Tag Archives: impact

A striking difference: How combat sports affect bone density

We have all seen it before, whether it is in Hollywood depictions, or watching competitors in the Ultimate Fighting Championship, there is always a sense of awe when watching humans strike and break surfaces with astounding force. Whether it is breaking bricks, a baseball bat or their opponents, the physiological phenomena that allows these athletes to perform such feats results from years of dedicated practice and study. By continuously placing their bodies under immense stresses and impacts, the actual composition and density of the athlete’s bones adapt to provide increased strength and durability. In practice this is done by repetitively striking a hard surface, such as a wooden planks, or a punching bad, with increasing force for a prolonged period of time. Although the practice of bone hardening has roots as ancient as the martial arts themselves, the scientific study of the phenomena has only occurred in the past few decades. So how do these athletes develop exceptionally strong bones?

Taekwon-Do Grandmaster Rhee Ki Ha breaking a solid concrete block with a punch
Courtesy of: Oakville Today

One of the most important aspects of bone hardening is increasing bone mineral density by continuously loading and unloading bones, as well as contracting the surrounding muscles consistently and for a prolonged period of time. It is particularly interesting to study how the typical bone mass gain that occurs during the adolescents is affected by sports that are high-impact and place great stress on one’s bones. Studies show that adolescents who participate in combat martial arts had significantly higher bone material density in their hands, arms, and legs than comparable adolescents who did not. Since the development of bone mass and structure is most significant during adolescence, the potential to increase the bone mineral density is greatest during this time.

However, as with most things there is a Ying to every Yang in the world of increasing the bone mineral density. The difficult and complex movements required to “harden” one’s bones make the athlete more susceptible to sustain a severe injury in training or competition. As it is typical to experience pain throughout the process of developing bone material density, the development and progression or micro-fractures and injuries can be ignored or mistakenly thought of as typical training pains. This results in there being a fine line between strengthening bone and causing injury to oneself.

Anderson Silva after suffering a gruesome leg injury.
Courtesy of: Lanna MMA

There are other benefits to increasing one’s bone mineral density outside the realm of combat sports. By engaging in high-impact activities during one’s adolescence into adulthood, one can decrease the risk of developing osteoporosis by having increased their bone mineral density. This further supports the reasoning to stay active and healthy to ensure a longer and healthier life.

Whether it is breaking boards to entertain sports, or fighting on the world’s premier combat stage, having strong and healthy bones is an essential aspect of being an athlete in high-impact combat sports. This is achieved through generating increased bone mineral density and is the result from years of dedicated practice and time. All in all, the difference it makes is rather striking.

Ditching the shoes: Minimalist trend or natural advantage?

The discussion of returning to minimalist ways, namely walking or running barefoot, is a question that rises in many circles, from new parents to elite runners. For example, parents are told to let children learn to walk barefoot, as studies have shown early use of footwear can lead to feet deformities and can alter natural gait, which is especially important when learning to walk. Likewise, many avid and elite runners have shown interest in barefoot running (or minimalist running shoes), as some are convinced that the forefront strike (FFS or also known as NRFS – non rear foot strike), more commonly used during barefoot running, lowers the loading rate on the foot and minimizes injuries from the repeated stress that occurs in the feet during running. 

Diagram illustrating four phases of foot contact with the ground for forefront strike and rear foot strike patterns
Forefront strike (top) and rear foot strike (bottom). Modified from Daniel E. Lieberman et al., Springer Nature 2010

In general, walking or running barefoot yields more frequent steps, a smaller stride length and a slower velocity (most noticeable while running). Barefoot running is thought to reduce some of the injuries many runners are prone to, such as shin splints, stress fractures or plantar fasciitis. Additionally, the stiff fit of modern shoes limits the width and spreading of feet in the natural walking or running motion. However, barefoot running also comes with a cost, with injuries in the achilles region more prevalent. 

