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Drop Vertical Jump

Landing mechanics from a controlled drop, followed by an immediate jump.

16
metrics
0
gradable today
9
events detected
Start an assessmentMetric reference
What this test measures

What it tests, what QOOM measures, what you get

What it tests
Landing mechanics from a controlled drop, followed by an immediate jump.
What QOOM measures
Drop-to-contact and contact time, jump height, RSI, knee flexion at contact, peak knee flexion, peak dynamic knee valgus, trunk lean and flexion at landing, landing asymmetry.
What you get
Landing-focused report with left/right comparison and metric zones.
How it is captured

The protocol

Two phones on tripods, stereo-calibrated once. The protocol below is the one the analysis pipeline is written against.

Subject stands on a box (30-40 cm), drops off, lands on both feet, immediately performs a maximal vertical jump, and lands again. Arms overhead or hands on hips per protocol. One trial per attempt.

Category
Jump
Environment
Any space
Trial structure
Single repetition, repeated as needed
Minimum capture
2 s

Camera setup guide

Events detected

The moments the analysis finds first

Every metric is measured between events. These are detected from the reconstructed skeleton before any metric is computed.

  1. 1

    Trial Start

    trial_start

    First frame of the captured trial.

  2. 2

    Drop Initiation

    drop_initiation

    Frame where the subject begins to step/fall off the box.

  3. 3

    First Landing

    first_landing

    Frame of first ground contact after the drop.

  4. 4

    Amortization End

    amortization_end

    Frame where downward COM velocity reaches zero after first landing (deepest point of the loading phase).

  5. 5

    Jump Take-Off

    jump_takeoff

    Frame where feet leave the ground for the reactive vertical jump.

  6. 6

    Flight Peak

    flight_peak

    Frame of maximum COM height during the reactive jump flight phase.

  7. 7

    Second Landing

    second_landing

    Frame of ground contact after the reactive jump.

  8. 8

    Stabilization Start

    stabilization_start

    Frame where COM velocity settles below threshold after second landing.

  9. 9

    Trial End

    trial_end

    Last frame of the captured trial.

Every metric

The full metric list

This is the complete list the analysis produces for this assessment — the same list the metric reference documents. A metric with a reference distribution shows the direction that reads as better and the evidence level behind it; where the evidence gate withholds the zone, the reason is shown instead of a grade.

  • Drop-to-Contact Timems
    drop_to_contact_ms
    No reference distribution

    Time from drop initiation to first landing.

  • Contact Timems
    contact_time_ms
    Zone withheld — no recorded sourceevidence: approximate

    Ground contact time from first landing to jump takeoff (amortization + propulsion).

  • Jump Heightcm
    jump_height_cm
    Zone withheld — source not resolved to a specific paperevidence: approximate

    Maximum COM height during the reactive jump flight phase relative to standing.

  • Reactive Strength Index—
    rsi
    Zone withheld — no recorded sourceevidence: approximate

    Jump height divided by contact time. Measures reactive ability.

  • Knee Flexion at Contact°
    knee_flexion_at_contact_degPer side
    No reference distribution

    Knee flexion at first landing. Soft-landing indicator.

  • Peak Knee Flexion°
    peak_knee_flexion_degPer side
    Zone withheld — no recorded sourceevidence: approximate

    Maximum knee flexion during the amortization phase.

  • Peak Dynamic Knee Valgus°
    peak_dynamic_knee_valgus_deg
    Zone withheld — metric does not measure the reference quantityevidence: consensus

    Maximum medial knee collapse at first landing. The primary landing-alignment marker of the drop vertical jump.

  • Trunk Lean at Landing°
    trunk_lean_at_landing_deg
    Zone withheld — no recorded sourceevidence: approximate

    Lateral trunk lean at first landing.

  • Trunk Flexion at Landing°
    trunk_flexion_at_landing_deg
    Zone withheld — no recorded sourceevidence: approximate

    Forward trunk flexion at first landing.

  • Landing Asymmetry%
    landing_asymmetry_pct
    No reference distribution

    Percentage difference in left vs right knee flexion at first landing. Left/right landing asymmetry marker.

