When I started getting back into playing badminton three years ago, I would play twice a week for a duration of 2-3 hours each. And then for half a year, I would have muscle ache all over my body the next day. But as I got more and more conditioned, the muscle ache went away. Now I play three times a week for a duration of 3-4 hours each, and feel fine the next day. Yesterday I went for the Mansfield Badminton Open, played 5 singles matches (1 easy match, and 4 of moderate intensity) and 2 doubles matches (1 moderate intensity, and 1 high intensity). And today the good old muscle ache is back!
well, just 6 more months of Open compeition and you'll need to move up to international competitions to get back that muscle ache
i did some weight training when i was young. when i first started, my whole body ached like crazy. i had problem even moving around, my back and leg muscles was in so much pain, i needed my arm to help my sit down. but after 2 weeks of regular training, i was no longer aching. i kept on for a few months and everything was good. then after i stopped for a months, i went back to weight training and again, the initial two weeks i was in pain. so i think the body needs to get used to the intensity, if you increase intensity, it will ache but after a week or two at that level, it will get used to it again.