A study in the Gait & Posture journal examined foot motion in children and found modern commercial footwear does have a large impact on gait, especially in regards to range of motions of different muscles and joints in the foot, likely due to the stiffness of shoes. More flexible shoes, similar to minimalist running shoes, were found to have a smaller impact on foot motion in reference to bare feet, but still had a significant difference in regards to the added support in the arch area. 

The common belief that barefoot motion lowers the impact on the body has been questioned by a recent research study from Southern Methodist University. The findings indicated that while running barefoot with a forefront strike, the feet strike the ground at a more pronounced angle which generates a longer contact time, thus decreasing the loading rate and allowing the muscles in the back of the feet and legs (especially the Achilles) to absorb some of the loading stress. When humans adapted to running in shoes, especially shoes with thick cushioning, the landing switched to a rear foot strike that allows the heel cushioning to absorb some of the loading stress, resulting in a fairly equal loading rate for both cases. The heel cushioning, with a flatter angle of contact, also allows for decreased impact time with the ground surface, which is why higher running speeds are achieved with footwear. 

barefoot person walking outdoors during the day
Photo by ‏🌸🙌 في عین الله on Unsplash

While the advice to encourage barefoot walking in young children certainly makes sense as they continue to grow and learn to control their bodies, the choice to use shoes or go barefoot for older children and adults remains an individual preference. There is no significant difference in the stresses the body experiences, but the footwear choice does influence the likelihood of certain, which is important for runners with past injuries to consider.

For more information, check out this extensive technical review of studies on barefoot vs. footwear mechanics or this video from Exercising Health comparing running shoes with minimalistic barefoot shoes.

Why is heading the ball so dangerous for youth soccer players?

young girl attempting to head an incoming soccer ball
Photo by Carson Ganci on THE42

I received my first concussion while playing soccer at 15 when I was knocked out by a ball that was “accidentally” punted directly into the side of the head. It seemed to me like this was one of the few, rare ways to get a concussion from the sport – an unlikely occurrence combined with an unusually aggressive impact. I was proven wrong, however, after I received two more concussions just from heading the ball – a frequently used technique involving seemingly mild impact forces. I have since come to discover that concussions, particularly due to heading the ball, are a huge problem for youth soccer players: currently, in the United States, youth soccer players aren’t allowed to start heading the ball until age 11 in an effort to reduce the risk of concussions. But how do headers cause so many youth concussions, especially when the speed of play is so much lower than for adults?

Physical vulnerability to concussion mechanics

illustration showing a head impacting a an object with arrows decribing the movement of the skull and the brain towards the object just before impact
Illustration of the movement of the skull and brain just before impact with an object. Upon impact, the movement of the skull decreases rapidly while the movement of the brain has a delayed response. Original image created for Wikipedia

In most sports, concussions are commonly caused by rapid acceleration/deceleration of the head that causes the exterior of the brain to crash into the interior wall of the skull, which is suddenly accelerating in a different direction. When headers are performed in soccer, this rapid acceleration is caused by impact with the ball, and the risk of concussion depends on both the acceleration of the head and the duration of the impact. The acceleration of the brain can be modeled by Newton’s Second Law (F = ma) for a given impact force F, and the resulting acceleration depends on the effective mass of the players head m, which depends on both the strength and weight of the players head and neck as well as their relative movement compared to the ball (which boils down to technique). This means that a major portion of the risk of concussion relies on the size, strength, and technical ability of the player, all of which have an inverse relationship with player age. So while the relative speed of play and impact forces may seem lower for youth players that can’t run as fast or strike the ball as hard as their adult counterparts, these factors are offset by their relative physical vulnerability.

Issues with injury recognition and response

Another factor contributing to the threat of concussions for youth players is their relatively low ability to recognise and respond appropriately to a brain injury when one occurs. Between 2008 and 2012, researchers observing elite female players aged 11 to 14 for 414 player-seasons (288 athletes were observed for a single season and 63 were observed for two seasons) discovered that 59 concussions occurred, with headers being the most frequent cause at 30.5%. In addition to this injury frequency, it was found that over half of these middle-school-aged athletes continued to play with symptoms after receiving a concussion. This is an additional a logistical problem for youth players, for as age decreases, athletes on average have less access to on-hand, qualified medical personnel and less of an ability to self-diagnose and respond appropriately to injury, putting them at increased risk for long term damage.

