Tag: prevention

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.

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Falling for You: How to Reduce Fall Risks?

The majority of people know what a fall is and, in fact, many people have unfortunately experienced one or a few. But what would be a good definition for what a fall is? Simply put, a fall is something that happens when you lose your balance and cannot recover. Falls have the potential to ruin anyone’s day. For some, however, the risk is far more severe than that as falls are one of the leading factors in injury and death among the elderly population. This will continue to be a problem as the number of elderly people in the United States is expected to increase dramatically over the next fifty years.

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Jumping into Better Bone Health: Impact Exercise and Your Bones

When exercising for overall health, the general public tends to disregard the importance of bone health. Often the focus is on consuming milk or calcium rich foods, but are there certain exercises that can increase bone health? Studies show that the presence of impact in exercise plays a major factor.

As we age, everyone loses bone mineral density, which is a determining factor in bone strength and stiffness. Decreasing bone mineral density can lead to bones that easily break and fracture, and will, in extreme cases, result in the disease osteoporosis. Women are at a higher risk of osteoporosis because they lose more bone mineral density as they age due to the process of menopause. Increasing bone mineral density at younger ages can ensure that even with the inevitable bone loss, peoples’ bones are still strong.

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Do your Foot Arches make you more or less likely to be injured?

Picture showing what a flat foot, normal foot, and high arched foot and what the footprint looks like

Have you ever wondered how your arch type may affect your everyday life especially in physical activities such as running or playing sports? Well it turns out that without taking precautions, a higher arch or a flat foot may cause you to more likely be injured! People have all different types of arches, and each foot can be affected differently based on the type of arch.

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The Benchmark of Upper Body Strength: Injury Prevention During the Bench Press

Who wouldn’t want to look like Captain America? This common desire to attain a strong Herculean physique, either for athletics or aesthetics, has led many ambitious men and women to weightlifting. An egotistical motivation puts these people at risk of injury, however, as they sacrifice proper form to achieve their next personal best. The bench press is one example of an effective but potentially dangerous lift.

This upper body exercise requires an individual to lie flat on a bench while repeatedly lowering and pressing a straight bar loaded with weights on each end. The hands evenly grip the bar slightly wider than shoulder width apart with the feet remaining flat on the ground and the arms fully extended. During the eccentric (or lowering) phase, the bar is brought in contact with the lower chest. The bar is then pressed up until the arms are once again fully extended (concentric phase).

Recreational weightlifters commonly use a wider grip on the bar, believing that this will increase activation of the chest muscles and allow them to mimic Terry Crew’s version of the Old Spice Man. One study performed on 12 powerlifters, however, found that the prominent muscles used during the lift, such as the pectoralis major, triceps brachii, and anterior deltoids (i.e. chest, triceps, and shoulders), experienced similar electromyographic activity despite varying hand spacing.

Diagram of a human upper body muscular system.
Image by OpenStax from Wikimedia Commons.

Although hand spacing does not significantly affect muscular activity, it can lead to injury. A review of several studies on the effects of hand grip found that a grip width greater than 1.5 times biacromial width, or shoulder width, naturally resulted in shoulder abduction, or rotation away from the body’s centerline, greater than 45°. As this angle increases, shoulder torque increases, causing potential injuries. For instance, the inferior glenohumeral ligament, a ligament restricting translational motion in the anterior direction at the shoulder’s ball and socket joint, may tear as abduction increases, causing instability at that joint. Repetitive cycles with this wider grip may also cause acromioclavicular joint (AC Joint) osteolysis – chronic destruction of the bone tissue at the joint between the clavicle and acromion.

Diagram of shoulder joint.
Image by OpenStax College – Anatomy & Physiology from Wikimedia Commons.

