It's easy to see people who help themselves to learn traction with elastics hooked to the bar and placed under the feet.
Biomechanics of movement in the gym
Correct execution of the leg extension exercise
The leg extension has a range and system of pulleys that engineer the movement so that, regardless of where it is placed, the pad will still feel the same internal load.
Limited movement on leg extension machine with ACL injured knees
It is therefore obvious to suggest to perform only the first half of the leg extension movement. Good, but how to strengthen the muscle in the second half of extension?
Pull-ups: With or without elastic assistance?
The prevalent theory on the gym floor is that if you cannot complete the pull-ups movement unassisted, the rubber band will give an extra push and counterbalance some of the body weight to allow the body to be lifted.
Among the packaged weight equipment, Vertical Traction of the Artis Line is the ideal solution to train the strength of the great dorsal and arm muscles from an ergonomic sitting position.
The target muscle of the pull-ups? The great dorsal.
Analyzing the force profile of elastic during this movement, one immediately notices how this is exactly opposite to that of the latissimus dorsi. During the pull-ups, the elastic is stretched and gives a lot of assistance but provides minimal support in the final part as it returns closer to its contracted shape.
What matters is not to train today but to achieve results with a rational training, having the opportunity to extend it over time without incurring risks of any kind, both with pull-ups or leg extensions
Pull-ups can start from a standing position, pull-ups suspending the entire body from a bar, pull-ups from a sitting position with some of the bodyweight resting on the floor to reduce the effective workload. If available, use rings for your firs pull-ups, to begin with as they allow a more rectilinear trajectory and the ability to rotate the wrist makes the movement like the mechanics of pull-ups action. If rings are not available, a bar located lower than the classic ones can be used. Both options are available using Omnia.
The dynamics of the pull-ups exercise are respected, and overload can be progressed gradually simply by changing foot position to offer less assistance over time. Once pull-ups can be performed with the legs outstretched (still maintaining foot contact on the ground but not pushing to assist) the addition of a foot rise such as an aerobics step under the heels will offer a means of further progression.
It is obviously a very general guideline that does not take into account all the complementary exercises of pull-ups (horizontal pulling, reinforcement of the scapulata movement, etc.) but which helps to respect the correct dynamics of the exercise you are learning.
It is possible to achieve results by contradicting every basic law of biomechanics, but at what cost?
What matters is not simply to train today, but to obtain predictable results in a time-efficient and safe manner, improving the likelihood of achieving goals and minimizing the risks inherent in exercise.