Validity of Ergograph as Measurer of Work Capacity 5 



neous movements which are energy-consuming and use up the 

 force that should be exerted in other directions. This subject 

 will come up again later. When all the muscle groups work 

 together for the same end, the performance of the movement is 

 said to be skilful. The difference of manner in which the skilled 

 and the unskilled bicycle rider "take a hill" is due to the way 

 they apply power to the pedals. The ability to throw the weight 

 on the pedals at exactly the right point and at the right instant, 

 and to make the proper movements with the other limbs and 

 trunk characterizes the skilful rider, and the inability to time 

 movements and apply power properly is the defect of the un- 

 skilled rider. In the game of golf perfect coordination of the 

 muscles is essential. It is not always the most powerful stroke 

 that sends the ball farthest, but it is the swing of the driver which 

 takes the ball exactly at the right angle. Such a drive depends 

 upon the success with which the player contracts all his muscles 

 at the right instant and applies them exactly to the point where 

 their combined effect will be greatest. 



Thirdly, by practice the power or contractile force of muscle 

 groups is greatly increased. After practice greater power is 

 shown by the baseball pitcher's arm. This is due not only to an 

 increase in the bulk of tissue resulting from increased nourish- 

 ment through practice, but also to increased power of the nervous 

 system to discharge in a definite way and to concentrate all the 

 force upon a movement in a given direction. The muscles grow 

 in contractile power., and the nervous system shows increased 

 tendency to confine the nervous currents within narrow pathways. 

 A given stimulus concentrated upon a few muscles will yield a 

 stronger contraction than the same stimulus spread over a less 

 definite area. Just as, when shooting at a target before practice, 

 the shot is scattered over the whole target, so the nervous stim- 

 ulus sent to the muscles in the first instance is distributed' more 

 or less widelv, and as more of the shot will probably fall around 

 near the center than towards the edge of the target, so the main 

 part of the nervous excitation reaches the desired muscles : but 

 during practice the nervous discharge comes to be confined 

 almost entirely to the few muscles whose contraction is desired. 



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