MySquatMechanics.com aims to help you understand the stickman squat model presented in a number of articles on squatting form. If this is the first time coming accross this model skip ahead for more information and helpful links.
The below sliders allows you to enter your own body's dimensions and identify areas such as your bodies squating angles, potential form issues and where your sticking position is located. Use it to see how the moment changes for your body when varying the bar position from low to high bar... or just play around with the sliders and make funny looking people squat.
Just remember that below is a model! The results shown are correct for the model and may not be right for you.
The stickman displays the body part lengths selected above with the sliders, bar path in blue and the current selected squat position. The squat position is based on the ankle, knee and hips breaking at the same time while the models center of gravity (CoG) is maintained over mid-foot.
The knee flexes linearly while the ankle flexes quicker in the beginning of the squat. 'Linear' meaning that when the model position is 25% of the way from standing to squatting, the knee has flexed 25% from the standing angle to max. When at the half way position the angle has gone through 50% of its max angle. Finally at max angle when the model is fully squatting. Breaking in a linear fashion may not be correct for the knee, nor the ankle flexing faster early in the movement. Just remember it's a model and won't show exactly how you squat.
CoG calculations take into account the bar mass, each body segments mass and each segments own CoG. This can cause the bar to travel forward past mid-foot to maintain the total models CoG over mid-foot. As a result the bar does not always travel in a vertical path.
Use the stance slider to change the angle of your feet e.g. feet pointing straight ahead equals 0 degrees and straight out equals 90 degrees.
Those of you with long legs will benefit from a slightly wider stance and feet angled out. This will make your torso more upright and bring your hips in closer to midfoot.
The Squat Stats plot displays the moment of the hips and knees along with the angle of the back, hips and knees throughout all positions of the squat. From squatting on the right to standing on the left. The vertical line shows the current position of the model and can be changed by sliding the position slider above.
This is useful to see how the moment changes throughout the squat and in identifying the sticking position.
Move the bar from a high bar position to low bar position. Distance is from the top of the torso e.g. 0cm for high bar and about 5-10cm for low bar.
If you have made it this far you probably love numbers and plots! These 2 show a breakdown of the knee and hip moments and what contributes to them. The summed moments are a total of the bar moment and the moment from each body segment.
Have a play with the body and bar weight sliders to see how the moment breakdowns change. You will also see how the bar path changes and starts to move forward with a lighter bar weight. Midfoot bar path is only possible with a very heavy bar weight and when it dominates the center of gravity calculations.
Based on the paper by Hawkins & Hull, this plot shows the calculated change in length for different muscles during the squat.