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Countermovement Jump

A vertical jump with a countermovement — the standard lower-body test.

21
metrics
0
gradable today
5
events detected
Start an assessmentMetric reference
What this test measures

What it tests, what QOOM measures, what you get

What it tests
A vertical jump with a countermovement — the standard lower-body test.
What QOOM measures
Jump height, contraction time, eccentric and concentric time and their ratio, modified RSI, peak centre-of-mass velocity, landing knee flexion and valgus, trunk position at landing.
What you get
Phase and event chart, joint kinematics 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 still, performs a self-paced countermovement jump with arm swing or hands on hips (per protocol), lands and stabilises. Single or double leg. Minimum 1 rep; multiple reps analysed independently.

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

    Standing Start

    standing_start

    First frame of quiet standing before the countermovement begins. COM velocity ~ 0.

  2. 2

    Countermovement Start

    countermovement_start

    Frame where COM vertical velocity first becomes negative (downward motion initiates).

  3. 3

    Bottom

    bottom

    Frame of minimum COM vertical position — deepest point of the countermovement.

  4. 4

    Toe-Off

    toe_off

    Frame where feet leave the ground (COM vertical velocity is maximal positive).

  5. 5

    Landing

    landing

    Frame of first ground contact after flight phase (rapid COM deceleration onset).

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.

  • Jump Heightcm
    jump_height_cm
    Zone withheld — source describes a different population, task or measureevidence: approximate

    Maximum COM displacement from standing to flight apex, derived from takeoff velocity or direct COM tracking.

  • Contraction Timems
    contraction_time_ms
    Zone withheld — no recorded sourceevidence: approximate

    Duration from countermovement start to toe-off. The total time from the start of the movement to leaving the ground.

  • Eccentric Timems
    eccentric_time_ms
    Zone withheld — no recorded sourceevidence: approximate

    Duration from countermovement start to bottom — the loading/braking phase.

  • Concentric Timems
    concentric_time_ms
    Zone withheld — no recorded sourceevidence: approximate

    Duration from bottom to toe-off — the propulsive push-off phase.

  • Concentric/Eccentric Ratio—
    concentric_eccentric_ratio
    No reference distribution

    Ratio of concentric to eccentric time. Lower values mean a shorter push-off relative to the loading phase.

  • Modified RSIm/s
    modified_rsi
    Zone withheld — no recorded sourceevidence: approximate

    Jump height divided by contraction time. A composite index of reactive strength.

  • Peak Eccentric COM Velocitym/s
    peak_com_velocity_eccentric_mps
    No reference distribution

    Maximum downward COM velocity during the eccentric phase.

  • Peak Concentric COM Velocitym/s
    peak_com_velocity_concentric_mps
    Zone withheld — no recorded sourceevidence: approximate

    Maximum upward COM velocity during the concentric phase (determines jump height).

  • Peak Knee Extension Speed°/s
    peak_knee_extension_speed_dpsPer side
    No reference distribution

    Maximum angular velocity of knee extension during concentric phase. Reported per side.

  • Peak Hip Extension Speed°/s
    peak_hip_extension_speed_dpsPer side
    No reference distribution

    Maximum angular velocity of hip extension during concentric phase. Reported per side.

  • Landing Knee Flexion°
    landing_knee_flexion_degPer side
    Zone withheld — no recorded sourceevidence: approximate

    Peak knee flexion angle in the first 100 ms after landing. More flexion means a softer landing.

  • Landing Knee Valgus°
    landing_knee_valgus_degPer side
    Zone withheld — no recorded sourceevidence: consensus

    Peak dynamic knee valgus in the first 100 ms after landing. Frontal-plane knee alignment marker on landing.

  • Landing Hip Flexion°
    landing_hip_flexion_degPer side
    No reference distribution

    Peak hip flexion in the first 100 ms after landing.

  • Landing Trunk Flexion°
    landing_trunk_flexion_deg
    No reference distribution

    Peak trunk flexion angle at landing. Describes the trunk strategy used to absorb the landing.

  • Landing Trunk Lean°
    landing_trunk_lean_deg
    No reference distribution

    Peak lateral trunk lean at landing. A lateral-lean marker for left/right comparison.

  • 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 metrics with normative zone colour bars.

  2. 2

    Metric Zone Overview

    All metrics displayed as gradient zone bars (green/yellow/red).

  3. 3

    Phases & Events

    COM vertical position + velocity with event markers.

  4. 4

    Joint Kinematics

    4-panel grid: trunk, hip (L/R), knee (L/R), pelvis translations.

  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 5 events must be detected with confidence >= 0.5

    cmj_all_events
    Partial

  • Flight phase (toe_off to landing) must be > 100 ms

    cmj_positive_flight
    Blocked

  • Standing start must be detected before countermovement

    cmj_standing_detected
    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 21 metrics can be graded today

8 carry a reference distribution · 8 zones withheld by the evidence gate: 1 × source describes a different population, task or measure, 7 × no recorded source

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.

  • approximate7

    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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