Have you ever wondered what happens to your heart when you begin to consistently exercise? How does the heart change and why? Well, the answer may not be very complicated.
During intense exercise, our heart is put under stress as it has to rapidly pump blood throughout the body. The heart often responds to this by increasing its size, but it does not do this like our other muscles. The heart has to add mass to its existing cells instead of adding new cells as we only have a limited amount of cardiac muscles; the amount we are born with is all we have. The health of our hearts is important. In the US, heart disease and injury are the number 1 cause of death. So, it is in our best interests to learn more about our health so as to minimize our risks of heart-related ailments.
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.
Different arch types and properties of each (ShutterStock)
Arches are important because they provide impact absorption and stability in the push-off phase in walking or running. Usually there are patterns of types of injuries that may occur based on the type of arch a person has. The injuries may be similar for different types of activities, but the location of the injury may vary. Running is one of the most popular activities for Americans to do and it is estimated that about “one-half to two-thirds of runners will sustain an injury”. This is a very high number so it is important to understand some of the biomechanics behind why this may be happening.
The dynamics of the foot cannot be studied without talking about the biomechanics of the leg as well. The main period that is studied to understand the biomechanics of the foot is called the gait cycle, which is the period of time for two steps to happen where the foot makes contact with a surface and the limb swings forward as shown in the image. When moving faster or running, the foot pronates (weight more on the inside of the foot) and supinates (weight more on the inside of the foot) differently and the pressure shifts medially.
Arch types affect where the pressure shifts on the foot. In the article by Rodgers, the collected research shows that high arches are more rigid, and there tends to be more pressure concentrated beneath the heel and forefoot. Low arches are usually associated with flexibility, where the pressure is spread out more including the area of the midfoot. The most common methods for determining the pressures in the feet are by having subjects stand on force plates and this was the method used by Rodgers.
Various studies came to a few conclusions about injuries based on arch type. The types of injuries in people with high arches tend to be bone or lateral ankle injuries based on the biomechanics that most of the pressure on the foot is in the front and back of the foot mainly when running or walking. The injuries that usually occur to people with low arches tend to be related to soft tissues and knee pain because of how the pressure is more evenly distributed through the foot, especially in the middle of the foot. While many of the results conclude that there is a correlation with injury type and arch type, the main conclusion was that people with high or low arches generally have a higher risk of injury than people with normal arches. The most common injuries seen are overuse injuries and pain to the knee. Luckily, there is technology within shoes that is specifically designed to mimic pressures on a regular foot. Choosing the right shoe based on arch type is important to preventing injuries when doing strenuous activities!
Guide to finding the right shoe based on arch type (taken from Thomas 2019)
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.
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.
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.
Ankle injuries – either sprains or fractures – are one of the most common sports traumas plaguing the US today. Sprains are overextensions or tears in ligaments. Fractures, on the other hand, are broken bones.
Here, we will focus on sprains of which there are three grades. To help visualise a sprain, think of a Fruit By the Foot (the gummy fruit snack you may have eaten as a child). A Grade 1 sprain involves stretching like if you were to pull on either end of the fruit rope and small tears start to develop along the middle. A Grade 2 sprain develops when the tear is larger and originates from a side; a grade 3 sprain is a complete tear into two pieces.
A Little Background
The ankle joint, also known as the talocrural joint is a synovial hinge joint that mainly moves in dorsiflexion and plantarflexion 1. If you were sitting on the ground with both legs extended in front of you, dorsiflexion is the movement of your foot upwards toward your shin, and plantarflexion is the action associated with pointing your toes moving away from your body.
Sprains & Pains
The most common type of ligament injury are lateral ankle sprains or inversion sprains where the ankle joint over rotates in the outward direction, especially an inversion while in plantarflexion 2. Exercises that include running, jumping, and/or cutting put the athlete’s ankle at high risk for sprains. This is especially seen in soccer, football, basketball and volleyball players.
Figure 1 above shows an ankle in the common and compromising position of an inversion sprain. The circled ATFL, PTFL, and CFL are ligaments in the joint, namely the Anterior Talo-Fibular ligament, the Posterior Talo-fibular ligament, and the Calcaneofibular ligament respectively. Additionally, the boxed call outs are bones in the foot.
Numbers show that close to 70% of patients that had experienced a lateral ankle sprain in the past repeated the same injury to their ankle1.
