To improve your fitness regime you should try to increase your swimming speed. You can do this by increasing the flexibility of your feet. When you have flexible feet, you can propel through the water faster. To increase this flexibility, you should sit on the floor with bare feet. Stretch out your legs with your heels on the floor. Point your toes out as much as you can and then flex them toward your shins as much as possible. Do this for one minute.
If you are going to use a bench, you should always test it first. If the bench is too hard, it may cause a misalignment in your spine that can weaken your arm. Test the bench by pushing a thumb into the padding. If you can feel the wood underneath the padding, find a better bench to use.