Why it matters: the countermovement jump (CMJ) is one of the most widely used tests of lower-body power and of neuromuscular fatigue (Claudino et al., 2017). The landing also shows how well the athlete controls the knee. A jump mat gives you a height.
VueMotion also shows how the athlete jumped and landed, from the side, from the front, or both.
The athlete stands on a marker, dips and jumps as high as possible, then lands back on the marker. One or two iPhones in portrait record the jump. VueMotion returns jump height, flight time, time to take-off, RSI-modified, joint angles at six key positions and, from the front, knee valgus and trunk tilt.
3
camera options: side, front or both
6
key positions, from dip to landing
3 m
camera distance, portrait
PhaseStart
Height0 cm
Time to take-off0.00 s
Sagittal (side)C1Frontal (front)C2
Why it matters
A jump mat tells you how high. VueMotion shows how.
Every CMJ gives you three layers. Together they turn one jump into decisions for performance, fatigue, injury risk, return to play, benchmarking and scouting.
OUT
Output
Jump height (two methods) and flight time: how much power the athlete produced.
STR
Strategy
Time to take-off, RSI-modified and squat depth: how the height was produced, fast and shallow or slow and deep.
MEC
Mechanics
Hip, knee, ankle and trunk angles from the side; knee valgus and trunk tilt from the front, at six key positions.
01
Performance monitoring
Is the athlete getting more powerful, or holding steady?
Output Jump height and flight time vs the athlete's baseline and cohort norms.
Strategy RSI-modified rising means the athlete jumps as high, or higher, in less time.
Trend Track every session to see the effect of a training block.
02
Fatigue & readiness
Is the athlete recovered enough to train hard today?
Quick check A few jumps take about a minute, so the CMJ suits daily or weekly checks.
Strategy first Time to take-off and RSI-modified often change with fatigue before jump height does (Gathercole et al., 2015).
Own baseline Compare against the athlete's own normal range, not just the squad average.
03
Injury risk reduction
Who lands in a way that puts more load on the knee?
Knee valgus Knees caving in on landing is a pattern linked to ACL injury risk in jump-landing studies (Hewett et al., 2005).
Stiff landing Little knee and hip flexion at landing means the joints absorb less force (Padua et al., 2009).
Is the athlete jumping and landing as before the injury?
Baseline match Jump height and RSI-modified against the athlete's own pre-injury results.
Left vs right Valgus on each knee from the front view shows whether the injured side is still collapsing.
Landing depth Squat depth and knee flexion at landing show whether the athlete trusts the leg to absorb force.
05
Benchmarking
How does the athlete compare with their peers?
Normative range Jump height, flight time, time to take-off and RSI-modified against sport and cohort.
Strategy profile Compare squat depth and joint angles with athletes in the same sport.
Squad view Rank the squad and set standards by position.
06
Scouting & talent ID
Who has the most explosive lower body?
Objective height Calibrated jump height from one or two iPhones: comparable across trials and venues.
Efficiency High jump height with a short time to take-off marks explosive athletes.
Landing quality See whether a recruit lands with control before you invest in them.
These metrics describe movement patterns linked to performance and knee loading in research. They support coaching and clinical judgement; they do not diagnose or predict an individual injury.
01 · Choose your camera setup
Side, front, or both
Pick the setup that answers your question. Jump height and timing come from any view. Joint angles need the side view; knee valgus and trunk tilt need the front view. Both views together give the full report.
Sagittal only
Power & strategy
1 iPhone, side-on · portrait · 3 m
The standard performance and fatigue test.
Jump height and flight time
Time to take-off and RSI-modified
Hip, knee, ankle and trunk flexion at six positions
Squat depth at take-off and landing
Frontal only
Landing control
1 iPhone, facing the athlete · portrait · 3 m
A quick knee-control screen.
Jump height and flight time
Time to take-off and RSI-modified
Left and right knee valgus at six positions
Trunk tilt (side lean)
Sagittal + frontal
Full assessment
2 iPhones, synced with Controller-Capture · portrait · 3 m
Everything in one jump: recommended for screening and return to play.
All output and strategy metrics
All joint angles from the side
Knee valgus and trunk tilt from the front
One synced capture, one report
Metric
Sagittal
Frontal
Both
★ Key metric shown in the results highlights.
02 · Setup
Jump marker and camera positions
Mark a small ‘x’ (the jump marker) on a firm, flat surface. The athlete stands on it facing the frontal camera. Every camera is 3 m from the athlete, in portrait.
