How soon strength improvements?

EccentricDad

I just started doing core exercises and I am feeling like poop after only a few crunches and planks. How soon before it hurts less and I can do more reps or longer ones? A few days? A week? How fast do initial muscle fibers grow after a sedentary lifestyle and not using the muscle group worked out in several years?

wmagoo27

The muscles will adapt to the exercise and recovery fairly quiclky. However, they won't start to grow and get stronger for a few weeks or so. Take it easy and stay consistant with your exercises, and you will progress in time.