Source : Webster's Revised Unabridged Dictionary (1913)

Jerking \Jerk"ing\, n.
   The act of pulling, pushing, or throwing, with a jerk. --
   {Jerk"ing*ly}, adv.

Jerk \Jerk\, v. t. [imp. & p. p. {Jerked}; p. pr. & vb. n.
   {Jerking}.] [Akin to yerk, and perh. also to yard a measure.]
   1. To beat; to strike. [Obs.] --Florio.

   2. To give a quick and suddenly arrested thrust, push, pull,
      or twist, to; to yerk; as, to jerk one with the elbow; to
      jerk a coat off.

   3. To throw with a quick and suddenly arrested motion of the
      hand; as, to jerk a stone.

Source : WordNet®

jerking
     adj : not having a steady rhythm; "an arrhythmic heartbeat" [syn:
           {arrhythmic}, {jerky}, {unsteady}]
     n : an abrupt spasmodic movement [syn: {jerk}, {jolt}]