I has a period of almost 5 months when I was doing at home the following exercises daily:

1. https://youtu.be/20zybMbnVoU - from UC San Diego Healtg

2. https://youtu.be/XkT7jxFfPHA - from UC San Diego Health

3. https://youtu.be/5M-b1c2spPE - from Mayo Clinic

4. https://youtu.be/GS_z6FG_jqE - this is from a fitness instructor but it is simple and easy to follow.

All of them are easy to remember after watching 2-3 times at max. And they can be done at home, no tools required.

I had some back pain and did them almost daily from January to May and the pain almost disappeared. But I was stupid enough to go into a very intense project and did not had time to do them. Now I try to get back into a daily routine (after 6kg extra gained in the last 3 months)

In case you want something which is more intense I also tried this one https://youtu.be/istOU9nxhm8 (from the same fitness instructor) and I liked it a lot.

I think it might help to actually formulate a goal, like, say, run 5K or bike 100 miles or do 100 pushups at once or something, and then build a workout regimen that will get you to that point. In my own experience, I've found that "I'll just do pushups and stuff" means I won't stick with it, because it's difficult for me to really measure progress and I get easily discouraged without a training plan.

What sports or fitness celebrities inspire you? Have you ever watched American Ninja Warrior or anything like that? That's one of the things that inspires me on my fitness journey. I'm primarily a runner, but I cross train with strength and climbing as much as I can. I still can't do more than two pull-ups, but someday...

As for resources, /r/fitness and /r/bodyweight on Reddit have a bunch of decent resources. The latter is especially useful because they can provide some really good routines that incorporate only yourself, so you won't need equipment or anything else. If all else fails, hire a personal trainer. Even in this COVID era, they can coach you over video call, and if you do that for a few weeks, you should have enough workouts to keep yourself busy on your own for a while.

My final tip is to do at least 10 minutes of exercise per day. You can do anything for 10 minutes a day. If after 10 minutes I'm bored or I'm tired or I just plain don't want to continue, then I give myself permission to quit. (I've been doing this for years and i've never actually stopped after 10 minutes... the hardest part about working out is STARTING!)

Anyway, good luck!

1. Total body workout for 45 minutes - you need a good yoga mat to protect your knee/back -> youtube, pick 2-3 different videos from different "instructors".

> If it has to be something like pushups it at least has to be a routine simple enough so I don't have to watch some fitness dude or gal on youtube and follow them. I'd rather watch or listen to something interesting in that time.

I tried doing fitness and have my mind somewhere else: didn't work well. Don't fight it, listen to what they say, focus 100% do it right so you can learn what muscle is targeted for which exercise and to avoid injury as well.

> any science based plan on how or what I should train?

Most trainings are science based.

Get a dumbbell (buy 1 pair) or kettlebell (buy 1 piece), expand your total body workout to include a little bit of strength training.

2. Run 5k/10k - you need good running shoes

Yes, it's boring, but the journey from couch to 5k then figured out how to reach 10k, has been a great challenge + journey + accomplishment. Learn how to run correctly. Learn how to reduce toll on your body via different training methods.

3. Cycling - yeah, it takes time; time well spent in my case

Sign up with strava. Track your metrics. See if you can climb higher elevation. See if you can bike longer/further. Plan your route. If you can do 50k with some hills, can you plan 70k without hills? All these planning is fun for me.

Personally exercise takes my mind off from routine works (regardless if you're doing R&D or CRUD app: they're the same, there's a pattern and routine even in "exciting ML research").

I feel relieved/recharged after a 5-10k run session or a long bike ride.

I enjoy the process c25k (couch to 5k). I enjoy the process to move the goalposts to hit 10k. I love that feeling of achievement too.

I realized that running 5-10k regularly requires me to take care of my body: sleep + nutritions + muscle building (this is why I do total body workout + strength training).

I acquired new sets of skills/ways of thinking from all these exercise.

Just like software has technical debt. Our body needs to be maintained as well.

I love/enjoy the journey from not knowing about fitness in general to where I am today. Fitness becomes my hobby aside from software development and I'm happy that I chose to invest in myself.

Jumping jacks, squats, push ups, ...

People in martial arts do exercises like those just a little more complex. (e.g. push ups w/ clap)

Yoga (see Sun Salutation)

I was going to suggest the same. Body weight workouts are fantastic and you can add progressions that increase difficulty or emphasize different aspects. You only need appropriate clothes, space enough for a yoga mat, and maybe a jump rope if you want some good indoor cardio.

Push-ups can be started against a wall or table until you’re better at them. Crunches and sit-ups on the floor. Dips with a chair. Rows with a sturdy table. Squats, jumping jacks, burpees, flutter kicks, leg lifts, mountain climbers. Yoga poses and routines like you suggest. Similarly static poses like wall sits and planks if you don’t want to seek out yoga lessons yet.

All of these can be made more difficult or easier with various progressions. Most (assuming you’re not doing crazy number of reps or times on the static poses) can be done daily. I used to do a circuit an hour during the work day to keep me moving. String together a set of exercises and reps for each that can be done in 5 minutes or so and repeat it throughout the day.

And like with weight lifting, you can fall back to easier progressions if something gets too hard. If you want to do 50 push-ups, but struggle after 20, drop the knees and do something to finish up. Try to go further each time.

And if you have a bike, get an indoor trainer. They’re aren’t too expensive, park it in front of the tv or put on a podcast and just pedal and look out a window.