Plantarflexion points the foot and toes away from the shin, whereas dorsiflexion brings the top of the foot toward the shin. They are opposite movements occurring mainly at the ankle joint.
The Movement Mechanism
In the anatomical position, the feet are flat and point forward. Plantarflexion and dorsiflexion occur in the sagittal plane around a transverse axis, primarily at the talocrural joint of the ankle.
During plantarflexion, the angle between the dorsum (top) of the foot and the anterior surface of the lower leg increases. This movement occurs when standing on tiptoes, pushing off during a sprint, or jumping.
During dorsiflexion, this angle decreases as the toes move upward toward the shin. It occurs when the heel contacts the ground during walking or when the knee moves forward over the toes during a squat.
| Feature | Plantarflexion | Dorsiflexion |
|---|---|---|
| Direction | Foot points downward, away from the shin | Foot moves upward, toward the shin |
| Main agonist muscles | Gastrocnemius and soleus | Tibialis anterior |
| Sporting example | Pushing against the ground during take-off | Lifting the toes while running to prevent them dragging |
| Everyday example | Pressing a car accelerator | Walking on the heels |
The agonists for one action act as antagonists during the opposite action. For example, the gastrocnemius and soleus contract concentrically to produce plantarflexion, while the tibialis anterior relaxes or lengthens. During dorsiflexion, the tibialis anterior becomes the principal agonist.
A common misconception is that plantarflexion means flexing the foot upward because most flexion movements decrease a joint angle. At the ankle, however, plantarflexion specifically means movement toward the plantar surface, or sole, of the foot.
IB Exam Technique
For B.1.1, identify the joint action from the direction of movement and use precise anatomical terminology. In an explanation, state the movement, plane, axis, agonist, and a relevant sporting example; do not describe plantarflexion simply as “ankle flexion.”