CENTRE OF PRESSURE IN SQUATS - HOW LOAD DISTRIBUTION SHAPES STRENGTH AND STABILITY
We’ve talked a lot in our previous articles about heel elevation, and its impact on squat depth and performance. However, not all heel lifts are created equal. Raise the heel one way and you unlock depth while the centre of pressure (CoP) stays around the midfoot. Raise it another way and pressure drifts to the toes, balance gets twitchy, and the load shifts toward the ankle plantar flexors.
Plantar pressure maps and force plate data show that where you load the foot predicts the strength you can express, and the stress your joints will see. This article translates those maps into practical choices – what wedges and slant boards tend to do to load distribution, how that affects stability, muscle recruitment, and range of motion, as well as how to test your setup in practice. We'll also explain why Ultraform Lift was engineered to elevate the heel without forcing a forefoot bias, maintaining an anatomically balanced pressure profile so your sets feel grounded, predictable, and stable.
CENTRE OF PRESSURE AS A MAP FOR THE NERVOUS SYSTEM
Centre of pressure (CoP) is the weighted average of pressure under your feet – the point on the support surface where the resultant ground reaction force acts. In a two-footed stance like the squat, there’s a local CoP beneath each foot, and a global CoP across the base of support (distinct from centre of mass). CoP is a key control signal for balance, providing fast, continuous feedback about how weight is distributed and how stability is being maintained.
In a well-controlled squat, CoP typically settles near the midfoot at depth. Small front-to-back shifts change how joints share work and how the rep feels. As CoP moves anteriorly, the ankle plantar flexors (calf muscles) take a greater share, while the knee extensors (quads) share falls – this is often felt as toe-grip or heel lift. As CoP shifts posteriorly, the hips dominate and the shins stall. Crucially, these force-sharing changes can happen even when your technique looks identical – hence why the pressure map matters.
GEOMETRY, MATERIAL, AND THE EFFECT OF SQUAT WEDGES AND SLANT BOARDS ON LOADING
When it comes to heel lifts, the amount of elevation isn't the whole story – the geometry and stiffness of the device also decide where the pressure goes. In lab models, shifting the CoP forward during squats increases the ankle plantar flexor moment and reduces the knee extensor share, even when joint angles look similar [1].
With slant boards, generally on a continuous decline, the angle matters. As decline increases (0-20°), studies show higher knee moments and increased patellofemoral and patellar tendon loads, while ankle moments drop [2,3]. You may still hit depth, but balance feels more reactive and the bottom position can get ‘tippy’ especially as load climbs. Useful if you want more demand on the knee and stabilisers around the calf and hamstrings [4], but not a neutral choice for balance or joint exposure.
Wedge blocks can create a similar forefoot bias for different reasons – narrow contact or compressible materials that encourage forefoot loading and dampen plantar cues during descent. Footwear research shows that changing midsole geometry and material redistributes internal loading and alters balance regulation during squats [5,6] – the same logic applies to wedges.
None of this makes wedges or slant boards ‘bad’ it just means they're rarely neutral. Elevation delivered with the wrong geometry or material can shift the pressure map and change loading more than intended. The practical goal is simple – access depth without shifting CoP to the toes, so you keep the tripod, stay centred over the midfoot, and let the big joints share work predictably.
PRESSURE MAPPING BASICS – TOOLS, SIGNALS, AND WHAT ‘GOOD’ LOOKS LIKE
There are two common ways to visualise how you're loading the foot. Force plates give you a global CoP trace across the base of support and show how it moves through the squat. Coaches often normalise CoP to foot length and check whether it stays around the midfoot at depth. In-shoe pressure systems split the foot into regions (rearfoot / midfoot / forefoot – sometimes medial / lateral) and show pressures in each.
A balanced squat shows tripod contact (big toe, little toe, heel) throughout, a CoP that hovers around the midfoot rather than migrating anteriorly even under heavy loads, and no spikes in medial pressure at depth. If the interface is working, the pressure map looks boringly repeatable. If you see a forefoot bias or late reactive pressure spikes, the interface is usually the culprit – geometry or material is distorting the map.
STRENGTH AND MUSCLE RECRUITMENT – HOW PRESSURE LOCATION CHANGES WHAT FIRES
Where you place pressure at the bottom of a squat changes which muscles do the work, often without a visible change in joint angles. When CoP drifts anteriorly, inverse dynamics models show the ankle plantar flexor moment increases while the knee extensor share falls [1]. In practice this means the calves do more of the work, and the quads give up some leverage.
EMG studies that cue lifters to shift pressure forward report higher gastrocnemius and soleus activity with lower quadriceps activity around the bottom position – more calf, less quad [4]. By contrast, keeping CoP around the midfoot preserves knee extensor contribution so the quads can drive the first part of the ascent more predictably. Two squats that look identical on video can have very different neuromuscular solutions.
The downstream consequence is a stability cost – a forefoot-dominant map forces the nervous system to spend bandwidth on balance corrections rather than clean and powerful lifts. This often shows up as toe-grip, heel lift, and reactive saves at depth, costing you repeatability and early force expression.
Device choices can amplify or blunt these effects. Heel elevation that preserves a midfoot CoP typically supports knee extensor demand and, in several studies, increases quadriceps activity depending on stance, depth, and load. Interfaces that drag CoP forward – steep declines, narrow or compressible contacts – skew contribution toward the ankle plantar flexors and make the bottom more reactive. That can be useful if you deliberately want an ankle-dominant emphasis, but it isn't a neutral choice when the goal is balanced strength.