Aside from a wide grip, injuries also commonly stem from over-training and using excessive weight. Research on 18 male college students demonstrated that repeating the bench press motion with high frequency until failure resulted in a significant increase in the medial and lateral force exerted on the elbow joint, which could result in injury over time. Furthermore, performing the bench press with heavier loads could result in a sudden rupture of the pectoralis major. At the bottom of the eccentric phase as the bar touches the chest, the muscle fibers are simultaneously lengthening while also contracting, which increases the risk of muscle tear in this region.

Unlike Captain America, people cannot instantly acquire strength or build muscle. Muscular development and improving one’s bench press require time, patience, and proper form. To learn more about injury prevention or variations of the bench press, check out the video below or read these papers by Bruce Algra and JM Muyor.

Sources can be found below:

The Affect of Grip Width on Bench Press Performance and Risk of Injury

The Effects of Bench Press Variations in Competitive Athletes on Muscle Activity and Performance

Elbow Joint Fatigue and Bench-Press Training

An In-Depth Analysis of the Bench Press

 

What Makes Someone More Likely to Tear Their UCL?

It takes a lot to make a professional athlete collapse to the ground during a game. After throwing a pitch on September 14, 2019, Toronto Blue Jays pitcher Tim Mayza knelt on the side of the mound while clutching his arm, expecting the worst. The next day, MRI revealed that what he had feared: Mayza had torn his Ulnar Collateral Ligament (UCL).

player following through after throwing baseball
Photo by Keith Johnston on Unsplash

Because of UCL reconstruction, or Tommy John, surgery, this injury is no longer the career death-sentence that it once was, but there is still a long road ahead for Mayza. He probably will not pitch in a game again until 2021. Sadly, this injury is only becoming more and more common among MLB pitchers. In the 1990s, there were 33 reported cases of UCL tears by MLB pitchers. In the 2000s, this number more than tripled to 101. From 2010 to the beginning of the 2015 MLB season, 113 UCL reconstruction surgeries had already been conducted. It has become so common that surgeons have called it an epidemic, and researchers in the US and abroad are attempting to find a way to combat this increase.

Digital image of elbow joint, with a small, red tear in the UCL
Orthopaedic and Neurosurgery Specialists, 2019

The UCL connects the ulna and humerus at the elbow joint, and its purpose is to stabilize the arm. During the overhead pitching motion, the body rotates in order to accelerate the arm and ball quickly, putting a large amount of stress on the UCL. In fact, according to a study by the American Sports Medicine Institute, the torque, or twisting force, experienced by the UCL during pitching is very close to the maximum load that the UCL can sustain.

Recently, many studies have investigated factors that could make pitchers more susceptible to UCL injuries, with a hope of identifying ways to prevent them. One of the biggest findings has been the correlation between UCL tears and pitch velocity. According to a study from the Rush University Medical Center, there is a steady increase in the frequency of UCL tears as max velocity increases. This makes intuitive sense, as more torque would be required to accelerate a baseball to the higher velocities. While this finding does have a very strong correlation, it does not help the players avoid injuries. Pitchers are unlikely reduce their velocity because it would also decrease their effectiveness, so another answer must be found.

The University of Michigan conducted another study, and found that, in addition to velocity, the number of rest days between appearances decreased by just under a full day for pitchers who later needed Tommy John surgery. While this does not seem like a large number, starting pitchers typically only receive 4 days of rest between starts, so the extra .8 days is equivalent to a 20% increase in rest time.

Because of these findings, the MLB has increased the max roster size from 25 to 26 for the 2020 season, with the hope that teams will use the extra player to reduce the frequency that each pitcher is used. In addition, pitch counts in Little League Baseball have had a positive effect on youth injuries. This can be explored further here. This discovery has already made a tangible impact on Major League Baseball, and hopefully more findings will reduce the rate of UCL tears in the future.

A Mystery: How Can Distance Runners Avoid the Most Common and Dreaded Injury?