  • Pelvis Vertical Excursionm
    pelvis_vert_excursion_m
    No reference distribution

    Trial-aggregate range of vertical pelvis-COM motion. Indexes how much the centre of mass rises and falls relative to the support base.

  • Pelvis Lateral Excursionm
    pelvis_lateral_excursion_m
    No reference distribution

    Trial-aggregate range of medio-lateral pelvis-COM motion. Quantifies side-to-side sway, including during single-leg stance.

  • Pelvis Forward Excursionm
    pelvis_forward_excursion_m
    No reference distribution

    Trial-aggregate range of anterior-posterior pelvis-COM motion. Forward progression in gait; forward travel and braking depth in jumps.

  • Pelvis Vertical Excursion (SD)m
    pelvis_vert_excursion_sd_m
    No reference distribution

    Cross-cycle (or cross-rep) standard deviation of vertical pelvis-COM excursion. Higher SD signals movement variability.

  • Pelvis Lateral Excursion (SD)m
    pelvis_lateral_excursion_sd_m
    No reference distribution

    Cross-cycle standard deviation of lateral pelvis-COM excursion. Used as a stability marker for repeated gait/jump tasks.

  • Pelvis Forward Excursion (SD)m
    pelvis_forward_excursion_sd_m
    No reference distribution

    Cross-cycle standard deviation of forward pelvis-COM excursion. Used as a stability marker for repeated gait/jump tasks.

What the report contains

Sections of the report

The per-trial report is assembled from these sections, in this order.

  1. 1

    Key Metrics

    Headline DVJ metrics.

  2. 2

    Metric Zone Overview

    All metrics as gradient zone bars.

  3. 3

    Phases & Events

    COM vertical position with all DVJ phase markers.

  4. 4

    Joint Kinematics

    Knee, hip, trunk kinematics through the drop-land-jump sequence.

  5. 5

    Description of Metrics

    Full-text description of every metric in the report and what each one measures.

  6. 6

    Quality Assurance

    QA verdict, reasons, warnings, schema version, report hash.

Quality checks

What can stop a result

Each trial is checked before metrics are reported. A failed check either blocks the result or marks it partial — it is never silently graded.

  • Mean pose-estimation confidence across trial must be >= 0.60

    min_pose_confidence
    Blocked

  • No contiguous occlusion > 0.5 s on key landmarks (hip, knee, ankle)

    no_major_occlusion
    Partial

  • All 9 events must be detected with confidence >= 0.5

    dvj_all_events
    Partial

  • Both first and second landing must be detected

    dvj_two_landings
    Blocked

  • A reactive jump (takeoff after first landing) must occur

    dvj_reactive_jump
    Blocked

  • Drop phase must show >= 0.15 m vertical COM descent

    dvj_drop_height
    Blocked
Blocked —
No metrics are reported for the trial.
Partial —
Metrics are reported with a warning; the affected values are flagged.
How grading is decided

When a metric gets a zone

A metric can be graded only when the norms registry holds a reference distribution for it, and a zone is shown only when the evidence gate admits that distribution’s provenance and evidence level. A distribution the gate refuses stays in the registry, auditable, with no zone.

0 of 16 metrics can be graded today

7 carry a reference distribution · 7 zones withheld by the evidence gate: 5 × no recorded source, 1 × source not resolved to a specific paper, 1 × metric does not measure the reference quantity

Evidence levels behind this assessment’s reference distributions

  • published0

    Values traceable to a peer-reviewed population study. Reserved; nothing in the registry currently qualifies.

  • consensus1

    Anchored to a recognised clinical guideline or expert-consensus cutoff. Values are approximate, but the cutoff is citable.

  • approximate6

    Informal literature ranges or general-adult estimates, not validated against a specific cohort. The honest default.

  • unvalidated0

    A two-point estimate or an inferred value. A distribution is declared, but the evidence gate withholds the zone.

How the evidence gate worksFull metric reference

Run this assessment.

Two phones, one guided protocol, and a report at the end.

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