With the rise of force plates, you might think contact mats and infrared contact grids would lose momentum on the market, but that is not the case. For decades, the contact mat has helped coaches gather data in the field, and professionals have recently started to look for options that can help capture the reactive strength index of athletes. While the contact mats and their respective alternatives are still not as informative as force plates, they are still viable tools if you use them correctly and interpret the data carefully.
In this buyer’s guide, we look at the market and the research on the validity of the contact mat and grid. We also present a short list that will help coaches get the information they need to make an appropriate purchasing decision.
What Is a Contact Mat or Contact Device?
A contact mat is basically a surface or sensor that detects a very binary status of the athlete: whether they are on the ground or in the air. While the information may not seem very useful at first glance, especially if compared to a velocity-based training device or force plate, it can serve as a very valuable tool for coaches. Researchers still use contact mats to see nominal changes in training, and they are reliable options for very simple purposes and information.Contact mats are reliable options for seeing nominal changes in training. Click To Tweet
A contact mat is usually a thin, flexible material with wires that senses if a body is on it, but the device doesn’t detect load or pressure like force plates or pressure mats. From an engineering perspective, the contact mat simply determines if the sensor circuit is on or off, and records the change over time. A few devices use lasers or infrared beams to determine the status or presence of a person on the floor, and this is extremely popular for sprint and jump coaches who want to get precise measures of ground contact time. Mats are usually a meter square, and grids can run from a few meters to nearly 40 meters long, depending on the brand and model.
Most contact mats and grids serve a simple purpose—to estimate jumping performance by calculating air time based on the assumption that the mechanics of the movement are uniform and repeated. Coaches must know that a contact mat is not a true measure, but simply a very useful calculation that has limits. Due to errors (which athletes gaming the testing sometimes make on purpose), contact mats and grids are very prone to accuracy issues if athletes are not compliant.
Some applications, such as the reactive strength index (RSI), are excellent measures because athletes can’t really cheat the test as they can’t manipulate landing mechanics to inflate the scores. Other applications, specifically linear sprints, can extract a lot of information if timing gates are used to get horizontal time intervals. Block clearance assessments, as well as maximal velocity tests, use contact times to determine how an athlete trends from a development standpoint. Some equipment can get stride length measures with a high degree of accuracy, and many applications in testing can’t embed force sensors or pressure systems.
Contact times and air times are valuable for deeper analysis of performance, when you can’t use video or the time available isn’t realistic in applied settings. Contact time and air time don’t truly represent running data, as contact length and stride length are two distinct measures. An athlete overstriding may have slower velocities because their mechanics increase unnecessary braking forces. A combination of video, stride parameters, and solid coaching experience provides just the right amount of insight to make changes that can show up on the record board or podium.
How Science Evaluates the Technology of Contact Mats and Grids
The strength of the data, regardless of the equipment and calculation, starts with the procedure or protocol of the test. Despite what you invest in, an athlete’s compliance and the coach’s or researcher’s instructions all limit the equipment. Athletes are very clever and often motivated to get better performances. Sometimes they will find movement or test strategies to improve their score, but their abilities may not change. Testing is a responsibility, not just an event with a measurement attached to it. Both the coach and the athlete should be fully vested in the process, and understand what information is useful and what they must discard.How fast a device can measure the contact period helps determine its value for use in analysis. Click To Tweet
After testing procedures, you can evaluate the instrumentation limits fairly. A contact mat and grid can sample (speed of sensing change) at different rates, thus giving precision and accuracy to the information. One millisecond may not sound like much, but due to the nature of sprinting, contact times of .091 and .095 can separate a national-level athlete from one that makes an Olympic team. Therefore, how fast the device can measure the contact period is a primary factor in determining if the device is valuable for analysis or not.
Nearly all the best investigations into the validity, accuracy, precision, reliability, and bias of contact mats are done with force plates and video. In summary, coaches need to know that a device can give a good indication of possible change in performance if they use the same setup. A contact grid or mat may not reveal true ability; this is acceptable when a professional needs to know if a change resulted from an intervention.
Another consideration for contact mats is the targeting problem that athletes can run into, and this is true for all sensors. If an artificial demand, such as landing on a specific region or knowing that you are being measured, effort will rise or fall depending on the technology. For example, the study from Gil and colleagues indicated that immediate feedback with a VBT tool increased performance, but the opposite is true with athletes juggling equipment limitations and the demands of an all-out effort test. PASCO plates, for example, are designed for simple science experiments for high schools and higher levels, and jumping on a small square during rebound tests is often awkward and ineffective. Contact grids use the surface and are excellent solutions to situations where athletes want to feel like they can perform without worry.