Man running on track surface.
Photo by Steven Lelham on Unsplash

Stress fractures are small cracks in the bone produced by repetitive stress. The most common locations include the tibia, fibula, and navicular bone [1]. An article by Crowell and Davis on gait analysis stated the occurrence of bone stress injuries in track and field athletes (male and female) to be as high as 21% [2]. Furthermore, approximately 50% of female track and field athletes have had at least one stress fracture [3] . Bone stress injuries  can have a devastating effect on the athlete, their team, and the willingness of these runners to continue to compete. The only treatment for stress fractures is to completely stop running for an average of 6-8 weeks [4].   Runners have no clear and confirmed guidance on injury prevention or appropriate volume of training.

Female Athlete Triad triangle consisting of energy deficiency, low bone density, and menstrual disturbance that make up the three corners of the triangle.
Female Athlete Clinic, Children’s Wisconsin, 2019

Most studies of stress fractures in women have been looked at from a purely biological standpoint. As seen in an article by Hames and Feingold, the female athlete triad is often considered the main reason for the large number stress fractures in female distance runners [5]. The female athlete triad is the connection between energy deficit (due to excessive exercise or under nutrition) and irregular hormone levels which cause a decrease in bone mineral density.  However, despite normal bone density and hormone levels, many competitive runners continue to suffer from season or career-ending stress fractures [6].

Taking a more mechanical rather than biological approach, the source of stress fractures can be explained in the same way as any other material fatigue. A fatigue fracture is caused by a repetitive cyclic stress. For example, consider a paper clip. When a paper clip is bent just once, it does not break. After bending it several times, the paper clip will eventually fracture. This same concept can be applied to bones with forces caused by running. There are two main differences. First, while a paper clip will break through an abundance of minimal stresses over an extended period of time, the bone works to regenerate, with the help of osteoblasts, to compensate for added stress [7].  However, the body’s work to restore the bone is unsuccessful if there is not enough time for repair. Secondly, unlike a paperclip, muscles surround the bone that work to absorb the impact stress. At a given force, the muscles are unable to adequately protect the bone. With a high force frequency and magnitude, a bone stress injury occurs.

While the reason behind stress fractures is known, the mystery of  how to reduce the risk remains. For many competitive runners, dramatically increasing recovery time or reducing mileage is not an option. There are several different factors than might play a distinct role in the solution, including footwear, running form, and running surfaces.

For more information, visit the following articles:

Preventing Stress Fractures“,

Risk Factors for Recurrent Stress Fractures in Athletes“,

Biomechanical Factors Associated with Tibial Stress Fracture in Female Runners.”

“The Relationship between Lower-Extremity Stress Fractures and the Ground Reaction Force: A Systematic Review.”

References:

[1] “Breaking Point: when running stress gets too much.”

[2] “Models for the pathogenesis of stress fractures in athletes.

[3] “Biomechanical factors associated with tibial stress fracture in female runners.”

[4] “Stress Fractures of the foot and ankle.”

[5] “Female Athlete triad and stress fractures.” 

[6] “Sex-related Differences in Sports Medicine: Bone Health and Stress Fractures.”

[7] “The relationship between lower-extremity stress fractures and the ground reaction force: A systematic review”

Look Strong, Be Strong, or Be Safe?: The Perils of a New Deadlifter

So, you’ve started deadlifting, but you’re not sure if you’re just weak, or if you’re going to break your spine, and there are plenty of “gym bros” slamming the weights, grunting, and walking around wearing equipment (wrist straps and back belts) that says “I’m literally too strong for my own body.” So, what do you do? Do you need to buy that stuff too?

This blog post will walk you through a biomechanical analysis of the deadlift while wearing supportive equipment, in the hopes of helping you face this daunting task.

First, let’s look at the proper form and muscles recruited in the Deadlift.  As can be seen in the graphic below, the lift begins on the ground in a hinged squat. From A to C, The gluteus maximus (butt), trapezius and lower erector spinae (long muscles that run alongside the spine) are primarily activated, whereas from C to D, the hip extensors and numerous smaller upper back muscles help to “lock out” the form, with the forearms supporting the load throughout.

