If you are in your fifties, read both Starting Strength and The Barbell Prescription [2].
[1] https://www.amazon.com/Starting-Strength-Basic-Barbell-Train... [2] https://www.amazon.com/Barbell-Prescription-Strength-Trainin...
Strength training with barbells fixed all those aches and pains in my knees and joints that braces and doctors and physical therapy couldn't. When I started squatting, I suddenly stopped being afraid to walk down stairs. My posture improved. I noticed I had way more endurance when riding, and it made ever part of that, from carving to pumping, easier and better and more powerful.
For me personally, resistance training with weights is better than almost any other exercise for managing ADHD. I don't know what it is, but something about lifting keeps me focused and calm for a few days after a workout. Cardio never really did that for me.
I highly recommend Mark Rippetoe's book Starting Strength[0] to learn the mechanics of the lifts. StrongLifts is a sorta rip off of Starting Strength.
[0] https://www.amazon.com/Starting-Strength-Basic-Barbell-Train...
Do you walk? If you don't, start there.
A study of sedentary, overweight men and women (aged 40 to 65 years) showed they lost body fat and weight when they walked or ran 12 miles a week during an 8-month study, without changing their diet. A control group of non-exercisers all gained weight and fat during the 8-month study."
https://jamanetwork.com/journals/jamainternalmedicine/fullar...
Do you sit at a desk a lot? You probably have poor posture associated with it. Do any yoga, at all. Literally any program.
Here's one from my favorite online yogi - https://www.youtube.com/watch?v=tAUf7aajBWE
Do you want to lift weights? For $8, one time, you can order Starting Strength by Mark Rippetoe. - https://www.amazon.com/Starting-Strength-Basic-Barbell-Train...
This book will teach you how to lift the weights, as well as how to program the lifts, which is twice as much as this app is claiming to do. At 1/12th the price for the first year, 1/24th the second, and 1/36th the third, etc..
* https://www.amazon.com/Starting-Strength-Basic-Barbell-Train...
After a few months you'll exhaust that (perhaps just take it out of the library?), and need more intermediate-level information:
* https://www.amazon.com/Practical-Programming-Strength-Traini...
Otherwise, some others have suggested a few Reddit threads; see also /r/fitness.
https://www.amazon.com/Starting-Strength-Basic-Barbell-Train...
What appeals to me about the method is that it's based on solid thinking about the physics and physiology involved. The book is full of anatomical drawings that wouldn't be necessary and wouldn't be found in your average workout book. The creator really made a thorough study of strength training his life's work.
From the gloss for Practical Programming for Strength Training [1]: "Exercise is physical activity for its own sake, a workout done for the effect it produces today, during the workout or right after you're through. Training is physical activity done with a longer-term goal in mind, the constituent workouts of which are specifically designed to produce that goal."
He emphasizes that a realistic means of progression is one of the most important aspects of any training program.
Practical Programming and Starting Strength [2] (which is a better introduction to these ideas for novices) are together the best analytical discussion of physical training that I've seen.
[1] http://www.amazon.com/Practical-Programming-Strength-Trainin...
[2] http://www.amazon.com/Starting-Strength-3rd-Mark-Rippetoe/dp...
it seems like crossfit doesn't quite appreciate how easy it is to destroy a knee, or your back, from improper deadlift or squat form. done properly, they are fantastic exercises. improperly, they are dangerous.
http://www.amazon.com/Starting-Strength-3rd-Mark-Rippetoe/dp...
It essentially focuses on just the squat, deadlift, press, bench press, and (later) power clean, devoting around forty pages to each, and explains why you really don't need much else. They're quite difficult to get right, but the incredibly in-depth explanations will especially appeal to programmers who like understanding how things work.
I say this just because the book completely changed the way I approach the gym, and it mirrors what the article author says about the exercises he used.
[1] http://www.amazon.com/Starting-Strength-3rd-Mark-Rippetoe/dp...
http://www.amazon.com/Starting-Strength-3rd-Mark-Rippetoe/dp...
Try Starting Strength ( http://www.amazon.com/Starting-Strength-3rd-Mark-Rippetoe/dp... ). Most people (read: me) dick around in the gym with bicep curls and nautilus machines, which is a mistake.
I got basically no results while doing that, and my improvements have been dramatic since I started SS.
[0] https://www.amazon.com/Starting-Strength-Basic-Barbell-Train...