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Tendon Strength for power, performance and Injury Prevention

Updated: Aug 3, 2023

For 1500 years Kung Fu has focused on developing tendon strength over traditional muscle strength, but why is this?


horse stance from kung fu


It's not that Kung Fu doesn't train the muscles, it certainly does, it's that the focus is skewed more towards developing the tendons while teaching the muscles to work more cooperatively with them.


This is for a number of reasons that mostly center around the tendons ability to create fast explosive movement and joint stability while using very little energy. It's easy to see why this would be of benefit in the realm of martial arts but it's equally true in other athletic endeavors and even in everyday life. Below is listed some of the primary benefits of strengthening tendons and afterwards we'll go through the methods used to develop this strength.


Primary Benefits of Tendon Training


Explosiveness


Tendon tissue isn't too dissimilar from muscle tissue, in fact they are made of much the same thing with the primary differences being that muscles are softer and have more blood flow while tendons are denser with fewer blood vessels.

The density of the tendon is primarily in the form of more numerous collagen fibers than that of the muscles tissue. These collagen fibers are very elastic by nature and allow for the storing of kinetic energy, much like a spring.

And like a spring, when the energy is released, the results can be immediate and explosive propulsion. In fact, in the animal world, you will notice that the fastest animals and the best jumpers will have very long tendons in their limbs with relatively short muscles.


This adaptation allows for maximum explosiveness, the benefits of which are easy to see. It allows cheetahs to chase down their prey, rabbits to make a quick getaway, and frogs to jump nearly 100 times the length of their own body on a moment's notice.

When applied to humans, tendon training can create quick and powerful punches, as in Kung Fu, explosive speed, such as in Olympic sprinters, or incredible vertical jumps as seen in many NBA athletes.


Joint Stability and Injury Prevention


Tendons also serve a protective mechanism to the joints. They absorb and dissipate forces applied to the joints so that sensitive tissues are not overwhelmed and injured.

For instance, the forces experienced on the joints of the legs during the landing phase of a vertical jump can be 3-4 times the body-weight of the jumper. For a 170-pound athlete this would mean 510-680 pounds of pressure, an amount of weight the athlete is almost certainly not going to be able to squat. So how can the body take these forces during repeated vertical jumps?


depth jump exercise

It's accomplished by temporarily allowing more than the normally allotted muscle fibers to quickly fire and hold a short isometric contraction (a contraction in which the muscle holds the same length). This strong isometric contraction allows the force of the landing to transfer from the soft tissue of the muscle, to the relatively dense and strong tissue of the tendon. The tendon then absorbs and dissipates the force or redirects the force by rebounding like an elastic coil.


Movement Efficiency


Muscles require the use of fuel in the form of calories in order to contract and move, making them a biologically costly source of movement.

Tendons on the other hand are much more automatic, with elastic properties being built right into the tissue. Meaning that as long as there is already motion to absorb, the tendons can produce further movement for nearly free in a biological sense.


This is why Kung Fu practitioners teach that tendon training is longevity training. When the athlete is older and muscles have become difficult to fuel, the tendons are still available at nearly full strength as long as one has the knowledge and skill to use them properly.

It is also why animals that rely on running for survival also tend to favor tendon strength over muscle strength, both can propel the body quickly, but using the muscles to maintain a top speed is very costly, especially in the wild where calories don't often come cheap.

You can see this in the difference between a bear and a wolf. Both can reach top speeds of around 40 mph, but the bear relies on large muscles to propel a huge body forward for short bursts of speed before wearing down due to the intense effort.


Wolves on the other hand can hold near top speeds for miles, utilizing the long elastic tendons of the lower legs to rebound them forward with each step in a relatively effortless manner.


bear and wolf anatomy comparison


How to Train the Tendons


There are three primary methods of developing tendon strength, all having been employed by modern professional athletes and ancient warriors alike. Each method strengthens the tendons well, but each does have its own specific flavor of adaptation, causing unique quality changes in the tissue of the tendon.


#1. Isometrics- Isometrics are simply muscular contractions done without moving. A great example is the horse stance used in Kung Fu. This stance is a wide legged, low squat which is held for extended lengths of time.


ma bu horse stance from kung fu


As the muscles begin to tire the body starts switching much of the strain over to the tendons. With consistent training the tendons become very good at this, with advanced practitioners becoming capable of holding the stance for 30 minutes without much effort.

In the process the tendons adapt by becoming thicker and stronger, more capable of handling the consistent load of the movement. This type of training is great for bulletproofing joints and making new ranges of motion more stable and safe.


#2. Repetitive Eccentrics- Eccentric contractions are simply contractions that happen while the muscle is lengthening. This type of contraction is seen when the bar is lowered to the chest in a bench press. The chest muscles must contract so that the weight can be controlled on the way down, but as the weight is lowered the chest muscles must also lengthen, causing an eccentric contraction.

These types of contractions put great demands on the muscles because the muscles nature is to shorten as it contracts. Due to this fact the body likes to shift as much of the eccentric load over to the tendons which are great at absorbing force while lengthening. Though without proper training and exposure, most people's tendons are not ready for this type of strain and so the muscles take the brunt of the necessary effort.

However, with high repetition the tendons become exceedingly good at this type of contraction. A great example of this is rock climbers. Rock climbers create an eccentric load on the arms and shoulders every time they reach up and support their weight from their hands. As their weight sinks down and pulls on the supporting arm, the tendons of the wrist and shoulder eccentrically contract and absorb the force.

In fact, a side-by-side comparison between climbers and bodybuilders will show very obvious differences in adaptation. The muscles in the arms of the bodybuilder will be very large while the flexor tendons of the wrist will be very minimal, often not even visible. However, in the climbers the flexor tendons of the wrists will be very thick and very easily seen on the underside of the wrist, even though the muscles of the arm may be thin and sinewy.


anatomy comparison between body builder and climber


This type of tendon training is great for force absorption and is often developed using depth jumps or eccentric weightlifting.


#3. Plyometrics- Plyometrics refers to a type of muscle contraction in which intense muscular contraction takes place in the shortest time frame possible.


This happens during sprinting, as the body reaches near maximum speed the strong contractions of the legs are applied in shorter and shorter intervals, with the foot only making ground contact for a split second at a time.


The ground forces created in this split second are very high and the muscle is already busy contracting to create movement. At this point the tendon steps in and uses its strong collagen fibers to absorb the intense ground forces and recycle them by rebounding them back into the ground, helping the muscles to propel the body forward.

This type of training adapts the muscles and the tendons together, increasing the tendons' ability to rebound and teaching the muscles how to work hand in hand with the tendons in order to create the highest possible power output during the rebound.

The primary result is an increase in speed, quickness, agility and explosive power. Though one should be cautious when beginning this type of training due to it's high propensity for injury.



box jump exercise


To stay uninjured simply be sure to build a solid foundation of strength and mobility in the muscles and movement patterns to be used plyometrically.


For instance, if you wanted to increase your vertical jump, you could do so utilizing box jumps (jumping off of a box, landing on the ground and rebounding back up onto the box with the quickest ground contact possible). But it would be wise to first spend 4-8 weeks building up squat strength and opening up the hips and ankles.


Done properly though, nothing creates a more explosive and powerful athlete than plyometric training.


Looking to start plyometric training? Check out Rogue Fitness' high quality Plyo Boxes and weight vests to help you get started.



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