Systems with side alternation usually have a larger amplitude of oscillation and a frequency range of about 5 Hz to 40 Hz. Linear/upright systems have lower amplitudes but higher frequencies in the range of 20 Hz to 50 Hz. Despite the larger amplitudes of side-alternating systems, the vibration (acceleration) transmitted to the head is significantly smaller than in non-side-alternating systems while at the same time muscle activation even at identical vibration parameters are increased in pivotal systems.However, standing with both heels on one side of a side-alternating machine facing side-ways results in significant acceleration transmitted to the head and center of gravity of the upper body. At least one such WBV owner's manual suggest this variation calling it "Stand-a-side Pose". At the outer edge of the plate the amplitude is typically about 10 mm, which is more than the 3 mm maximum of a linear vibrator and not practical. The amplitude and impacte can be reduced by centering, e.g., a gardener's knee pad, ~ 16"x 8" x 3/4", on the plate and standing with the heels toward the outer edge of the pad. While this is useful it does not replace a machine whose entire plate moves up and down in a linear fashion allowing for a variety of positions and activities.
stimulation generates acceleration forces acting on the body. These forces
cause the muscles to lengthen, and this signal is received by the muscle
spindle, a small organ in the muscle. This spindle transmits the signal through
the central nervous system to the muscles involved