Recently I have had a number of letters about sore backs experienced when people exercise on the rowing machine. At the moment we are involved in a research project at Imperial College into back problems specifically related to rowing. Once this is completed we will have some very useful advice for back sufferers but these things tend to take some time. Meanwhile, here are some general housekeeping tips that maybe helpful.In my experience, back problems fall into two categories: those that are brought on directly by the action of the rowing machine, and the rowing action aggravating and old or existing injury.In the first instance, if you do anything that requires the muscles to operate over a range of movement and a loading they are not used to, then you can expect some sort of reaction. This would apply equally to rowing, digging the garden or even going for a long walk if you were not used to it. The reaction is usually soreness in the muscles and stiffening in the joints.This can be particularly uncomfortable if the muscles in question are the muscles in the back, especially in the lumbar region. These muscles, erector-spinae, run either side of the spinal column and their main role is controlling posture and supporting the spine. This means that they are always working whether you are sitting, standing, running or jumping. They don't normally operate over a wide range of movement and they don't normally take on a load like the muscles in the arms and legs. When these muscles are suddenly required to work, either statically bent over a shovel in the garden or dynamically as on the rowing machine, then they become stressed. Because their main function is to support the spine, they go into spasm and lock up tight, which makes any movement in the back difficult and can be quite painful. This would normally ease off after a couple of days but if it persists then you should seek medical advice.The best way to avoid this type of problem is to build up the time spent on the machine gradually. Warm up properly before the session and stretch and cool down afterwards. Get the muscles used to the range of movement by carrying out flexibility exercises. As you get older this is even more important as flexibility is reduced with age. You may find that Yoga is complementary to rowing training.When introducing young people to indoor rowing it is important to develop core stability along with fitness on the machine. Young people will often have a muscle imbalance where their leg strength is proportionally greater than their upper body. In this case it is better to coach a reduced body swing, letting the child sit upright and use a longer leg drive until the upper body strength is developed.The second problem is where there is an existing and often unknown problem that flares up when rowing. These can often be traced back to some impact damage like a car or motorcycle accident. These may go unnoticed, especially if there is some other more obvious problem like cuts or broken limbs. In many cases while recovering from these injuries, the body adjusts to a minor misalignment, which causes no problem until exposed through strenuous exercise. These problems are more difficult to deal with and have to be referred to the medical experts.As I said at the beginning, these are just a couple of the most common problems but by no means all, so don't try to squeeze your symptoms into one of these categories. If you are in the slightest doubt get it sorted.