By Carl Valle
I consider tensiomyography, or TMG for short, one of the most valuable muscle diagnostic tools, and I have grown to use it more and more over the last 10 years. Therefore, it horrifies me that only a few people use TMG or even know about it today.
Being a skeptic, I dismissed TMG for nearly a decade, until pioneering coaches and sports training experts like Dan Pfaff and Jose Fernández began to share their expertise with the instrument. Now, leading colleges such as Baylor and Iowa here in the U.S. are doing TMG testing and evaluations on their athletes, and I believe professional teams will start to follow.
Tensiomyography isn’t for everyone, but coaches committed to solving problems such as injuries and poor performance will naturally gravitate to what TMG can do for athletes. If you are already using TMG, keep it up; if you are not, it’s time to catch up.
What Is Tensiomyography?
Slovenian researchers invented TMG in the 1990s and it came onto the market a decade later. Tensiomyography exploded in Spain when Julio Tous Fajardo integrated the technology into his arsenal of equipment, which already included flywheels and muscle lab devices. Julio’s work with Juventus, Barcelona, and tennis ace Rafael Nadal was innovative and provocative, and helped the market explode. Today, some leading therapists use TMG here in the States and with elite soccer clubs in Europe.
Many people are still unaware of TMG and want to know what it is and how can it help athletes perform better or get fully back to play. The second question is a little bit trickier to explain, but I will take a stab at it later in this article. Tensiomyography is a measurement method that evaluates individual superficial muscles with the use of muscle stimulation and a tensiometer. The sensor resembles a piston-like rod that samples the tension of a surface by moving back and forth with a high degree of precision, and then sends the data to a laptop.
Video 1. To test a muscle group, neuromuscular stimulation from electrical current fires the muscle, and the sensor reads the physical response of the tissue from the contraction. TMG is not like EMG, as the information is more physical and collects the movement of the muscle, rather than reading the electric potential of the muscle.
Each muscle test takes a few seconds to sample and is completely painless (although the sensor looks like a needle, it isn’t one). After the computer receives the data, the software receives the information for review.
Due to the fact the muscle groups require EMS for stimulation, TMG can only test external muscles like hamstrings and other superficial muscles. Training and practice can decrease the time required to test athletes, and I tend to use the rule of thumb of one muscle per minute to estimate the time demands of player evaluation. A lower body test usually takes less than 10 minutes for those really experienced, and the entire body takes under 20 minutes.
What Exactly Does TMG Measure?
The evaluation of superficial muscles with TMG requires interpretation, as it measures parameters that are unique to the system. It’s safe to say that tensiomyography assesses readiness acutely and locally at the tissue level. It’s not a strength test or range of motion test, but a way to look at the tonal qualities of the muscle. The tissue characteristic TMG provides can guide both performance and medical staffs to very actionable pathways that conventional methods simply can’t replicate.It’s safe to say that #tensiomyography assesses #readiness acutely and locally at the tissue level, says @spikesonly. Click To Tweet
When a muscle contracts, the change from resting to firing provides very subtle but important information on the functioning of the muscle. A simple way to look at tensiomyography parameters is to see the displacement (millimeters) over time (milliseconds) from an electrically induced involuntary contraction. The TMG software slices the contraction into milestones, similar to research-grade software for force plates extracting key time points of a countermovement jump.
The measures are exactly what they are called, meaning they are direct summaries of the muscle changed over time by a maximal contraction from electrostimulation. How far, how fast, and how long are oversimplified here, but it’s a good thought process that can help new users understand what is being measured. From start to finish, here are the key parameters and my personal definition of each.
- Delay Time: The time period from rest to a rise in early but significant displacement of the muscle.
- Contraction Time: The time period from early displacement to relative completion of the isometric contraction.
- Sustain Time: The calculated time period of the contraction from mid contraction to the end of the relaxation milestone.
- Relax Time: The estimated duration and distance back to rest after isometric contraction.
- Maximal Displacement: The total distance from rest to peak contraction of the muscle in millimeters.
You can see other metrics and calculations when you compare muscles bilaterally or in conjunction with multiple muscle groups near a joint. For example, many professionals look at the integrity of the knee by testing the entire leg to see whether risk may exist acutely and over the course of a season. In addition to muscle function, professionals can see the composition of fast and slow muscle fiber types with testing. By calculating the slower fiber types, they can profile an athlete with a high degree of accuracy if they are healthy.
The Reporting of TMG Data
The reporting of tensiomyography data is important because interpretation is much easier when a coach or therapist can see the parameters organized visually. I have used custom charts for years, but now the TMG-BMC company does a fantastic job migrating from raw research files to PDF-ready reports that nearly anyone can understand. The software makes TMG reports instantly and can export the data for power users pushing the boundaries of the system.#TMG line plotting allows professionals to see muscle groups alone or compared with the other side, says @spikesonly. Click To Tweet
Since TMG uses line plotting to visualize the contractions, professionals can see each muscle group alone or combined for comparison purposes with the other side. Most muscles in the body are paired, and comparisons between the same right and left muscle groups are common.
