Muscles Targeted with a Stationary Bike

Call it indoor cycling or call it stationary biking — feeling the burn on a bicycle machine comes with a whole host of benefits, from the brain all the way to the belly.

While the primary perks of working out on a stationary bike include getting your daily dose of cardio and burning extra calories, this joint-friendly workout also engages your hip and leg muscles as you pedal, with some variations affecting the targeted muscles in surprisingly different ways.

Despite the fact that they're immune to rainy days, never need to have their tires pumped and won't get stolen when they're not chained to a post, bicycle machines provide many of the same basic benefits as riding a regular bicycle. And those benefits are exceptionally wide ranging.

Regular biking is particularly notable for its potentially positive effects on cardiovascular health, with even 30 minutes or an hour of biking per week linked to lower rates of heart disease and a reduced instance of heart attacks. But that's just the beginning — about 30 minutes of stationary biking and other cardio workouts performed at least five days per week can yield health benefits, like:

• Increased blood flow (making for a decreased chance of stroke) and better circulation
• Improved memory and reduced decline in brain function with age
• Lower blood lipids and greater blood sugar control
• Decreased pancreatic stress
• Reduced chance of developing type 2 diabetes
• Healthy weight maintenance
• Increased lung capacity
• Improved sexual function in both men and women
• Better range of motion in the joints
• Prevention of osteoporosis
• More and longer lasting energy (via the release of endorphins)
• Reduced stress and anxiety and a better mood (via the release of serotonin, dopamine and norepinephrine)

Read more: Can You Do Cardio Exercise Every Day?

Pedaling on a stationary bike (or a moving bike, for that matter) engages various muscles in both a dynamic and a static fashion, acting as a low-impact exercise that focuses on working the joints. Dynamic engagement is the contraction of muscles — specifically concentric and eccentric contractions — resulting in movement.

Primarily, the motion of pedaling engages your hips in a type of articulation known as extension, a movement defined by straightening the hip joint in such a way that increases its angle and moves the thigh or top of the pelvis backward. When you engage in hip extension, your body works the following muscles in the area of your thighs and rear end:

• Gluteus maximus (yes, the butt)
• The semitendinosus of the rear thigh
• The semimembranosus, also located at the rear of the thigh
• Biceps femoris (the long head of the inner rear thigh)
• The adductor magnus (ischial fibers) at the inner thigh, just below the groin

Long story short, you're hitting those hamstrings and hip adductors. So if you haven't gotten the hint by now — yes, riding a stationary bike is a pretty good bet for toning the legs.

Read more: How to Tone Your Hips and Thighs One Minute at a Time

Your hips aren't the only body parts engaged in extension when you're hitting the stationary bike. Similarly, you're getting your knee extension on by straightening those joints too. Like hip extension, knee extension occurs when you increase the angle of the joint, in this case moving the lower leg away from the back of your thigh.

When you perform a knee extension on your bicycle machine, you're targeting the quadriceps femoris. Also known as the quads, this muscle resides at the front of the thigh and is made up of these four heads:

• Rectus femoris
• Vastus lateralis (externus)
• Vastus intermedius
• Vastus medialis (internus)

Fun fact: These four heads are responsible for the name "quadriceps," which translates as "four headed." The group of vastus muscles starts at the long femur bone and stretches to the kneecap, making them a pretty important part of one of the body's biggest muscles — those all-important quads.

Read more: Bad Knees? Try These 14 Knee-Strengthening Exercises

While dynamic engagement ultimately results in movement, isometric muscle engagement — more commonly called static tension — happens when your muscles contract without significant movement. In stationary bike exercise, this type of static engagement occurs at the ankles, making for some particularly ankle-friendly cardio.

