Speedflex machines have a free motion bar which, unlike traditional resistance exercise machines, requires users to apply force through an entire exercise, as opposed to force in one direction, followed by a controlled movement back to the starting position. This means that even the most basic of exercises will become bigger and more complex, requiring the use of opposite muscle groups.
As there are no weights and the resistance is set at all times in both directions, the momentum users would usually experience during resistance training, is eliminated, meaning the user must work to their optimum level to complete the exercise.
Speedflex machines also operate on a closed loop circuit which means resistance is automatically adjusted in response to user-generated forces. When the body begins to fatigue, the machine will adjust the resistance to maintain an individualised optimum workout.