Back to riding after ten years and I'm so old and unfit

Like riding a bike!
I'm happy to report that only the first time was really tough.
I was walking like a geisha for a few days where you only move the feet to walk. I was so sore.
But already by the next lesson things had come back. Riding was easier and I was less sore.
I did splurge and get me one of those kneeling posture chairs due the office. So it feels like I'm in the saddle even at work lol
 
I was told to go down on my knees and hands and then pull my tummy up. But to be honest I dont think one needs athletic fitness to ride a horse, indeed it could be an obstacle. A horse needs to move forward freely. A rigid human in the saddle will prevent the hind legs moving freely. The tension in the rider acts like a brake.

One does need to have strong ankles to ride and uness you have a high level RDA mounting block you need a strong left leg to lift you into the saddle,

I started riding aged 61 and in those days one just sat on the horse and was lunged.

Like you my main problem has been weight gain. And it is 5 weeks since I last rode
Sorry disagree here- athletic fitness benefits your horse. Being rigid is not the same as being strong and stable. A rider should be able to maintain a neutral spine and pelvic position and move with control in the saddle- this helps the horse with balance too.
Off horse training has been shown to improve peoples riding in research. Yes lunge can help too - but an unbalanced rider on a horse on tight circle repeatedly can be considered a welfare issue now given we know that can cause back pain in horses.

Its finding a riding fitness/exercise program that works for you- your current level, what you want to achieve, previous injuries and medical conditions etc
 
The kneeling chair
Sorry disagree here- athletic fitness benefits your horse. Being rigid is not the same as being strong and stable. A rider should be able to maintain a neutral spine and pelvic position and move with control in the saddle- this helps the horse with balance too.
Off horse training has been shown to improve peoples riding in research. Yes lunge can help too - but an unbalanced rider on a horse on tight circle repeatedly can be considered a welfare issue now given we know that can cause back pain in horses.

Its finding a riding fitness/exercise program that works for you- your current level, what you want to achieve, previous injuries and medical conditions etc
Yes. You said this perfectly
 
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