I remember when i was 16, im now 30, my very first full time job was a tyre fitter, very physical job. Well i worked with a guy who was 10 years older than me and every morning before work he used to stand out the back and warm up. He used to stretch, shake his arms ect ect. I said after i had been there a few days what on earth are you doing?? He said that like before any physical activity you must always get your body ready for it. I do this for ten minutes in the morning then at the end of the day i do five minutes warm down. So from that day on i have always in the mornings stretched the muscles, do 10 push ups and 10 sit ups gets my body ready for the day ahead. So far so good, maybe some of you guys should give it a go, it may make you feel a little better.