We are all familiar with sunburns and sunscreen. From our first day playing outside, we are taught to put on sunscreen to protect our skin. But why? Why do we need to protect our skin from the sun? And how does sunscreen, if at all, protect us?
Continue reading “Sunscreen’s Secrets: How Is It Really Helping?”Tag: prevention
Spatial Disorientation in Military Pilots: How does aerodynamic forces lead to pilot error?
Icarus, the prisoner that dared to touch the heavens; his story of flight captivated humanity with the dream of flight for centuries. With the coming of the first powered and controlled flight in 1903 by the Wright brothers, to fifth-generation fighter aircraft, this ancient dream became reality. Yet, as Icarus ignored his father’s warnings and fell from the sky, modern pilots too can be deceived, not by the sun, but by their own senses.
But how does this deception happen?
Flight & Spatial Disorientation
Unlike birds who have been flying for around 150 million years, the human body has evolved to move on solid ground, meaning in a two-dimensional space. Not through a three-dimensional space where one can experience differing flight maneuvers, or acceleration at multiple gravitational forces (G-force), that make orientation difficult to maintain. Naval Pilots rely not only on their flight instruments, but also their visual, and vestibular senses to navigate in the skies. Any variation in these senses causes spatial disorientation (SD); which according to a study done in 2014, 20% of all plane accidents are related to the pilot’s optical illusions. There are three classifications to SD:
Type 1: Unrecognized
- These SD’s are unrecognized by the pilot.
Type 2: Recognized
- The Pilot recognizes the SD, and can attempt to correct it.
Type 3: Incapacitating
- The pilot is incapacitated and cannot save himself nor recover the aircraft
The Lying Senses
Within the inner ear lies the vestibular system acting as our built-in balance sensor, and gyroscope; with its main goal being that we are oriented upright, straight, and level. There’s two parts to the vestibular system: the semicircular canals that detect angular/rotational movement, and the otolith organs that detect linear acceleration. But, like any man-made sensor, it has limits. The vestibular system is sensitive to G-force, and prolonged maneuvers, creating illusions that fall into two categories: somatogyral for spinning illusions, and somatogravic, for acceleration illusions.
Imagine you’re flying through the clouds in an F-35C, no visible terrain, and the horizon is obstructed. You bank into a turn, the fluid in your semicircular canals start moving, but after a while your brain no longer recognizes that you’re still in a bank as the fluid in your ear has reached equilibrium within the canal wall. Then you exit the clouds and level out, your eyes and instruments may say your level, but the fluid in your inner ear is still moving, giving pilots the urge to bank the aircraft into an attitude to correct this feeling; a situation called “the leans,” a somatogyral illusion.
Vision isn’t the savior
During flight, vision is the most important sense needed not just for flying, but to achieve accurate spatial orientation. But, vision can betray you in the sky. Your eyes and brain work together in order to decipher how light reflects off things, this “vision” allows pilots to see their surroundings and help navigate through the skies. However, if a pilot is in an maneuver where their exposed to high G-Forces, they can be “G-Locked,” or have an G-induced loss of consciousness that can negatively effect their vision as it constricts blood flow to the brain causing pilots to lose sharpness in their vision. 3-4 G’s is whenever a pilot without adequate G-force protection can expect gray vision (blurred central vision), with the pilot blacking out between 5-7 G’s.
Bringing it Home
Aerospace technology is only continuing to get better, and the understanding of the human physiology, and the biomechanics of Spatial Disorientation remain a constant. Pilots must not only learn to master their aircraft, whether it be for a commercial purpose to protect the lives of the passengers, or a military purpose to fulfill the mission, but they must also understand their own biology as well. This understanding of the human body’s limitation is the only way to prevent and counteract spatial disorientation. After all, as Icarus learned long ago, the sky may be beautiful, but it is not forgiving.
Featured Image from USN
Further Reading:
Well, if the Boot Fits! The Effect of Ice Skating Boots on Overuse Injuries in Competitive Figure Skaters
Every 4 years, viewers around the world tune into the Winter Olympics to watch the world’s best athletes compete in events like figure skating. With each passing Olympics, skaters push the limits of what is possible on the ice, always attempting jumps with more revolutions than ever before to impress judges and amaze viewers. However, these high-revolution jumps pose serious risks to the skaters who perform them, mainly in overuse injuries resulting from countless hours of practicing these jumps to perfect them for competition.