The Dangers of Using Your Head: The Biomechanics of Sports-Related Concussions

Anyone that has ever had the misfortune of banging their head know how painful it can be, but does everyone understand just how dangerous it can be? Concussions occur when the brain hits the interior walls of the skull, either due to a direct blow or a sudden start or stop. These brain injuries most often result in confusion, headaches, and loss of memory but more severe injuries can cause vomiting, blurry vision, and loss of consciousness. In rare instances, they can even cause a brain bleed and result in death. Repeated concussions can lead to neurocognitive and neuropsychiatric changes later in life as well as increase a person’s risk of developing neurodegenerative diseases like Alzheimer’s.

So, who is at risk for concussions?

Athletes sustain 1.6-3.8 million concussions every year in the US. They are most common in contact sports such as soccer and hockey, but the largest contributor is American football. Players are constantly hitting or tackling each other in football, and each impact risks serious injury for both individuals.

How does it happen?

It all comes down to conservation of energy and momentum. Newton’s second law states that an object in motion tends to stay in motion while an object at rest tends to stay at rest, unless acted on by an outside force. When player 1 starts to run, he has a set energy and momentum based on his velocity (speed). Once he hits player 2, he either slows down, stops, or bounces off in the opposite direction. However, the initial energy and momentum that he had doesn’t just magically disappear, it needs to be conserved so it is transferred to player 2. This means that player two will start moving in the direction that player 1 was initially running. This is how billiards is played: the energy is transferred from the pool stick to the cue ball and then to the intended solid or stripe.

However, injury occurs when player 2 or his head cannot move. This may be because he hit the ground or another player or even simply because his neck stabilized his head, but regardless, that energy still needs to go somewhere. When the head stops, the brain keeps going until it collides with the inside of the skull.

Fortunately, not every hit results in a concussion. The brain is separated from the inside of the skull by cerebrospinal fluid that can protect it from collision to a certain degree, so not every impact reaches the injury threshold. What that injury threshold is has become the focus of many scientific studies.

Finding the injury threshold

The search for the injury threshold is a vital one that could help in the development of more effective helmets and rule changes to the game that could keep players safe. Three factors are believed to dictate this threshold: linear acceleration, angular acceleration, and location of the impact. The linear acceleration is what causes the collision with the skull, as previously described. The rotation of the cerebrum (the bulk of the brain) about the brain stem can cause strain and shearing within the upper brainstem and midbrain, which control responsiveness and alertness (causes the confusion symptoms). Finally, certain areas of the brain are more susceptible to injury- like the frontal lobe, temporal lobes, and brain stem since they are near bony protrusions– so the location of the impact can have a major influence in the injury threshold.

While there is still no set threshold, one study was conducted in which 25 helmet impacts from National Football League (NFL) games were reconstructed and the resulting helmet kinematics measured. The study found that the heads of concussed players reached peak accelerations of 94 (+/-) 28 g (acceleration due to gravity-9.8 m/s^2) and 6432 (+/-) 1813 radians/s^2. A separate study focused on the location of concussions of football players and that resulted from specified linear accelerations, as seen in Figure 1.

While there is still much that needs to be learned about sports-related concussions and their long term effects on athletes, scientists are well on their way to understanding the biomechanics that cause them. The next step is using that knowledge to create better protective headgear and a safer game.

Locations of concussions and their linear accelerations.
Back: Case 13-168.71 g (1 concussion)
Front: Case 12-157.5 g, Case 2- 63.84 g, Case 6- 99.74 g, Case 4- 84.07 g (4 concussions)
Right: Case 11-119.23 g, Case 8-102.39 g (2 concussions)
Top: Case 9-107.07 g, Case 1- 60.51 g, Case 7- 100.36 g, Case 10- 109.88 g , Case 5: 85.10 g, Case 3: 77.68 g (6 concussions)
Location of concussions and their linear accelerations. Modified from Neurosurgery

To learn more, check out these links!

https://pubmed.ncbi.nlm.nih.gov/23199422/

https://pubmed.ncbi.nlm.nih.gov/23299827/

Packing a punch: Does strength indicate boxing performance?

