Start below what feels possible
Cardiovascular fitness can return faster than joints and connective tissues adapt. Begin with short, conversational efforts and alternate running with walking. Finish feeling capable of doing more.
Progress one variable
Increase total time before adding speed. Keep most runs easy and avoid increasing duration, frequency, and intensity in the same week. Strength work for calves, hips, and hamstrings can support the return.
Separate discomfort from warning signs
General muscle fatigue is common, but pain that changes your stride, worsens as you run, or remains sharp should not be ignored. Seek an appropriate health professional when symptoms persist.
Bottom line
Use this guidance as a framework, then adapt it to your experience, equipment, budget, and health needs. Sustainable choices are the ones you can repeat.