Another option is to look at the group of muscles of one joint like the knee. Stated earlier, solid insight is possible when you evaluate the relationships between multiple muscles at the same time. Researchers have made some interesting studies on ACL injuries and rehabilitation with TMG (see list later in article); expect more research to follow to assist practitioners needing precision guidance on return to play and risk analysis.
I have shared the final visualization perhaps a dozen times on SimpliFaster—the estimated fiber typing of a very talented soccer player we tested in 2012. The data was exciting because we collected readings from multiple teams in the English Premier League and compared it to our own athletes. A very explosive athlete may seem like a gift, but speed and power are a responsibility, not a winning lottery ticket. Talent is usually a quality that is “off the charts,” and managing talented athletes with loading requires extra attention.
Exporting the data is perfect for athlete management systems and researchers doing additional statistical breakdowns. Some teams are doing amazing work, but most of the innovation outside of the company is with consultants like Julio Tous Fajardo and Jose Fernández, who experiment with different training and rehabilitation methodologies. I have done a few experiments that were unconventional, but the limits to TMG are really about the curiosity to see connections of muscle function and a variable of choice.
Interpreting TMG Data for Better Training and Medical Decisions
With multiple parameters per muscle group, handling an entire body can seem like a challenge for support staff. Don’t be alarmed. Classic clinical evaluation and experience working with athletes will connect the data you collect and add more specific information for what you would typically do. Too many systems make professionals feel like slaves to the machine, but TMG empowers coaches and medical teams.
In general, TMG adds a clear, objective comparison of a normal muscle’s actions and a likely muscle impairment. Severe injuries, like an acute tear or pull, are obvious and TMG just confirms what everyone involved already knows. Its strength is in the gray area between injury and optimization.TMG’s strength is in the gray area between injury and optimization, says @spikesonly. Click To Tweet
The biggest fear of professionals is that TMG will require advanced analysis to interpret the data, and the truth is anyone with a college exercise science degree can handle the data easily. In fact, management and agents are comfortable with reports presented to them with before and after data.
- When compared bilaterally, does the data look radically different or similar?
- Compared to baseline data, do the shapes and values appear significantly different?
- If the data is different, what is the context of when the data collection took place, such as after games or training?
Of course, these questions are just the tip of the iceberg, but to me they are the foundational directions that lead to the right answers. Like all data and clinical evaluations, I suggest cross-referencing TMG data to get to the bottom of the problems faced by professionals.#Tensiomyography is the equivalent of a lie detector for muscles, says @spikesonly. Click To Tweet
Coaches care about managing fatigue, and medical professionals tend to want to know about the risk for a new injury and the recovery for existing injuries. Screening has always been murky, but sometimes an athlete still struggles with a lingering problem that is a ticking time bomb. Athletes can pass movement screens and range of motion tests and still have a neuromuscular impairment.
Tensiomyography is the equivalent of a lie detector for muscles. Athletes often know when something is wrong and while medical professionals may listen to their complaints, TMG connects the subjective information to something tangible for the professional. Since the information is objective and quantified, it’s a permanent record of how the tissues trend over a season.
The Scientific Support for TMG in Sport
Sports practitioners ask me if TMG is valid, and its reliability in environments that will have different professionals using it when working with the same athlete. Those two questions are fair discussion points: Why test if the measurement doesn’t assess what is expected, and why use it if data isn’t solid when different staff uses it with athletes?
There is plenty of research on the answers tensiomyography can give, and many of them focus on rehabilitation and quantification of the response to training loads. Dozens of research studies show the value of the system in quantifying complex interactions such as impingement of the hip and muscle response, and many soccer studies on player injuries and seasonal workload have been published recently.
Reliability research on TMG is available and the data integrity is high, but the metric of relaxation seems questionable. In my experience, this is likely because relaxation times are not stable like other parameters but I have yet to see this as a problem in the field. Ideally, anyone can come in and have the same results as another person using the equipment, but like most human-operated devices, consistency issues will happen.
I have read perhaps all but two or three research studies on tensiomyography, and my favorites are ones that use TMG to discover the link between interventions and profiling loads. Here are several examples of fascinating studies that should help teams and researchers be more creative.
- Effect of cold-water immersion on skeletal muscle contractile properties in soccer players.
- The effect of recovery strategies on contractile properties using tensiomyography and perceived muscle soreness in professional soccer players.
- Between-day reliability of a method for non-invasive estimation of muscle composition.
