of these properties occurred in a clever demonstration devised by Bud Abbott, Brenda Bigland, and Murdoch Ritchie. They connected two stationary cycle ergometers back-to-back with a single chain, such that one cyclist pedaled forward and the other resisted this forward motion by braking the backward-moving pedals. Because the internal resistance of the device was low, the same force was being applied by both individuals, yet the task was much easier for the individual braking. This demonstration cleverly revealed that a tiny female resisting the movement of the pedals could easily exert more force than, and hence control the power output of, a large burly male pedaling forward. Energy During the eccentric phase of movement, the muscle absorbs energy. This work is done "by stretching the muscle and in this process the muscle absorbs mechanical energy". This mechanical energy is dissipated or converted into one or a combination of two energies. Heat Elastic recoil Heat The energy that is absorbed by the muscle will be dissipated as heat if the muscle is being used as a "damper or shock absorber". This leads to increase in body temperature. Elastic recoil The energy that is absorbed by the muscle can be converted into elastic recoil energy, and can be recovered and reused by the body. This creates more efficiency because the body is able to use the energy for the next movement, decreasing the initial impact or shock of the movement. For example, kinetic energy is absorbed in running every time one's foot strikes the ground and continues as one's mass overtakes the foot. At this moment, elastic recoil energy is at its maximum and a large amount of this energy is absorbed and is added to the next stride. This movement is similar to the action of springs, where the muscle is continually shortened and stretched resulting in enhanced effectiveness and force. It can lead to the perception of "less effort" even though dealing with higher force. But time matters in elastic recoil. If this energy is not used quickly it is dissipated as heat. The role of eccentric training is to use these principles of energy conversion to strengthen muscle and tendon groups. Physiological mechanisms The muscle has "tension producing tissue comprising small contractile units referred to as sarcomeres" that each contain a "thick (myosin) and thin (actin) myofilament (muscle filaments or proteins) that overlaps to format a cross-bridge bond (attachment)".