What Does Cycling Do To Your Legs And Thighs: Will they get bigger or smaller?

Many people take up cycling in an attempt to improve their physique. Some of the main areas that people look to work on are their legs, thighs, and bum. But others also have concerns that cycling will actually make their legs bigger? Given there was so much information going around, I’ve taken a look into what changes cycling will actually have on your legs and thighs.

Cycling will initially cause your thighs to get smaller as you lose fat, and over time your legs will start to get more toned. If you train in a certain way that prioritizes muscle growth, then in the long term your legs will get larger, however, this is only the case if you prioritize this through your training.

As you can see, the changes that occur in your legs, thighs, and bum will change over time depending on the type of training you are doing and other factors such as your diet. But how do you make sure you are getting the legs you want, and how do you train certain areas of your legs to increase their size if this is your goal?

Does cycling make your legs bigger or smaller?

Your leg is made up of many different layers, be that fat, muscle, skin, or other tissues. The size of your leg is determined by the total size of all of these individual layers. By far the two largest factors are fat and muscle.

In reality, if you are overweight, cycling will cause your legs to get smaller, this is because the loss of fat will outweigh any increase in your leg size through muscle growth.

Once you get to a low enough body fat percentage, or if you start at a low body fat percentage, then your legs may start to get bigger over time.

How big they get will depend on the type of riding you are doing and your training regime. This includes your diet and which other exercises you do.

Will cycling make your thighs bigger or smaller?

The thighs are an area where the body stores a lot of its fat. As a result, you will likely find that regular cycling does have an impact on the size of your thighs.

Most cyclists will notice their thighs getting smaller, especially at the start of their cycling journey. As with the rest of the leg though, once you have lost fat around this area, you may find your legs start to get bigger again as the fat is replaced by muscle.

Starting SizeTraining RegimeInitial ResultsLong Term Results
Large ThighsTargeting weight lossSmaller ThighsLean Thighs
Large ThighsTargeting muscle gainSmaller ThighsMuscular Thighs
Small ThighsTargeting weight lossAverage ThighsLean Thighs
Small ThighsTargeting muscle gainLarger ThighsMuscular Thighs

Will cycling make your buttocks bigger or smaller?

As with your thighs, the buttocks are another area where people suffer from excess fat. However, in contrast to the thighs, you are likely to notice larger buttocks earlier on than your thighs.

This is because the muscles in your bottom are much larger than those in your thighs, and so an equal increase in both thigh muscles and buttock muscles will be more noticeable around your bum.

Does cycling reduce or increase fat around your legs?

It’s clear to see that cycling is a good way to lose fat. If you take a look at any professional bike racer, such as those in the Tour De France, you won’t be able to find one with any excess fat.

Cycling is primarily an aerobic exercise. Aerobic exercises are those that involve cardio and endurance workouts. They focus on doing light exercises for long periods of time, which is great for burning lots of calories.

Burning calories is the way that our bodies burn fat. As we use calories our bodies will break down the fat it has stored up over time, to make more energy to keep us cycling.

It is however important to note that the place where you lose fat is not decided by what area of your body you are exercising. Your body uses fat stores as it sees fit when it needs the energy. The way your body chooses what fast to burn first is typically defined by your genetics and if you are male or female.

On the plus side, this does still mean that you can burn thigh fat, leg fat, and excess bum fat as you cycle, but not necessarily because you are working those areas.

How long should I ride a bike to lose thigh fat?

We’ve already established that you can’t lose fat from one particular area of your body by choice. This means how long it will take you to get slim thighs will be quite person-specific.

The only way to lose fat is by maintaining a calorie deficit. While you may find that your body loses fat in other areas, such as your belly or chin first, eventually it’ll come off your thighs too.

If your main goal from cycling is weight and fat loss, take a look at my article here on how long it should take to lose 10kg from cycling.

When looking to lose weight from cycling, you will typically want to focus on road biking over other types of riding such as mountain biking.

While road biking, the two best cycling regimes will be endurance riding (riding for many miles at a moderate pace), or high-intensity training. High-intensity training has been shown in recent studies to be more effective for fat loss than other types of cycling.

High-intensity training (also called HIT) involves cycling as hard as you can for a short burst of time (think 20 or 30 seconds), before taking a minute of very slow exercise as a rest period. This cycle is then repeated multiple times. For an example of a HIT Bike training regime, take a look at this plan from anytime fitness.

It’s important to remember when looking to burn fat that your diet is just as, if not more important than how much exercise you are doing. At the end of the day, it comes down to calories in vs calories out.

Does cycling ever increase thigh fat?

As we’ve established, cycling is going to be burning fat and not putting it on. Some people might think that thigh fat is increasing, but this is likely to just be the result of muscle growth or toning in the area, or even excess water being stored by the muscles as they are having to work harder.

Does cycling tone your legs?

Muscle tone is not really a well-defined term. In reality, it just means having a low body fat percentage in the area in question, while also having a suitable level of muscle there to look “toned”.

As a result, any muscles that cycling works on can become “toned”, as you have a low enough body fat percentage to be able to see the.

If you are looking to get more toned to reduce cellulite, take a look at my article here, which focuses on the best way to get rid of cellulite through cycling.

What muscles does cycling tone?

Body AreaMuscles
ButtocksGluteus Maximus
Gluteus medius
Gluteus minimus
FootPlantar flexors

If you want to tone up a certain area of your body, take a look at the section below on does cycling increases muscle.

How long does it take to tone legs by cycling?

The time it takes to tone your legs through cycling will be very dependent on each person. Factors such as your starting body fat and muscle mass have a large impact on the time it will take.

