How to Quantify “Getting Back in the Game”

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Sports injuries are a major roadblock for athletes, keeping them from playing their best, or even at all. Even after an injury is healed, athletes have to build back up muscles that atrophied over recovery time.  During rehab time, patients undergo different exercise routines to build the muscle that was left unused while the injury was healing. But how do the trainers know when it is safe to allow the athlete back in the field?

One way to quantify the “readiness” of the player is by using an Isokinetic Dynamometer machine to determine how much power the questioned muscle can exert and how that compares to its counterpart.  For example, let’s say a female athlete tears her right ACL. Throughout her rehabilitation, her trainers will set her up on an Isokinetic Dynamometer machine (Figure 1) to determine the power exerted by the right quadricep and hamstring, which are muscles that commonly experience atrophy during ACL recovery, and compare it to the power of her left quadricep and hamstring. Based on the presettings of range of motion, force, and speed, the device can calculate the torque provided by the athlete and then multiply it by the constant speed (isokinetic part) to find the power exerted by those specific muscles. It is obvious that time is needed to heal, but every patient is unique and time could vary. It is important to find a quantitative way to determine when each patient is back to normal strength and this design does just that.

One patent of an isokinetic dynamometer is the “Exercise Physical Rehabilitation and Testing Method and Apparatus” (Patent number: 5,722,937), which was filed in April 17, 1996 and issued on March 3, 1998.  Invented by James F. Smith, it is still used by assignee Cybex International, Inc to this day.  U.S. classifications are as followed: 601/23; 601/24; 482/4; 482/137; 482/142; 482/908.

Figure 1: Set-up of limb to lever arm and dynamometer. The user pushes leg up and back and the dynamometer, comprised of the motor and cycloidal speed reducer, monitors and alerts the computer if the motor needs to slow down or speed up to keep a constant speed depending on the torque exerted by the user.

The main claims of a total 30 for this patent is to help athletes and patients in rehabilitation for muscle atrophy or decreased muscle strength by evaluating the strength of a targeted muscle by forcing the patient to keep a constant speed through resistance. This machine consists of a base with a track to allow adjustability of the chair to customize the fit for each user. There is also a lever arm, where the user will push against during exercises, connected to the chair and to the dynamometer. The dynamometer is comprised of a motor to change torque and a cycloidal speed reducer with a high and low speed shaft to keep a constant speed during exercise (Figure 1).  This machine helps build muscle fibers by forcing the patient/athlete to provide maximum force to move a lever arm while the machine provides resistance (or takes away) to keep the patient moving at a constant speed. Not only can this machine provide biofeedback on the power of the muscle to help physical therapists plan an exercise regimen to help patients, but it can also help athletes build their muscles and ensure their body is balanced to avoid straining and injury. This device has various protocols that subjects the muscles of the user to “concentric or eccentric motion in isotonic or isokinetic modes or continuous passive motion.”

Physical Therapists, Athletic Trainers and athletes will primarily use this machine.  It is very bulky and expensive, so only established facilities can afford this technology.  This product helps physical therapists and athletic trainers assess the muscle strength of their patients to determine what the state of the targeted muscle strength is and help them prepare an exercise routine to get their patients to where they need to be to be healthy and avoid further injury. Athletes can also use this technology to grow muscles due to the max force and full range of motion the lever and program provide.  This product is designed for determining when muscles have developed enough to start playing again after suffering from atrophy during rehabilitation.

Figure 2: Schematic of Isokinetic Concentric mode feedback loop depending on the performance of the user.  If threshold torque is too high, the motor will accelerate. If threshold torque is too low, motor will decelerate to zero speed.

Patients sit in an upright position and strapped at the waist and thigh to stabilize the body and to force the patient to only use the targeted muscle. Next, after setting up the machine with the desired weight and speed, the patient must push and pull a lever arm as hard as they can.  The lever arm, attached to a low speed shaft of a cycloidal speed reducer follows a negative feedback and the machine. For example, Isokinetic Concentric mode, the mode most commonly used for determining the power produced by the muscle, uses the dynamometer control board to determine the angle (boundaries of range of motion) of the lever arm and signals the dynamometer to slow down to a stop until the user pushes the lever arm in the other direction. The torque on the dynamometer control board, which is measured by strain gauges, is sampled every two milliseconds.  The computer monitors the the measured torque (force of the limb attached to the lever arm multiplied by the distance to the targeted muscle) and compares it to the threshold torque. If the measured is greater than the threshold, the motor will accelerate (less resistance) based on the magnitude of the torque and the direction of the measured torque to approach the isokinetic speed. If the measured torque is not sufficient, the motor will decelerate to zero speed until sufficient torque is met (Figure 2).

Compared to other designs, this patent is less costly, smaller in size, and has less parts. Also, the speed reducer incorporated in this design does not create a high pitch noise that is  disruptive in quiet clinical scenes, which was commonly found in previous designs. As for the infrastructure of the machine, this new design fixes a previous problem of slack resistance during start up, which creates a loose and not smooth feeling for patients (also known as backlash). The slack would allow for additional bending torque on the shafts, which creates that loose and unnatural feel. This design fixes this problem because the cycloidal speed reducer specific to this design has a higher torsional stiffness. The cycloidal speed reduces also has a longer life and will reduce the overall effect of backlash throughout time. This patent is still the primary patent for CSMi Medical Solution’s HumacNorm Testing and Rehabilitation System, so it is reasonable to assume these claims are valid and the design is reliable and effective!

