Force plates are flat, rigid platforms embedded with sensors that measure the forces your body exerts against the ground. When you stand, walk, jump, or land on one, the plate captures exactly how much force you’re producing, in which direction, and how that force shifts over time. They’re used across sports science, physical therapy, and research labs to turn human movement into precise, measurable data.
How Force Plates Work
Every time your foot contacts the ground, the ground pushes back with an equal and opposite force. Physicists call this a ground reaction force, and it’s what force plates are designed to capture. The platform contains sensors (typically piezoelectric crystals or strain gauges) that detect pressure and convert it into electrical signals, which software then translates into force measurements.
A standard force plate measures forces along three axes simultaneously. The vertical component captures how hard you’re pushing down against gravity, which is the largest force during most activities. The anterior-posterior component tracks forces directed forward and backward, like the propulsive push during a sprint or the braking force when you decelerate. The mediolateral component measures side-to-side forces, which reveal how much you sway or shift your weight laterally. Together, these three directions give a complete picture of the force vector: its size, its direction, and where exactly on the plate it’s being applied.
Center of Pressure and Balance
Beyond raw force numbers, force plates calculate something called the center of pressure, or CoP. This is the single point on the plate’s surface where all the ground reaction forces effectively concentrate at any given instant. Think of it like a moving dot that tracks where your weight is focused as you stand or move.
When you’re standing still, your center of pressure constantly shifts in small patterns as your body sways naturally. Everyone sways a little, both forward-to-back and side-to-side, but how much and how fast that dot moves tells clinicians a lot about your balance and stability. Larger or faster CoP movement can signal balance deficits, neurological conditions, or increased fall risk. In rehabilitation settings, tracking CoP over time shows whether a patient’s stability is improving after an injury or surgery.
What Force Plates Measure in Athletes
In sports performance labs, force plates are most commonly used during two tests: the countermovement jump and the isometric mid-thigh pull. Both produce detailed force-time curves that reveal far more than a simple vertical leap height or max strength number.
During a countermovement jump, a force plate captures the entire sequence: the dip down, the transition from lowering to rising, the explosive push-off, and the landing. From that single jump, software can extract metrics like peak force, peak power, flight time, impulse (the total force applied over time), and how stiff or compliant your legs are during the movement. Research from Ohio State University found that most of these metrics are reliably repeatable within a single testing session, though some, like the rate at which force builds during the eccentric (lowering) phase, show more variability.
One of the most valued metrics for power athletes is the rate of force development, or RFD. This measures how quickly you can ramp up force from the moment a contraction begins. A sprinter who generates high force in 100 milliseconds has a clear advantage over one who needs 300 milliseconds to reach the same level. RFD has been directly linked to performance in jumping, sprinting, weightlifting, cycling, and even golf swings. Studies consistently show that elite sprinters produce force faster than sub-elite sprinters, and that power-trained athletes develop force significantly faster than endurance athletes or untrained individuals.
Coaches use these metrics to track athlete readiness throughout a season. A drop in jump impulse or peak power from one week to the next can flag fatigue or incomplete recovery before an injury happens.
Clinical and Gait Analysis Uses
In clinical settings, force plates are standard equipment in gait analysis laboratories. They’re typically mounted flush with the floor so patients walk across them naturally. The goal is to capture how forces distribute during a normal walking stride, which helps identify asymmetries, compensations, or abnormal loading patterns that might not be visible to the naked eye.
One practical challenge is that people tend to adjust their walking pattern when they can see the plate, aiming their steps to land squarely on it. This “targeting” effect can distort the data. Labs address this by embedding plates in longer walkways or disguising them, so patients walk as naturally as possible. Despite this limitation, force plates cause minimal interference with normal movement compared to wearable sensors or other measurement tools.
Clinicians use the data to evaluate patients recovering from knee or hip replacements, ACL reconstructions, ankle sprains, and neurological conditions that affect walking. By comparing the force patterns between your left and right legs, they can quantify exactly how much you’re favoring one side and track whether loading becomes more symmetrical as rehabilitation progresses.
Pairing Force Plates With Motion Capture
Force plates are powerful on their own, but they become even more useful when synchronized with motion capture systems. Motion capture tracks how your joints move through space (kinematics), while the force plate records the forces causing that movement (kinetics). Combining the two allows biomechanists to calculate the forces and torques acting at each individual joint, not just at the ground.
Traditional setups use reflective markers and infrared cameras, but newer approaches are making this more accessible. Systems like OpenCap can estimate three-dimensional joint movements from smartphone video alone, then synchronize that data with force plate readings by matching the moment a heel contacts the plate in both the video and the force signal. This kind of integration feeds into musculoskeletal models that can estimate how much load your knee cartilage or Achilles tendon absorbs during a specific movement, information that’s valuable for both injury prevention and surgical planning.
Types of Force Plates
Most force plates fall into two categories based on their sensor technology. Piezoelectric plates use quartz crystals that generate an electrical charge when compressed. They’re highly sensitive, respond extremely fast, and handle high-frequency impacts well, making them the standard in research labs and professional sports facilities. Strain gauge plates use metal elements that change electrical resistance when deformed. They’re generally less expensive and work well for clinical applications where the highest sampling rates aren’t necessary.
Plates also vary in size and intended use. Smaller, portable plates are designed for field testing with athletes. Larger platforms or instrumented treadmills with built-in force plates allow continuous gait analysis over multiple strides without requiring the subject to hit a specific spot on the floor. Dual-plate setups, with one plate per foot, let clinicians compare left and right limbs independently during standing or jumping tasks.