Every sport has a different “ideal” body type, which is largely dictated by the muscle groups it focuses on training. Swimmers prioritize developing the muscles in their shoulders and backs, which allows them to propel themselves through the water with their arms. On the other hand, runners prioritize the hamstrings and quads in their legs, which allows them to generate greater force when pushing off of the ground. So, what is the ideal body type for boxing? Strength is clearly important when punching an opponent, but is it even the most important factor in boxing performance? Should either upper- or lower-body strength be prioritized over the other?

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Photo by Bradley Popkin for Men’s Journal.

The overall goal in boxing is to either knock out your opponent with a single punch or land more punches in the scoring area than your opponent. One of the best ways to achieve the latter is by wearing down your opponent with powerful strikes to reduce their ability to retaliate. Therefore, hitting your opponent, and hitting them hard, is crucial within the sport of boxing. 

First, let’s take a look at upper-body strength. Boxers execute punches by using muscular force to accelerate their arms, so it is easy to assume that arm strength is the most important factor in punch performance. However, this may not be the case. One of the most common upper-body strength exercises is the bench press, and research has shown that there is no significant correlation between the maximum weight a boxer can bench press and the force they deliver in a punch. While this may be surprising, the relationship between upper-body strength and punching actually comes down to speed rather than force. Based on data from both professional and elite amateur boxers, the maximum speed at which a boxer can bench press is indicative of improved punch performance. More specifically, professional boxers showed a strong relationship between the maximum velocity of their bench press and maximum punch velocity of their rear, or dominant, arm. 

If upper-body strength does not indicate punch force, then does lower-body strength? A study of amateur boxers found a positive correlation between maximum punch force and lower-body strength measures, including countermovement jump (see video below) and isometric midthigh pull. In contrast to the upper-body exercises, the maximum force generated in lower-body exercises is more important for increasing maximum punch force than the speed at which the exercise is completed.

Plot of countermovement jump force in Newtons versus punch force in Newtons. The data has a correlation of 0.683 and a p-value of less than 0.001. Plot of isometric midthigh pull force in Newtons versus punch force in Newtons. The data has a correlation of 0.680 and a p-value of less than 0.001.
Plots showing a strong, positive correlation between punch force and the lower-body strength exercises, countermovement jump, CMJ, (left) and isometric midthigh pull, IMTP, (right). Adapted from “Relationships Between Punch Impact Force and Upper- and Lower-Body Muscular Strength and Power in Highly Trained Amateur Boxers” by Emily C. Dunn, et al.
Video of how to execute the countermovement jump test by Training & Testing.
Kinetic Chain: Force is generated from the floor and transferred from foot to fist. Leg force, hip and torso rotation are key. Arrows show movement of force from foot, through the body, to fist.
Graphic of Kinetic Chain in a boxer from Boxing News.

When executing a punch, a boxer gains forward momentum by pushing off of the ground with their legs. Through a kinetic chain, force moves through a boxer’s body from the floor to the foot, then through the legs and torso, and finally, to the arm and hand. This phenomenon is what explains why lower-body force is crucial to a boxer’s maximum punch force. 

So, what does this all mean? How should boxers train in order to improve their punching performance? Most importantly, boxers should focus on their lower-body strength, as it is the most direct indicator of maximum punch force. While lower-body strength should be a primary training goal, exercising muscles within the upper-body, specifically while focusing on the speed of the movements, will also likely improve overall punch performance. We now know that developing strength is clearly beneficial in improving a boxer’s punch; however, brute force alone does not win a fight. Boxers should develop correct boxing technique through methods such as those suggested in this article, which will allow them to implement their new strength in the most effective manner.    

For additional information on the impact of strength on athletic performance click here and here.