- Tensiomyography of selected lower-limb muscles in professional soccer players.
- Assessment of neuromuscular risk factors for anterior cruciate ligament injury through tensiomyography in male soccer players.
- Tensiomyography parameters and jumping and sprinting performance in Brazilian elite soccer players.
- Muscle mechanical properties of strength and endurance athletes and changes after one week of intensive training.
- Tensiomyographical responses to accelerometer loads in female collegiate basketball players.
- Skeletal Muscle Contraction Time and Tone Decrease After 8 Weeks of Plyometric Training.
Locally, a muscle won’t have the same characteristics if loading is unique to that area, so quantifying those differences makes sense. Usually, the choice of when someone goes hard again in practice or competition isn’t based on an “average”; it’s done based on the trending risk areas. TMG targets problem spots and estimates their function. No device can make a decision, but the data and process in place are strong enough to make smarter choices even if you simply observe the testing.
My Personal Story with Tensiomyography
For years, I have had athletes compete in Europe and talk about the “muscle machine” when they came back to the U.S., but it wasn’t until 2010 that I started seeing the big picture and full power of tensiomyography. I was experiencing the huge challenge of inheriting athletes with complex injuries and very demanding rehabilitation and training needs.
For the next five years, I dealt with more than a dozen cases of the dreaded chronic hamstring tear athlete and TMG was the beacon of light for us. Most of the time, I had to juggle athletes who were in the middle of a botched return-to-play program and we were on the clock, which meant that we had very little time to work with. TMG acted as an objective readiness check for each session that needed a progress report, and was the final litmus test to determine if the next phase was appropriate. While we used clinical and training information to draw strong conclusions, it was TMG that provided the proof that our training was working, and let us know when to progress safely as we aggressively rehabbed.#TMG isn’t just an instrument—it’s a paradigm shift in thinking, training, and managing injuries, says @spikesonly. Click To Tweet
The best case study I have ever done was with a college soccer player who eventually played professionally for a short period of time. He was nearly out of the sport halfway through college and simply had bad luck in choosing a physical preparation coach. Every time he got hurt, we could trace his injuries to the way he trained and it didn’t take much expertise to make a connection. In addition to bad luck with some poor performance training, the original injury to his ankle joint was never managed properly, thus causing a firing problem visible with pressure mapping and electromyography.
We finally got his muscle groups firing properly with a custom orthotic from Bruce Williams, but he still had contact injuries and various challenges that were out of our control. TMG was the glue and we used the test results to keep us on the right track when the odds were against us. Resurrecting an athlete who wanted to quit the sport halfway to being able to play at the professional level in front of their mother was more rewarding than sending someone to the Olympics or working with an All-Star. TMG was instrumental to us every step of the way.
What I learned from using the system and what I was able to do better were both dramatic. TMG isn’t just an instrument—it’s a paradigm shift in thinking, training, and managing injuries. I know I do these things better now than before TMG.
- Management of muscle tone: Manual therapy has always been a mystery in sport, as athletes crave it but science says “it doesn’t do much.” Most of the research on massage simply looked at transient biochemistry, not muscle function and tone status.
- Monitoring change in rehabilitation: If an athlete is injured, TMG is great for getting an established baseline of function. Over time, professionals can see how things trend with their return-to-play program.
- Profiling the training load response: Tensiomyography can assess positional and playing styles, down to the individual muscle group of players.
- Understanding intervention strength: Looking at the way different modalities affect the neuromuscular system with tensiomyography is one of my favorite benefits. Instead of guessing or eyeballing change, an objective measure is a great approach.
I have to give credit to Jose Fernández, who is currently with the Houston Astros, for elevating my knowledge of TMG and bringing it to a level I can apply effectively and creatively. We have done some amazing work in past collaborations, and we were the first to test athletes with TMG in the MLB, NBA, NFL, and NHL. New practitioners need to drive and push the limits of what TMG can do for now, but the benefits listed above should be more than enough to show a major return on investment.
Why I Recommend TMG Testing and Training
I believe every team should have a TMG system, period. The information provided is gold when a practitioner is trained and specific strategy is correctly in place. Having a TMG system without a comprehensive and holistic set-up isn’t going to solve every problem, but on the other hand, just committing to a unit and basic training will make the entire program or organization accountable.
Let’s be honest here: Joint and muscle tears represent the bulk of the injuries in sport, and many teams use indirect ways to reduce and rehabilitate them in vain. While managing the load on a body or evaluating system fatigue is something I believe in, it is just as important to monitor local and specific problems. Managing high risk areas of the body like the hamstrings or shoulder for speed and overhead athletes is not easy, but using TMG consistently will raise the entire standard of performance by a sports support staff. I made the move to TMG after doing my homework, and my goal for this article is to help teams take the next step forward.