 

 

Source:

Smith, J.F. (1998). U.S. Patent No. 5,722,937. Retrieved from http://pdfpiw.uspto.gov/.piw?PageNum=0&docid=05722937&IDKey=C45CA52352DA%0D%0A&HomeUrl=http%3A%2F%2Fpatft.uspto.gov%2Fnetacgi%2Fnph-Parser%3FSect1%3DPTO1%2526Sect2%3DHITOFF%2526d%3DPALL%2526p%3D1%2526u%3D%25252Fnetahtml%25252FPTO%25252Fsrchnum.htm%2526r%3D1%2526f%3DG%2526l%3D50%2526s1%3D5%2C722%2C937.PN.%2526OS%3DPN%2F5%2C722%2C937%2526RS%3DPN%2F5%2C722%2C937

 

Body Composition Testing for All

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Patent Number: US 6,631,292 B1

Filing Date: March 23, 2001

Issue Date: October 7, 2003

Inventor(s):  Rudolph J. Liedtke (Grosse Pointe Park, MI)

Assignee: RJL Systems, Inc. (Mt. Clemens, MI)

U.S. Classification: 600/547

Claims: 20

                                                               

Figure 1. A functional block diagram of a single aspect of a device based on the invention

 

A bioelectrical impedance analyzer is an apparatus used to determine bioelectrical impedance measurements. This particular analyzer is used to measure a particular area of impedance in a subject. This works by having a constant source of current where the currents input is controlled by a feedback loop. This feedback loop uses an error signal that represents the difference between the actual impedance of the area measured, the target current. The analyzer also contains an impedance measuring circuit that detects and output voltage from the area of the subject. This circuit splits the measured output voltage into a reactance output signal and a resistance output signal. The image above shows a block diagram of the electrical components within this analyzer.

Bioelectrical impedance analyzers can be used to find measurements within the human body. These measurements    can then be used to determine many different things about the body being tested. Using these measurements, blood flow, cardiac output, lean body mass, and body fat can be found for the tested individual. This invention of the bioelectrical impedance analyzer differs from those before it because it separates the electrical components of the analyzer from the individual using it. This is different from previous designs that directly attached electrodes to the individual. Another difference in this invention its temperature insensitivity. This allows the analyzer to be easily portable compared to its related technologies.

This analyzer invention had 20 claims outlining the main components of this device. These claims all referred to the electrical components of the analyzer. The main claims of this invention are that the constant current sources input current is controlled by an internal feedback loop that uses error signals to calculate an output. Another main claim is that the impedance measuring circuit is made to give out both a reactance and a resistance output signal.

This particular bioelectrical impedance analyzer invention would be ideal for any individual who is concerned about their body composition. It is easily portable and safe to use. For example, an individual who is looking to cut body fat, but doesn’t want to pay for the expensive body fat testing, would benefit from this analyzer. This analyzer would also be good for people who are body builders that travel often. This way they would have a way to test their body composition so that they could stay on track with their goals. Having had personal experience using a portable bioelectrical impedance analyzer, I think this would be ideal for someone wanting a close estimate on different body composition measurements. Even though the measurements aren’t as accurate as some other more expensive and invasive techniques, these portable analyzers work great and are more easily accessible. It is interesting to think about how this analyzer will advance and become more accurate in the future.

Reference

Liedtke, Rudolph J. (2003). United States Patent No. US6,631,292B1. Retrieved

from https://patents.google.com/patent/US6631292B1/en

Tired of Blood Tests? Don’t Sweat it! (Or do, I Suppose)

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I think I stand with the majority of the population when I say that I do not like needles. Blood work, as I’m sure you can imagine, is not really my cup of tea. As I sit there in that dreadfully uninviting chair with a rubber tourniquet tied way-too-tightly-for-comfort around my upper arm, I find myself wishing there was a less invasive alternative, ideally one that doesn’t leave me with a puncture wound. Well, luckily for me and any other sane individual who shares my distaste for needles, the future looks bright. Sweat has historically been overlooked as a biosensing platform despite carrying many of the same biomarkers, chemicals, and solutes that are carried in blood. This stems from a variety of different complications associated with sweat sensing that simply don’t exist for blood tests, and these complications have been enough to prevent any significant progress in the field for a long time. It was not until a group of scientists from the University of Cincinnati were issued an intriguing patent on January 22nd of this year that the field of sweat sensing technology began to see hope.

Now all of that is a bit dramatic, but let’s be real. How many of you would have kept reading if I started off with “Devices for integrated, repeated, prolonged, and/or reliable sweat stimulation and biosensing” (the official name for the patent in question)? I’m sure sweat stimulation isn’t something you planned on spending a great deal of time thinking about today, but you’re here now and boy let me tell you, this is exciting stuff. US patent number 10182795 could have some major implications in the near future across multiple facets of life. Inventors Jason Heikenfeld and Zachary Cole, working out of the assignee of the patent, the University of Cincinnati, have put forth some novel approaches to addressing the complications associated with sweat biosensing, specifically the inability to consistently gather enough sweat from one area for testing, skin irritation, and the contamination of sweat samples from chemicals used to stimulate sweating, like pilocarpine. Their patent, filed on October 17, 2014 and classified under CPC A61B 5/1491 (using means for promoting sweat production), among other classifications, describes a medical technology that has potential for a wide-ranging impact, and the many claims they make (13 to be exact) sound promising.

