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The optimum length of a muscle to deliver maximum tension is slightly greater than the resting length of the muscle. This can be related back to the discussion earlier. Many people do not squat deep enough because the length of their muscles is allowing them to push back up with less effort, due to the length-tension relationship. However, this is how injuries to joints and ligaments can occur. It is much harder to fully squat because fewer cross bridges are making contact within the muscle, so full contracting force cannot be generated. Delivery of Energy To Working Muscle: Assuming the subject is executing a heavy squat, the main energy source to fuel the muscle is the phosphagen system.
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In this system, phosphocreatines (ATP-PC) from the muscles are broken down into ADP, a phosphate ion and energy. This is a rapid and immediate energy source for a muscle which is being heavily stressed.
Should the squat continue for several repititions, the anaerobic system can take over. While this energy source provides half the energy of the phosphagen system, it does last considerably longer. The lack of oxygen in this energy system will create the bi-product of lactic acid, which accumulates in the muscle causing a burning sensation. Similarly, the lactic acid hinders the re-supply of ATP-PC in the muscle, causing it to feel fatigued.
There is also a small amount of aerobic energy being supplied. However, as with most activities as strenuous as the squat, it is often below 5%.
The delivery of energy is a combination of the respiratory and cardiovascular system. Maintenance of Working Muscles: The type of muscle fibre in the body can determine the endurance and power of a person executing a squat. For instance, having a ratio with higher than average fast fibres would mean an individual would generate a more powerful contraction. However, their endurance would suffer, as these muscle fibres fatigue faster than their slower counterpart. Therefore it can be said that someone with a ratio favouring slow muscle fibres would not generate the same power or speed in their squat, but they would not fatigue anywhere near as quick. This is because there is a better supply of O2, meaning that there is more aerobic energy being supplied to the body. This energy lasts longer than both anaerobic and the phosphogen systems. The flexibility of the muscles in an individual can hinder a squat. …show more content…
A good example is the hamstring. If a hamstring is very flexible, the subject can squat much deeper than if his hamstring was not flexible.
Integration of the Body Systems and Functions:
A muscle contracts when it is given an electrical impulse. This impulse is given from the brain through the nervous system. Motor neurons send information to the muscle, and once it has contracted, sensory neurons receive the information. The way a muscle receives a message is through myotomes. In the squat, many myotomes are activated to deliver the specific messages to the muscles. For instance, the flexion of the hip is controlled primarily by the myotomes L1 and L2. Knee flexion is controlled by L5 to S2 and knee extension by L3 and L4.
The nerves in the lower limb associated with the squat are the femoral nerve, superior and inferior gluteal nerves, tibial nerve and the obturator. A beginner’s brain automatically sends messages to the muscles, via the peripheral nervous system to tell them how to contract in a squat. However, it is in the intermediate phase that an individual must retrain their brain into executing proper form. This is where the body systems and functions must be combined. While the delivery of energy and the sensory receptors (including muscle spindle, Golgi tendon organ and joint receptors) are automatic procedures, an intermediate squatter must give manual instructions to specific muscles at certain times to properly perform a squat. For an advanced squatter, these are also now automatic procedures. References: http://en.wikipedia.org/wiki/Squat_(exercise) www.exrx.net in particular: http://www.exrx.net/WeightExercises/Quadriceps/BBFullSquat.html and http://www.exrx.net/ExInfo/Squats.html http://www.4-men.org/increasing-testosterone.html http://www.memorialhermann.org/library/healthguide/en-us/images/media/medical/hw/nr551499.jpg knee tendon picture http://forum.bodybuilding.com/showthread.php?t=998224 http://lifegetinit.fitdv.com/new/articles/article.html?artid=37 http://www.laboratorium.dist.unige.it/~piero/Teaching/Gait/Malanga%20and%20DeLisa%20Clinical%20Observation.htm http://www.fpnotebook.com/ORT247.htm “Gray’s Anatomy for Students” Richard L. Drake, PhD, Wayne Vogl, PhD, Dam W. M. Mitchell, MBBS, FRCS, FRCR. Copyright 2005. Published by Elsevier Churchill Livingstone.
In this system, phosphocreatines (ATP-PC) from the muscles are broken down into ADP, a phosphate ion and energy. This is a rapid and immediate energy source for a muscle which is being heavily stressed.
Should the squat continue for several repititions, the anaerobic system can take over. While this energy source provides half the energy of the phosphagen system, it does last considerably longer. The lack of oxygen in this energy system will create the bi-product of lactic acid, which accumulates in the muscle causing a burning sensation. Similarly, the lactic acid hinders the re-supply of ATP-PC in the muscle, causing it to feel fatigued.
There is also a small amount of aerobic energy being supplied. However, as with most activities as strenuous as the squat, it is often below 5%.
The delivery of energy is a combination of the respiratory and cardiovascular system. Maintenance of Working Muscles: The type of muscle fibre in the body can determine the endurance and power of a person executing a squat. For instance, having a ratio with higher than average fast fibres would mean an individual would generate a more powerful contraction. However, their endurance would suffer, as these muscle fibres fatigue faster than their slower counterpart. Therefore it can be said that someone with a ratio favouring slow muscle fibres would not generate the same power or speed in their squat, but they would not fatigue anywhere near as quick. This is because there is a better supply of O2, meaning that there is more aerobic energy being supplied to the body. This energy lasts longer than both anaerobic and the phosphogen systems. The flexibility of the muscles in an individual can hinder a squat. …show more content…
A good example is the hamstring. If a hamstring is very flexible, the subject can squat much deeper than if his hamstring was not flexible.
Integration of the Body Systems and Functions:
A muscle contracts when it is given an electrical impulse. This impulse is given from the brain through the nervous system. Motor neurons send information to the muscle, and once it has contracted, sensory neurons receive the information. The way a muscle receives a message is through myotomes. In the squat, many myotomes are activated to deliver the specific messages to the muscles. For instance, the flexion of the hip is controlled primarily by the myotomes L1 and L2. Knee flexion is controlled by L5 to S2 and knee extension by L3 and L4.
The nerves in the lower limb associated with the squat are the femoral nerve, superior and inferior gluteal nerves, tibial nerve and the obturator. A beginner’s brain automatically sends messages to the muscles, via the peripheral nervous system to tell them how to contract in a squat. However, it is in the intermediate phase that an individual must retrain their brain into executing proper form. This is where the body systems and functions must be combined. While the delivery of energy and the sensory receptors (including muscle spindle, Golgi tendon organ and joint receptors) are automatic procedures, an intermediate squatter must give manual instructions to specific muscles at certain times to properly perform a squat. For an advanced squatter, these are also now automatic procedures. References: http://en.wikipedia.org/wiki/Squat_(exercise) www.exrx.net in particular: http://www.exrx.net/WeightExercises/Quadriceps/BBFullSquat.html and http://www.exrx.net/ExInfo/Squats.html http://www.4-men.org/increasing-testosterone.html http://www.memorialhermann.org/library/healthguide/en-us/images/media/medical/hw/nr551499.jpg knee tendon picture http://forum.bodybuilding.com/showthread.php?t=998224 http://lifegetinit.fitdv.com/new/articles/article.html?artid=37 http://www.laboratorium.dist.unige.it/~piero/Teaching/Gait/Malanga%20and%20DeLisa%20Clinical%20Observation.htm http://www.fpnotebook.com/ORT247.htm “Gray’s Anatomy for Students” Richard L. Drake, PhD, Wayne Vogl, PhD, Dam W. M. Mitchell, MBBS, FRCS, FRCR. Copyright 2005. Published by Elsevier Churchill Livingstone.