HOW TO BENEFIT FROM CADENCE, CRITICAL POWER AND OTHER RUNNING METRICS

Running is one of those things that we take for granted, something that we have been doing for so long that we don’t really ever think about it. However, do we really know how to run? Are we really sure we do not need to learn how to run?

Running is an extremely complicated task that requires the conglomeration of different capacities: cardiovascular, neurological, psychological, physiological, anatomical, muscular and biomechanical. In this post, we will focus on the last three, trying to explain them in the clearest possible way.

Having the possibility of quantifying the effectiveness of the gesture performed and the accuracy of the workload through easily detectable metrics means training with quality and, if implemented with your workout routine, will surely bring enormous improvement to your running performance.

Simplifying the mechanics of running, we could describe it as a ball that bounces on the ground. The body’s bouncing motion on the feet allows us to store elastic energy and to use it in the following step (with considerable energy savings). It is therefore very similar to what happens in a spring; a biological spring!  

However, how does this biological spring really work? It depends on the task:

1. Are we looking for metabolic economy and energy saving (like when running or walking on flat ground)?
2. Are we trying to amplify our power output (for example, when jumping, accelerating, incline running, etc.)?
3. Or do we need to absorb forces (such as when landing, decelerating or decline running)?

If we are in the first scenario (energy saving), the body transmits its forces and momentum to the tendons, which return most of that energy to the body itself in a cycle and repetitive motion. This means that our muscles need to do very little in order to keep the body moving.

This is not the case for the second scenario (power amplification), when higher power production is required. In fact, when accelerating, the muscles start the movement by transmitting the generated power to the tendons, which amplify it and transfer it in a greater fashion to the body.

The exact opposite is true for energy absorption: the body transfers all its energy to the tendons, which promptly carry it to the muscles capable of efficiently absorbing most of that energy¹.

In every condition, there is always a seamless, finely coordinated mechanism between body, tendons and muscles.

 

The mechanics of proper running

In order for this mechanism to work efficiently, its components need to be perfectly aligned. It is exactly here that a proper running form becomes fundamental. From several biomechanical studies, it is known that a proper technique requires:

• compact arms
• balanced forward posture with the feet always falling under (or almost) the body’s center of mass
• good load distribution (symmetry)
• high cadence
• low ground contact times
• proper foot strike

So, next time you are out there running and struggling to maintain your pace at the 6th mile (~10th kilometer) of your run, you just need to make sure that all the aforementioned requirements are under control. Easy, right?! Well, not really; however, here’s where technology comes in handy.

Training indoors, on a device that can monitor all these parameters for you, returning a few clear, instant feedbacks, can no longer be seen as an alternative, but as an implementation that could actually improve the quality of your training and, ultimately, of your runs.

 

An insight into the ideal 5 parameters

At this point you might still be wondering why the aforementioned requirements are correlated with a good running form and how you can benefit from monitoring them. To clear these doubts, let’s analyze 5 metrics that should be taken into greater consideration and try to understand how to “play” with them.

1. Contact Time. Experienced runners have low contact times² (time that the foot spends on the ground), with sprinters averaging values between 110 and 150 milliseconds and distance runners between 170 and 350 milliseconds. The relationship between flight and contact time is called flight ratio and is greater in more efficient runners (with values ranging between 0, when walking, and about 50 percent).

    

2. Stride and Cadence. Equally as important is monitoring your stride length and cadence. Runners with a short stride and high cadence have minor impact forces and consequently a lower incidence of injuries³. Moreover, a higher level of frequency “unlocks” those elastic properties mentioned earlier, allowing you to reduce oxygen consumption by about 20 percent and to increase running efficiency up to 50 percent⁴.

    

   Be careful, though. There is no ideal stride or cadence, since these parameters can vary in relation to speed, acceleration and body type. That is why the best way to raise awareness of your cadence and turn it into a fatigue control system is to choose a speed, check your natural cadence at that given speed and train with cadence variations in a defined range between +5 percent and -5 percent.

    

3. Symmetry is another value that is worth checking. Better load distribution between the right and left foot brings many advantages to both performance and preventive aspects, and it represents a parameter that can be monitored easily. Just remember that a range of variability of less than 5 percent is perfectly normal for healthy subjects and requires no intervention.

    

4. Running power. We can describe running power output as how much force and speed a runner is exerting at any given moment. The power of our human engine should be equal to the sum of the power required to overcome running resistance, air resistance and climbing resistance (if present).