Read more: Well, if the Boot Fits! The Effect of Ice Skating Boots on Overuse Injuries in Competitive Figure SkatersWhen landing these jumps, skaters’ lower bodies are subjected to large impacts on their joints and bones due to the dissipation of kinetic energy resulting from their rapid rotations while in the air. As the number of jump revolutions increases, so too does the kinetic energy required to successfully perform them as skaters must rotate faster while in the air.
Additionally, high-rotation jumps place skaters’ completion of rotations closer to the ice, as skaters have less time to complete rotations while in the air. This results in a collision-type impact between the skaters’ landing foot and the ice that shortens how long skaters have to absorb forces from landing their jumps and further increases the impact on their joints and bones. Combined with the sheer number of jumps that skaters perform daily to perfect their skills, these high-revolution jumps greatly increase the risk of overuse injury development in skaters’ lower bodies.
To better preserve skaters’ joint and bone health, researchers have studied how ice skating boots impact skaters’ performance. These boots, which are worn by all skaters regardless of skill level, rise high on skaters’ ankles and are tied like shoelaces around metal hooks mounted on the boot. Tying the laces around these hooks provides extra stability to skaters’ ankles and ensures a secure fit of the boot around a skaters’ foot. A stiff platform runs under the boot and slightly raises the boot’s heel. Finally, a thin metal blade with a jagged pick at the toe of the boot and a rounded edge at the heel is mounted to the underside of this platform.
The most important feature of these boots is their stiffness around skaters’ feet and ankles to serve as braces that protect their ankles from wobbling and losing balance when landing jumps. However, this boot stiffness limits the ability of skaters’ feet and ankles to absorb the impact experienced upon landing jumps. This results in landing forces traveling up the skaters’ lower bodies and mainly impacting their knees, hips, and lower backs.
Therefore, boot models must strike a balance between structural stability and joint mobility, and researchers aim to identify this balance by observing how boot stiffness and fit around skaters’ feet impact their range of motion. Ankle and foot range of motion is important for skaters because it controls which joints are impacted most in skaters’ lower bodies. Studies have found that boots with angled forms and raised heels result in increased ankle range of motion and thus improved force dissipation in skaters’ feet and ankles rather than transferring more of these loads upwards to their knees, hips, and lower backs. Additionally, lightweight boots made of materials like fiberglass, plastic, and soft memory foam absorb a greater amount of the landing force impact than boots made of heavier materials like leather and wood. With these findings, skaters can make educated choices for their ice skating boots that prioritize their long-term joint and bone health, protecting themselves from overuse injuries to prolong their skating careers and get the most benefit out of their daily training.
Featured image by Sandro Halank from Wikimedia Commons.
Does Boxing Headgear Prevent Concussions?
In boxing, behind every punch connecting and glove pushing into a face, there is a complex collection of engineering principles at play that can vibrate a human skull and cause serious neurological damage. The impact of a punch can jolt the brain, causing it to move across the cerebrospinal fluid that it sits in and putting the person at risk. The rotation and rebound of the brain inside the skull from the rapid force applied is what produces concussions in the sport. Theoretically, headgear will reduce the likelihood of a concussion by softening the blows.
Continue reading “Does Boxing Headgear Prevent Concussions?”Taking Collagen and Copper Supplements can decrease the risk of bone fractures
When we think of building strong bones, most of us picture drinking plenty of milk for its calcium—at least, that’s what our elementary gym teachers used to tell us. But building and maintaining strong bones requires more than just calcium from milk; supplemental vitamins play a key role in the development and maintenance of strong bones. Bone fractures are common in young, but especially elderly people, and adding collagen supplements to one’s diet can have a major impact on bone toughness reducing the risk of fractures.
Continue reading “Taking Collagen and Copper Supplements can decrease the risk of bone fractures”Limiting Repetitive Subconcussive Impacts in Rugby
It is no secret the danger head injuries can pose for player safety in contact sports. While the public is aware of the danger of large hits and concussions, many remain unaware of the danger small blows to the head can have on an individual. Formally, these incidents are known as subconcussive impacts, which are defined as blows to the head that result in mild brain trauma without the presentation of typical concussion symptoms. Recent studies have indicated repetitive subconcussive impacts can lead to cumulative, long-term brain damage. This discovery has been increasingly alarming for rugby players who can average 77 of these impacts per game! With the discovery of this newfound danger, the question must be asked: what is being done to protect at risk rugby players?
Continue reading “Limiting Repetitive Subconcussive Impacts in Rugby”Dancers: Athletes or Artists?
Throughout history, there has been a long-standing debate about whether dancers should be classified as athletes or artists. Athletes need strength to be proficient in a sport. Artists require creativity to produce works of art. Dancers combine strength with artistry to not only leap high into the air but also look graceful as they do so. Yet, many people still refuse to classify dancers as athletes or even as athletic artists.