So let’s talk about the invention. At its core, it’s a method of sweat stimulation and sampling through device-skin interface that could be deployed through a variety of different mediums, including patches, bands, straps, clothing, wearables, etc. Utilizing multiple sweat stimulation pads controlled by a timing circuit capable of selectively activating/deactivating individual pads, this technology is able to rotate through the pads over time. This prevents skin irritation caused by the single-pad, continuous sweat stimulation that has been used in this design’s predecessors, and also allows more consistent sweat collection due to the rotation between fresh sweat stores. One commonality between this design and previous sweat sensors is the method of sweat stimulation, but even within that apparent commonality there are improvements that have been made. While this design still plans to use a molecular method of drawing sweat out of the skin, like pilocarpine, it also includes a filtration component, or membrane, to ensure purity of the sweat sample collected. Once collected, the sample is pumped to a sensor by a microfluidic component to analyze the concentration of the analyte of interest for that sensor. The design can be seen in better detail below.

The inventors claim that this device will collect and analyze sweat over extended periods of time through the components and methods described above. If that is in fact true, this technology could soon be in use everywhere. From athletes seeking to maximize their body’s performance to nurses caring for neonates to patients undergoing pharmacological monitoring, this technology could be a real breakthrough in systemic biomarker detection. Why bother with a needle when you can get the same information by slapping a patch on your arm? This patent has the potential to render most blood tests for analytes present in sweat obsolete. There is likely still a long road ahead before it reaches the market, and it may very well end up like the vast majority of US patents that never make it there. But I know I’ll be on the lookout for clinical trials over the next 5-10 years. I hope you will too.

Reference

Heikenfeld, Jason C., Sonner, Zachary Cole. (2019). United States Patent No. 10182795B2. Retrieved from http://pdfpiw.uspto.gov/.piw?PageNum=0&docid=10182795&IDKey=263AB8D65766%0D%0A&HomeUrl=http%3A%2F%2Fpatft.uspto.gov%2Fnetacgi%2Fnph-Parser%3FSect1%3DPTO2%2526Sect2%3DHITOFF%2526p%3D1%2526u%3D%25252Fnetahtml%25252FPTO%25252Fsearch-bool.html%2526r%3D3%2526f%3DG%2526l%3D50%2526co1%3DAND%2526d%3DPTXT%2526s1%3Deccrine%2526s2%3Dsensor%2526OS%3Deccrine%252BAND%252Bsensor%2526RS%3Deccrine%252BAND%252Bsensor

Just Trying To Reach 10,000 Or Competing To Step Above The Rest – How Do Wrist Pedometers Count Our Steps?

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People everywhere are getting their steps in. Whether they’re attempting to reach 10,000 steps a day or participating in competitions with friends, family, or coworkers to see who can step the most, people are moving – and they want to know exactly how much. Wrist fitness trackers with built in pedometers have become a popular mode for individuals to track their daily activity, but how do these devices work?

Let’s look at Apple Incorporated’s Wrist Pedometer Step Detection technology. This technology uses motion data to determine a force comparison threshold that can be used to accurately count steps while a user is running and walking.

An illustration of a person using a wrist pedometer for step detection, included in United States Patent No. US20140074431A1

 

Patent title: Wrist Pedometer Step Detection

Patent number: US20140074431A1

Patent filing date: 2012-09-10

Patent issue date: 2014-03-13

Inventor: Yash Rohit Modi

Assignee: Apple Inc

U.S. classification: G01C22/006 Pedometers

How many claims: 18

Forces acting on a wrist pedometer can be associated with user movement, specifically when they’re walking or running. The force of gravity as well as the forces exerted by the user against the force of gravity are measured by the pedometer; changes in forces acting on the device can be used to determine step count as well as type of exercise. While standing the force detected by the pedometer is 1G (one times the force of gravity). When a user is pushing against the ground to step forward the force detected by the pedometer can rise above 1G, and while the user is between steps the force detected by the pedometer can go below 1G. The pedometer can detect when a user takes a step by monitoring forces and determining when the 1G threshold is crossed.

Forces are compared based off magnitude and frequency to accurately count user steps. Other pedometer technologies worn at the trunk have used a 0.2G comparison threshold to account for steps, meaning when the pedometer experiences a for change of at least 0.2G one step will be added onto the step count. This threshold has been set to prevent noise and standing movements from being accounted for in step count.  However, the force differential experienced by wrist pedometers change with alternating steps. With the step on the side opposing the pedometer, the force acting on the pedometer is often less than 0.2G and may not be detected by the device with this threshold in place. To overcome this issue, this devices step algorithm has included frequency of threshold crossing to account for opposing steps. If the comparison threshold has been crossed twice over a set step time, then the technology will account for two steps rather than one. This prevents the technology from missing steps – thus, increasing device accuracy.

Motion data is also utilized in this technology to account for user activity and adjust parameters appropriately count steps . Fast Fourier Transform (FFT) is used to determine dominant frequency of motion and determine user activity. If the dominant frequency is below run threshold, then steps are counted for within walking parameters, described above. If the dominant frequency is above run threshold, then steps are counted for within running parameters. While running, there is a reduction in change of force acting on the pedometer; the change of parameters takes this into account and utilizes this information to properly account for steps.

Unlike other step counting technologies on the market, this product has improved accuracy in step count. The step counting algorithm has parameters that better define noise and non-walking movement as well as a mode to account for the imbalance in force acting on the wrist pedometer during walking. Less steps are unaccounted for and less random movements are counted – making for more accurate step counts.

There are a number of pedometer technologies that exist on the market today. Regardless of brand and step counting algorithm – these technologies are giving indiviudals the ability to count their steps and measure their fitness levels, promoting an active lifestyle for those who utilize them.

