The Indoor Rower is an excellent way to develop all round fitness which, depending on the way you programme your sessions, will benefit both your aerobic and anaerobic energy systems. In 1999 we brought out the DYNO, which is a strength-training machine. By using the same principles of air resistance as the rowing machine, but with a modified fan arrangement, a much greater load can be developed. The advantage of this machine is that with no fixed weight a load of 1000kgs can be developed on a machine weighing 55 kilograms.Because the load is dependent on the force developed by the user it is a very safe method of strength training. Also, because the load varies with the force applied, it mirrors the varying force that muscles are able to develop over their range of contraction. Despite many advantages of the DYNO over traditional strength training systems it has its critics. The main criticism is that there is no eccentric component to the exercise. While it is true that there is no eccentric element to the DYNO, this would only be relevant if we were suggesting that the DYNO should replace all other forms of exercise, which of course we don't.Muscles cannot push they can only shorten and this action is known as a concentric contraction. The way this works is that there are two long strand proteins called actin and myosin arranged in bands along the length of the muscle fibre. On receipt of an electrical stimulus from the brain a chemical reaction takes place called the actomyosin complex that requires ATP to supply the energy for contraction. A bridge is formed and the actin glides over the myosin, which has a series of tentacles that draw the actin along. These are microscopic movements individually but repeated over the length of the muscle fibre combine to move a limb over its full range.Muscles can be used in two other ways, contraction without shortening (static or isometric) and contraction while lengthening (eccentric). Which of these three options are used will depend on the task but the actomyosin process is common to all three, the difference is a neurological function.Muscles are made up of a number of fibres and for any task only a relatively small proportion of the total number of fibres are recruited at any one time. Consider a situation where you are lowering an object to a colleague. While you are waiting for him to get into position and holding the load still, the muscles are neither shortening nor lengthening. The brain has balanced the number of fibres to the load and so this is a static situation. You now want to lower the object so the brain switches off some more fibres so that those still working cannot stop the muscle lengthening. This process controlled by the brain is known as the neural-muscular system. The development of the neurological element is a vital ingredient in the preparation of an athlete and so eccentric as well concentric exercise is essential. Eccentric use of the muscle occurs for example in ball games where the athlete has to stop suddenly and change direction and when landing in jumping events. Static, eccentric or concentric are functions of the muscle and because of the sport specific nature of these functions I believe it is best done whilst practising the sport and specific sport drills.Strength on the other hand is determined by the cross sectional area of the muscle fibre and is a limiting factor of the loads that can be tolerated during the muscle functions. The best and safest way to increase the cross sectional area of the muscle fibre is by progressive overload of the muscle in concentric contractions. This is only one aspect of training and greater strength alone will not necessarily improve performance. This new strength then has to be developed into greater speed or more power in the context of the end game by using a comprehensive programme of exercises and practice.Whatever your game, if you need to develop strength the DYNO is a safe and effective way of doing it. More on the DYNO can be found at http://www.therowingcompany.com/v4/dyno_main.htm