Jump markerCamera field of view
C1
Sagittal camera
Side-on to the athlete, 3 m from the athlete, on a tripod in portrait, 1× lens. The whole body, from feet to raised hands, stays in frame at the top of the jump.
C2
Frontal camera
Directly in front of the athlete, 3 m from the athlete, on a tripod in portrait, 1× lens. Both knees and feet must be clearly visible.
⇄
Both cameras
Use VueMotion's Controller-Capture so one tap starts both iPhones together. Keep each camera square to the athlete.
Short on space? If you can’t get 3 m back, move the camera closer and record with the 0.5× (ultra-wide) lens so the whole jump stays in frame. Jump height and timing are unaffected; joint-angle estimates may change slightly because the wide lens distorts the image, so use the same lens and distance every time you retest.
Capture in HD at 60 or 120 fps on iPhone (or 4K 120 fps on GoPro), with Auto-FPS off. iPhone 11 or newer. Use a firm, flat surface, and make sure no one else stands in either camera's view.
Why frame rate matters
Jump height from flight time is h = g·t²/8 (Bosco et al., 1983). Each video frame you miss at take-off or landing changes the flight time, so higher frame rates give more precise heights. For a 30 cm jump:
60 fps± 2.0 cmper frame (16.7 ms)
120 fps± 1.0 cmper frame (8.3 ms)
240 fps± 0.5 cmper frame (4.2 ms)
Worked from the formula for a 0.49 s flight; use 120 fps where you can.
03 · Capture
Record in a few minutes
1
Equipment
1 or 2 iPhones (11 or newer), tripods, tape for the jump marker and a measuring tape.
2
Marker
Mark an ‘x’ on a firm, flat surface, with clear space around it.
3
Cameras
Place each tripod 3 m from the athlete, portrait, 1× lens (0.5× if space is tight): side-on, in front, or both.
4
Tag + record
Choose the athlete and the CMJ test tag for your camera setup, then record. With two phones, use Controller-Capture.
5
Upload
Upload the original files from the VueMotion app and submit the AI request.
Athlete
Warm up, then a few practice jumps
Stand still on the jump marker, feet hip-width apart
Hands on hips for the whole jump, unless your protocol uses arm swing (keep it the same every time)
Dip, jump as high as possible, land back on the marker and hold still
Camera settings
HD at 120 fps preferred (60 fps minimum)
Auto-FPS off (Settings → Camera → Record Video)
Portrait, 1× lens (0.5× only if 3 m isn’t possible), no zoom or panning
Do Not Disturb on, Auto-Lock never
Scene & upload tips
Start recording before the athlete moves; stop after they are still again
Bright, even light; no light source behind the athlete
Clothing that shows the knees helps the front view
Upload original files from the app; avoid AirDrop or messaging apps
04 · What the camera sees
Six key positions
Markerless pose tracking follows the athlete through the jump. VueMotion measures the joint angles at six key positions, from standing to the deepest point of the landing.
START
SagittalC1FrontalC2
TD1
Sagittal metrics
Frontal metrics
Illustration only: a stick figure drawn to show each position, with mild valgus added at landing so it is visible. Your results show the athlete's own stick figure, joint angles and kinograms. The positions play in order; tap one to hold it.
05 · Outputs
What you get after upload
Highlights
Key metrics at a glance: jump height, RSI-modified, time to take-off, flight time and the main joint angles.
Full metrics table
Every metric for the views you recorded, compared with norms and previous tests.
Six key positions
Stick figures and joint angles at start, deepest dip, take-off, top of the jump, landing and deepest landing.
Left vs right (frontal)
Knee valgus on each knee at every position, to spot a knee that caves in.
AR video
Pose overlay on the jump for each camera.
Progress over time
Every metric across previous tests.
CSV / API
CSV/Excel export for Enterprise and Academy users; API access for Enterprise.
Linking jump and landing to fatigue and injury risk
Most injury research used drop-jump or jump-landing tasks rather than the CMJ itself, so treat these as patterns to coach and track, not predictions.
Metric
Link to performance, fatigue or injury
Evidence
Performance linked to power or fatigue Prospective linked to future injury in a cohort study Mechanistic linked to knee loading in lab studies
Metric definitions
Key positions
TD1 · Start
Standing still on the marker before the countermovement begins.
PF take-off
Peak flexion before take-off: the deepest point of the dip.
TO1 · Take-off
The last frame with the feet on the ground.
MH · Max height
The highest point of the jump.
TD2 · Landing
The first frame with the feet back on the ground.
PF landing
Peak flexion after landing: the deepest point of the landing.
