Pete here, really excited to contribute to this community! I share the need to get back to effective training as quick as possible while dealing with injury.
Good news/Bad news here! If you can intervene when it first starts, your success rate goes way up. I often deal with plantar fascitis that has gone on for MONTHS, that can be a different story. You first start with treating locally: arch support, change in footwear to more supportive, deep massage to the arch surfaces, kinesio taping or traditional athletic tape for support, and activity modification…ugh. Cycling with stiff shoes is usually well tolerated. Low rpm or standing intervals will address muscular endurance work. Deep water running in the pool would be better than swimming.
If you dig a little deeper to the origins, you can avoid it in the future. Training errors are the usual cause, poor progression in volume/intensity/terrain/equipment (Shoes)! Have a plan, a coach, and follow the path.
Calf and hamstring stiffness will create more restriction through the fascia, exacerbating heel pain. Dig a little deeper, and if your are over `30-40 the spine comes in to play as the cause of calf/hamstring tightness giving heel/foot pain. Of course every therapist will tell you the hip is ‘weak’ which increases the amount of work the foot has to do to control movement. One of my Olympians felt that getting really glut strong helped, but this does not work for everyone.
Whew, a lot of ground to cover here. As you can see, there can be several causes and therefore people have success with different treatments and approaches. Start working on the calf mobility, arch soft tissue support, and have your therapist run down what is the cause of your plantar fascitis.
Pete