Normal range of motion for plantarflexion is:

The normal range of motion for plantarflexion, which is the movement that points the toes downward and is essential for activities such as walking, running, and jumping, is commonly accepted as 40 to 70 degrees in healthy adults. This range allows for optimal performance of various physical activities and is crucial for proper biomechanics of the foot and lower limb.

Understanding the context of the other options helps clarify why they do not represent the normal range for plantarflexion. For instance, a range of 20-40 degrees would be too restrictive to accommodate the full motion needed for adequate mobility and heel rise during walking and running. Similarly, the ranges of 30-50 degrees and 50-90 degrees exceed or fall short of the generally accepted limits, indicating either insufficient motion or excessive motion that could lead to instability or other biomechanical issues.