5.2.1 User Manual Isoforce
REV 5
01st July 2014
page 8 von 77
TUR Therapietechnik GmbH | Grubenstr. 20 | 18055 Rostock | Germany
the speed is fixed but the resistance is variable. Thus we can see that isokinetics is the opposite of
isotonics.
These types of exercises can be designed in musculoskeletal rehabilitation to optimize joint integrity by
strength. Strength has been defined as the “maximum voluntary force exerted in a single muscular
effort.”
Mechanical muscle-strength testing has played a key role over the years in the prescription of exercise
programs, the identification of the sequence of orthopedic disabilities, and the prevention of
musculoskeletal injuries. The evaluation of strength is crucial in determining overall musculoskeletal
fitness. Indeed, the lack or impairment of strength can seriously affect an individual’s success in any
musculoskeletal endeavor.
“Active exercise may be either static or kinetic. Static (isometric) exercise is performed without
producing joint motion. The muscle exercised maintains a fixed length. Kinetic (isotonic) exercise is
performed to produce joint movement. Contracting muscles shorten, causing movement of the joint at
which they are attached. Isokinetic exercises produce joint motion at a controlled rate of speed.
Concentric contraction occurs when a muscle is contracted from an extended to a shortened position.
Eccentric contraction occurs when a tense-shortened muscle lengthens. Power is the ability to release
muscular work as a function of time. Endurance is the ability of muscles to perform work by holding a
maximum contraction for a given length of time or by continuing to move a submaximal load.”
Iso-Force offers a wide range of operation modes. Below you can find information regarding main
clinical implications and considerations for each one of them.
1.2.1 Isokinetic Mode
In the concentric isokinetic mode, the dynamometer acts to control velocity, allowing the subject to
accelerate up to, but no higher than, the maximum speed value selected for each direction of shaft
rotation (accommodating resistance). The subject may freely decelerate or
change
direction
of
movement at any point within the range of motion.
In the eccentric isokinetic mode the dynamometer responds to torque exerted by the patient by moving
in the opposite direction of the applied torque.
The Isokinetic mode may be used at higher speeds in order to simulate functional or sports activities. It
can also be used early on in the rehabilitation process to prevent compression and translation in the
knee joint. Different bi-directional velocities can be set. Thus you can simulate physical activities. By
choosing different type of contraction con/ecc or ecc/con, you can isolate but also more precisely
simulate every functional patterns.
Keep in mind that it is possible to generate 30-40% more force eccentrically than concentrically. In
concentric isokinetic contractions the lower the velocity the higher the muscular tension. Therefore, the
torque produced is much higher. On the contrary in eccentric exercise, the force increases as the
velocity of contraction increases (up to a certain point)