The calculations of contact grids and mats are done with assumptions, meaning the readings require a compliant and strict execution of the jump or sprint. Since, during sprinting, contact grids are combined with video and timing gates, they are, for the most part, great for research. Jumping, especially for squat jumps and countermovement jumps, can be very problematic because a piece of equipment can’t determine if the athlete was complicit with the procedure and will still deliver a score. Force plates calculate jump height from the force into the device and athletes can’t cheat the measurements because they can’t jump high without putting force into the ground.
Common Contact Mat Jump Tests
The contact mat is the oldest testing option for sports as they originated in war technologies, specifically landmines. Bosco popularized the contact mat by using it to help make jump testing more accessible for coaches and removed from the limitations and costs of force plates. As the contact mat became more commercial, the data became more inaccurate: the responsibility needed to perform simple jump tests declined because of the popularity of the NFL Combine’s jump and reach devices. A specific guide to using contact mats for jumping and a general guide to jump testing both illustrate the need for proper administration. Most coaches perform bilateral jumps, as hops are single leg movements.
Vertical Jump with Arms: Most athletes can jump using a movement strategy that combines their arms and legs. Many athletes jump to catch or block a ball, and even heading uses the arms to gather force transmission properly. The jumping ability of the body is not the same as the explosive jumping ability of the legs in isolation. Several athletes are excellent jumpers in sport but not very good jumpers in field tests. Athletes often jump with preceding movement and speed, so sport-specific testing may be necessary.
Squat Jump (No Arms): An athlete can do squat jumps without arms using a light dowel or with their hands on their hips. The air time is estimated when the athlete becomes airborne and doesn’t make contact with the mat, and the landing leg mechanics can determine if the jump was inflated. If the athlete is consistent, this has a high degree of value to the coach.
Countermovement Jump (No Arms): Like the squat jump, the data can be wildly off if the athlete lands low with a deep bend. A countermovement uses the momentum of the body to transmit a greater force into the ground, which is the reason most athletes have a significant difference between their static (squat jump) and dynamic (countermovement) performances.
Reactive tests are far more useful for coaches if they use a contact grid or mat. A contact time and flight time ratio is perfect for the device as that’s what it is designed to measure. Coaches can have athletes do repeated jumps (rebound) with one or two legs or jump off a box to challenge their reactivity. Drop jumps require the device to be very sensitive and precise as the contact times are usually less than a quarter of a second.
Rebound Jumping: Athletes that perform continuous jumps on the ground get RSI values, and contact mats and grids are excellent tools for this. The Scandinavian rebound jump test is a specific repeated measure that extracts the best jump and uses it as an indication of elasticity and stiffness.
Drop Jumps: Jumping off a small box or platform can help coaches with training prescription or fatigue detection, but is not as popular due to the lack of skill most athletes have with this style of test. Athletes tend to plantarflex their ankle and score poorly, and those that overthink the movement have delayed contact time periods that severely lower the score and are not indicative of their ability.Contact grids become more valuable when combined with other testing tools. Click To Tweet
A word of caution: Contact grids are good for simple measures in isolation, but become more valuable when combined with other instruments. They can’t measure force, and you can really only detect asymmetry through separate leg testing, as testing the legs simultaneously doesn’t tell the whole story. You can use contact mats in conjunction with speed timing as a way to gauge first movement or serve as a repeatable way to start the clock, but for the most part, they are vertical jump testing options. Even grids, the option that increases the field of detection by several meters, still fail to measure true horizontal force. This is because of landing strategies and technique issues such as learning to apply force longer at the right time, which is a tactic that some athletes find foreign and strange.
Common Contact Grid Speed and Power Tests
A contact grid can do all of the testing that a contact mat does, and you can also use it to capture larger surface areas in sport. The benefits of using a contact grid are that it provides an athlete with a larger area to jump without mental fear of equipment limitation and allows them to use the same surface they will likely use in competition. For example, an athlete can use a hardwood floor in basketball or a track surface for jumping, even if it’s outdoors. On the other hand, you can’t use grass unless the cut is fresh and extremely low, such as a putting green or similar. A contact grid is designed to be as low as possible so the beam spreads just above the ground, but not so low that an uneven surface will false trigger it.
Coaches using speed gates and video often employ a setup that measures contact times during maximum velocity or during early acceleration. High performance centers can collect entire sport event runs, but due to the cost, most coaches need just a part of a sprint, such as 40m or shorter. Contact grids can get contact times but they are not interchangeable with video, because the ground is 5-10mm lower than the sensor.