Therefore, speed (and consequently contact time), cadence (and so stride), body weight and its distribution (and therefore symmetry) all fall into the equation. Varying any of these will consequently vary our power output, making this parameter a sort of immediate and qualitative measure of our running form for a given task. For example, if your goal is endurance at a fixed constant speed, you want to keep lower values of power (which correlate with a better efficiency) while, if your aim is to accelerate and sprint, you want to produce the highest values of power possible.

Having the possibility of quantifying the effectiveness of the gesture performed and the accuracy of the workload through easily detectable metrics means training with quality and, if implemented with your workout routine, will surely bring enormous improvement to your running performance.  

 

REFERENCES

1. Roberts TJ, Azizi E. Flexible mechanisms: the diverse roles of biological springs in vertebrate movement.  J Exp Biol. 2011 Feb 1;214(Pt 3):353-61.

2. Hayes PR, Caplan N. Leg stiffness decreases during a run to exhaustion at speed at VO2max. Eur J Sport Sci. 2014; 14(6):556-62.

3. Lyght M, Nockerts M, Kernozek TW, Ragan R. Effects of foot strike and step frequency on Achilles tendon stress during running.  J Appl Biomech. 2016; 32:365-72.

4. Cavagna GA, Saibene FP, Margaria RJ. Mechanical work in running. Appl. Physiol. 1964; 19:249-56.

Author:
Roberto Nicoletta works in the Medical-Scientific Research & Innovation department of Technogym and holds the role of Head of Sport Science for the Italian Rugby League National Team. He also collaborated with the NBA as a Strength and Conditioning Coach during the NBA Global Camp 2018.

Roberto Nicoletta holds an international Master of Science in Sport Science, Health and Physical Activity obtained studying across 4 different European universities (the University of Foro Italico of Rome, the University of Southern Denmark in Odense, the German Sport University of Cologne and the University of Vienna).

We at ACSM are excited that, in 2019, attendees of Sports Medicine Essentials – An Interactive Course will have a completely new experience. The redesigned course (formerly the ACSM Team Physician Course, Sports Medicine Essentials) uses a dynamic and interactive format to present fundamental information. Taught by a diverse group of highly trained and nationally recognized faculty, Sports Medicine Essentials provides for ample opportunity to learn from experts in the sports medicine field who are prepared to answer your questions.

The course is designed for a broad range of primary care practitioners who desire to expand and improve their clinical musculoskeletal knowledge and skills. Sports Medicine Essentials will be a valued experience for physicians, residents-in-training, athletic trainers, physical therapists, nurse practitioners, chiropractors and allied health care professionals who will have primary access to athletes of all types and ages.

What sets Sports Medicine Essentials apart from other courses is the new, interactive, hands-on design. Breakout exam stations and sports medicine skills stations will allow small groups to work directly with the faculty to practice the skills that will improve your care of patients in the clinic and athletes on the field. This design allows for instruction and direct feedback on the techniques most important to you, such as imaging review, injections techniques and bracing/splinting.

In addition to the hands-on sessions, attendees will:

• Learn the complexities of the new concussion guidelines and practice concussion exam skills;
• Experience sessions in a case-based design to help apply the learnings in a clinical setting;
• Hear about the latest advancements in injury prevention and pain management;
• Practice examinations of joints susceptible to athletic injury.

A preconference session on basic ultrasound in sports medicine will also be offered on Wednesday, February 6^th.

Along with co-chairs Dr. John Hatzenbuehler and Dr. Mary Lloyd Ireland, I invite you to join us in New Orleans, February 7-10, 2019  for this educational learning opportunity!

View the preliminary program and register for the course by December 19^th to take advantage of early pricing.

 

Mark R. Hutchinson, M.D., FACSM, serves as chair of the ACSM Medical Education Committee. He practices in the Department of Orthopaedics at UI Health (University of Illinois). Dr. Hutchinson is the director of Sports Medicine, and he serves as the head team physician for UIC Flames Athletics. He has nearly three decades of involvement with Team USA Athletics, and he was part of the official medical staff for Team USA at the 2016 Olympic Games in Rio de Janeiro. 

1. Look Beyond Weight When Determining Health It’s not your weight that matters, it’s what constitutes your weight. Find a way to learn if you have too little muscle or too much fat and find a strategy (exercise and eating well) that increases muscle and lowers fat. The number on the scale might stay the same, but you will look better, perform better and will be healthier.
   
   
2. Building Muscle Takes More Than Just Protein Building muscle requires a combination of:
   • Added resistance to muscles
   • Staying in a good energy balanced state to encourage anabolic hormone production
   • Having a good distribution of nutrients to sustain tissue health
   • Adequate sleep
   • Consuming more protein in the right amounts and at the right times to encourage muscle protein synthesis
3. Protein: It’s Not Just More, But When and How Much If you are an athlete, you need about double the protein as nonathletes, but just eating more protein isn’t enough. It must be consumed in the right amounts, at the right times and when in a reasonably good energy balanced state. Randomly eating more protein doesn’t accomplish what the body needs.
   
   
4. Infrequent Meals Cause Problems Meal skipping, or eating in a pattern that fails to satisfy energy requirements in real time, creates many problems including higher body fat levels, lower lean mass and greater cardiometabolic risk factors. Interestingly, more frequent eating is associated with lower total caloric intake because of better ghrelin (appetite hormone) control.
   
   
5. Eating Good Foods Helps the Microbiome Keep You Healthy Inadequate intake of fresh fruits and vegetables may alter the microbiome, resulting in higher body fat percentage and reduced athletic performance. Consuming plenty of fresh fruits and vegetables helps to sustain good bacterial colonies that live in the gut. Additional benefit: Fruits and vegetables give you the carbs you may lack for maximal performance.
   
   
6. Good Food, Bad Food, Wrong Choice There is no perfect food, and if you keep eating the same food(s) because you believe it’s good for you, you place yourself at nutritional risk. There is no substitute for eating a wide variety of foods that are well-distributed throughout the day. You don’t get too much of anything potentially bad, and you expose tissues to all the nutrients they need.
   
   
7. Relative Energy Deficiency in Sport (RED-S) can be a Problem The best exercise performance occurs when you have enough energy to support the exercise. If you frequently post-load by consuming the energy (calories) after the workout/competition, be aware of the potential health and performance consequences. You can’t drive your car on an empty tank of gas, and neither can you perform well if your tank is empty.
   
   
8. Poor Hydration, Poor Performance Sustaining the best possible fluid balance is important for many reasons, including sustaining heart stroke volume, sustaining sweat rates, enabling delivery of nutrients to working cells and enhancing removal of metabolic waste products from cells.
   
   
9. Recovery from Exercise is Just as Important as the Exercise Putting stress on muscles through exercise isn’t enough to reap the full health benefits. You must give muscles an opportunity to recover from the stress so that they can benefit from the exercise. Adequate sleep is important by helping to sustain appropriate eating behaviors and muscle recovery.
   
   
10. It Is Important to Learn How to Lower Stress Stress levels impact eating behavior. High stress levels can lead to the consumption of energy-dense foods that are high in fat and sugar. Find a strategy for stress-reduction that can help you sustain optimal nutrition, which will positively influence both performance and health.

 

Dan Benardot, PhD, DHC, RD, LD, FACSM is Professor Emeritus at Georgia State University, and Visiting Professor in the Center for the Study of Human Health at Emory University. He is the author of the new title ACSM’s Nutrition for Exercise Science. For more information about the book and to download an excerpt, visit https://www.acsm.org/read-research/books/acsms-nutrition-exercise-science.

When Medicine & Science in Sports & Exercise (MSSE)’s Editor-in-Chief, Bruce Gladden, Ph.D., FACSM, asked me to consider the position as Associate Editor-in-Chief for Contrasting Perspectives (CP) I didn’t need much time for contemplation. I consider that CP articles occupy a position at the very heart of MSSE and ACSM’s missions to review, publish and promote the best science across our fields of interest. The first CP under my watch is published this month (November, 50:2379-82) in MSSE and is already generating substantial readership numbers and letters:

“The respiratory compensation point and the deoxygenation break point are/are not valid surrogates for critical power and maximum lactate steady state”

Proponents: Daniel A. Keir, Silvia Pogliaghi, Juan M. Murias

Opponents: Ryan M. Broxterman, Jesse A. Craig, Russell S. Richardson

As a young scientist in the 1980’s I was captivated at the Federation (Experimental Biology’s precursor) and ACSM meetings by vocal debates from scientific giants. Indeed, watching Brian J. Whipp and George A. Brooks spar over the scientific bases (or not) of the “Anaerobic Threshold” concept helped convince me that a scientific career could be both immensely rewarding and, above all, fun! 