Specifically, the type of static muscle extension that your ankles experience as you pedal a bike is called plantar flexion, the movement of the forefoot away from the body. During plantar flexion, plenty of small muscles of the lower legs are engaged:

• The gastrocnemius, better known as the calf
• The soleus at the inner and outer sides of the calf
• The thin plantaris at the posterior of the leg
• The central tibialis posterior, which stabilizes the lower leg
• The flexor hallucis, another posterior leg muscle that connects to the big toe
• The flexor digitorium longus, a tapered muscle at the tibial side of the leg

While the standard variety of stationary bike puts your body in an upright position just like the normal, outdoorsy kind of bike, recumbent cycles place your body in a more reclined position.

Cycling on a recumbent bike often makes for a more comfy experience, but it works the muscles in much the same way as an upright stationary bike, encouraging dynamic hip extension, dynamic knee extension and static ankle engagement, and engaging all the accompanying muscle groups. So are there any differences?

None too great, as it turns out. In an April 2016 study published in the International Journal of Sports Physical Therapy, researchers compared trunk and lower extremity muscle activity across upright bikes, recumbent bikes, treadmills and other devices.

While activity in the lateral head of the gastrocnemius was higher during upright cycling, muscle activation in the lumbar erector spinae, rectus abdominus, gluteus maximus, gluteus medius and biceps femoris remained low to moderate across all equipment tested (including a treadmill and an elliptical-bike hybrid device).

Just as powering your way up a steep incline on a moving bike can affect the way your muscles engage, modifying the crank resistance on a stationary bike also impacts muscle activity. It's easy to guess that more resistance leads to more intense muscle engagement, but December 2014 research from the Hungarian journal Acta Physiologica Hungarica conveniently confirms that guess.

The Acta Physiologica study has found that electromyography (EMG) amplitudes — muscle activity measured by assessing the electrical pulses that nerves in the muscles send out to communicate movement — were higher in both the quads and the hamstrings when resistance is increased. This remains true across various pedaling speeds, of course.

That's not all that the study found out, either. As two different pedaling speeds (fast and slow) were investigated across the varying resistance conditions, the researchers made a somewhat surprising discovery: Hamstring activation was increased at higher speeds more so than quadriceps activation. If you're targeting the hams, the cadence of your pedaling might just come into play.

Read more: Knowing the Difference Between Hamstrings and Quads Can Prevent Injury

It's not uncommon for stationary bikes to be used in rehabilitation-oriented physical therapy, given their low-impact, joint-friendly benefits. A November 2015 study from the Journal of Physical Therapy Science explores this application of bicycle machines and finds some interesting results about how they strengthen muscles along the way.

In a test of 32 chronic stroke patients, researchers have found that 30 minutes of rehabilitative stationary cycling five times per week (there's that magic 30 minutes, five days again) over the course of six weeks significantly improved both balance and gait abilities. This suggests that regular stationary cycling may reduce musculoskeletal impairment and improve locomotor function.

Likely, these positive results are due to increased muscle strength in the legs encouraged by the biking routine. By routinely activating and strengthening the hamstrings, rectus femoris, gastrocnemius and tibialis anterior and engaging in flexion and extension of the hips, knees and ankles, the lower body is eventually able to bear more weight.

Of course, engaging all those lower-body muscles means you're burning calories too. The exact amount of calories you burn while working out on a stationary bike varies widely based on several factors, including your body weight, duration of the exercise and workout intensity. With that in mind, though, you can still take a look at some average stats, according to ExRx.net's Exercise Calories Burned Calculator, to get a general idea of what to expect.

Start with the United States body weight averages provided by the Centers for Disease Control and Prevention's National Center for Health Statistics in 2019, which place the average adult man at 197.8 lbs. and the average adult woman at 170.5 lbs. In this case, a man cycling at 10 miles per hour for a fairly standard 30-minute workout session burns about 297 calories, while a woman in the same situation burns roughly 256 calories.

Although stationary biking is typically low-impact, trendier indoor cycling classes last about 45 to 60 minutes and often focus on more heart-pumping speeds. Splitting the difference at a 50-minute session pedaling at an average of 13 mph, an average-sized woman can easily burn 605 calories, while a man could burn up to around 702 calories. Bump that up to racing speed and you're looking at 662 or 768 calories burned, respectively.