Due to the speed and reliability, the values are solid enough to use as a way to show progress or regression. Early acceleration, the period from first movement to the first three steps, can leverage the air time and contact time of sprints to determine how the athlete mechanically uses their body to gain speed. The manual effort of collecting training data from film is a burden, but for races and research, video analysis is a valuable option due to the inclusion of the kinematic information. Also, you can analyze projectiles such as medicine balls and shots by the repeated pattern of motion sensors and the implement’s contact with the ground.
Top Contact Measurement Technology Options in Sport Testing
Several companies provide affordable testing equipment for jump testing and first movement timing signaling. Most of the companies produce contact mats, but two employ infrared to determine foot contact. Microgate and Ergotest are very effective for both jumping and linear speed tests, and you can use either for treadmill setups. Here are the leading options for coaches and researchers for contact time and flight time sports testing.
Probotics Just Jump Mat: The only analog product on the market, the system is still popular today because of the simplicity of its design. The mat is a little short of a meter long and uses a wired connection to transmit the data to a handheld LCD screen. The device can test vertical jumps or continual jumps with limits. You can connect the Just Jump system to a running test, and you can purchase an additional chip to get contact times for decent RSI testing. The data accuracy is not very good, so is appropriate for youth testing and similar.
SMARTJUMP by Fusion Sport: This contact mat from Australia has features such as RFID connectivity for group workflow and can be used fluidly with Fusion Sport’s AMS system, SMARTABASE. You cannot purchase the contact mat alone, as it requires a relay device that they usually bundle into the purchase. Research on the system is available, and the data is reliable enough for some testing needs, such as the RSI and screening for basic asymmetries with hop tests.
Ergotest MUSCLELAB Contact Grid: The two IR (infrared) systems have a pair of bars that form a grid of infrared beams to sense foot contact. The system is excellent for jump testing and performing the reactive strength index family of assessments. What makes the two systems very popular is that other MUSCLELAB systems can be integrated, like timing gates and sports lasers, as well as the rest of the line of Ergotest products. The combination of speed and contact time measures makes the Ergotest option very popular with coaches who are traveling or need a high-value tool for contact times.
Microgate Optojump: Italian company, Microgate, offers a contact grid like MUSCLELAB, but when four bars combine into a square, it can get both contact time and contact location. While MUSCLELAB has a grid of binary information, if you use two pairs of Optojumps, you can see the very precise location of foot drift on the hop test. While you can expand the Optojump product to get linear speed, the cost is very expensive, but some high-performance centers like Formia need the stride length and other metrics for their national teams.
Swift Performance Contact Mat: This new contact mat is very durable and resembles a thin force plate, but only collects contact data. While the system collects each foot independently, it can’t truly assess the power or force of an individual leg like a bilateral force plate can. The system uses iOS to connect to an Apple device, and you can export the data via email if needed. The system is about a meter square, like typical contact mat solutions. This Australian company’s previous product was popular as it leveraged the simplicity of Apple iPads and Bluetooth technology.
Innervations Contact Mats: The two options from Dr. Robert Newton are USB and Bluetooth contact mats. They include Kinetic Measurement System software and offer other tests such as fast feet assessment and other movement tests like first step. The starting or entry point size of the contact mat is much smaller than other systems at 58 by 43 centimeters, but larger sizes are available.
ChronoJump Contact Mat: The least expensive option on the market is an open source project widely used internationally. The system is fairly useful for small projects and coaches and researchers who are very technology savvy, but you shouldn’t use it if you expect a plug-and-play experience. In addition to the contact mat, the company also provides other tools for sports testing, such as an LPT device and timing gates.
gFlight: The gFlight, developed by the U.S.-based company Exsurgo, is a straight to the point jump device offering several contact time-derived jump metrics (ground contact time, time in air, and reactive strength index). Its wireless setup and small footprint makes it ideal to travel with and easy to store. Metrics are immediately shown on the display screen, allowing for real-time objective feedback to both the coach and the athlete. The low price point and portability of the gFlight makes it quite unique when compared to other jump mat and contact zone technologies. The gFlight is part of a new wave of sports tech designed to be both budget- and user-friendly.
All of the equipment above has a digital reading or smart device display, or connects with a laptop or full Windows tablet. It is also all battery-powered or powered by a computer via USB or similar.
Parting Thoughts on Contact Grids and Contact Mats
Although there are advances and price reductions in the force plate market, investing in contact grids and mats is a worthwhile idea. Most of the indirect measurement devices are highly portable and simple to use, making them very suitable for training camps and coaches who need to perform field tests. Nearly every system can export data into either CSV files or Microsoft Excel.
If you plan to buy a contact mat or contact grid, look specifically at the model and make, as there are several investigations available to validate the data integrity and show where they are strong within the market. Even with the smartphone app market growing, contact grids and contact mats are staples and they are not going away. They are easy to use in groups and allow coaches to administer the tests without restrictions.