The cycle continues as the mass vibrates back and forth about a fixed position. The springs inside of a bed mattress, the suspension systems of some cars, and bathroom scales all operated as a mass on a spring system. In all the vibrating systems just mentioned, damping is clearly evident.
[Continued from above] . . . Contraction of the quadriceps group extends the leg at the knee and flexes the thigh at the hip. The hamstring muscle group extends across the posterior surface of the thigh from the ischium of the pelvis to the tibia of the lower leg.
There is a bump on the outer side of the of the upper part of the thigh bone (femur) called the greater trochanter. The trochanteric bursa is located over the greater trochanter. , or irritation and inflammation of the bursa. A bursa is a fluid filled sac that acts as a cushion between tendons, bone, and skin.