One study by Doherty et al. followed emergency room visits for ankle injuries and found that 40% of patients with ankle sprains had to seek medical treatment for another ankle injury within the year. Yet, another statistic found that over half of people who experience ankle sprains don’t even go to a hospital.
Ankle sprains are sometimes deemed as a “walk-off injury“, or one that hurts momentarily but just needs a few minutes before resuming activity. However, many people suffer from prevalent and reoccurring ankle sprains. Officially dubbed Chronic Ankle Instability or Sprained Ankle Syndrome, this condition is characterised by a host of symptoms including pain, swelling, perceived and actual instability, balance issues, and joint weakness. Chronic Ankle Instability, or CAI more commonly, can also cause a decrease in physical activity, changes to walking or running form, onset arthritis, and problems with knees and hips due to overcompensation1.
The tried-and-true course of action to prevent CAI is efficient rehabilitation. A study showed that if the patient recovers fast enough, the body won’t change movement patterns.
Problem: Altered Movement Patterns
The changing of movement patterns in the ankle joint, or arthrokinematics1 is one of the main factors that contributes to CAI. The brain, like a protective mama bear, trains the body to operate (walk, run, jump) in a different manner to protect the strained ligaments. Over time, muscle memory kicks in and the compensation for ankle mobility becomes your new normal. This adoption of an incorrect form of walking, running, jumping, etc. can backfire and translate to repeated ankle injuries. This muscle memory has been identified as a neurosignature2from Melzack’s neuromatrix of pain theory; however, this pain theory also describes how elimination of the pain, stress, or chronic symptoms associated with an ankle sprain can prevent reoccurrence – elimination, that is, through efficient rehab.
Solution: Efficient Rehabilitation
A quick recovery can be achieved through various muscle strengthening exercises from a licensed physical therapist or “ankle disk training,” which basically consists of a flat board mounted on a semi-circle. By standing on this unbalanced board, stability can be practiced as well as specific ligament targeting to build muscle. A more serious solution of ankle surgery showed a 90% success rate of mediating mechanical instability, but this is not a widely-practiced nor traditional treatment plan for CAI3. In fact, ankle taping and/or lace-up 3 bracing when exercising proved most helpful in preventing over rotations of the lateral ligaments.
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.
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.
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.
We have all likely heard the saying, “Work smarter not harder.” While this is generally referenced in an academic setting, it is also very applicable in athletics! One of the benefits to being a runner is that it’s a sport people can participate in at any age and nearly anywhere. Unfortunately, however, anywhere from 65-80% of runners get injured in a given year. A large portion of these injuries are related to overuse.
It’s a common misconception amongst runners that the harder you push during your runs, the faster you will be on race day. As a result, the majority or runners overdo their “easy” days. This leaves their legs fatigued and tired going into workouts and races. The majority of fitness is gained during a “workout” day, so overdoing easy days reduces your ability to push hard on workout days. To truly maximize their potential, an athlete must focus on their recovery. Recovery is a broad term that includes a variety of factors such as sleep quality, nutrition, and post run stretching and rehab exercises. Monitoring your heart rate is one way to manage your recovery, reduce overtraining, and limit bone stress injuries.
Managing Heart Rate
Heart rate monitors are used by runners to train smarter and ultimately race faster. Resting heart rate and heart rate recovery measurements are indications of how an athlete’s body is responding to stress and exercise long term. Heart rate measurements can be used to guide what the pace of a run should be. Heart rate measurements are commonly separated into five “zones.” On different days of the week and stages in a training cycle, a run should fall into the different zones. It may be beneficial for an athlete to also have a general idea of what their heart rate is at a given running pace. If their heart rate is more than 7 beats per minute above the usual rate, it may be a sign that the athlete has not fully recovered from their last training session and that they should continue with easy days until having another intense session. This is also important for runners since the weather conditions can greatly affect the difficulty of a run. Rather than having a goal pace for a given day, it is better to have a goal range of heart rates to make sure the run is best serving the athletes body. This will enable an athlete to get the appropriate effort in whether it is 70° and sunny or 30° with 20 mph winds.
Monitoring heart rate after exercise can also accurately indicate whether or not an athlete is fully recovered. It is important to note that your heart rate fluctuates, so it is more valuable to observe general trends than it is to overanalyze specific data points. A morning heart rate 5 beats per minute above your usual heart rate may be indicative that your body needs more rest or that you are getting sick. The image below shows a chart with ranges of resting heart rates depending on gender and age.