Graphic of a side view of the proper deadlifting motion
Graphic Depicting Proper Form

The science of using wrist straps as discussed here.  Your forearms are significantly weaker than your gluteus and back, and as such, they will fail first. A comparison of different kinematic variables as a function of wrist straps and unsupported showed a higher activation in the back when using straps.  This means, when using wrist straps, you reduce the load on your forearms, which allows you to go heavier with weight.  In essence, it takes grip strength out of the lift.

Improper form, like arching your back, hips rising too early, leaning too far forward, or many other small inefficiencies can lead to concentrated shear stresses between the vertebrate in the back (not good), excessive reliance on small ligaments in lower back (not good), and high stress concentrations at the moment hinge (especially not good considering your lower back is a nerve junction between your sciatic and spinal nerves).  So how do you prevent this?

Many people instantly reach out to supportive equipment as their saving grace, but does this really prevent injury or does it just add a false sense of security to allow dangerous form? Studies by Thomas and Kingma both look at the effectiveness of weightlifting belts in protecting your spine in various loading conditions.  Although I encourage you to read them and discover their findings for yourself, they both reach generally the same conclusion.  Belts might help, by increasing Internal Abdominal Pressure (IAP) says Thomas, and by decreasing spinal load, tested by Kingma, however, any benefit is nominal.

As far as my suggestion goes, you should begin deadlifting at lower weights, without a belt or straps, until you get a feel for the form.  This will begin to increase your strength in the smaller muscles and form muscle memory required for heavier lifting.  Listen to your body. If a lift went well, and you think you can increase the wight without sacrificing form then go up in weight. Eventually, a weightlifting confidence will step in, and you’ll be able to determine for yourself which strength you want to strive for (grip strength, or bigger deadlift numbers).

If profane language is no issue for you, I STRONGLY encourage watching the YouTube video appended below. Eddie Hall, a now retired professional strongman, owns the record for the ONLY 500 kg Deadlift, and he most certainly knows what he’s talking about.

PS he trains without any supportive equipment, and safe to say he’s lifting heavier than you.

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What an Optimized Running Gait Can Do for You

Running is one of the oldest and most common forms of exercise, but there are many ways that running mechanics vary from person to person. Identifying the different running gaits is important so that their efficiencies and effects on the body can be analyzed. Injuries in runners are common and having an understanding of how different gaits apply stresses on the body differently can be used to educate runners on how to run in a way that will reduce the risk of injury.

Running with poor mechanics can lead to overuse injuries, which are more common than acute injuries in serious runners. The majority of these injuries occur in the leg either at or below the knee and include patellofemoral pain syndrome (PFPS) and medial tibial stress syndrome (shin splints). Running gait analysis can be used to identify the poor mechanics and the potential risks associated with the mechanics. Further studies have grouped the variations so that the effects of similar gaits can be identified. Extensive analysis has led to the identification of several potential variations in running gait.

A study at Shanghai Jiao Tong University‘s School of Mechanical Engineering determined the effects of step rate, trunk posture, and footstrike pattern on the impact experienced by the runner. Data was collected by instructing runners to run with specified gait characteristics. Sensors made used to make sure that the gait was correct and the impact forces on the running surface were measured. This study showed the lowest impact was experienced with a high step rate, a forefoot strike pattern, and an increased anterior lean angle. Limiting the impact reduces the effects of the loading. As a result, running with these gait characteristics reduces the risk of knee pain and stress fracture in the tibia.

Runner on treadmill with attached sensors following instructions to modify gait
from: Huang, Xia, Gang, Sulin, Cheunge, & Shulla, 2019

While the most important factor in this analysis is how forces are translated through the body, this is difficult to measure directly. The technology does not exist to measure these forces accurately and noninvasively. Since invasive techniques would not allow the person to run normally, indirect ways of measuring this data have been developed. One of these alternatives involves collecting kinematic data which can be used to calculate the forces and observe different gait patterns. They do this by recording high speed video of runners. Usually, photo reflective stickers or LEDs are fixed to critical points of motion so that the motion of these points relative to each other can be plotted and analyzed. This data can be used to develop algorithms that describe different gaits.