Reference

Modi, Yash Rohit. (2014). United States Patent No. US20140074431A1. Retrieved from https://patents.google.com/patent/US20140074431A1/en

A Closer Look At: Cupping

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Among Olympic athletes you may have noticed something different in recent years – spots. Big red spots. Elite athletes from a variety of different sports have been spotted with – well- spots. But where are these markings coming from?

Michael Phelps, Alex Naddour, and Natalie Coughlin are a few of many athletes who have utilized cupping, an ancient therapeutic technique that has given them their spots.

Michael Phelps, male US swimmer, 2016 Rio Olympics

Cupping is a practice used in traditional medicine in which suction is created using a glass, bamboo, plastic, or ceramic cup. Negative pressure is generated within the cup and used to lift the skin and surrounding tissues. There are over ten different types of cupping therapy, each utilized to treat a variety of ailments. Most broadly cupping can be categorized in to wet cupping, where incisions are made on an indiviudal prior to applying negative pressure via cup, and dry cupping, where no incisions are made. However, treatments can be further classified by their power of suction, method of suction, and material inside the cup [1].

Since 3500 BC cupping has been practiced across several cultures. The earliest references to cupping therapy are found in the Ebers Papyrus, one of the oldest and most important medical papyri of ancient Egypt dating back 1550 BC. However, this form of therapy has not just been exclusively used by the Egyptians, rather it has been used across many cultures for thousands of years. In ancient Macedonia, cupping therapy was used to treat diseases and health disorders. Ancient Arab practitioners utilized cupping therapy to treat hypertension, polycythemia, headache and migraine, and drug intoxication. Hippocrates advocated cupping therapy as a treatment for many ailments in his treatise Guide to Clinical Treatment. Greek and Roman practitioners regularly used wet and dry cupping to treat a variety of diseases. To this day, Cupping therapy acts as one of the cornerstones of traditional Chinese medicine [2].

Today, athletes utilize cupping to decrease recovery time between training sessions, improve range of motion, alleviate inflammation, and reduce pain [3,4,5].

Research suggests that cupping may alleviate pain in individuals. A 2012 pilot study was conducted to assess the effects of a single wet cupping session on pain. Fifty individuals suffering from non-specific chronic neck pain were selected to receive a single wet cupping therapy session. Relative pain levels were measured through participant questioners and mechanical sensory and pain threshold values. Measures taken directly before therapy sessions and three days after treatment and were compared to assess changes in pain levels. Participants reported a statistically significant reduction in pain three days after treatment; however, because measures in reduction of pain are directly correlated with patient reporting, findings may be based on placebo effect or patient bias making it difficult to draw significant conclusions from this study [6].

Several systematic reviews (SR) assessing the impact of cupping on pain relief suggest there may be a positive correlation between the treatment and pain reduction. Several published randomized clinical trials including cupping interventions have been associated with a reduction in pain; however, these studies are limited by size and potential bias, and share a poor study design. Many studies are limited in longevity, participant sample size, and lack of a sufficient placebo for cupping therapy making it difficult to draw significant conclusions regarding the impact of cupping on pain relief [7,8,9,10].

Little is known about the mechanism of action of cupping. Several theories look to explain the pain relief experienced by individuals, including the following two:

  • The Pain Gate Theory: Chronic pain is influenced by altering pain signaling at the nociceptor level. Through stimulating pain via cupping, the frequency of nociceptor impulses will be increased, leading to the closure of pain gates and inevitably pain reduction.
  • Diffuse Noxious Inhibitory Controls: “Cupping therapy may produce an analgesic effect via nerves that are sensitive to mechanical stimulation. This mechanism is similar to acupuncture in that it activates A∂ and C nerve fibers which are linked to the DNICs system, a pain modulation pathway which has been described as ‘pain inhibits pain’ phenomenon”[9]

The potential mechanisms by which cupping may alleviate pain are not well understood, and certainly require validation by scientific studies. However, in addition to participant pain relief, reported effects of cupping also include increased blood flow to the skin [11] and a reduction in inflammation [12]. These physiological impacts may also influence pain relief experienced in clinical trial participants; however, further research is required to draw any conclusions about the mechanisms by which cupping works to potentially reduce pain.

Although it is difficult to draw significant conclusions relating cupping therapy with pain relief, research study participants, athletes, and thousands of other people claim cupping has helped reduce their pain. Cupping has been practiced for over 5000 years across a number of cultures and has alleviated the pain of many. It’s long history of helping indiviudals enduring pain and illness gives it promise as an effective treatment method. Bottom line- whether it directly facilitates pain relief or acts as a placebo – cupping has helped alleviate pain for thousands of years and can be beneficial.

Questions to consider

  • Cupping therapy – placebo or effective? Does it matter?
  • Measures of patient pain have been qualitative in many clinical trials, is an effective way to evaluate the impact of treatment? Are there any other ways to measure pain that may be more effective?
  • Recently cupping has become more commonly seen in popular culture – featured in films such as The Karate Kid and The Gua Sha Treatment and publicly displaced on the bodies of Olympic athletes: what impact does the integration of this traditional treatment in popular culture have on public perception?

References

[1] Aboushanab, T.S., AlSanad, S. (2018). Cupping Therapy: An Overview from a Modern Medicine Perspective. Journal of Acupuncture and Meridian Studies, 11(3), 83-87.

