The key here is that plantar fasciitis is an inflammation of the fascia where it attaches at its origin--the heel bone. My general rule is that this inflammation must be calmed down before returning to walking and running. Hold off on using a treadmill until the pain is gone or greatly decreased.
To heal the pain and inflammation of plantar fascitis, it’s important to identify what is contributing to it. First, is it your foot type. Do you have high arches or flat feet? Do you have tight calf muscles? Are your shoes stable? Problems in any of these areas can lead to plantar fasciitis and must be addressed first.
Once your plantar fasciitis is healed it's important to learn proper form and use of a treadmill to prevent future problems.
To learn more about how plantar fasciitis is treated visit here!