What's the Difference Between Flexion and Extension?

Health Line

6 hours ago

Flexion or extension of a certain body part typically refers to joints. Flexing a joint usually means closing it, and decreasing the angle between the body parts, while extending a joint means opening it, or increasing the angle.
Flexion and extension are two important motions that allow us to coordinate our body movements. We all perform them in our day-to-day life without thinking about them too much.
We might extend our elbow to grab a glass from the cupboard, then flex it or bend it back to bring the water glass to our lips for a sip.
These are typical activities that require our body to bend or stretch the joints.
Read on to learn more about flexion and extension, and how flexion or extension exercises could be beneficial for health and lower back pain.
What's the difference between flexion and extension?
When we flex or bend our joints, we reduce the angle between the body parts, which brings them closer together. Extension is the opposite movement, when we increase the distance between two body parts by stretching or straightening the joint.
Flexing brings the body parts closer, while extending moves them further away from each other.
Body parts that flex and extend include:
elbow
arm
fingers
hips
toes
neck
spine
When do we perform flexion or extension?
Some examples of flexion include bending or flexing:
the elbow to bring a glass to your lips
your fingers to grab a pen or pencil
your neck to look down at something at our feet
the spine to slouch in your seat
your knees when you sit down
Extension is the opposite action. Examples of extension include extending or straightening:
the elbow to place something on the top shelf
your palm and fingers forward to feel drops of rain
the neck to look up at the sky
your back when sitting at your desk so that you won't slouch
your knees when you stand up
Can flexion and extension exercises have health benefits?
Performing exercises that include flexion or extension could have certain health benefits. A 2023 study concluded that trunk flexion and extension exercises that required control of the spine improved spinal mobility and reduced muscle tension in the participants.
Another 2024 study compared the effectiveness of flexion and extension lumbar exercises in people diagnosed with chronic lower back pain.
The researchers followed up with the participants after 1 year and concluded that the group who performed extension back exercises experienced less pain than the group who performed flexion exercises.
Here are a few examples of exercises that include flexion of your joints:
What are extension-type exercises?
These are some examples of exercises that involve extending your joints:
upward neck extensions
bed hangs
glute bridges
hip thrusts
stepups
quadruped kickbacks
standing kickbacks
upright hip thrusts
Takeaway
Flexion and extension are motions that everyone performs in their day-to-day lives. Flexing or bending your joints means bringing your body parts close together, while extending or straightening them means putting more distance between them.
Flexion and extension exercises can help relieve pain and muscle tension, so it can be worthwhile to include them in your routine.