A CP entitled “The anaerobic threshold concept is/is not valid in physiology and medicine” is underway for publication in 2019 and will assess where we are now in this fascinating saga. Not only will this present an intriguing history for our less senior readers but it will also look at the concept’s present utility and future research imperative.

At national scientific meetings, well-posited, contemporary and, above all, pithy debates pack the auditoriums and scintillate audiences much like medieval duels must have done. Recently, at the Integrative Physiology of Exercise meeting in September 2018, the irrepressible Mike Joyner, M.D., FACSM, squared off against legendary genetics researcher Claude Bouchard, Ph.D., FACSM. Their debate will be encapsulated in a CP entitled “Genetics really do/do not influence exercise capacity or trainability.” Until then, you can read a blog recapping the event.  

Following Joseph Joubert’s tenet that “The aim of argument, or of discussion, should not be victory, but progress” CPs by their very nature and eponymous style permit high visibility and, above all, seek scientific clarity.

Given “Strong minds discuss ideas, average minds discuss events, weak minds discuss people” (Socrates), so CPs avoid ad hominem arguments and focus on the data and their interpretation from opposing viewpoints. This serves the time-honored adage that progress emerges more readily from error than confusion.

As Associate Editor-in-Chief for Contrasting Perspectives I am always interested in what MSSE readers and ACSM attendees are interested in seeing debated. Please feel free to send me your ideas (as a brief statement that can be posited in the positive and negative) and also, and most importantly, a short list of potential proponents/opponents. MSSE plans to publish ~two CPs per year.

So, I hope that you will join me in supporting MSSE’s CP initiative and continuing to promote the best science for our journal. For those unfamiliar with the CP mechanism, author guidelines are appended below.

And do please be on the look-out for Glenn Gaesser, Ph.D., FACSM, and Steven Blair, P.Ed., FACSM, facing off against John Jakicic Ph.D., FACSM, Renee Rogers, Ph.D., and Joseph Donnelly, Ed.D., FACSM, in their CP entitled: “The health risks of obesity have/have not been exaggerated” scheduled for publication in the January 2019 edition of MSSE!

Cheers and thanks, David 

Contrasting Perspectives Guidelines and Information

Topic & Authorship selected/invited by Associate Editor-in-Chief for Contrasting Perspectives in consultation with the Editor-in-Chief

Rules and Instructions for Authors

Format:  Initial Perspective Pro (1500 words) followed by Con (1500 words) followed by Responses/Rebuttals (Pro 1000 words, Con 1000 words) which end in a concise (one to five sentences) summary, clearly indicated as: Concluding Statement.  Authors are to use appropriate literature citations to support their arguments, but are encouraged to be selective (references will not be included in the word count).  It is recommended that authors use figures and tables judiciously since these too will be included in the word count using a formula determined by the Managing Editor.

General Details:  Authors will be allowed the widest latitude in interpreting published data in support of their perspective. Each author will be provided the opposing author’s perspective for use in preparing a response/rebuttal, and each author will be encouraged to make specific recommendations for needed research studies, and each allowed a concluding statement. The Editor-in-Chief for Contrasting Perspectives will establish tight timelines for initial and response/rebuttal submissions.

Peer-review:  These papers will not be peer-reviewed in the traditional sense. Editorial review will be limited to format and fact checking (authors must not misrepresent what is published) to expedite publication. The Editor-in-Chief for Contrasting Perspectives will oversee the review process and will appoint Associate Editors, Editorial Board Members, or invited Ad Hoc Reviewers to assist as required.

David C. Poole, Ph.D., FACSM currently serves as the MSSE Associate Editor-in-Chief for Contrasting Perspectives. He is a University Distinguished Professor in the Departments of Kinesiology, Anatomy and Physiology at Kansas State University. 

This is part eleven, and the final installment, in a series of blogs from attendees at ACSM's Conference on Integrative Physiology of Exercise. The following blog is a reflection on the symposium titled "Recent Advances in Exercise and Arterial Stiffness." 

The first scientific conference I ever attended made me consider quitting graduate school. Everyone was speaking English, but I was convinced that I was the only one who couldn’t speak or understand the language of physiology. Thankfully, I didn’t quit and continued to attend conferences. Each time I do, it gets easier to understand and engage in the conversations about what is new in the world of exercise physiology. I’m entering my second year as a Ph.D. in Biomedical Science, and 2018 was my first time attending ACSM’s Conference on Integrative Physiology of Exercise. My current research focus is on vascular health/function, so I was thrilled to see a symposium on Exercise and Arterial Stiffness!

I love the cardiovascular (CV) system with all my heart (no pun intended) for many reasons, not the least of which are the redundancies that collaborate to keep us alive, oxygenated and able to run, lift or play. The entire system is an intricate dance constantly striving to combat every assault thrown its way, from Type II diabetes to obesity to aging. Arterial stiffness is a problem for many different people and for diverse reasons, and each symposium speaker had a unique contribution to the intricate puzzle we call the CV system.

Rong Zhang, Ph.D., of University of Texas Southwestern Medical Center, presented that his cerebral research witnesses not only an increase in vascular damage with aging, but also mitigation of this damage and a 50 percent decrease in the incidence of dementia from walking about two miles per day. You read me correctly—just walking provides this benefit! Though disease and aging have modified the standard signaling and function of the cerebral vasculature, something as simple as walking enables another redundant system to take over and battle arterial stiffness. 

Douglas Seals, Ph.D., University of Colorado – Boulder, brought up the ever-present “vicious cycle” that is so detrimental to the CV system. A few mitochondria step out of line and BAM! You’ve got endothelial damage, arterial stiffness and CV disease. I do like to think, though, that there can also be a “viciously good cycle” brought about by chronic exercise and, as Dr. Seals suggests, certain nutriceuticals. 

Martin Shultz, Ph.D., of the University of Tasmania, dove into exercise hypertension hemodynamics and discussed measuring blood pressure in order to recognize exercise hypertension; it is normally pretty sneaky and hard to find in resting individuals. His clinical perspective on the CV system was refreshing to me since I work in isolated animal vessels and sometimes forget that all my efforts are in hopes of eventually helping people, not just the pigs (who devote their lives to good CV research and delicious bacon).

What stood out to me the most was the lecture from Kerrie Moreau, Ph.D., from the University of Colorado Anschultz Medical Campus. Maybe it’s because I am a woman, but I geek out over sex-related differences in physiology. I’ve heard, and you probably have too, that the incidence of cardiovascular disease (CVD) has been decreasing over the past few years, which is awesome no matter how you look at it. However, I was surprised to see that the observed decreases have been primarily in men, and though women’s rates of CVD are lower anyway, they’ve stayed consistent over the years. I was even more surprised to see that there may be sex differences between exercise improvements in endothelial function and arterial compliance. There are some studies that have shown improvement in measures of arterial stiffening with exercise in postmenopausal women, but where we see diminished benefit is at the endothelial level. That is, estrogen-deficient postmenopausal women have diminished and even absent responses compared to men. Dr. Moreau presented data from several studies concerning this and the importance of estrogen in vascular response to exercise, which I hope to pursue and implement into my own future studies.

As a student and young researcher, it is exciting to get a glimpse of all we have left to discover and, as a woman, it is exciting to see my own physiology represented in research when it is found to be unique compared to a man’s. This may be my first IPE, but it definitely won’t be my last!

Read part 1 of this series: "Can Exercise Fill the Reductionist Gap? Reflections on Dr. Michael Joyner's Keynote."
Read part 2 of this series: "Are Exercise 'Mimetics' a Realistic Substitute for Exercise Training? Reflections on the Debate." 
Read part 3 of this series: "Exercise and Energy Restriction to Improve Health: Recent Research." 
Read part 4 of this series: "Molecular Transducers of Physical Activity (MoTrPac) Update." 
Read part 5 of this series: "Metabolic Flexibility in Health & Disease: A Symposium Summary." 
Read part 6 of this series: "How Exercise Promotes Brain Health in Aging." 
Read part 7 of this series: "Molecular Transducers of Exercise-Induced Muscle Hypertrophy: A Symposium Summary." 
Read part 8 of this series: "Exercise Pressor Reflex Function in Health and Disease." 
Read part 9 of this series: "Do Genetics Influence Exercise Capacity and Trainability?" 
Read part 10 of this series: "Is Mitochondrial Respiration a Limiting Factor of Oxidative Metabolism: A Symposium Reflection." 

Kalen A. Johnson, M.S. is a Biomedical Sciences PhD student in the Coronary Physiology lab in the Department of Veterinary Physiology and Pharmacology at Texas A&M University. She is also a graduate research assistant.