These several details present an apparently formidable list of detailed studies to be followed in order to execute a series of strokes and recoveries in the most approved fashion. In performance the operation is far more homogeneous than would appear from the above disjointed analysis of the several movements to be performed. The division of movements is made for the purpose of observation and appreciation of possibly several faults, which may occur in any one of the movements detailed. As a fact, the correct rendering of one movement--of one detail of the stroke--facilitates correctness in succeeding or contemporaneous details; while, on the other hand, a faulty rendering of one movement tends to hamper the action of the body in other details, and to make it more liable to do its work incorrectly in some or all of them. Experience shows that one fault, in one distinct detail, is constantly the primary cause of a concatenation of other faults. To set the machine in incorrect motion in one branch of it tends to put the whole, or the greater part of it, more or less out of gear, and to cripple its action from beginning to end of the chapter. Taking these various details _seriatim_. 1. The back should be set stiff, and preserved stiff throughout the stroke. Obviously, if the back yields to the strain, the stroke is not so effectual. Besides, if the back is badly humped the expansion of the chest is impeded; and with this the action of the pectoral muscles and of the shoulders (of both of which more anon) is also fettered. Further, the lungs have less freedom of play when the back is bent and the chest cramped; and the value of free respiration requires no explanation. We have said that the back must be stiff. If the back can be straight, from first to last, stiffness is ensured, _ipso facto_. If the back is bent, care must be taken that the bend does not increase or decrease during the stroke; whether straight or bent, the back should be rigid. The conformation and development of the muscles of the back are not quite the same in all subjects. With some persons absolute straightness of back comes almost naturally; with others the attainment of straightness is not a matter of much difficulty. With others, again, a slight amount of curve in the back is more natural under the strain of the oar, even with all attention and endeavour to keep the back flat. With such as these any artificial straightening of the back, that places it in a position in which the muscles, as they are adapted to the frame, have not the fullest and freest play, detracts from rather than adds to the power of the oarsman.