Continue reading “Dancers: Athletes or Artists?”Knee Pain from Golf? Look No Further.
If you like golf, you probably remember watching Tiger Woods win the 2008 U.S. Open with a torn anterior cruciate ligament (ACL). This may have seemed like a rare injury for a golfer, as most golf-related injuries involve the lower back, but knee injuries due to the golf swing are more common than you may think. In fact, the prevalence of knee injuries in golf is roughly 18%, with an even higher percentage when you only consider the elderly. Since most of these injuries are a result of overuse, it is important for golfers to understand why these injuries occur if they want to keep playing for years to come.
Read More: Knee Pain from Golf? Look No Further.Unlike traumatic injuries in high-intensity sports like football or basketball, most golf-related injuries are the result of overuse. As for the knee joint, there are multiple mechanical factors in the golf swing that contribute to overuse injuries. During the downswing, the lead knee rotates rapidly from a state of adduction (external rotation) to a state of abduction (internal rotation). This creates an abduction moment on the lead knee, which can cause ACL tears. The graph shows a plot of adduction/abduction moments on the knees during a golf swing, which was measured using force plates and retroreflective markers on golfers’ legs.
The magnitude (roughly 1 Nm/kg) is not large enough to cause traumatic stress on the ACL but is enough to potentially cause an injury over many repetitions of the golf swing. In addition to rapid rotation, the lead leg undergoes rapid extension during the downswing. The combination of these movements in large volumes over time can lead to other ligament tears or osteoarthritis. Osteoarthritis occurs when tissues in the joint break down over time.
In addition to these biomechanical movements, other factors like pre-existing knee conditions play a significant role in golf-related injuries. Over 30% of golfers with previous knee pain feel that golf has made their symptoms worse. The same is true for golfers with a previous total-knee arthroscopy (TKA), as nearly 34.9% experience pain after playing. Considering that golf is very popular among the older population, it is important to understand how to limit the risk of injury in the golf swing.
While the golf swing can lead to overuse injuries, there are a few preventative methods golfers can implement to protect their knees. Several studies recommend that golfers rotate their lead foot open (towards the target) by roughly 30 degrees. This decreases the stress on the medial (inner) side of the knee, a common area for osteoarthritis. Another adjustment golfers can make in their setup is how close/far they stand from the golf ball during the swing. Standing closer to the ball lowers the peak abduction moment on the lead knee, while standing farther away reduces the peak adduction moment. Depending on which area of your knee is in pain or has experienced previous injury, you may want to implement these adjustments to your setup. If you are experiencing pain on the inside of your knee, you should stand closer to the ball. Conversely, if your pain is on the outside of your knee, you should stand further away from the ball. Other preventative methods include warm-up stretching and regular exercise to activate and loosen the knee joint and surrounding muscles. If you’d like to learn more about these preventative methods, click here.
Do Humans Get Weaker in Outer Space?
We have entered an era of renewed excitement regarding human space travel. The international community has lofty goals for the future of human spaceflight: returning to the Moon, sending crewed missions to Mars and other planets, and even colonizing space to save the human race when Earth is no longer habitable. These goals are beyond exciting, but before we can safely accomplish any of them, we must understand the biological consequences of space travel. For instance, it is well documented that space travel causes muscle atrophy, or deterioration. What causes this atrophy, and can how it be prevented?
Continue reading “Do Humans Get Weaker in Outer Space?”Slipping or Tripping? Researchers Find Best Way to Regain Your Balance
Everyone has slipped or tripped at some point in their lives. Whether it is walking on an icy road to get to your car or tripping over the Lego set your kid refused to put away, everyday obstacles can cause us to lose our balance. Often this results in a brief moment of panic followed by the uneasy relief of regaining your footing, but for those who aren’t lucky enough to avoid falling, the results can be devastating. This is especially prevalent in populations more susceptible to falling. Falling in the workplace accounts for 16.8% of all non-fatal injuries leading to days taken off work. It is thought that this is due to the high volume of slipping or tripping obstacles encountered in some occupations. Additionally, 36 million falls resulting in 32,000 deaths were reported for the 65+ year old population of the US. Elderly individuals may lack the strength and reflexes necessary to recover their balance quickly. This is especially worrisome because the elderly are also the most at risk for the major health complications that can be caused by fall related injuries.
Continue reading “Slipping or Tripping? Researchers Find Best Way to Regain Your Balance”