Minimizing Bone Stress Injuries
Building a training plan with runs in a variety of zones will help limit overtraining and make the development of overuse injuries less likely. A bone stress injury (BSI) is defined as the inability of a bone to withstand repetitive loading. There are varying degrees of bone stress injuries from stress reactions to complete bone fracture. When performing repetitive motions such as running, micro-cracks form in your bone. These micro-cracks are actually healthy because loading your bones makes them stronger. In the process of remodeling, the micro-cracks are healed. Generally, additional remodeling units can be recruited in response to increase loads. The increase in remodeling units present, decreases the amount of bone mass. This results in a decrease in the ability for the bone to absorb energy and an increase in the number of cracks formed. When insufficient time is given for remodeling, the micro-cracks will begin to accumulate and stress reactions and fractures will form. A stress reaction in the right femur of a female runner is shown in the image above. The white highlights represent inflammation in the bone.
Although overuse injuries are very common in runners, research shows that the use of heart rate monitors can help regulate recovery and positively influence training plans to limit overtraining.
Have you ever been out running on a gorgeous fall day, only to have the run cut short by a painful misstep on a tree root covered by leaves? I have, and let me tell you – it’s awful! And even if you aren’t a runner, according to the Sports Medicine Research Manual, ankle sprains are a common, if not the most common, injury for sports involving lower body movements. Now, the solution to preventing this painful and annoying injury could be as simple as avoiding tree roots and uneven ground, but the real problem behind ankle sprains deals with the anatomy of the ankle.
The ankle is made up of many ligaments, bones, and muscles. However, when sprained, it is the ligaments that are mainly affected. Connecting bone to bone, ligaments are used to support and stabilize joints to prevent overextensions and other injuries. The weaker a ligament is, the easier it is to injure. There are three main lateral (outer) ligaments supporting the ankle joint that can become problematic: the anterior talofibular ligament, the calcaneofibular ligament and the posterior talofibular ligament. According to a study from Physiopedia, these lateral ligaments are weaker than those on the interior (medial) of the ankle, with the anterior talofibular ligament being the weakest.
The next question that has to be asked is why are these ligaments so much weaker than other ones? The answer to this question is based on their physical make up. Ligaments are made of soft tissue that has various collagen fibers running parallel to each other throughout it. The more fibers there are, the more structure and rigidity there is. Think of the fibers as a rope: The rope can stretch to a certain point, but once it hits that point it will snap and break. But if you have a thicker rope (such as the medial ligaments), it becomes much harder to break.
The ligaments on the outer part of the ankle have fewer collagen fibers than those on the inside of the ankle. Thus, when the ankle is moved in an awkward position, it is more likely that the lateral ligaments will break.
Once you sprain your ankle, the focus turns to treatment. Treatment will differ slightly for every individual depending on the severity of the ankle sprain. The simplest way to treat a sprained ankle is to follow the RICE (Rest, Ice, Compression, Elevation) method. Other forms of treatment include taping the ankle or using a brace to restrict movement and to add support and extra stability. Wearing proper footwear is another way that one can prevent and help treat a sprained ankle, as certain shoes are specifically designed to help avoid such injuries. To prevent future ankle sprains, exercises are recommended to help strengthen and stabilize the joint and surrounding ligaments and muscles.
For more information on ankle anatomy and sprains, check out these articles on BOFAS and SPORTS-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 . 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 .
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 .
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 . 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.
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 . 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.
 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/]
 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]
 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]
 Heid, M. (2017, June 6). Why Weight Training Is Ridiculously Good For You. Retrieved from http://time.com/4803697/bodybuilding-strength-training/
 (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/
 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]
 Going SB, Laudermilk M. Osteoporosis and Strength Training. American Journal of Lifestyle Medicine. 2009. [https://journals.sagepub.com/doi/abs/10.1177/1559827609334979]
Stress fractures are small cracks in the bone produced by repetitive stress. The most common locations include the tibia, fibula, and navicular bone . 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% . Furthermore, approximately 50% of female track and field athletes have had at least one stress fracture  . 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 . Runners have no clear and confirmed guidance on injury prevention or appropriate volume of training.
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 . 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 .
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 . 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: