Skeletal muscles help us do many things. They help us push, pull, lift, throw, and smile. They help us to chew, swallow, and digest our food, and play video games and sports. Muscles are highly organized and work well together and with the bones of the skeleton. But before the muscles and bones can work together, they must attach to each other. Associated with the skeletal system are two other connective tissues, tendons and ligaments.
Each skeletal muscle is surrounded by a sheet of connective tissue that draws together at the ends of the muscle, forming the tendons. Muscular contractions allow for skeletal movement because muscles are attached to bones via tendons. These attached muscles pull the bones, which pivot at joints, creating a specific body movement.
Without making things too complicated, this article will briefly explain all you need to know about the anatomy and function of your tendons.
What are tendons?
Tendons are narrow, nonelastic, dense, white fibrous bands (connective tissue) that attach muscle to skeletal bones. They provide an anchor from which the muscle can exert force and control the bone and joint. Without tendons, your muscles are useless chunks of meat.
Tendons have different shapes and sizes depending on the role of the muscle. Some of them are shorter and wider while other tend to be longer and thinner.
Tendons do not usually contain any elastic fibers since their muscle belly acts as an energy damper such that elastic fibers are not required. They do have the ability to store and release elastic energy, however, and rehabilitation programmes should aim to increase tendon elasticity.
What are the main characteristics of a tendon?
- glistening bands of collagen fibers;
- bright white in color;
- flexible, but not elastic;
- an inert structure which does not contract;
- poor blood supply;
- heals slowly;
What are the functions of tendons?
Tendon is a cord that attaches itself permanently to a part of the bone, holding one end of the muscle to the bone. The movement of the bone is produced by the transmission of force from the muscle through the tendon to the bone. Without tendons, your muscles are useless chunks of meat. Skeletal muscles produce movement by pulling on tendons, which in turn pull on the connecting bone.
Additional functions of tendons:
- First and foremost, they attach a muscle to bone;
- Secondly, they transmit the force of muscle contraction to the bone to produce functional movement – serves as mechanical pulleys;
- Thirdly, tendons set the muscle belly in the optimal position for functional movement and to affect the direction of muscle pull;
- To be able to glide within the surrounding tissues, accepting stress and tensile forces with minimal drag;
- Preventing and reducing injury to a muscle during high velocity action or the sudden application of the external force;
- Joint stabilization;
Tendon structure and composition?
Each tendon is made up of different bundles. This structure keeps them strong.
The tendon structure is represented by the following image:
Tendons are composed of closely packed parallel bundles of collagen microfibrils, fibrils and fibres, bound together by irregular connective tissue sheaths into larger bundles. Most fibres are oriented in one direction, parallel to the long axis, which is the direction of normal physiological stress.
How strong human tendons are?
Tendons are exposed to strong, unidirectional forces and to function they require great tensile strength and inelastic properties.
Human tendons are remarkably strong—about half the strength of a stainless steel cable. The strength of a tendon depends on its size, and a 1 cm thick tendon can support a weight of more than 1,000 pounds (450 kg).
What is the difference between ligaments and tendons?
People often talk about tendons and ligaments as if they are the same thing, but these two types of soft tissue actually perform different functions for the body.
Ligaments connect a bone to other bone while tendons connect a muscle to a bone.
Tendons are very similar to ligaments in that they have poor vascularity (blood supply), which leaves them susceptible to slower repair and adaptation.
Ligaments are formed from collagen as well, but they also contain an elastic protein called elastin. This affords ligaments some ability to stretch, thus allowing for a balance between stabilizing a joint and permitting some mobility.
Finally, tendons are able to withstand much greater tensile forces than ligaments.
What is the difference between a muscle and a tendon?
Tendons, ligaments, and cartilage are tissues that have relatively few living cells dispersed within an abundance of non-living extracellular material. This characteristic, along with a poorer blood supply to these tissues, prolongs the time period for training adaptations as compared to other types of tissue. Poor vascular supply also increases the time it takes for these tissues to recover from injuries. In many cases tendon doesn’t have the ability to heal itself or it heals at a rather pokey pace. Often the surgery is only solution to fix the problem.