[2] Qureshi, N. A., Ali, G. I., Abushanab, T. S., El-Olemy, A. T., Alqaed, M. S., El-Subai, I. S., & Al-Bedah, A. M. (2017). History of cupping ( Hijama ): A narrative review of literature. Journal of Integrative Medicine,15(3), 172-181. doi:10.1016/s2095-4964(17)60339-x

[3]How Cupping Therapy Benefits Athletes. (2018, August 31). Retrieved from https://www.communityacupuncture.org/2018/05/01/how-cupping-therapy-benefits-athletes

[4] Is cupping therapy effective among athletes?. (2018, January 13). Retrieved from https://medicalxpress.com/news/2018-02-cupping-therapy-effective-athletes.html

[5] What is Cupping Therapy? (Or Why Do Athletes Have Red Spots?). (2019, January 29). Retrieved from https://wellnessmama.com/129773/cupping-therapy/

[6] Lauche, R., Cramer, H.,Hohmann, C., Choi, K.E., Rampp, T., Saha, F.J, Musial, F., Langhorst, J., Dobos, G. (2011). The Effect of Traditional Cupping on Pain and Mechanical Thresholds in Patients with Chronic Nonspecific Neck Pain: A Randomised Controlled Pilot Study. Evidence-Based Complementary and Alternative Medicine, 2012. doi:10.1155/2012/429718

[7] Kim, J.I., Lee, M.S., Lee, D.H., Boddy, K, Ernst, E. (2011) Cupping for Treating Pain: A Systematic Review. Evidence-Based Complementary and Alternative Medicine, 2012.

[8] Kwon, Y.D., Cho, H.J. (2007). Systematic Review of Cupping Including Bloodclotting Therapy for Musculoskeletal Diseases in Korea. Korean Journal of Oriental Physiology and Pathology, 21(3), 789-793.

[9]Al-Bedah, A.M.N., Ibrahim, S.E., Qureshi, N.A., Aboushanab, T.A., Ali, G.I.M., El-Olemy, A.T., Khalil, A.A.H, Khalil, M.K.M., Alqaed, M.S. (2018). The medical perspective of cupping therapy: Effects and mechanisms of action. Journal of Traditional and Complement Medicine, 1-8.

[10] Mehta, P., Dhapte, V. (2015) Cupping therapy: A prudent remedy for a plethora of medical ailments. Journal of Traditional and Complementary Medicine, 5(3), 127-134. 

[11] Liu, W., Piao, S.A., Meng, X.W., Wei, L.H. (2013). Effects of cupping on blood flow under skin of back in healthy human. World Journal of Acupuncture, 23(3), 50-52.

[12] Lin, M.L., Lin, C.W., Hsieh, Y.A., Wu, H.C.,Shih, Y.S., Su, C.T., Chiu, I.T., Wu, J.H. (2014). Evaluating the effectiveness of low level laser and cupping on low back pain by checking the plasma cortisol level. 2014 IEEE International Symposium on Bioelectronics and Bioinformatics.

Patent Blog Post: Fitbit’s Wearable Heart Rate Monitor

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Perhaps you’ve been barraged by emails from Fitbit that try and get you to buy one of their products during one of their many sales. Perhaps you’re a trendy techie and have a wearable in the form of a Galaxy or Apple Watch. Or perhaps you’re simply the owner of a smartphone made within the past few years. All these technologies have heart rate monitoring built into them from the get-go, and it is increasingly hard to get away from gadgets that don’t have some form of heart monitoring. With how ubiquitous the technology has gotten, I would like to look today at one of the patents put forward by Fitbit, one of the more popular brands when it comes to wearable fitness trackers. For this post, I’ll be using the information put forward by Google Patents, seen here.

One of the many figures in the patent, detailing the backside of the wearable.

The patent is simply titled as, “Wearable heart rate monitor,” and has a patent number of US8945017B2. It was originally filed on June 3rd, 2014, and was then approved on February 3rd, 2015. This makes the time to issue a little under a year, which is quite fast for an electronics product. The two inventors credited in the patent are Subramaniam Venkatraman and Shelten Gee Jao Yuen. Looking at the other patents associated with them, Venkatraman seems to have worked on more navigational devices, while Jao Yuen has worked on several other gyroscope-related projects. The assignee is, of course, Fitbit Inc. themselves. Officially, one of the classifications of the patent is, “signal processing specially adapted for physiological signals or for diagnostic purposes for noise prevention, reduction or removal.” This one patent has 30 different claims to its name.

Of the 30 different claims in the patent, many of them tie into 2 main claims. The first is that the wearable heart monitor has a way to efficiently, accurately, and quickly determine the heart rate of the user. The second is to ensure that the wearable is capable of compiling the heart rate monitor’s data, including the heart rate data. This patent is aimed at both casual and advanced fitness enthusiasts, as the data gleaned from the wearable is handy to track. Runners, in particular, would find this tempting as it also mentions step tracking and other forms of movement.

The heart rate monitor works by using a waveform sensor, which reads signals at the surface of the skin. These signals are sent to the rest of the device, where the data is processed. The raw data from the sensor is rough and has a lot of noise from several factors, including movement and moisture. To remove the noise, the data has to be passed through several filters. From that data, a heart rate can be determined, and then presented to the user. Unlike the monitors of prior ages, this heart rate monitor would not rely upon disposable components, instead simply being able to be used multiple times by wearing it. In addition, the heart rate tracker would track more than just heart rate, including details about steps.

References:

Venkatraman, S., & Yuen, S. G. J. (2014). Wearable heart rate monitor. Retrieved from https://patents.google.com/patent/US8945017B2/en

Can You Beet The Competition With Nitrate Supplements?