JOINT STRESS AND LONG-TERM TOLERANCE – WHY PRESSURE LOCATION MATTERS
Pressure location doesn't just change which muscles do the work, it also changes which joints get stressed. Two big levers drive patellofemoral (PFJ) demand – depth and load. Fundamental analyses show PFJ forces rising as knee flexion and external load increase [7]. Add a decline or slant board and the picture shifts further – as the decline angle increases towards 20°, studies report higher knee moments with greater PFJ and patellar-tendon loads [2,3,8].
CoP matters too – cueing an anterior CoP can raise PFJ stress during squats, even when kinematics look similar [9]. Practically, a forefoot-dominant map stacks more demand toward the knee joint and tendon while reducing the ankle's share. A midfoot-centred map distributes moments more evenly and keeps the bottom position calmer.
You can use this knowledge in your programming – if you're PFJ-sensitive, avoid steep declines and devices that pull CoP forward. Aim for upright depth with balanced pressure, heel elevation that preserves a midfoot CoP, then let exercise selection dose the knee sensibly. If you want a knee-emphasis block, you can use moderate decline strategically – just pair it with a firm, foot-shaped interface and track symptoms alongside load x depth exposure.
DESIGN MATTERS – CHOOSING A HEEL LIFT FOR SHAPE, STIFFNESS, AND STABILITY
A good heel lift should elevate without distorting your pressure map – think of it as part of a control system from floor to skin to central nervous system. Anything that alters the signal will alter your squat. Alongside heel height, three variables affect that map:
Foot-shaped contact
You want full-foot support so the tripod (big toe, little toe, and heel) can share load at depth. Narrow edges or a sharp ridge under the forefoot push pressure forward – a foot-shaped platform lets CoP hover around midfoot instead of migrating to the toes.
Non-compressible stiffness
Soft foams act like a low-pass filter for plantar feedback – they blur cues and encourage late corrections. A rigid, non-rocking material preserves both spatial (where pressure sits) and temporal (how quickly it changes) resolution, so balance remains proactive, not reactive.
Base stability and footprint
The interface between foot and floor must be stable front-to-back and side-to-side, with enough width for your stance and no ‘teeter’ as load climbs. A grippy and foot-shaped surface helps you keep gentle toe contact without clawing.
Ultraform Lift as the smart solution
Ultraform Lift was engineered to the above constraints – foot-shaped geometry, a rigid non-compressible construction, a stable footprint, and a balanced decline angle that preserves heel and big toe contact at depth. The result isn’t just comfort, it’s signal integrity. You get heel elevation for access to depth without a forefoot bias, so the tripod stays intact, CoP lives around the midfoot, and heavy sets feel grounded.
On the floor this feels quiet – big toe and heel still in contact at depth, pressure centred over the midfoot, and no last-second saves. If that isn't what you feel, the interface could be steering you in the wrong direction – try swapping to a firm, foot-shaped, non-compressible lift and retest in your setup.
ENGINEERING A STABLE SQUAT
Squat performance comes from a stable conversation with the floor. Keep that conversation clear and you express more strength with fewer rescues – calm midfoot pressure, knees tracking over the second/third toe, vertical bar path. Tools matter because they shape that conversation.
Ultraform Lift is our answer to the ‘good position vs good feel’ trade-off – raise the heel and keep the pressure map balanced. If your current setup feels tippy or forefoot biased, try switching to a firm, foot-shaped, non-compressible interface, and confirm the feel with a slow set pausing at depth. Elevate the position, keep the signal, and make your squats repeatable with Ultraform Lift.
REFERENCES
[1] Ishida, T, Samukawa, M, et al. (2022). Effects of changing center of pressure position on knee and ankle extensor moments during double-leg squatting. Journal of Human Kinetics, 82(1), 37–46.
[2] Richards, J, Selfe, J, et al. (2016). The effect of different decline angles on the biomechanics of double-limb squats. Journal of Human Kinetics, 52(1), 59–68.
[3] Zwerver, J, Bredeweg, S.W, & Hof, A.L. (2007). Biomechanical analysis of the single-leg decline squat. British Journal of Sports Medicine, 41(4), 264–268.
[4] Kitamura, T, Kido, A, et al. (2019). Muscle activity pattern with a shifted centre of pressure during the squat exercise. Journal of Sports Science & Medicine, 18(2), 248-252.
[5] Southwell, D.J, Petersen, S.E, et al. (2016). The effects of squatting footwear on 3D kinematics and internal loading patterns. Journal of Applied Biomechanics, 32(1), 8–15.
[6] Cohen, J.W. (2017). The effects of footwear on squat movements. International Journal of Exercise Science, 10(5), 764–775.
[7] Wallace, D.A, Salem, G.J, et al. (2002). Patellofemoral joint kinetics while squatting with and without an external load. Journal of Orthopaedic Sports Physical Therapy, 32(4), 141-148.
[8] Kongsgaard, M, Aagaard, P, et al. (2006). Decline eccentric squats increases patellar tendon loading compared to standard eccentric squats. Clinical Biomechanics, 21(7), 748-754.
[9] Ishida, T, Ueno, R, et al. (2025). The effect of real-time feedback regarding the center-of-pressure on patellofemoral joint loading during double-leg squatting. Orthopaedic Journal of Sports Medicine, 13(3).