Running gait does not only affect risk of injury, but also efficiency. Kinematic studies have shown that as running speed increases, a runner’s gait changes to accommodate this change in speed. One change in the gait was the foot strike pattern changed from rear foot to forefoot. This motion shortens the gait cycle and increases the step rate. However, when the runners ran at their top speeds for an extended period of time, their mechanics broke down and some of the gait characteristics that increase injury risk became pronounced. Because of this tendency, incremental training with focus on proper mechanics is necessary to reduce injury risk.

 

 

 

Ways to Prevent and Treat a Common Annoyance: Headaches

Headaches can range from a mild annoyance to a debilitating condition that results in the inability to complete simple daily tasks. Odds are you have experienced a headache since about 50% of the population has suffered some type of headache. While there are many different variables that may have triggered it (injury, stress, chemical imbalances, etc.), the resulting symptoms are always negative. Scientists have been investigating what causes different types of headaches in hopes that they can help people prevent their occurrence and mitigate their symptoms.

One of the most common types of headaches is a cervicogenic headache – a secondary headache caused by referred pain from the neck to the head and facial regions. The high prevalence of cervicogenic headaches – 70% of people who suffer from headaches – prompted one study using a MyotonPRO device to measure and compare the tone, stiffness, and elasticity of the suboccipital and upper trapezius neck muscles in people who have and have not suffered from cervicogenic headaches.

Human suboccipital muscles located underneath the back edge of the skull.
Modified from BodyParts3D, Copyrightc 2008 Life Sciences Integrated Database Center licensed by CC Display-Inheritance 2.1 Japan.

Human trapezius muscle shown spanning the upper back through the neck.
Modified from BodyParts3D, Copyrightc 2008 Life Sciences Integrated Database Center licensed by CC Display-Inheritance 2.1 Japan.

The results showed that the tone – the degree of tension in a relaxed muscle – and stiffness – movement ability of the muscle – values were significantly higher in people who have suffered from cervicogenic headaches in the past. This can likely be attributed to overuse or high levels of past activity of these muscles. This can cause inflammation or other physiological changes that aggravate the nerve fibers in the neck resulting in a cervicogenic headache. The tone and stiffness data can be used to help educate patients on the importance of properly stretching their neck muscles before and after physical activity in order to keep them from tightening and shortening due to overuse. Muscle relaxing medications could also be used as a type of treatment when someone is suffering from a headache.

Tone and stiffness data for people with and without cervicogenic headaches.
Modified from Park, et al., The Journal of Physical Therapy Science 2017.

Another common type of headache is a migraine – a primary headache that has occurred multiple times throughout someone’s life. While a migraine can also have many different triggers, one study investigated the impact of a chemical imbalance of dopamine. This study found patients who suffer from migraines experience a decrease in dopamine levels before they feel the symptoms. There are a couple theories as to why decreased dopamine levels result in migraine symptoms: 1) decreased dopamine increases sensory sensitivity which may result in normally painless signals becoming painful, 2) decreased dopamine impacts motivation and reward/aversion to a point where patients withdraw and seclude themselves. In general, these findings can be useful for the advancement of dopamine regulating drugs in order to combat migraines. Further reading on different chemical causes of headaches in mice can be found here.

Figure showing dopamine levels decreasing during the onset of a migraine.
Modified from DaSilva, et al., Neurology 2017.

Overall, there are many different headache triggers and a lot more research needs to be done before science fully understands how they work. However, there are some things people can do now in an effort to lessen the probability they will suffer from headaches. Additionally, there are  medications and other techniques that work through different paths to mitigate the symptoms of a headache.