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Nitric Oxide (NO) is a supplement currently used by many athletes because it is a known vasodilator, which can increase blood flow, mitochondrial efficiency, and contractility of muscles. While there are a few different kinds of nitrate supplements, the most common comes in the form of beetroot juice. When ingested, the nitric oxide is easily broken down into nitrate, which can be used by the body to help increase efficiency of exercise. Multiple studies have been done regarding the effect of beetroot juice supplementation in both trained and untrained athletes; as well as by acute or long term dosing. Due to the nature of NO in exercise, it is generally used to supplement endurance activities, with only a few studies looking at shorter length, or strength exercise. Currently, there is data to suggest that beetroot juice has a more noticeable effect in untrained individuals than in trained athletes, which is not surprising. The trend normally seen in these studies is that acute doses of beetroot juice will lower VO2 during submaximal exercise, allowing individuals to exercise more efficiently. Another effect of nitrate is the increase in mitochondrial efficiency. This effect was tested through long term studies regarding beetroot juice supplementation. In low-moderately trained athletes it was also found that VO2 decreased at submaximal exercise, similar to acute dosing. Additionally, exercise tolerance was also increased by up to 16% after one week of supplementation. While this may be due to the effects of training it was a significant difference. In highly trained athletes, it was found that beetroot juice increased workload and reduced energy cost at exercise intensity. However, the variability in performance could have been the cause of this as noted by the authors of the study. Overall, while there is some evidence to support the use of beetroot juice as an ergonomic aid, there is also a large amount of data to suggest that it has very little to no effect of athletic performance.

Table of studies done to research the effects of acute nitrate supplementation in elite athletes

This topic relates to class in that it aims to determine what affect different training methods/supplements have on athletic performance. It seems that there are potential benefits to using beetroot juice or other nitrate supplements as a training tool in both acute and long-term doses. One of the issues seems to be in determining the proper dosage of beetroot juice. There were multiple studies where no benefit was seen with small doses and significant benefits were seen with a higher dose. Determining this value will be important in future studies to ensure that possible benefits are not being overlooked. Additionally, larger studies should be conducted as only one study referenced in the article had more than 20 subjects. This could be a potential major limitation given the large amount of variability in and between different athletes and sports. NO supplements also would seem to be more beneficial to endurance athletes than it would be to strength athletes during training. While there is only a small amount of evidence to support the claim that beetroot juice will improve athletic performance, there is no data to suggest that taking this supplement will have negative effects on performance so trying it in your next training cycle may be worth it.

 

 

References                                                                                                                         Andreas Zafeiridis. The Effects of Dietary Nitrate (Beetroot Juice) Supplementation on Exercise Performance: A Review. American Journal of Sports Science. Vol. 2, No. 4, 2014, pp. 97-110. doi: 10.11648/j.ajss.20140204.15

How it Works: Air Displacement Plethysmography

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Recommended Further Reading:

https://www.topendsports.com/testing/tests/bodpod.htm

http://www.cosmed.com/hires/Bod_Pod_Brochure_EN_C03837-02-93_A4_print.pdf

https://www.bcm.edu/bodycomplab/bpodtheorypage.htm

https://academic.oup.com/ajcn/article/75/3/453/4689336

http://www.nifs.org/fitness-center/fitness-assessments/bodpod

https://www.doylestownhealth.org/medical-services/nutrition-counseling/bioelectrical-impedance-analysis-bia–body-mass-analysis

https://www.medicinenet.com/script/main/art.asp?articlekey=25893

Is chronic stretching actually beneficial?

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Jackie Haffey and Matt Ballman

 

Have you ever wondered why stretching was always emphasized so heavily in gym classes growing up? Stretching is something that has been coupled with exercise all of our lives. Growing up we are taught to stretch before and after exercise in order to help prevent injury, promote recovery, and enhance your overall performance, but does it actually work? There are professional athletes out there who undergo strict training regimens that involve lots of stretching, but still manage to have career altering injuries like tearing their ACL. There are many athletes who are out there that are very talented but almost never stretch before or after a workout. On the flipside, there are many professional athletes out there that vow that stretching helps them extend their careers and improve recovery. In the NBA, yoga has become a common practice among players doing all that they can in order to help their bodies sustain their elite level of play and handle the rigors of playing in an 82 game season. Arguably the best player of all time Lebron James practices yoga regularly [6]. He even attributes it to helping him extend his career and play at a high level for as long as he has [6]. So does stretching actually help people perform better or avoid injury or is it all just a myth?

Figure1. Passive hamstring stretches

For a long time, stretching was highly recommended with little evidence to support it. Now studies are showing that acute stretching before exercise can actually be harmful as discussed in the previous blog post, “Holding Your Stretch is Holding You Back”.  So what is evidence saying about chronic stretching?When discussing effects of chronic stretching, it is referring to long term effects of consistent stretching. People normally associate this with increasing flexibility, or joint range of motion (ROM). The American College of Sports Medicine (ACSM) has recommendations for maintaining flexibility. A study was done in 2010 to support the ACSMs advice specifically for hip flexion [5]. There was a significant improvement in ROM for all stretching groups and a decrease for the control group [5]. The paper did mention its own limitation in only studying one muscle group, saying its findings should not be generalized to any muscles in the body. Another limitation was that the participants could not start a new or increase intensity of an existing exercise program during the study [5]. This may have allowed the collected data to have less noise but it may not accurately translate to real world scenarios as many athletes aim to increase workout intensity or switch up their workout programs. So with the knowledge that chronic stretching can increase ROM, how does it affect performance?

Table 1. Data from the 2007 study showing the improvements of the stretching group.

Table 2. Data from a study on D3 athletes showing no difference between stretching and control groups.

