This may seem a bit bizarre, but stick with it for a little while!
One of our cats died last week and we buried it in the garden so the kids could see where it was buried. I say we buried the cat but it was all left down to me.
Now remember I live just out side of Cambridge and the ground is very clayey ie hard and the vet very helpfully said "you had better bury the cat deep otherwise the fox will dig it up!!", so whilst I was digging the grave, my wife would helpfully say "I think you need to go a bit deeper!!".
You are getting bored by now and want to know what this has to do with getting fit, well before now if I did any sort of heavy gardening I would get cronic tennis elbow and very sore muscles, but 18 months worth of sit ups and press ups later and after 2hrs of digging a quarry in our back garden, no ill effects.
See getting fit helps to dig graves!!