Quite likely some don't feel quite familiar with the notion of kinetic chain, even if being used by some as if they have been born with the concept. Using my multi-segment mathematical model - actually developed to analyze large deflection flexing in shafts - I have put together a conceptually easily grasped example of a kinetic chain. It consists of eight segments of equal length of 1m, connected with revolute joints. Overall maximum length hence 8m. The mass for the inner segment is arbitrarily chosen to be equal to 1.28 kg, with each segment half the mass of the previous one. Hence, successively, 1.28, 0.64, 0.32, 0.16, 0.08, 0.04, 0.02, and 0.01 kg for the most distal mass.

The eight segment pendulum is simply released from the initial position as shown in Fig1. Only gravity is operating on the segments. Hence no external torques applied. It is truly remarkable the very high velocity obtained by the tip,  - 329 miles/hour - with only gravity force acting on the eight segment pendulum, see Fig2. It is very easy to observe that, by noting the separation between the red dots, the 7 inner segments all reduce considerably their speed, and so transferring a considerable amount of their  kinetic energy towards a more distal element. Especially for the proximal elements this transfer is quite considerable.

From Fig3 one can readily observe some essential features of a kinetic chain -

- A sequential motion where starting form the center sequentially elements reach a certain maximum velocity, and hence a maximum kinetic energy, and subsequently giving it up to the next adjacent segment.

-  The amount of kinetic energy flowing down to a more distal segment increases steadily till there is a very large transfer to and an almost explosive action of the most distal segment - a rather whip like behavior.

Notice that deceleration occurs in sequence for each segment without any external braking force applied. Some seem to have the impression that an external braking force/torque is required to initiate/maintain the sequential kinetic energy transfer. But is clear from above that all this takes place here automatically. Also it is interesting to note that an in-line condition is obtained, even with 8 segments, corresponding with the maximum distal velocity, see Fig2. Note the whip like behavior of the model.

When Cochran & Stobbs et al. and also Jorgensen calculated the horsepower required for a pro type golf swing they came to the conclusion that the contribution of the big muscles was necessarily required. However they overlooked the additional power available due to the typical action of the kinetic chain. The linear inertial reaction forces acting at the joints have a neutral effect overall but are quite important as a means of transferring power down the kinetic chain.

mandrin