Most people will start to see more of a toned physique when they fall below a body fat percentage of 14%, obviously, this is provided they have a good layer of muscle underneath their fat.

Does cycling build muscle?

While cycling will typically cause you to lose fat, it is going to cause you to build muscles in your legs. This can even get to the point where professional cyclists have trouble finding trousers than can fit over certain areas such as their thighs.

However, cycling alone will only get you so far, and only if you are training in such a way to focus on muscle growth will you notice any significant changes.

If you think about it, marathon runners have a different physique from Usain Bolt. Just because both are runners does not mean their bodies look the same.

The type of muscle you build and the amount will depend on the type of cycling you are doing. Long rides on flats at constant speeds won’t make your legs much bigger. Short sprint repeats weekly on steep hills will. This is why mountain biking tends to improve leg muscles more than road biking.

If your main goal from cycling is to build leg muscles, it may be worth adding in some resistance training at the gym, doing exercises such as squats to help build bigger quads and hamstrings in addition to cycling regularly.

You will also want to ensure you are eating enough protein and eating a calorie surplus (more in than out) and getting enough sleep.

How to build thigh and inner thigh muscles from cycling

In the image below, you can see the area in green is the portion of a pedal that activates your thigh muscles the most when cycling in a clockwise direction. If it is easier, you can think of the thigh muscles as working between the 10 and 4 hands of a clock.

In order to work these areas the hardest, you want to focus on tough inclines. This will help you to build muscle more quickly.

Make sure to spend as much time sitting on the saddle while you pedal as you can. This forces your quads (the main muscles in your thigh) to do more of the work than other areas such as your calves.

How to build buttock muscles when cycling

In the image below, you can see the area in green is the portion of a pedal that activates your buttock muscle the most when cycling in a clockwise direction. If it is easier, you can think of the thigh muscles as working between the 12 and 4 hands of a clock.

You can help to improve your muscle strength and tone by heading for the hills, as inclines and mountains force you to work harder with each pedal stroke. Working the muscles harder for a short period of time such as when on a street hill is the way you gain muscle the fastest.

Whatever riding position you are in, your glutes (the main muscles in your buttocks) will be working hard, and so any cycling will help to tone up and build muscle in this area.

How to build calf muscles when cycling

In the image below, you can see the area in green is the portion of a pedal that activates your calf muscles the most when cycling in a clockwise direction. If it is easier, you can think of the thigh muscles as working between the 2 and 8 hands of a clock.

Calves store very little fat compared to your thighs and bum, as a result, you are likely to notice muscle gains here first.

In order to work your calves the most, try to ride at an incline while standing up on the pedals. This raises your heels and puts more work through the back of your legs and calves.

How do you avoid big thighs when cycling?

As we’ve established above, to get huge thighs like the bike sprinters you see on TV, you will have to be putting serious hours into bike sprinting, incline work, and additional gym work.

This is on top of eating a diet that aids this muscle growth (high calories and high protein).

Cycling long distances with a balanced calorie intake is going to result in lean thighs that are going to be the same size or marginally bigger than average-sized legs.

Which exercises are best for your legs and thighs?

Is walking or cycling better for toning thighs?

Both walking and cycling can be used for weight loss. However, walking only burns 257 calories per hour, far less than cycling. This means that walking will be less effective at burning fat off of your thighs as you are burning fewer calories per hour.

Walking is also less effective at building up your thigh and leg muscles (unless you are spending your whole time walking up huge hills and mountains), as the work you are doing is less intense.

As a result, cycling will be better at toning your thighs than walking, as the tone of your thighs and legs is based on both muscle and fat percentage.

Is cycling better than running for thigh fat?

As with walking, running is another great option for losing weight and fat loss.

Running for 1 hour at an average speed of 8mph (average running speed for a man) will burn 992 calories. This is more calories than walking or cycling and so will be very good for fat loss.

Running will be less good for muscle building in your thighs or buttocks than cycling will, as you will not be able to work those muscles as hard or intensely as when you are cycling on an incline.

Running is however very good at building calf muscles, especially when you are running up a hill or incline.

Is indoor cycling as good as outdoor cycling for your legs?

Does indoor cycling make your thighs bigger?

While indoor cycling is a great choice for a cardiovascular workout, indoor cycling is less effective for building bigger thighs than outdoor cycling, especially when you compare it to certain types of cycling such as mountain biking.

Building muscles on a stationary bike is even harder than building muscles while road biking. This is because while riding a stationary bike, you do not get the benefit of the outdoor air or breeze to cool you down, and as such your cardio system will be pushed to its limit before your leg muscles are.

On top of this, stationary bikes have a different seating position than road or mountain bikes (they tend to be in a more relaxed or sat-up position). This means that you will be working different muscles than when you cycle on a normal bike.

Finally, indoor cycling is not as “stop-start” as outdoor cycling. This limits the amount of time you have to spend setting off from a standstill, which is one of the times when you work your muscles the most.

Is indoor cycling good for losing fat on your thighs?

While indoor cycling is not very good for building muscle, it shouldn’t be understated how effective it can be for general fitness and losing weight. Losing weight will result in slimmer thighs and may be exactly what many people are looking for.

Indoor cycling is great for fat burning as you are able to clearly set the speed and incline at which you are cycling, and you can also do exercise more frequently as you are not affected by factors such as the time of day or weather.


As you can see, when it comes to cycling impact on your legs, there are many factors you need to think about, be that the size of your legs when you start, the type of cycling you are doing, or other factors such as your diet and lifestyle.

Mark Holmes

30-year-old doctor with an interest in cycling, bikepacking, and statistics.

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