Overview
Your joints and muscles have a certain range of motion that the body allows. Flexibility is the ability of the body to move freely through this allowed range. Flexibility is also known as limberness. The parts engaged more while moving are usually more flexible than those that are not put to much use.
Some people are more flexible than others. Genetics play a role in determining how flexible your joints and muscles are. Exercise can also improve a person’s flexibility to a certain extent.
There are two types of flexibility.
Dynamic flexibility - The ability to move joints to the maximum of their allowed range of motion (e.g., bending down to pick up an item or stretching to take something from a higher shelf).
Static flexibility - The ability to maintain a position for a longer time without any external support (e.g., lifting your leg and keeping it high without holding any support).
Importance Of Flexibility
Reduced Injury Risk
When you have higher flexibility, your body can handle physical stress much better. Hence, when you are exercising or doing a strenuous physical activity, the chances of getting hurt are lesser.
Improved Balance and Posture
A study concluded that people who take up flexibility exercises and stretching two times a week for 12 weeks saw improved balance and lumbar strength.
Improved Athletic Performance
A study that explored the effects of yoga on athletes reported that yoga improved flexibility in adult athletes. Flexibility, in turn, improved athletic performance.
Lesser Body Pain
When your body is more flexible, the muscles are better relaxed. This reduces general body pain in adults and children.
Reduced Risk of Heart Diseases
A 2009 article relates poor trunk flexibility to increased risks of arterial stiffening. Arterial stiffening is the stiffening and thickening of the artery walls that can lead to heart diseases.
Is Flexibility Genetic?
The Influence of ACTN3 Gene on Flexibility
The ACTN3 gene helps produce the Alpha-actinin protein. This protein gives structure to muscles in the body.
A 2014 study analyzed the effects of polymorphism of the ACTN3 gene in flexibility and injury risk in ballet dancers in Korea.
The result concluded that those ballerinas with the ACTN3 TT genotype of the rs1815739 SNP are less flexible than others and have higher risks for ankle-joint injuries. Ballerinas with the CT and CC genotype were more flexible and hence had lesser risks for injuries.
The Influence of COL5A1 Gene on Flexibility
The COL5A1 gene is called the ‘flexibility gene.’ This helps produce the type V collagen. Collagen helps in strengthening your bones, muscles, skin, and tendons. It keeps your joints mobile and flexible. Lowered levels of collagen can result in stiffness and reduced flexibility.
rs12722 is an SNP of the COL5A1 gene. The T allele of this SNP causes quadricep stiffness and an increased risk of muscle injuries while the C allele is not associated with flexibility issues.
Ehlers-Danlos Syndrome
Ehlers-Danlos Syndrome (EDS) is a genetic disorder that results in loose joints, very stretchy skin, and overly flexible joints. People with the syndrome have extra ranges of joint movements, also called hypermobility. EDS can cause joint pain, frequent injuries, and bruises in the skin.
More than 100 different mutations in the COL5A1 gene are noted in people with EDS.
Non-genetic Factors Affecting Flexibility
Age - Newborns are extremely flexible. Flexibility in the body reduces as you age. After 55 years of age, collagen production reduces, and tissues start losing water. This brings down flexibility levels.
Body Bulk - If you have more bulky, it may be difficult to stretch or move limbs and muscles.
Gender - Women are considered more flexible than men.
The temperature and time of the day - You might be surprised, but your body’s flexibility depends on what time of the day it is and the external temperature. Warmer climates improve flexibility, and people are more flexible in the afternoons than in the mornings.
Over-flexibility - Is It a Problem?
Over-flexibility is a problem when your muscles, ligaments, and tendons stretch beyond what’s normal for them. It puts stress on your tendons and ligaments and results in injuries.
Ligaments are not to be stretched more than 6% of their length. Some people can be over flexible because of their genes, which increases their risks of injuries and ligament tear.
Recommendations To Improve Flexibility
Exercise Right
Yoga, stretching exercises, pilates, etc., are all different kinds of exercises that help improve your flexibility. All these exercises gently stretch muscles and improve mobility.
Practice Static Flexible Exercises
Static flexible exercises require you to hold a stretch or a position for 30 -60 seconds before relaxing. Static flexible exercises help improve flexibility.
Relax Your Muscles
Taking a warm water bath can instantly relax your muscles and improve your flexibility.
Professional massages
When done right, massages can help improve flexibility and your range of motion, keeping your joints stronger and agile.
Hydration
Water is essential for the normal functioning of the body. Dehydration can cause inflexibility and limit your range of motion. Make sure you drink adequate water to improve flexibility.
Stay Stress-free
Stress is known to tighten muscles and decrease physical flexibility. Working on mental stress levels can help the muscles relax and improve your flexibility levels.
Summary
- Flexibility is the range of motion that your joints and muscles have. There are two types of flexibility, namely, dynamic and static flexibility.
- Flexibility depends on genetics and other factors like age, body bulk, and physical fitness.
- Flexing and stretching muscles, tendons, and ligaments beyond their capacities can cause injuries.
- Some genes are known to play a role in flexibility levels. Changes in the ACTN3 and COL5A1 genes can increase/decrease flexibility and may make you more susceptible to injuries.
- Practicing certain forms of exercise, keeping the body hydrated, and staying relaxed can improve flexibility.
