Fatigue Monitoring in Training - What is the best Metric?

If one looks at all of the available research and products on the market, getting lost in what is the best way to assess fatigue is easy. More and more options are available to coaches and fitness enthusiasts today, and making the decision on what can be used daily requires a brief primer on the science of testing fatigue. What is accurate and practical? Does the test measure what it’s supposed to measure? How does the information make better decisions? In this entry, we will explain what are the best options in assessing fatigue and why our option stands at the top for athletes wanting to push themselves to the limit. 

Fatigue, it’s not under the Microscope or is it?

The neuromuscular system is far more difficult to evaluate than the cardiovascular system, but recent advancements make neuromuscular assessment accurate and convenient. When we came up with the CHECK™ solution, we looked at all the existing solutions to see if we could provide something better. Coaches, athletes, and trainers were discouraged with what they were using, and the results of other monitoring systems made no observable changes on injury lists or record boards.  We saw a gap in the area of neuromuscular assessment, an area that nobody was investigating or providing accurate evaluation. The three popular measurements to monitor fatigue are explored in this blog and let’s see the pros and cons.

Neuromuscular Power Tests

A simple and straightforward way to evaluate power and the absence of power (fatigue) is to actually measure performance and observe changes. Using the Bosco tests such as the counter movement jump (CMJ) and squat jump (SJ) coaches can evaluate how the athlete is responding to training programs. The jump tests are convenient in testing, but they are not a practical monitoring solution, because they lack several qualities and include a few problems with testing. Investing into jump testing equipment for teams or individuals is expensive. The data is not precise to pick up sensitivity levels needed to see trends over weeks of training with fatigue, since an athlete can be able to summon enough power for a few bouts of explosive jumps. Repeat jumps are very fatiguing, especially when you add up warming up and several samples. Testing the jumps properly takes a lot of time, and is nearly impossible to do with teams unless one is sacrificing the day of training to get the data.

Electrocardiography (ECG) Indices

Information from the heart is helpful for getting an estimate of fatigue in sports training. Coaches have used resting pulse rate and the rate of recovery for decades, and now Heart Rate Variability is gaining popularity. Beat to beat variation calculations estimate the strain on the body through extrapolating autonomic nervous system changes, a very broad area that may not indicate the true status of the neuromuscular system.

Electroencephalography (EEG) and other Brain Indices

Brain waves and fatigue are nothing new, but sport performance coming from a central origin, or in this case central organ, has the same problems as the heart. The Central Nervous System, or CNS for short, is considered the “Holy Grail” measurement of fatigue but so far no reliable measurement that is precise enough for functional testing exists. The brain is receiving so much noise, that when slow wave measurements are used the information, it is not enough to reveal the true neuromuscular status of the body. Central fatigue is very volatile and subject to different influences such as stimulants, emotional factors, and even circadian rhythms. Sleep disturbances, illness, and latent alcohol consumption are part of the myriad of variables that will interfere with a single sampling of data, reducing the confidence in the data from a hunch to near guessing.

The CHECK™ System and Neuromuscular Status Research

All the above tests have pros and cons, but neither set of tests are sensitive enough to provide actionable decisions in training, or not valid to give a reliable measurement on how the body was ready for explosive activity.  Ten years ago, here in Finland, the University of Jyväskylä performed an important study with the Frequency Analysis Method or FAM, a non-invasive way to unlock true neuromuscular status. During the fatigue study, researchers used force production, blood analysis, and the precursor to the CHECK™ system to measure fatigue objectively. The conclusions reached were a breakthrough for coaches, neuromuscular status matched the lab results, creating a new way to assess fatigue quickly and reliably. Multiple studies compared the FAM approachwith additional blood tests and ECG, but the conclusions were similar to previous studies.

“Strongest correlations between neuromuscular and FAM variables were found after eccentric exercise in MVC whereas after concentric exercise also variables related to power correlated with FAM.”

No one measurement will ever be in isolation because training is a mixture of different processes of the human body. The Neuromuscular system will respond to different physiological responses but will be highly influenced by direct peripheral fatigue. The CHECK™ measurement runs either parallel to ones power or mirrors training effects with fatigue. For example, a high training load of explosive work should mirror a drop in power from fatigue, showing up when using the CHECK™ system. An athlete feeling good and is able to produce high levels of power should have his or her readiness run parallel.

Neuromuscular Status and the Sport of Weightlifting

Over three weeks, a high level weightlifter who was training daily, decided to use the CHECK™ system to monitor his training load as well as use it as a way guide him on his most demanding week, a period of time he was purposely overtraining briefly, or correctly known as overreaching. Overreaching is an advanced method of driving fatigue up in order to adapt to higher levels of performance later. Coaches for years use careful strategic overreaching to break through plateaus in performance and training.

The athlete overreached in the middle phase of training. After a prescribed rest, the athlete rebounded and was able to hit new highs in both training and performance later. Athletes using CHECK™ can confidently follow the readiness of training and make smarter or more aggressive choices in what to do with each training session.

Neuromuscular Status and HRV Monitoring with Mixed Martial Arts

One of our CHECK™ users is a professional MMA competitor and he wanted to find a way to identify fatigue specific to his power development. Mixed Martial Arts - or MMA for short - is a sport that demands not only extreme conditioning, but the need to be explosive. For each round it is imperative to deliver strikes and defend attacks. The athlete was using a mobile system - popular with combat sport athletes - to collect a Heart Rate Variability Score derived by using a mathematical calculation and a special formula to provide a score. The data did provide just a little help because it was mainly showing good readiness even when the athlete was very tired. During those days, the athlete was not fresh enough for power activities and had neuromuscular fatigue. HRV is a very broad indicator and can’t identify or isolate every system of the body. Also the variation of the HRV score was significantly lower than with CHECK™. Using the CHECK™ system the MMA athlete was able to monitor training effectively, and make choices in training that are not simply possible with HRV monitoring alone.

Nearly all athletes, not just MMA competitors, want to more than just which day to go hard, they want to know how hard on what day they should be training.  Athletes can share the data instantly with their coach or guide themselves better with the information more intelligently when training on their own. 

Next week we will explore the Central Nervous System and review how sport science is using the CHECK™ system to ensure how athletes can be both fit and fresh at the right time. In the blog entry we will show how professional hockey is using our system to get higher levels of power from using very precise training adjustments unique to neuromuscular status.

Juha Ruohonen
Juha Ruohonen


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