Guides · HumanTrak · 9 min read
HumanTrak results explained: how to read an overhead squat, single-leg squat, hip rotation and balance screen
How to read VALD HumanTrak results: overhead squat, single-leg squat, hip rotation and balance. Joint angles, knee valgus, left against right, and data checks.
By Vikas Kashyap · Updated 13 October 2026
HumanTrak captures movement with a depth camera and no markers, and reports the angle of each joint through the movement. A full screen returns dozens of angles per athlete, most of them on two sides. That is rich, and it is the reason movement data so rarely reaches the weekly report: nobody has time to turn it into a sentence. This guide is the reading we use, test by test, and the checks that stop a tracking error becoming a finding.
What each test tells you
| Test | Angles worth reading | The question it answers |
|---|---|---|
| Overhead squat | Ankle dorsiflexion, trunk forward lean, hip flexion against knee flexion | Can the athlete get deep with an upright trunk, and is the squat led by the hips or the knees? |
| Single-leg squat | Knee flexion, hip flexion, hip-to-knee ratio, knee valgus at the deepest point | How much depth and control does each leg have on its own? |
| Seated hip rotation | External rotation, internal rotation, sideways trunk lean during each | Is the hip's rotation range there, and does the trunk move to fake it? |
| Single-leg balance, eyes closed | Sway forwards–backwards, sway sideways, sway area | How well does each leg hold still without vision? |
A countermovement jump can be captured as well, which adds joint angles at the bottom of the jump and after landing, including knee valgus on landing.
Two readings for every angle: level and side
Each angle is read twice. First against a target: is this range enough? Then left against right: is one side behind the other? They are separate findings and should be kept separate. An athlete with 20° of ankle dorsiflexion on both sides is symmetrical and restricted. An athlete with 38° and 30° has range and a gap.
Knee valgus: read the angle, not the percentage
Knee valgus is the measure most often over-read, because it usually sits close to zero. Two degrees on one knee and four on the other is a 50 % difference and, clinically, the same knee twice. For any angle that lives near zero, a left–right percentage is an artefact of small numbers. Read the absolute angle on each side against fixed bands and leave the percentage out.
The hip-to-knee ratio: who is doing the squat?
Dividing hip flexion by knee flexion at the bottom of a squat gives one number for the pattern. Above 1 the hips are contributing more than the knees, a hip-led squat. Below 1 the knees are bending further than the hips: an upright, knee-led squat that puts more of the load on the front of the knee. It is a simple ratio and it sorts a squad quickly: the athletes below 1 on at least one side are the ones to watch squat in person.
Balance: three numbers and a picture
Eyes-closed single-leg balance is reported as how far the body swayed forwards and backwards, how far sideways, and the area that sway covered. Lower is better on all three. The picture matters as much as the numbers: a long, narrow footprint front to back and a wide one side to side point at different controls. Compare the two feet on the same scale, and remember that for sway the weaker side is the one with more.
When the camera loses a limb
Markerless capture occasionally loses a joint, behind the other leg, in loose clothing, at the edge of the frame. The result is an angle that is wildly different from the other side, or a balance reading a hundred times the normal range. These are the most important values to catch, because they look like spectacular findings.
- A joint angle on one side that is less than half the other side deserves a look at the recording before it is believed.
- A sway value far outside the rest of the squad is far more likely to be a tracking loss than an athlete who cannot stand.
- Do not delete the value. Mark it as 'check this trial', keep the number visible, and stop it stretching every chart it appears on.
Camera targets are not goniometer targets
Range-of-motion targets often come from clinical norms measured with a goniometer or a loaded lunge test. A camera measuring the same joint in the middle of an overhead squat will usually read lower, because the movement, not the joint's end range, sets the angle. In one professional squad the typical overhead-squat ankle dorsiflexion was about 21° against a target of 38°, which put most of the squad in the red.
When most of a squad fails a target, the target is the first suspect. Show where the squad's own middle athlete sits beside the target, and judge an individual against both.
A checklist for reading a movement screen
- Level first, side second, for every angle.
- Absolute bands for knee valgus and trunk lean; no percentages.
- Hip-to-knee ratio to sort hip-led from knee-led squats.
- Balance as forwards–backwards, sideways and area, with the two feet on one scale.
- Outliers marked for a check of the recording, not reported as findings.
- The squad's own median beside every target.
- One sentence per athlete that says which joint, which side and what to do.
How Kinexis handles this
Kinexis reads every HumanTrak capture into the athlete's profile and draws each joint as a dial with left, right and target, with balance as a sway footprint per foot. For the squad it builds a joint map: how many athletes are restricted at each joint, on which side, against both the target and the squad's own median. The movement findings sit on the same profile as the force plate and strength testing, and the written interpretation says where they agree.
- Every joint as a dial: left arc, right arc, and the target line.
- Knee valgus and the hip-to-knee ratio on fixed bands, the same for every athlete.
- Values the camera probably lost marked “check”, still printed, and kept off the chart scales.
- A squad joint map with the weaker side per measure, and each test's coverage stated openly.