 

A study completed in 2007 had the goal of determining the effects of chronic stretching on specific exercise performances. Performed on relatively inactive people, the study lasted eight weeks long and tested whether stretching had an impact on power, strength, and endurance in the lower body by using various exercises according to each fitness category [1]. The, “stretching,” or experimental group showed significant improvement in all categories whereas the control group showed no improvements [1]. On the contrary there was a study completed on hamstring performance in female D3 athletes [4]. Six weeks long, this study found there to be no significant difference in power performance in either the stretching and control groups [4]. So maybe stretching just has an effect on sedentary individuals?

Another aspect of stretching that is renowned is its ability to decrease the body’s risk of injury. A study completed on patients with chronic neck pain had subjects undergo 6 weeks of stretching and/or global posture reeducation twice a week during that time [2]. After the study was completed it was found that both the stretching and posture reeducation groups had significant reduction in pain [2]. However, this study also lacked a control group so it is hard to tell whether the reduction in pain was at the result of a placebo effect. On the opposite end, a large scale literature search evaluated over 90 different studies trying to determine whether there was sufficient evidence that stretching does indeed reduce the risk of injury [3]. After reviewing a large amount of literature it was found that it cannot be determined whether stretching reduces the risk of injury [3]. In fact, it found it is more than likely to not have anything to do with injury risk because stretching depends on different characteristics of muscles than characteristics that rely on eccentric movement which is often the movement where non-contact injuries occur [3].

After reviewing the above literature and evaluating research that studied chronic stretching it really cannot be determined whether chronic stretching is essential in order to maintain performance and prevent injury. All of the studies observed either could not find data to support the fact that stretching indeed plays a pivotal role in exercise or the study was to limited in its structure to provide accurate results. The biggest problem was how the term, “chronic,” is defined. The longest study that we found was only 12 weeks long which can hardly represent professional athletes who have been stretching throughout their entire lives. Without longer studies it’s hard to determine anything about chronic stretching because there’s simply not enough data out there. Although stretching cannot be supported with factual scientific data it is hard to argue that it can’t hurt to stretch after exercise. With successful athletes swearing by its benefits why could it hurt to spend a little time after you exercise to stretch out? Even if it’s just for peace of mind stretching does have at least some benefit after all.

 

Questions to Consider:

In what populations is it most important to determine the effects of stretching?

Since most current studies are on the lower extremities, should studies been done on the effect of stretching the upper extremities ?

What would be your personal definition of chronic? Do you think 6 or 8 or 12 weeks studies count towards data for the effects of chronic stretching?

 

References and Further Readings:

  1. Kokkonen ’ J, Nelson AG, Eldredge C, et al. Chronic Static Stretching Improves Exercise Performance Chronic Static Stretching Improves Exercise. Performance Med Sci Sport Exerc. 2007;39(10):1825-1831. doi:10.1249/mss.0b013e3181238a2b.
  2. Aure OF, Hoel Nilsen J, Vasseljen O. Manual Therapy and Exercise Therapy in Patients With Chronic Low Back Pain. Spine (Phila Pa 1976). 2003;28(6):525-531. doi:10.1097/01.BRS.0000049921.04200.A6.
  3. Shrier I. Stretching before exercise does not reduce the risk of local muscle injury: a critical review of the clinical and basic science literature. Clin J Sport Med. 1999;9(4):221-227. https://www.colorado.edu/intphys/iphy3700/shrierCritRev.pdf. Accessed May 7, 2018.
  4. Bazett-Jones DM, Gibson MH, McBride JM. Sprint and Vertical Jump Performances Are Not Affected by Six Weeks of Static Hamstring Stretching. J Strength Cond Res. 2008;22(1):25-31. doi:10.1519/JSC.0b013e31815f99a4.
  5. Sainz de Baranda P, Ayala F. Chronic Flexibility Improvement After 12 Week of Stretching Program Utilizing the ACSM Recommendations: Hamstring Flexibility. Int J Sports Med. 2010;31(6):389-396. doi:10.1055/s-0030-1249082.
  6. Toland S. The Rise of Yoga in the NBA and Other Pro Sports | SI.com. Sports Illustrated. https://www.si.com/edge/2014/06/27/rise-yoga-nba-and-other-pro-sports. Published 2014. Accessed May 7, 2018.

DOMS: Why do your muscles hurt days after exercise?

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Chris Hernandez and Christian Poindexter

Soreness is a typical and often expected side effect of any moderate level of physical activity or exercise.  However, contrary to popular belief, there are many different types of soreness which are a result of separate things. For example, the soreness that many people experience during or immediately after exercise is known as acute soreness. Acute soreness typically develops within a couple of minutes of the muscle contraction and dissipates within anywhere from a few minutes to several hours after the contractions have ended[1].  It is widely accepted that this soreness is a result of the accumulation of chemical byproducts, tissue edema, or muscle fatigue.  Delayed Onset Muscle Soreness (DOMS) typically develops between 12-24 hours after muscle contractions end, with peak ‘soreness’ being experienced 24-72 hours after the exercise is over[1].  Exercises typically associated with DOMS include strength training exercise, jogging, walking down hills, jumping, and step aerobics. Apart from soreness, people suffering from DOMS also experience swelling in their sore limbs, stiffness of adjacent joints, tenderness to the touch, and temporary reduction of strength in affected muscle[1].  Unlike with acute soreness, there are several competing theories on the cause of DOMS, none of which have been ultimately proven to be the predominant cause.  

