Will Running Make My Legs Bigger Or Smaller

As an avid runner, I’ve often wondered how my favorite form of exercise impacts the size of my legs. Many people have the misconception that running will make their legs bigger due to muscle growth, while others believe it will make their legs smaller by burning fat. Let’s explore the effects of running on leg size to uncover the truth behind this debate.

Running and Muscle Growth

When we run, our leg muscles, including the quadriceps, hamstrings, and calves, work hard to propel us forward. This repetitive motion can stimulate muscle growth, especially in individuals who are new to running or engage in high-intensity sprinting. However, the extent of muscle growth largely depends on individual factors such as genetics, diet, and training intensity.

Body Fat and Leg Size

Running is a fantastic cardiovascular exercise that effectively burns calories and helps reduce overall body fat, including fat stored in the legs. Over time, a consistent running routine can lead to a decrease in fat accumulation in the lower body, contributing to a leaner appearance. However, the impact of fat loss on leg size varies from person to person.

Types of Running and Leg Size

It’s essential to consider the type of running when discussing its effects on leg size. Endurance running, such as long-distance running, primarily focuses on improving cardiovascular endurance and may not significantly increase muscle mass. On the other hand, sprinting and hill running can engage the leg muscles more intensely, potentially leading to muscle development.

Personal Experience

From my personal experience, as someone who has been an enthusiastic runner for years, I’ve noticed that my legs have become more toned and lean without appearing significantly bigger. The combination of running, strength training, and a balanced diet has helped me achieve a well-proportioned lower body without excessive muscle bulk. It’s important to remember that individual results may vary.


In conclusion, the effect of running on leg size is influenced by several factors, including genetics, training intensity, and overall body composition. While running can contribute to muscle growth, especially in the initial stages of training, it primarily aids in reducing body fat, leading to a leaner and more toned appearance. Ultimately, a well-rounded approach that includes running, strength training, and a healthy diet can help individuals achieve their desired leg size and improve overall fitness.