Punch like a nerd: Utilizing Biomechanics in Boxing Form

Why we punch and how we do it

You and I are living creatures. Every living creature on Earth has some means of self-preservation, and while society and technology have advanced humans far beyond the norms of the animal kingdom, deep down at our core is the self-preserving instinct known as “fight or flight”. When the moment arises that flight is not possible, that unarmed self-defense is the only option, a human will most likely throw a punch. Unless you are trained in a combat sport or a style of self-defense, that punch will likely be inefficient and ineffective. I’m here to break down, with biomechanics, the most effective way to throw that punch.

This diagram shows 4 main punches in boxing. This blog will focus mainly on the cross, hook, and uppercut. Photo from neilarey.com

In boxing, that sport that deals with punching a good bit, there are three main types of punches: straight (jab/cross), hook, and uppercut. As pictured above, the three motions have varying paths traveled by the fist and they engage different muscles in different ways.

“Hold on a minute, why not throw a karate chop or a big ol’ open hand slap?” A study was done to answer this question, where untrained men and women hit a target with an open hand, a karate chop and a closed fist. For each of the techniques they calculated the effective mass, which measures the impact the target experiences. The results showed that while the open hand slap and karate chop had similar effective masses, the closed fist punch had an effective mass that was more than double the other techniques. So, unless you’re a black belt in karate with a mean karate chop, let’s stick to punching if the need arises.

Which punch to utilize

Now that you have decided that the first step is to clench your fist and rear up for a punch, how exactly do you do that? Biomechanical studies have shown for low-level boxers the cross, which is a straight punch with the dominant hand, generates noticeably more punching force. When elite level boxers such as Olympic athletes are observed, however, all three techniques produce extremely similar punching forces. This suggests that for the average untrained human, the most effective and efficient punch to use is going to be the cross.

While it is not the most scientific diagram, this graphic gives some biomechanically sound tips on how to throw an effective straight cross. Photo from The Art of Manliness.

But why is the straight cross generating more force in amateur boxers, and how can elite boxers generate high forces with the other techniques? It’s all answered by biomechanics.

Each punch is unique in how force is generated due to the motion of our bodies and the muscles each motion uses. For example, elite level boxers generate much more of their punching force from extension of their back leg and the extension of their elbow when throwing the cross. This is similar to how a baseball pitcher generates force by driving off the mound with their back leg in their throwing motion. When throwing hooks and uppercuts, elite boxers tend to utilize their hip rotation much more than lower-level boxers, who rely on their shoulder motion. All of this leads to the fact that while you’re throwing your fist at a target, most of the power comes from your waist and legs, so mixing a leg day into your workout schedule could be beneficial.

Sources and Further Reading

Heads Up and Eyes Steady – The Optimized Mechanism for Human Running

In the insightful words of Bruce Springsteen, we as human beings were Born to Run. Humans have never been a sedentary species. The tendency to constantly relocate for survival purposes required skill in obtaining food efficiently, which heavily influenced early human evolution. Humans with optimal body mechanics for running ultimately held an advantage in hunting and gathering for food, and over time, the human body adapted to these survival requirements and developed a self-optimizing mechanism for running. This implies that initiating the act of running activates certain responses in the body to perform most efficiently.

Two aspects of the human body that the mechanism for running must account for, more so than other living species that depend on running for survival, is the bipedalism of humans and the disproportional size and weight of the head compared to other living species that run. For optimal locomotion, the head must remain stable while the body is in motion and experiencing the impacts of running not only to minimize the strain on the neck, but to allow for a steady gaze and safe navigation of the environment and potentially dangerous terrain. In order to achieve this, the human body has developed aspects within the mechanism for running that specifically protect against body pitching and head instability.