One of the first and most touted theories was the Lactic Acid Theory.  This was based on the concept that the muscles continue to produce and accumulate lactic acid even after the exercise is abated.  The accumulation of this lactic acid is thought to cause the noxious stimulus associated with soreness[2].  The paper we are using, “Delayed Onset Muscle Soreness: Treatment Strategies and Performance Factors”, cited a study done by French researchers regarding misconceptions about lactic acid, and more specifically lactate[3].   This study goes on to explain that during the recovery phase post-contraction, accumulated lactate gets oxidized by lactate dehydrogenase (LDH) into pyruvate.  This pyruvate is either oxidized in the mitochondria where it contributes to the resynthesis of ATP, or it is transported in the blood to be used or disposed of elsewhere in the body[3].  It has been observed that for test subjects whose lactate levels were monitored for 72 hours before, during, and after exercise, their lactic acid levels returned to pre-exercise levels within 1 hour of the cessation of exercise[2].  Since DOMS does not set in for 24-48 hours, it is very unlikely that lactic acid accumulation is the cause of the pain and other symptoms associated with this disease.  

These researchers did note some conditions however that were noted to affect the lactate levels of those participating in the study.  For example, a participant with a diet rich or low in carbohydrate concentrations can cause lactate levels to decrease or increase respectively[3]. Further, participants who had undergone strenuous exercise the day before are likely to show signs of glycogenic depletion, which could cause them to have irregular lactate levels[3]. Further, the type of exercise performed was also shown to have an effect on not only lactate levels but also on the time frame required for levels to return to normal[3].  To improve this study and potentially get better results it would be best to make sure that all test subjects were undergoing the same exercise regimens.  It would also be beneficial if the amount of carbohydrates (based on body weight) was held standard, and that they all experienced 48 hours of rest before data collection[3].  However, even given these potential weaknesses, given that the lactate levels return to below normal within an hour of exercise cessation, it can be said with reasonable certainty that lactic acid is not the cause of DOMS[2,3].

A more current and well-supported theory is the Muscle Damage theory, which is based on the disruption of the contractile component of muscle tissue after eccentric exercise. Type II fibers have the narrowest z-lines and are particularly susceptible to this type of disruption. Nociceptors located in the muscle connective tissue and in the surrounding tissues are stimulated, which leads to the sensation of pain that we know as DOMS. In practice, muscle soluble enzymes can be used as an indicator of z-line disruption and sarcolemma damage. Creatine Kinase (CK) is used as one of these muscle permeability indicators; any disruption of the z-lines and damage to the sarcolemma will enable the diffusion of  CK into the interstitial fluid, where it can be measured.

To test the connection between eccentric exercise and changes in CK, this study[4] used five healthy adults and had them walk on a treadmill for an hour at a 13-degree incline to test the effect of concentric exercise, and then a 13-degree decline five weeks later to test eccentric exercise. Venous blood samples were taken pre-test and every 24 hours until CK levels had returned to pre-exercise levels. Following downhill walking, all subjects reported muscle pain and tenderness in the calves and glutei muscles, which developed several hours post-exercise and was maximal between 1-2 days after. The severity of pain differed between subjects, but following uphill walking none reported any pain or tenderness. Both concentric and eccentric exercises showed increases in CK levels, but eccentric work showed much greater levels and peaked after 4-7 post exercise, as shown in figures 1-2.

Newham, et al. conclude that rises in CK levels are a result of eccentric work, and suggests that the extent to which muscle is lengthened and the level of habituation to eccentric work play a role in the enzyme response, and thereby in DOMS. However, they acknowledge that there is only a correlation between CK levels and DOMS and not necessarily a causation. Additionally, the sample size they used is small which could lead to inaccurate data.

There are many theories of the cause of DOMS, and none can fully explain the phenomenon. A combination of models has also been proposed[5], drawing aspects from various theories. Of the two theories we examined, the muscle damage theory was the most conclusive, showing a relationship between plasma CK levels and DOMS. Additional studies will be necessary to determine whether the muscle damage theory, another theory or possibly a combination of multiple can best explain the symptoms of DOMS.

 

Questions to Consider:

  1. Which types of exercise would help to prevent DOMS?
  2. How would you better design an experiment to correlate DOMS with enzyme activity?
  3. Can we conclusively rule out lactic acid as an explanation?

 

References/Further Reading:

[1] American College of Sports Medicine. Delayed Onset Muscle Soreness. Delayed Onset Muscle Soreness, American College of Sports Medicine, 2011, www.acsm.org/docs/brochures/delayed-onset-muscle-soreness-(doms).pdf.

[2] Schwane JA, Hatrous BG, Johnson SR, et al. Is lactic acid 63. Hasson SM, Wible CL, Reich M, et al. Dexamethasone related to delayed-onset muscle soreness? Phys Sports Med phoresis: effect on delayed muscle soreness and muscle function 1983; 11 (3): 124-7, 130-1

[3]Léger , L., Cazorla , G., Petibois , C. & Bosquet , L. (2001). Lactate and exercise: myths and realities. Staps , n o 54, (1), 63-76. doi: 10.3917 / sta.054.0063.

[4]Newham, D. J., Jones, D. A., & Edwards, R. H. T. (January 01, 1986). Plasma creatine kinase changes after eccentric and concentric contractions. Muscle & Nerve, 9, 1, 59-63.

[5]Cheung, K., Hume, P. A., & Maxwell, L. (2003). Delayed Onset Muscle Soreness. Sports Medicine,33(2), 145-164. doi:10.2165/00007256-200333020-00005

[6]Armstrong, R. B. (January 01, 1990). Initial events in exercise-induced muscular injury. Medicine and Science in Sports and Exercise, 22, 4, 429-35.