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Train Smart - Exercise Selection
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Train Smart!
Are you doing leg curls for your hamstrings? Leg extensions and quad sets for your knees? Side lying external rotations for the rotator cuff? Have you ever thought about why you use these exercises?
These are traditional exercises that athletes have used for years, but do they really work? The answer is yes, but with mixed results. The better question is, are they functional?
The term “functional training” means training the respective muscle groups and involved areas to work in the same manner as they are used in activity. To train function, it is necessary to understand the goal is to get better at the activity or things you want or need to do. Function involves the muscular system that provides control, and the proprioceptive system that coordinates and directs movement. Where functional is concerned, isolated strength gains are minimized and the neuromuscular system is emphasized.
The best way to figure out the function of a muscle is to role play and become the involved muscle. Ask the muscle what it does in movement – not what it does in the anatomy book.
Typical training programs that utilize exercises like the leg extension and leg curl fail to take into account these functional criteria. These exercises may even contribute to the problems they are designed to solve. For example, the knee extension is commonly used to strengthen the quads to help with patella femoral problems when in actuality, it increases shear force at the knee, causing even more problems. The hamstring curl is used to prevent hamstring pulls. In fact, it may contribute to pulled hamstrings because of the imbalanced muscle development that result from doing the exercise.
Programs that use these exercises are training muscles not movements. The functional goal is to prepare the legs to effectively use ground reaction forces and gravity. Let role play and be the muscles…
Quadriceps
Conventional wisdom tells us that the quad extends the knee. The primary exercise used to train this muscle group is the leg extension. Functional wisdom is quite different. According to Gary Gray PT, for the quads “primary closed chain function is anterior stabilization of the knee via deceleration of knee flexion.” In the mid-stance phase of the gait cycle, extension of the knee is a result of forward momentum of the body moving over the foot and the quads deceleration of knee flexion. Assisting with knee extension include the muscles that decelerate the forward momentum of the tibia including the soleus, posterior tibias, flexor hallucis longus, flexor digitorum longus, and the peroneus longus (Gray, 1994)
Functional exercise to work the quads should be closed chain exercises that cause the muscles of the lower extremity to work together synergistically. Remember, the quads are powerful, two-joint muscles that work at both the knee and the hip. Therefore, they should be trained as two-joint muscles.
Hamstrings
Conventional wisdom says the leg curl is and important exercise because the hamstring flexes the knee. Therefore it is necessary to train the hamstring as a knee flexor. Functional wisdom tells us that in movement the hamstring groups of muscles are two joint muscles that work at both the hip and knee. They extend the hip and decelerate the lower leg at the knee. On foot contact, the force of gravity and ground reaction cause the knee and hip to flex while the foot is impacting the ground. The hamstrings eccentrically decelerate hip flexion. In addition, this lengthening action stabilizes the knee in the transverse plane. The hamstrings actually help decelerate knee flexion by slowing down forward momentum of the lower leg. (At the heel off and into the swing phase of the gait, it is the eccentric force generated at the hip by the hip flexors that is transferred into hip flexion and knee flexion.)
The clear choice is between joint isolation exercises and kinetic chain exercises. Joint isolation exercises create an incorrect motor program causing confusion to the muscles. If in training the muscles are asked to do one thing, then in performance, they can not be asked to do the opposite. Kinetic chain exercises, on the other hand, work the muscles in integrated movements as part of the whole kinetic chain.
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