Plot title: Brain-to-Body Mass Ratio
X-axis: Body Mass (kg)
Y-axis: Brain Mass (kg)
where the ratio for humans is the largest compared to various other animals.
Image from Charlotte Swanson, Science World

The default mechanics of an individual’s natural stride minimize the shock through the body so that it may function as metabolically efficient as possible. This is true for most processes found in the universe; systems are constantly seeking a lower state of energy, and human beings are no different. Thus, as found in the research conducted by Michael A. Busa, Jongil Lim, Richard E. A. van Emmerik, and Joseph Hamill, the human body reacts to the external stimulus of running with a tendency toward an optimal stride frequency, which allows the head to be most stable during the motion.

Looking even further into the human body’s mechanism for running, a study was conducted by Andrew K. Yegian and Yanish Tucker investigating the involvement of neuromechanics. The researchers hypothesized that there was a neuromechanical connection between the biceps brachii and the superior (or upper) trapezius that served to provide stability for the head during running.

Biceps brachii highlighted in color on skeletal diagram.
Image from Wikipedia “Biceps Brcachii”
Sections of the trapezius muscle, upper or superior in orange, middle in red, and lower in fuchsia
Image from Wikipedia “Trapezius”

Although the activation of these two muscles is seemingly uncorrelated, the connection points on the shoulder are very close to once another and the line of action of both muscles is almost parallel. Both muscles are known to resist rotational impulses, and thus body pitching initiated by the significant weight of the head, during the foot’s contact with the ground during running.

In the study, the researchers observed human subject running on a treadmill and tracked muscle activity with electromyographic (EMG) sensors. They found the timing of muscle activation to be strongly coincident, and the magnitudes of both activation levels in both muscles were generally larger when mass was added to the runner’s head to further test the neuromechanical linkage. Due to the approximately parallel lines of action, the coincident forces from the biceps brachii and the superior trapezius, which act in opposite directions, directly support the stability of the scapula, which ultimately controls the stability of the head and upper body above the torso during running.

At this time, it is unknown whether the neuromechanical linkage between the biceps and the upper trapezius muscles to stabilize the head during running is direct or indirect, so further research is required to determine the mechanism that causes the muscle coordination.

For more general information about the biomechanics of running, visit this article found in Psysiopedia.

Big Air: The mechanics of SKIERS and snowboarders landing after jumps

Snowboarder getting big air off a jump
Photo by Jörg Angeli on Unsplash

Have you ever watched the X-Games or Olympics or any other skiing or snowboarding competition and marveled at the sheer heights that the athletes achieve? Depending on the type of jump the skier goes off, they can reach heights of up to 50 feet off the ground [1]. How exactly do the skiers land what are essentially free falls from such heights? Supposedly “survivable injuries” occur from falling heights above the “critical threshold” of 20-25 feet, so how do these athletes land from heights of up to double this [2]?

First, let’s talk about the limits of the human body and falling. The critical fall height threshold, or the height at which injuries from falling start happening, is defined as “> 20 feet (6 meters)” by the American College of Surgeons Committee on Trauma [2]. This means that “survivable injuries” happen when people fall from the “critical threshold of a falling height of 20-25 feet” [2]. These athletes are falling from heights of up to double this, meaning that they should be sustaining some type of injury, yet they will do multiple runs and emerge completely fine. How is this?

To answer this question, we need to understand the design of the jumps that they are going off. Despite ramps for ski and snowboarding competitions typically being “purpose-built to fit their particular venues,” or built for the specific competition and run they will be used for, the ones that lead to athletes getting big air all share the same general structure, which is displayed below [3].

Diagram of typical ski and snowboarding jump layout

It starts with the inrun, a long, straight drop that allows the athletes to accelerate, and then the “kick,” or the actual jump itself that launches the athletes into the air, and last is the landing ramp, another section that is essentially the same as the inrun where the athletes land [3].

The most important part of the jumps, and the part that allows the athletes to land safely is the landing ramp. The landing ramps downhill slope allows the athletes landing to “convert” their downward momentum from falling into forwards momentum, which spares them the “ruinous impact of a multi-story fall” [3]. The fall impact in situations like this is quantified by physicists as “equivalent fall height,” because “when a snowboarder [or skier] lands at an angle and keeps moving down a slope, the impact is equivalent to falling from a much lower height” [4]. This is the case because gravitational energy gets transformed into “forward-moving energy,” leaving a smaller impact to be absorbed by the knees [4].

