FORCE PLATES – changing the game in performance and rehab
Ever heard of the saying: “if you are not measuring you are only guessing”?
Well, this could not be truer when it comes to training in the gym, whether you are an athlete seeking to achieve the smallest worthwhile change, or a housewife trying to get rid of back pain.
Nowadays devices and apps make the measurements/tests look easy and so intuitive, that it is rare to find a gym who does not test their members in a way or another.
Force Plates have been around for 40 odd years, but relegated to sport science and university labs.
They are designed to help scientists, S&C coaches and medical teams gather important information about their athletes and clients.
The current use of Force Plates touch a broad variety of population, including older individuals, who can test their physical capacity improving, with good programming, their quality of life.
Since we acquired them on site, the main questions we receive are:
- What are Force Plates?
- What do you measure with them?
- Why do you use them in training facilities?
Let’s try and answer these questions in easy terms.
WHAT ARE THE FORCE PLATES?
Force plates are a mechanical device, which is designed to measure and track forces applied onto them (Ground Reaction Forces). The dual plate (in the pic) has “load cells” on each plate, allowing for unilateral limb readings while performing bilateral exercises; when there is a pressure (force) onto the plate, the sensor is triggered, the mechanism delivers a trace/measure of the given force, also providing a numerical value (generally in Newton).
WHAT DO WE MEASURE WITH THE PLATES?
The number of tests a force deck can measure is very large. The main parameters we measure are:
- Velocity (m/s)
- Power (Watts)
- Vertical Displacement (i.e., cm, meters)
- Temporal parameters (i.e., Flight times)
- Asymmetry Left/Right – emerging from any of the bilateral and unilateral tests.
The cool things are that tests can provide information not just on the chosen movement, but when combined with other tests can also provide valuable info about the muscle’s behavior (read more about it in the Performance chapter)
APPLICATIONS OF FORCE PLATES:
Finally, there are 3 main areas we use the testing for at Athletix:
Our Athletes are screened weekly to understand and monitor their fatigue, by checking their neuromuscular response. When and if their nervous system is fatigued, their scores will be lower than average, generating some alarm bells. We use these red flags to adjust the training for the week, also advising their sport coaches who can modify their weekly workload, ensuring the athletes recover and do not incur in injuries.
The tests we use for monitoring generally are:
- Hamstring Isometric test (we use an overcoming resistance to test on the plates)
- Groin Squeeze (with the Dynamo)
- Hop Tests or Drop Jump – to measure the Reactive Strength Index (RSI) the ability to perform an eccentric rapidly and efficiently–concentric muscle contraction within a stretch shortening cycle movement.
This is our choice especially with Field/Court athletes, but other tests can be implemented, depending on what parameters/sports you deal with.
Whenever an injury occurs, the affected side/limb will lose strength because of the lack of use.
Force plates, especially when it comes to important Sports rehabs (ACL, hamstring, shoulder, ankle) provide a great insight into the musculoskeletal capability and its progress, allowing the physio, the exercise physiologist and/or the Strength and Conditioning coach to modify and implement strategies to increase effectiveness of the return to play/activity protocols.
The tests used depend on the injury/surgery, so they can vary from upper to lower limbs, testing internal and external rotation, knee flexors and extensors peak power, asymmetry of the limbs etc. etc.
Physical benchmarks are routine into competitive sports, athletes are tested across a variety of areas. This is generally quite time-consuming. In the old days we had to test with the Vertex or chalk on the wall for jump height. The Strength Tests would take ages because of the need of long warmups and build up sets.
Now, at Athletix, we get athletes to simply use one or two pieces of equipment (the force plates and the Dynamo) and all the data we need comes through in the same database, so in a few minutes we have their physical performance profile, and we can easily see how they get to produce the power and how quickly (Rate of Force Development).
Extras on Testing:
Now, for the more science-focused individuals… a little deeper look into the Tests we can perform.
Just for your information, here we focus on tests for lower limbs (which we can correlate with athletic activities such as sprinting and jumping) but there is almost every single time a counterpart for upper limbs.
- Squat jump (SJ) measures the vertical lower body power and is purely concentric (the jump starts from the bottom of the squat, in a static position, so no elastic energy is used for the jump).
- Countermovement Jump (CMJ) is primarily used to measure an athlete’s explosive lower body power and has become one of the most frequently used tests by coaches and researchers to indirectly measure power in the lower limbs.
- Abductor and Adductor strength
- Hamstring Strength (either with the Nordboard– providing peak power through eccentric body deceleration; or using the force decks performing a bridge test.
- Isometric Mid-Thigh Pull (IMTP) provides a great deal of information on peak and mean power which has strong correlation with athletic movements such as jumping and sprinting abilities (1). Furthermore, it is a safer way to test lower limbs than Max strength tests.
From the above tests we can generate a bunch of other interesting information about muscles’ behavior.
- EUR – Eccentric Utilization Ratio is (for lower limbs) the ratio between CMJ and SJ. It can determine the effectiveness of one’s stretch shortening cycle. This provides some info about the muscle’s behavior and help programming for their needs more accurately (more strength-based vs more ballistic/explosive work). (2)
- DSI: The ratio between IMTP and CMJ provides the Dynamic Strength Index, which gives similar info to the EUR and offers a great snapshot of the jumping capabilities, suggesting (with other variables) where one is placed on the Force Velocity profile and where the training should be focused on. 3)
- FVP (Force Velocity Profile) helps evaluating the optimal balance between force and velocity capabilities. It can be estimated using an incremental test (BB or Trap Bar Jump Squat for lower limbs) to determine the athlete profile as they move across the force-velocity curve. This will allow the practitioners to collect reliable data comparing them with the ideal values, showing where the biggest potential for the athletes lie across the force-velocity curve. (4)
The popularity of Force Plates in elite sports and training facilities is growing, however there is one only negative, the potential reason why you might not see FORCE PLATES in your gym – and it is not the cost, as you might think (the subscription model is so convenient that any gym can afford and justify having one).
The real hurdle is that using force plates clearly requires competent staff, interested in using the equipment not only to collect/show numbers; the point of testing is to be able to make sense of the numbers and make informed decisions on future programming to improve one’s physical benchmarks, whatever the goal.
If interested in testing any of the above, for performance, monitoring , rehab or simply to get a more tailored exercise program, feel free to get in touch via email or book your testing session directly at reception!
Townsend, J.R., Bender, D., Vantrease, W.C., Hudy, J., Huet, K., Williamson, C., Bechke, E., Serafini, P.R. and Mangine, G.T., 2019. Isometric midthigh pull performance is associated with athletic performance and sprinting kinetics in division i men and women’s basketball players. The Journal of Strength & Conditioning Research, 33(10), pp.2665-2673.