Accessing Neuromuscular Fatigue

Accessing Neuromuscular Fatigue- A Practical Approach

When an athlete goes down because of injury, specially a non-contact one, attention will be directed to the medical and performance staff for answers. Countless questions on why it happened will be raised with the media and outside observers, but internally the answers are usually unknown. Several approaches are thought as leading metrics for monitoring and managing fatigue, but gross fatigue to the neuromuscular system is the most revealing and unfortunately the most difficult to assess in the past. Subjective questionnaires, blood testing, Heart Rate Variability, Electroencephalography, and even power tests such as jumping are all valuable, but what is best? Most importantly what are the field and physiological tests truly sharing, and are they a true window to the current status the nervous system? How does the information collected equate to what the athlete can actually do on the playing arena? The answer is clear, neuromuscular fatigue is the most effective way to manage speed and power athletes, either Olympic sports or team sport. Until now, neuromuscular fatigue required lab equipment, and took too much time for it to be a real world solution. Fortunately, the CHECK™ system can monitor athletes quickly and accurately with just a smartphone and Bluetooth device.

Monitoring Fatigue and Power

The right balance of training stress and recovery, timed right, improves performance and reduces injuries, something easily stated but difficult to achieve without monitoring. The narrow margin for error decreases with intense training, to the point that athletes will walk a razor thin tightrope. To mitigate athlete risk, sport science focused on player tracking and monitoring, but what is convenient to collect is sometimes not valid enough to make confident decisions. Decisions, such as having an athlete rest in practice, or allow a player to play long minutes in back to back games, are bold choices and requires very strong supportive data. When coaches become too conservative, conditioning is compromised to the point athletes are risking injury from not being prepared to play, thus creating a vicious cycle of an athlete under conditioned and over competing.

One of the unique challenges of monitoring athletes, specifically force production, is that in order to measure it one needs to strain the body with power training to evaluate it. Coaches have gone to physiological monitoring to estimate fatigue, or the absence of power, and are getting mixed results. Some athletes are perfect for subjective indicators while others will not provide reliable information. Coaches find some athletes are excellent for Heart Rate Variability (HRV) for general fatigue but not neuromuscular fatigue, or specific power status. The Autonomic Nervous System (ANS) is currently a trend with some teams, but without measuring specific neuromuscular fatigue a coach is lost in a vast sea of possible variables with ANS interpretation. Fatigue has many sources and causes of reduction of power, but the most effective way to create clarity is to see how a measurement relates to functional expression of force production. Simply stated, if the tool indicates fatigue, does that show up in annual field tests such as sprinting, jumping, and other sporting actions? If the tool indicates fatigue, then in actuality, it’s predicting fatigue at that moment, and athlete readiness is about the athlete being ready at the specific time of testing.

Monitoring the training load is not about seeing what the athlete can do, since many tests can find that information out. Monitoring is about seeing patterns and trends to predict possible overtraining and show areas that can be challenged more safely.  Coaches need to know what the current level of fatigue is, not just how much power they can generate at that given time. Multiple factors contribute to fatigue, but the end product tends to be a summary value, is what many coaches need daily.

Managing Power and Fatigue

When athletes and coaches make decisions on what to do for training, it usually boils down to a few primary options, and most of the time those choices are educated guesses at best. When guesswork is moved aside from valid options from proper monitoring, better choices are made. Managing fatigue requires coaches to adjust their plans based on unexpected changes. After getting objective neuromuscular status, coaches can choose to push the athlete, reduce the work slightly, or sometimes giving them a day off with active rest and regeneration activities. Better management is not only better adjustments, it’s usually better anticipation so plans are followed and not adjusted and compromised. Reactive type approaches that many monitoring systems employ are slaves to what the athlete responding to instead of directing the athlete to the better path that was originally planned.

Management is about making the right decisions, but the right information is needed first before one can chose on the best options. The growing interest in player monitoring in the NFL is reflecting what European clubs have done with professional Rugby and Soccer over the previous decade. Strength coaches, both team and private, are looking for ways to peer into the nervous system without invasive methods and time consuming practices. A common approach is to use jump testing to monitor both power and fatigue, and while that approach has value, jump-testing daily becomes a burden in several ways. Most team environments don’t have a way to test a group at one time, as most jumping equipment is limited to one user at a time. Jumping is fatiguing if done too frequently, and motivation becomes an issue as well.

From the data above it’s clear that the morning vertical jump performance doesn’t change much, but does follow the same trend of the CHECK™ score, a measurement of neuromuscular fatigue. The power and jumping results may not be clear visibly, the level of fatigue drops during Friday through Sunday as the player is recovering from the previous week’s competition and the accumulation of practice. One problem is that the jumping option isn’t easy with collision sports like Rugby and American Football, making collecting jumping scores a near impossibility during the competitive season. Athlete motivation and soreness makes the data very subjective, regardless of the equipment used to collect the data.

The same CHECK™ scores compared to training load showed above illustrates how the athlete recovered precisely at the right time. In addition to the timing of readiness, the data explained how the weekly set-up was successful due to the volumes being lighter and having two virtually off days. In the matter of seconds, the athlete had a way to gage his fatigue and instantly share that information with his coaches through the CHECK™ Cloud options. Morning testing, either at home or at the practice facility takes seconds to perform and the data is securely shared though Wi-Fi or cellular transmission. A simple score easily communicates general fatigue with all parties, and effectively evaluates daily readiness to the athlete directly. Using neuromuscular fatigue scores from CHECK™ is an effective way to guide coaches and medical professionals and see objective responses to their choices in training.

In the next blog, a scientific breakdown of how fatigue can be seen in different metrics physiologically and through field tests and see how they are useful in real world settings. Many options exist currently but very few are practical in team settings and are not useful outside a short research study in the lab. Also in the next blog a few case studies of actual athlete data in different sports will be displayed to show how practical and precise CHECK™ is with sports monitoring.


Juha Ruohonen
Juha Ruohonen

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