Flexion and Extension

Flexion and Extension – When describing an anatomical movement, flexion is the closing of the angle between two segments of the body. For example, when you bring your hand from your side up to the shoulder, you are performing an elbow flexion movement.

Partial list of the flexion muscles:

Sternocleidomastoids (neck flexion)
Anterior Deltoid (shoulder flexion)
Biceps (elbow flexion)
Rectus Abdominus (trunk flexion)
Iliopsoas (hip flexion)
Hamstrings (knee flexion)
Anterior Tibialis (ankle dorsiflexion)

Those muscles are directly opposed by the extensor muscles. Extensor muscles, which help us fight gravity, increase the angle around a joint. An example of a extensor muscle in action would be sitting in a chair with bent legs and then lifting your feet out until the knee is straight.

Partial list of the extensor muscles:

Splenius Capitus/Cervicus (neck extension)
Posterior Deltoid (shoulder extension)
Triceps (elbow extension)
Erector Spinae (trunk extension)
Quadriceps (knee extension)
Gastrocnemius (plantar flexion)

As a general rule, if a muscle lifts a weight, the same muscle lowers the weight. Consider sitting down. When we sit, our ankles, knees, and hips bend, allowing us to get comfy in our leather barcalounger. However, despite all of that bending (flexing) we used our extensor muscles to sit. That is because when we sit we are resisting gravity to slowly descend to a sitting position. Our extensor muscles control our descent into a flexed position. On standing up, again, our extensors contract so we can over come gravity and stand erect.

Here at Vertex Fitness, we use a total body, high intensity workout that works both the muscles that flex and the muscles that help extend. We do exercises that isolate different ,useless and we do exercises that work more than one muscle group at a time. From flexion to extension, we’ve got your muscles covered with a safe, effective, and efficient workout!


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