Jump designers and builders have become very adept at making the jumps for competitions very safe by using this concept of “equivalent fall height.” It has reached a point that the park and pipe contest director for the International Ski Federation (FIS), Roberto Moresi, stated in an email to Scientific American that “A good jump is when landing, they barely feel the impact,” meaning that through the design of the jump a fall of 50 feet can lead to a nearly imperceptible impact [4].

Sources:

[1] https://www.usskiandsnowboard.org/news/aerial-skiing-101

[2] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3212924/

[3]https://www.wired.com/story/big-engineering-big-air-olympics/

[4]https://www.scientificamerican.com/article/olympic-big-air-snowboarders-use-physics-to-their-advantage/

Why Not Running Could Lead to Bad Bone Health

Is staying active and fit enough to avoid bone loss? Maintaining high bone mineral density (BMD) is important for preventing osteoporosis, fractures, and other conditions associated with bad bone health. However, high-impact sports that often involve running or jumping might be necessary in order to preserve and improve BMD among athletes of all ages. Low-impact sports (such as cycling) as well as weight training may not be enough to maintain high BMD and avoid associated health risks.

Among senior athletes, a 2005 study examined BMD among those competing in the Senior Olympics [1]. They concluded that competing in high-impact sports (basketball, running, volleyball, track and field, and triathlon) correlated with a higher BMD compared to low-impact sports (including cycling, race walking, and swimming), among other factors such as younger age and absence of obesity. Similar results were found in a Norwegian study comparing elite cyclists and runners, as cyclists—despite heavy weights programs as part of their training—were shown to have lower BMD than runners [2].

On the other hand, a study comparing younger men and women showed BMD increases as a result of resistance training, but only among men in the spine and neck. Women showed no significant BMD increase [3].

Bone mass changes with age, peaking for both genders at around 30-40 years old.
Modified from Wikimedia Commons

In light of unsubstantial data to support resistance training as a method to increase BMD, why do many articles online praise weight training as the perfect way to promote healthy bones? Online articles with catchy titles claim that “resistance training is really the best way to maintain and enhance total-body bone strength” and it “increases bone mineral density,” but either provide no sources or cite research that showed no significant increase in BMD [4] [5] [6] [7]. Promoting weight training as the perfect solution to late-in-life bone problems sounds wonderful, but formal research concerning its effects on BMD is as best contested and inconsistent. It is not a blanket solution for those looking to improve bone health through staying fit, and should not be used as the only supplement to other low-impact sports such as cycling or swimming.

Running is among high-impact sports that can promote bone health
Modified from Wikimedia Commons

Ultimately, it seems as though staying fit through low-impact sports and weight training might put an athlete at risk for low BMD and associated health risks. Regular participation in high-impact sports (such as running, basketball, and volleyball) has been shown to correlate with higher BMD across different age groups and athletic skill levels [1] [2]. Even though cycling and weight training might cover all the bases from cardiovascular and strength fitness standpoints, bone health requires more impact than just staying fit.

For further reading on the relationship between running and bone health and how other factors play a role, look at Runner’s World’s article.

 

[1] Leigey D, Irrgang J, Francis K, Cohen P, Wright V. Participation in High-Impact Sports Predicts Bone Mineral Density in Senior Olympic Athletes. Sage: Sports Health. 2009. [https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3445153/]

[2] Andersen OK, Clarsen B, Garthe I, Morland M, Stensrud T. Bone health in elite Norwegian endurance cyclists and runners: a cross-sectional study. BMJ Open Sport & Exercise Medicine. 2018. [https://bmjopensem.bmj.com/content/4/1/e000449]

[3] Almstedt HC, Canepa JA, Ramirez DA, Shoepe TC. Changes in bone mineral density in response to 24 weeks of resistance training in college-age men and women. Journal of Strength and Conditioning Research. 2011. [https://www.ncbi.nlm.nih.gov/pubmed/20647940]

