My 2 cents. Many, many injuries are the results of inactivity not activity.
What ever else you do, (bicycling is awesome!), make sure you strength train. Not just go through the motions but train. I.e follow a progression and actually get stronger. I am a masters (53yr old) competitive powerlifter. I squat, I deadlift, I press. Start slow. Do it correctly. A bar and weights. Full range of motion. Skip the machines. I know.....I hear everyone's eyes rolling...
People always say, I can't squat...I have bad knees, I can't deadlift I have a bad back, I can't press I have bad shoulders. In reality, most people have these chronic problems because they DON'T squat, deadlift, or press. Strength is fundamental to EVERYTHING we do. Getting out of bed, off the toilet, shoveling the driveway, and riding a bike. Strong people are harder to kill, and more useful in general.
If you are interested, read anything and everything by Mark Rippetoe. Start very slow, correct form, progressively increase (slowly). Start with a broomstick if you have to. I did.