gov/32605065/

This systematic review analyzed muscle activation during leg press exercises. Findings highlighted that the vastus lateralis and vastus medialis exhibited the highest activation levels, indicating the leg press's effectiveness in targeting these quadriceps muscles.

https://pmc.ncbi.nlm.nih.gov/articles/PMC6206431/

This study compared quadriceps activation between leg press and Smith machine squats. Results showed that the leg press elicited significant quadriceps activation, underscoring its efficacy for quadriceps development.

https://pubmed.ncbi.nlm.nih.gov/27735888/

This research compared the effects of squat and leg press exercises on strength and body composition. Both exercises were effective in enhancing lower body strength, with the leg press specifically contributing to quadriceps hypertrophy.

https://www.researchgate.net/publication/337400852_Evaluation_of_Muscle_Activities_During_Different_Squat_Variations_Using_Electromyography_Signals

This research evaluated muscle activation during various squat variations, including the hack squat. Results demonstrated that the hack squat elicited significant activation of the quadriceps muscles, particularly the vastus lateralis and vastus medialis, indicating its effectiveness in quadriceps-focused training.