[4] Heid, M. (2017, June 6). Why Weight Training Is Ridiculously Good For You. Retrieved from http://time.com/4803697/bodybuilding-strength-training/

[5] (2018, February 2). 10 Health Benefits of Strength Training That Are Backed by Science. Retrieved from https://www.myoleanfitness.com/health-benefits-of-strength-training/

[6] Nelson ME, Fiatarone MA, Morganti CM, Trice I, Greenberg RA, Evans WJ. Effects of high-intensity strength training on multiple risk factors for osteoporotic fractures. A randomized controlled trial. JAMA. 1994. [https://www.ncbi.nlm.nih.gov/pubmed/7990242]

[7] Going SB, Laudermilk M. Osteoporosis and Strength Training. American Journal of Lifestyle Medicine. 2009. [https://journals.sagepub.com/doi/abs/10.1177/1559827609334979]

How much wood can a woodpecker peck? The Science Behind a Woodpecker’s Anatomy

Woodpecker anatomy: showing the location of the tongue
Diagram showing the tongue of a woodpecker, obtained from “BirdWatchingDaily.com”

Have you ever wondered how a woodpecker is capable of banging its head against a tree so furiously without seriously injuring itself? The impact of a woodpecker’s beak with a tree can exceed speeds of up to 6 meters per second and occur over 12,000 times a day.These kinds of numbers are what allow woodpeckers to smash through trees to get to those tasty bugs that live inside.

How is this possible you may ask? Scientists have studied the anatomy of a woodpecker and have come across an extraordinary discovery: the tongue of a woodpecker wraps completely around its neck before exiting the mouth, constricting the blood flow to and from the brain. This increases the amount of blood volume in the skull, making it, and its precious cargo, filled to the brim with fluid. This creates an effect known as “slosh mitigation”, where an object that is completely enclosed by an incompressible fluid becomes protected from an outside force due to the constant stabilization of pressure within the enclosed system. Thus, the harsh vibrations translated throughout the skull of the woodpecker are mitigated by a cushioning effect induced by the increased volume of blood in the brain. Ever notice how a snow globe always has a little pocket of air sitting on top of the water? Without it, there would be no pressure changes, and the flakes of snow would be restrained from ever creating that magical snowy blizzard we all love.

This incredible discovery is not just a fascinating fact you can pull out to impress your friends. In fact, companies have begun applying the science behind a woodpecker’s anatomy to the sports arena. A company by the name of Q30 Innovations has been on a mission to curb the estimated 3.8 million concussion occurrences every year. Their latest product, the Q Collar, features a tightly fitted neck brace that applies a mild compression to the jugular in the neck, thus creating the “slosh mitigation” effect on the brain. The Q-Collar has already been put to the test, showing positive results on football players and hockey players. Their latest test showed the effects of wearing the Q-Collar for a high school girls soccer team, whose total head impacts were collected via an accelerometer throughout the entire season. Half the team was selected to wear the Q-Collar, and at the end of the season, the accelerometers of both groups reported similar levels of head impact, both in quantity and severity. However, it was shown the group wearing the Q-Collar required less brain activity to complete a concussion protocol than those of the control group. This shows that despite any of the girls having a reported concussion, the high impact loads exhibited on the brain during the season were enough to prohibit the brain from performing at its optimal level.

Want to learn more about breakthrough technologies covering the challenges of concussions? Learn more at Q30 Innovations.

 

References:

  1. “Do Woodpeckers Get Concussions?”http://explorecuriocity.org/Explore/ArticleId/6734/do-woodpeckers-get-concussions.aspx
  2. “Response of Woodpecker’s Head during Pecking Process Simulated by Material Point Method” https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4406624/
  3. “What is a Concussion?” http://www.protectthebrain.org/Brain-Injury-Research/What-is-a-Concussion-.aspx
  4. “Q-Collar tests produce positive results in protecting girl soccer players from concussions” https://www.news5cleveland.com/news/health/q-collar-tests-produce-positive-results-in-protecting-girl-soccer-players-from-concussions