References
https://www.frontiersin.org/articles/10.3389/fphys.2017.01080/full
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4241924/
https://medlineplus.gov/genetics/gene/col5a1/#conditions
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4523805/
https://physoc.onlinelibrary.wiley.com/doi/10.1113/EP085974
https://sites.psu.edu/kinescfw/health-education/exercise-articles/the-importance-of-flexibility-and-mobility/
https://www.sciencedirect.com/science/article/pii/S0002929707635290
About Xcode Life's Gene Fitness Report
Update on 16th January, 2021
Abstract
ACTN3, popularly called the Speed Gene, is responsible for the production of α-actinin-3, a protein expressed in fast-firing skeletal muscle fibers. This protein is deficient in approximately 1.5 billion people worldwide.
Previous studies indicate that α-actinin-3 is associated with muscle function, and an α-actinin-3 deficiency adversely affects performance in speed and power activities. Recent research suggests that α-actinin-3 deficiency generates heat in the body (thermogenesis), and as a result, α-actinin-3 deficient humans adapt better to lower temperatures.
What Is -actinin-3?
The α-actinin-3 protein was first identified during research into muscular dystrophy defects. Further studies showed that a deficiency of α-actinin-3 was common- roughly 18% of the world population has an ACTN3 deficiency mutation. This deficiency correlates with the following factors:
- Athletic performance
- Greater altitude and lower temperatures
- Evolutionary selection
A previous study exploring the evolutionary implications of α-actinin-3 deficiency indicated that a version of the ACTN3 gene became more abundant as humans migrated out of Africa into the colder climates of Northern and Central Europe.
Studies also suggest that an X derivative of the ACTN3 gene is overexpressed among marathoners and endurance athletes but underexpressed in sprinters. The X derivative indicates an incomplete ACTN3 gene and is thereby associated with α-actinin-3 deficiency.
In general, an α-actinin-3 deficiency is detrimental for sprint and power activities. Evolutionary evidence also indicates a strong positive selection of the X derivative of the ACTN3 gene in European and East Asian populations. Positive selection is the process by which the "advantageous" changes or gene variants are passed on consistently in a population.
Loss of α-actinin-3 and Better Cold Resilience
A study conducted by a team of researchers examined the mechanism responsible for the positive selection of the X derivative of the ACTN3 gene. It aimed to understand the thermogenic role of skeletal muscle during cold exposure in humans.
The study was conducted on the following two groups: Healthy males aged 18 to 40 years, residing in Kaunas, Lithuania. They followed moderate physical activity and had no exposure to an extreme temperature for at least three months prior to the study. Thirteen age-matched 3-month-old wild-type mice and mice with inactivated ACTN3 genes, housed in a specific-pathogen-free environment. They were maintained at a constant ambient temperature of 22°C and 50% humidity on a 12 h light-dark cycle, with limited access to food and water.
The following parameters were measured in humans:
- Weight (in kg)
- Body fat percentage
- Height (in cm)
- Skinfold thickness (in mm)
Based on the above parameters, the following were calculated:
- Body mass index
- Body surface area (in m2)
- Mean subcutaneous fat layer thickness
Coldwater exposure was conducted as follows:
- Humans were subjected to an intermittent whole body cold-water immersion
- Mice were exposed to acute temperature exposure treatments
The following parameters were examined in both humans and mice:
- Collection of genes
- Body temperature measurements
- Heart rate
- Oxygen intake and Carbon-dioxide output
- Signal measurement associated with heat-generating muscle activation
Apart from these, protein analyses in humans and RNA sequencing in mice were performed, and the data obtained were statistically analyzed.
The Results of the Study
The study observed that the percentage of individuals able to maintain their body temperature above 35.5°C during the cold-water exposure was higher in the ACTN3 deficient (XX) group than the ACTN3 efficient (RR) group. However, there was a significant overall increase in energy consumption induced by the cold irrespective of the ACTN3 gene status. This implies that α-actinin-3-deficient individuals exhibit superior protection of core body temperature during cold exposure without a corresponding increase in energy consumption.
Researchers suggest a physiological mechanism underlying the energy-efficient cold protection in XX individuals. Mammals regulate their body temperature when exposed to acute cold temperatures through involuntary muscle contraction. This is colloquially referred to as shivering - this activity was twice as high in RR individuals as in XX individuals. In individuals with the X derivative, these contractions most likely happen in slow twitch-type muscles with a heat-generating increase in muscle tone. This conserves more energy when compared to shivering.
The X derivative of the ACTN3 gene occurs more commonly in people living in colder climates, indicating an evolutionary survival advantage of α-actinin-3 deficiency as humans migrated to colder places.
In conclusion, α-actinin-3-deficient humans use a more energy-efficient mechanism of generating body heat, thereby exhibiting improved cold tolerance.
Recommendations to Improve Cold Resilience
- Take cold showers to acclimate your body to the cold
- Avoid wearing too many layers of clothes when you feel cold
- Spend more time in cold temperatures
- Exercise regularly and improve body metabolism
- Drink cold water or cold beverages
Summary
- α-actinin-3, a protein expressed in fast-twitch skeletal muscle, is commonly deficient in humans.
- This deficiency is associated with:
- Athletic performance
- Greater altitude and lower temperatures
- Evolutionary selection
- A study conducted by a team of researchers explored the thermogenic role of α-actinin-3 deficiency during cold exposure in humans.
- The study found that α-actinin-3-deficient individuals exhibited superior protection of core body temperature during cold exposure without any increase in energy consumption when compared to α-actinin-3-efficient individuals.
