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Does Leg Press Range of Motion Affect Quad Growth? What the Research Says

Written by:

Atlas Team

Does Leg Press Range of Motion Affect Quad Growth? What the Research Says

When it comes to building stronger, more muscular legs, one of the most debated questions in the gym is whether range of motion matters. Should you lower the weight all the way down during a leg press, or is a partial range just as effective? A recent study tackled this question directly, examining whether knee flexion range of motion during the leg press exercise meaningfully influences quadriceps muscle growth in people who already have resistance training experience. The findings offer a useful perspective for anyone looking to optimize their lower body training, and they may challenge some common assumptions about how depth and range affect muscle development.

What This Study Examined

The central question this research aimed to answer was straightforward: does the degree of knee flexion during the leg press exercise affect how much the quadriceps muscles grow over time?

Range of motion in resistance training has been a topic of ongoing interest in exercise science. Some evidence suggests that training through a longer range of motion can produce greater mechanical tension on the muscle, which may theoretically drive more hypertrophy. However, it is not always clear whether those principles apply equally across all exercises, populations, and conditions.

This study specifically focused on the leg press and looked at whether different knee flexion ranges — essentially how far the knees bend during the movement — produced different levels of quad muscle growth. Importantly, the researchers examined this question in resistance-trained individuals rather than beginners, which makes the findings more relevant to people who already have a consistent training background.

How the Study Was Conducted

The study used a resistance-trained population, meaning participants already had experience with structured strength or hypertrophy training. This is a meaningful distinction because trained individuals respond differently to exercise stimuli than untrained beginners, and findings from one group do not always transfer directly to the other.

Participants performed the leg press exercise under different knee flexion range of motion conditions. The researchers designed the protocol to isolate range of motion as the key variable, allowing them to observe whether differences in how far the knee traveled during each repetition led to measurable differences in quadriceps muscle size over the course of the study.

Muscle hypertrophy — the increase in muscle size — was measured to assess the outcomes. The study tracked changes in quadriceps size across the training period to determine whether one range of motion condition produced meaningfully greater muscle growth than another.

Key Findings

The study's results suggest that knee flexion range of motion during the leg press may not significantly influence quadriceps hypertrophy in resistance-trained individuals. In other words, the researchers observed that different ranges of motion did not produce meaningfully different amounts of quad muscle growth.

Key takeaways from the findings include:

  • Range of motion differences did not appear to significantly alter quad hypertrophy in the trained participants studied

  • The results suggest that, at least in the context of the leg press and among trained lifters, varying knee flexion range may not be the determining factor for quadriceps muscle growth

  • These findings add nuance to the broader conversation about range of motion and hypertrophy, indicating the relationship may be more complex or exercise-specific than previously assumed

It is worth noting that these findings apply specifically to the leg press exercise and to the quadriceps. Results should not be broadly assumed to apply to all lower body exercises or all muscle groups without further research.

What This Means for Training

Taken together, these findings suggest that trained individuals performing the leg press may not need to prioritize a specific range of knee flexion in order to stimulate quadriceps growth. This could have practical implications for how people approach leg training, particularly those managing joint discomfort or limitations that prevent them from achieving a very deep range of motion.

For lifters who have been told they must always use a full range of motion to maximize hypertrophy, this research offers a more nuanced perspective. It does not suggest that range of motion is irrelevant across all exercises — but it does suggest that for the leg press specifically, flexibility around depth may not come at the cost of quad development.

From a coaching standpoint, this kind of evidence can help trainers make more individualized programming decisions. For example, a client dealing with knee sensitivity who cannot comfortably achieve a deep leg press may still be able to train their quads effectively through a more comfortable range. Similarly, someone who prefers a particular depth can feel more confident that their approach is not significantly limiting their results.

That said, range of motion is just one variable among many in a resistance training program. Load, volume, effort, exercise selection, and recovery all continue to play important roles in driving muscular adaptations. If you are training with a Reno personal trainer, these are the kinds of nuanced, evidence-based details that can be incorporated into a structured program tailored to your goals.

Limitations of the Study

As with any individual study, it is important to consider the limitations before drawing broad conclusions.

  • Population specificity: The study focused on resistance-trained individuals. The findings may not apply equally to beginners or advanced athletes, who may respond differently to range of motion variations.

  • Exercise specificity: The results are specific to the leg press. Other quadriceps exercises, such as the squat or leg extension, may respond differently to range of motion changes.

  • Muscle group specificity: Only the quadriceps were examined. Other muscles involved in the leg press, such as the glutes or hamstrings, were not the focus of this study, and range of motion may influence those muscles differently.

  • Study duration and sample size: As with many hypertrophy studies, the duration and number of participants can limit how broadly the findings can be generalized.

These limitations do not invalidate the research, but they do reinforce the importance of interpreting any single study within the broader context of available evidence.

Conclusion

This study adds a valuable data point to the ongoing conversation about range of motion and muscle hypertrophy. The results suggest that in resistance-trained individuals, knee flexion range of motion during the leg press may not be a significant driver of quadriceps muscle growth. This challenges the assumption that more depth automatically equals more gains — at least in this specific context.

For everyday gym-goers and serious lifters alike, this is a reminder that training decisions are rarely black and white. Research like this helps inform how coaches and trainers structure resistance training programs, allowing for more flexible, individualized approaches that account for each person's anatomy, comfort, and goals.

If you are looking for evidence-based guidance on building your training program, working with a qualified coach can make a meaningful difference. Browse the Atlas Personal Trainings in Reno to find a coach who can help you train smarter.

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Source

Knee flexion range of motion does not influence muscle hypertrophy of the quadriceps femoris during the leg press exercise in resistance-trained individuals. Journal of Sports Sciences. 2025. https://www.tandfonline.com/doi/pdf/10.1080/02640414.2025.2481534