So, I am a martial artist and my Sifu has some interesting ways to get us fit.... He uses plastic garden chairs. You can use them to do press ups, sit ups, stretches and as a weight. The best one is hold the garden chair by the front two legs, sit in a horse riding stance and have your arms out straight at shoulder height and HOLD..... Trust me, you'll feel it.
I now look at garden chairs with a new-found respect