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The Leg Extension Returns                                                                                                                         

Closed-kinetic-chain exercises are physical exercises performed where the hand or the  foot is fixed in space and cannot move.  Open-kinetic-chain exercises are said to be performed whereby the hand or foot is free to move.  The leg extension would be considered an open-chain movement and the barbell squat a closed-kinetic chain exercise.

In the early 1990’s Lutz and his colleagues studied these two conditions examining shear forces during rehabilitation of the knee.  They concluded that closed-kinetic-chain exercises produced significantly greater compression forces and increased muscular co-contraction at the same angles at which the open-kinetic-chain exercises produced max shear force and minimum muscular co-contraction.  Co-contraction meant the quadriceps and hamstrings were working together during rehabilitation to protect the joint from shear.

describe the imagePendulum Leg Extension


The conclusion of the aforementioned study led doctors and athletic trainers to reevaluate their approach to the rehabilitation of knee injuries.  Since shear forces are perpendicular to the direction of extension and rehab was occurring on repaired tissue, they gathered the leg extension was not a positive.  Based on the findings they also assumed that leg extensions could  be dangerous, especially since there was little co-contraction of the hamstring and quad to protect the knee as it was being re-strengthened.  The medical staff went even further, the leg extension was deemed a bad exercise for many years even though it had been the staple of rehabilitative exercise.

In the 2000’s Mikkelsen and colleagues dispelled the myth.  They determined that by adding open- kinetic chain exercise to rehabilitation after ACL reconstruction resulted in a significantly better improvement in quadriceps torque without reducing knee joint stability.  At 6 months those using open-chained exercise were returning to activity earlier and at the same level as before injury.

The leg extension was vindicated!  Many studies since have substantiated that a leg extension is not only a great rehab tool, but that muscular strength of the knee extensors is related to the speed an athlete can produce during a single-sprint performance.

The leg extension is back and the quads are Getting Strong.


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Closed And Open Chain

Open kinetic chain exercises of the lower limb are movements, where the distal segment is unloaded and free to move. The opposite is true of closed kinetic chain exercises, whereby  there is enough resistance to prohibit free motion.

Closed kinetic chain exercises are movements such as squats, Pendulum Squat Pro, leg presses and lunges, while open chain exercises are actions like leg curls, leg extensions and the Pendulum Reverse Glute Ham.

The kinetic chain can be understood as interrelated joints and body parts working with one another during motion. This creates a chain of events that affects the movement of neighboring joints and segments.

The advantage of open chain movements is that they tend to be better at isolating muscle and often are selected for specific rehabilitation and used to accentuate performance. While closed chain movements in general would be classified as more functional and closely approximating movements that are used in sport and daily life.

Pendulum Reverse Glute Ham Machine

Open Chain Reverse Glute Ham

Pendulum Power Squat Pro

Closed Chain Pendulum Power Squat Pro

Pendulum Power Squat Pro XT

Closed Chain Pendulum Power Squat Pro XT

Arkansas Baseball Weight Room
arkansas weight room
arkansas weight room
arkansas weight room
arkansas weight room
arkansas weight room
2-for-2 Method

Some trainers, coaches and athletes use what is called the 2-for-2 Method for increasing training load. The rule is if the trainee can perform two or more repetitions over one’s ‘repetition goal’ in the last set of an exercise, for two consecutive workouts, the weight is added for that particular exercise the next training session.

Bench Rep