Output and strategy
Jump height (cm)
From flight time: h = g·t²/8.
Jump height TO1–MH (cm)
How far the body rises from take-off to the top of the jump, measured from the tracked body position.
Flight time, FT (s)
Take-off (TO1) → landing (TD2).
Time to take-off, TTO (s)
Start of the countermovement → take-off. Shorter = faster jump.
RSI-modified (cm/s)
Jump height ÷ time to take-off. Higher = more height in less time (Suchomel et al., 2015).
Squat depth take-off / landing (cm)
How far the hips drop in the dip, and after landing.
Joint angles
Hip, knee, ankle flexion (sagittal)
Joint angles from the side view at each key position. Peak knee flexion during flight is also reported.
Trunk flexion (sagittal)
Forward lean of the trunk from vertical.
Knee valgus, left and right (frontal)
How far each knee moves inward relative to the hip and ankle, seen from the front (frontal-plane projection angle).
Trunk tilt (frontal)
Sideways lean of the trunk from vertical.
06 · Practitioner value
More than a jump height
No mat, no plates
One or two iPhones replace a jump mat or force plate for height, timing and strategy, with joint angles a mat can't give.
Fast enough for daily use
A few jumps take about a minute per athlete, so the CMJ fits into a warm-up.
Strategy, not just output
Two athletes can jump the same height in very different ways; time to take-off, RSI-modified and squat depth show the difference.
Landing screen built in
Add the front camera and every jump doubles as a knee-control screen.
Validated approach
Video-based flight time is a valid, reliable way to measure jump height with a smartphone (Balsalobre-Fernández et al., 2015).
Pair with sprint tests
Compare with Acc, Fly and 10-0-5 to see whether the athlete is limited by power, speed or the ability to stop and turn.
07 · Support
FAQs
Which camera setup should I use?
Sagittal only for performance and fatigue monitoring; frontal only for a quick knee-control screen; both for screening and return to play, when you want the full picture from one jump.
Hands on hips or arm swing?
Hands on hips removes the arms from the jump and is the most common way to monitor fatigue. Arm swing gives higher jumps. Either works, as long as you use the same one every time.
Why are there two jump heights?
One comes from flight time; the other measures how far the body rises from take-off to the top of the jump. Landing with bent knees or tucking the legs can make the flight-time height read high, so comparing the two is a useful check.
How many jumps should I record?
Record a few jumps with a short rest between them and use the same number every session, so results stay comparable.
Are CSV exports and APIs available?
CSV/Excel export is available for Enterprise and Academy users, and API access for Enterprise users.
Claudino JG, Cronin J, Mezêncio B, et al. The countermovement jump to monitor neuromuscular status: a meta-analysis. Journal of Science and Medicine in Sport. 2017;20(4):397–402.
Gathercole R, Sporer B, Stellingwerff T, Sleivert G. Alternative countermovement-jump analysis to quantify acute neuromuscular fatigue. International Journal of Sports Physiology and Performance. 2015;10(1):84–92.
Suchomel TJ, Bailey CA, Sole CJ, Grazer JL, Beckham GK. Using reactive strength index-modified as an explosive performance measurement tool in Division I athletes. Journal of Strength and Conditioning Research. 2015;29(4):899–904.
Bosco C, Luhtanen P, Komi PV. A simple method for measurement of mechanical power in jumping. European Journal of Applied Physiology. 1983;50(2):273–282.
Balsalobre-Fernández C, Glaister M, Lockey RA. The validity and reliability of an iPhone app for measuring vertical jump performance. Journal of Sports Sciences. 2015;33(15):1574–1579.
Hewett TE, Myer GD, Ford KR, et al. Biomechanical measures of neuromuscular control and valgus loading of the knee predict anterior cruciate ligament injury risk in female athletes: a prospective study. American Journal of Sports Medicine. 2005;33(4):492–501.
Padua DA, Marshall SW, Boling MC, et al. The Landing Error Scoring System (LESS) is a valid and reliable clinical assessment tool of jump-landing biomechanics: the JUMP-ACL study. American Journal of Sports Medicine. 2009;37(10):1996–2002.
Hewett TE, Myer GD. The mechanistic connection between the trunk, hip, knee, and anterior cruciate ligament injury. Exercise and Sport Sciences Reviews. 2011;39(4):161–166.
Munro A, Herrington L, Carolan M. Reliability of 2-dimensional video assessment of frontal-plane dynamic knee valgus during common athletic screening tasks. Journal of Sport Rehabilitation. 2012;21(1):7–11.
VueMotion · Movement Analysis