Why IET   The Concept   General Principals   IET Operation   How it Works   IET vs. Other Exercise   Sample Programs

Operation of the Impulse




Exercises and Exercise Positioning: Regardless of the exercise application (rehabilitation or general conditioning), the following factors must be considered in order to maximize the benefits of inertial exercise:


Pull Line Apparatus:  With each of the exercises contained in this manual, the pull line apparatus appropriate for the exercise is specified and appropriately depicted (ankle strap, line handle or sport handle) 


eaternal rotation

Adjustment of the Vertical Adjustment Pulley:  Each exercise depicts a view of the exercise position relative to the post assembly.  The pulley position is recommended for each exercise. Use an anatomical landmark on the user to determine and record exercise positions.  The example at left depicts the pulley position level with the elbow.  Exact positioning of the pulley is not necessary. However, you should be within 2" up or down from the position depicted in each exercise figure.  The approximate relationship of the pulley to the individual performing an exercise is important.  Many of the exercises in this manual can be performed while sitting rather than standing as shown.  If the exercise is performed while sitting, the pulley must be adjusted so that the relationship of the pulley to the exercise motion remains approximately the same (i.e., level with the elbow).


Body Orientation to the Direction of Line Travel:  Each exercise figure depicts the relationship of the exercise motion relative to the direction of travel of the pull line.  The exact position for each exercise will need adjustment according to the requirements of each individual.  It is important that body positioning be in the proper work envelope relative to the force line (see above).  Note the positions of the feet in the example above are depicted perpendicular to the line travel.  Other exercises will depict feet position at 45 degrees to line travel or parallel to line travel.


The distance of the body from the post will vary according to the demands of each exercise.  When the exercise technique is tonic, position the patient such that when the object limb is at the desired end of ROM the sled will be centered on the return pulley.  If the exercise technique is phasic, then position the patient closer (3” to 6”) to the pulley so as to allow for the creation of slack in the travel line during each exercise repetition.

Weight on the Travel Sled: Generally, this is specified with each figure for each exercise.  However, if you desire higher acceleration rates than comfortably available with the weight specified remove weight as needed.


 Range of Motion: A sled motion of 12 to 24 inches from either side of the return block is generally all the range of motion needed for any exercise.  This range of motion is dictated by the distance of the individual from the post assembly and the motions involved in each exercise.  Each exercise figure depicts the respective recommended ROM.  This ROM may need adjustment relative to the specific needs of each patient. With these criteria in mind, range of motion will be correct.


Rate of Acceleration: Generally, acceleration that produces a repetition rate of 1 rep per second is excellent for introduction to therapy.  The exercise objective is to increase performance relative to acceleration and deceleration.  Increase acceleration only to levels that are comfortable during acceleration, return motion, and deceleration phasesSmooth repetitious motion is far more important than the velocities achieved during the acceleration phase. General conditioning exercises should employ an acceleration rate that produces smooth repetitious motion.  One to two repetitions per second are all that is required for a proper workout.  However three to four repetitions per second is common in therapy.  This aspect should be dictated by the patient’s safe competence.


Number of Repetitions: Normally, 30 repetitions for any exercise motion are all that is required for a proper workout (rehabilitation or general conditioning) when initially introduced to the system.  After the user has become proficient with control of the system, progress to three 30-second bouts with a one-minute rest of the involved muscle group between bouts.  The benefits of each exercise motion are achieved through the practiced control and intensity of exercise, not the number of repetitions.  Concentrate on producing a smooth repetitious flow of motion with each cycle.  Overexertion and extended duration of exercise (through excessive repetitions) is potentially dangerous and can cause injury.  Increase beyond 30 repetitions per exercise to the 30-second rule only if you experience none of the effects of fatigue using high acceleration rates (2 reps per second and greater).


Degree of Coordination:  Typically, if one lacks the degree of coordination necessary to perform an exercise with the amount of weight specified, weight should be added and the rate of acceleration decreased. Concentrate on smooth control.