To put it simply, a muscle is tissue that contracts. We need to think of muscles as being similar to rubber bands. Just like rubber bands they have a certain amount of elasticity, when not under stress, they are nice and relaxed, floppy, and not much damage can be done to them. Muscles have both a good blood supply and a functioning nerve supply. This rich supply of blood is essential for delivering oxygen and nutrients to generate the enormous energy supply required by muscle cells. The blood also carries away the waste products of muscle cell metabolism and the excess heat that is produced. Given their good supply of blood, injured muscles usually heal quickly.
Muscle are red. As opposed to muscles, tendons are white. The red color of muscles is from their vast network of blood vessels. On the other hand, the white color of tendons is because they have little blood supply. Tendons don’t require a lot of blood because they’re not very active – they just connect your muscles to your bones. That’s why they’re classified as connective tissue.
What is Golgi tendon organ?
Within the tendons you will find the Golgi tendon organs, whose function is to send signals to the brain to indicate stress and fatigue. You can think of GTOs as circuit breakers that act as safety switches.
Golgi tendon organs (GTOs) are specialized sensory receptors located at the point where skeletal muscle fibers insert into the tendons of skeletal muscle. It appears to play a role in protecting the muscle from injury. The Golgi tendon organ is deformed when the muscle is activated. If the force of the muscle action is great enough, it will cause the Golgi tendon organ to convey sensory information to the spinal cord, which will lead to relaxation of the acting muscle and stimulation of the antagonist muscle. This protective reflex presumably prevents injury to the muscle and joint due to a potentially excessive force of muscle action.
When a muscle is stretched beyond a certain point, the GTO fires and shuts the muscle down to prevent further contractions. If the GTOs didn’t exist you could easily tear a muscle or tendon from its attachment. You may have experienced this phenomenon: you’re ripping out on dumbbell presses when your pecs just give out, with little or no warning. You may be sure you have the strength to force out a few extra reps, but the muscle just won’t contract.
How tendons and ligaments respond to resistance training?
Regular resistance training improves not only muscular strength and endurance, but also the strength
of tendons, ligaments, and other supporting structures around each joint.
Training for muscular strength and endurance also makes the tendons, ligaments, and cartilage cells stronger and less susceptible to injury. Resistance exercise prevents injuries best when the training program is gradual and progressive and builds all the major muscle groups. Also you have to actively protect your tendons by following some tips for trouble-free tendons.
What is the largest and strongest tendon in the body?
Tendons are found throughout the body, from the head and neck all the way down to the feet. The Achilles tendon is the largest tendon in the body. It attaches the calf muscle to the heel bone.
The longest tendon in the human body is the plantaris tendon, measuring between 30cm and 45cm.
What is the most familiar tendon from a bodybuilding perspective?
From a bodybuilding perspective, the biceps tendon, which connects the biceps to the radius bone of the forearm, is probably the most familiar.
What is the best way to prevent tendon injuries?
The best way to avoid training injuries is by taking care to stretch and warm up before working out and by observing proper technique when training with heavy weights. Remember, the stronger you are, the more strain you are able to put on your muscles and tendons, but often the muscles gain strength at a faster rate than the tendons, thus creating an imbalance that can cause problems. You must allow yourself to progress at a reasonable rate, and not attempt to train too intensely or with too much weight without proper preparation.
Closing thoughts
Tendons are soft, fibrous tissues that have an organized hierarchical structure. They connect muscle to bone, and their main function is to transfer force generated from muscle to bony structures resulting in joint movement.
You could have the biggest muscles in the world, but without tendons, you’d be weaker than the weakest weakling on Earth. Without tendons, you wouldn’t even be able to get out of bed. In fact, you’d be so weak you wouldn’t be able to get into bed in the first place. You’d just lie there on the bedroom floor, wishing you had tendons to join your muscles to your bones.
