With so much focus on strength training to build new muscle and slow the age-related muscle loss, it’s easy to forget that another type of tissue that changes with age–your tendons. Just as we work our muscles to keep them healthy, it’s important to keep your tendons healthy and resistant to injury too. These strong, flexible bands of connective tissue matter!
Tendons are a weak link for some people, and if you tear one it can make it hard to exercise for weeks or months. In addition, tendons are susceptible to injury from overuse. That’s why it’s important not to do the same exercises over and over without allowing your muscles and tendons adequate time to rest and repair. Runners are prone to Achilles tendon injuries and the risk increases with the number of miles they run each week.
The odds of developing an injured tendon increases with age, but have you ever wondered why and what you can do to slow the process and reduce your risk of a tendon injury?
Tendons are Tough but Still Can Tear!
Tendons are one of the strongest tissues in your body. They have to be! Each time you contract a muscle, the tendon must stretch to allow the muscle to move yet have enough tensile strength to stretch without tearing or breaking. If you have a weak tendon, a forceful muscle contraction could rupture the tendon. The largest and strongest tendon in the body is the Achilles tendon. A rupture of the Achilles tendon is a serious injury that requires surgery.
How do tendons work? When you contract a muscle, the tendon pulls on the bone to allow movement. Therefore, a tendon transmits mechanical force from the muscle to the bone and forms a vital link between the two types of tissue. If you cut open a tendon and looked at a cross-sectional slice of it, you’d see bundles of collagen that supply strength but also enough elasticity to allow movement.
To make the tendon even stronger, the collagen fibers are linked to form bundles that add even more strength to the tissue. Within a tendon, you’ll also find a stretchy protein called elastin. Plus, tendons have cells called tenocytes that produce the collagen and elastin that makes a tendon strong but still stretchable.
Healthy tendons absorb enough force to prevent injury during normal circumstances. However, tendon injuries are still one of the most common sports-related injuries among athletes. Although women are more prone to some types of sports injuries, injury to the Achilles tendon is more common in men and the most common way men acquire it is jumping while playing basketball. One reason may be that women have higher levels of estrogen, which may have a protective effect. However, estrogen levels decline with age in women. Therefore, if you’re a female, you may lose estrogen’s protective effect after menopause and be at higher risk of tearing a tendon. The most common sports-related activity linked with tendon injuries in women is tennis.
How Tendons Age
Just as muscles age, tendons age too. Research shows that as we age our tendons become stiffer and less pliable. One reason tendons stiffen is that they lose water and dry out. The other has to do with the collagen and elastin fabric that gives them strength and the ability to stretch.
With age, the elastin and collagen fibers become damaged and less capable of repairing themselves. Studies show that the amino acids that make up collagen are altered through a process called glycation and this reduces their strength. In addition, older tendons get less blood flow, so they don’t get as much fluid and nutrients to stay healthy and pliable. Aging tendons also have less healthy elastin, the protein that makes the tendon stretchable.
Another problem that causes a tendon to age is the tendon cells, or tenocytes, that produce the collagen matrix age. At some point, the cells undergo senescence, the failure of the cells to divide. The stem cells that give rise to the tenocytes also decrease in number. So, aging happens at the cellular level too.
Factors that Age Tendons
You might wonder what you can do to slow the rate of tendon aging. Does staying active help? Studies suggest that regular exercise increases the collagen content of tendons, so they stay stronger. Exercise also boosts oxygen and nutrient delivery to the tendons. Studies suggest that physical activity can enlarge the tendon just as it does the muscle, although the collagen fibers don’t increase in size. Circulation also declines to tendons as we age. Exercise helps by boosting blood flow to these important structures.
What type of exercise is best for enlarging tendons? Research shows that running increases the cross-sectional area of the Achilles tendon. Other studies show that resistance training boosts the area of tendons too, mainly along the periphery of the tendon. Therefore, just as your muscles respond to exercise, so do your tendons. There’s also some evidence that exercise reduces damage to tendons through glycation.
Other than drinking plenty of fluids to boost circulation to your tendons and eating a healthy diet that contains enough protein, exercise is your best bet for slowing tendon aging. Make sure you’re training with good form to avoid injury. Tendon injuries heal slower after the age of 50. Don’t over-train and make sure you’re including a variety of exercises in your routine to avoid repetitive stress on the same muscles and tendons. As always, warm-up and cool down before any form of exercise.
The Bottom Line
Tendon aging is a fact of life, but you can keep your tendons healthy for a lifetime by staying physically active and by not doing repetitive activities that stress the same tendons over and over. Keep your workouts varied. Strength training is important as it may modestly enlarge the tendons you work but include aerobic exercise in your routine as it increases blood flow to your tendons. Also, keep moving and keep living healthy!
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