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.
Pinched nerve: Numbness in upper thigh is usually caused by a pinched nerve near outer groin. The nerve is called lateral cutaneous nerve of thigh. It causes numbness, tingling and burning in the front and outer side of thigh. Condition is referred as meralgia paresthetica.