Measurement notes
Define immobility as minimal movements needed to remain afloat and specify whether the first minutes are excluded. Keep water temperature, cylinder dimensions, prior exposure, and drying/warming procedures identical across groups.
Endpoint methods library
Stress-coping behavior endpoint
Forced swim immobility
Duration spent floating with only movements needed to keep the head above water during a forced swim test.
Unit
seconds or percent session time
Readout
Time spent immobile or floating during a defined swim epoch
Assays
Forced swim test, antidepressant pharmacology, stress-coping studies
Decision summary
Use forced swim immobility only when the protocol and ethics approval support a stress-coping or pharmacology question. Report it with swimming, climbing, latency, water conditions, and locomotor controls rather than presenting immobility as depression by itself.
| Primary value | Time spent immobile or floating during a defined swim epoch |
|---|---|
| Common units | Seconds, percent session time, latency to immobility, bout count |
| Compatible assays | Forced swim test, antidepressant pharmacology, stress-coping studies |
| Required boundary | Immobility definition, water depth, water temperature, and scoring epoch |
| Do not infer alone | Depression, despair, motivation, fatigue, or antidepressant efficacy without controls |
Interpretation limit
Increased immobility can reflect passive coping, fatigue, hypothermia, motor impairment, prior stress, drug sedation, or altered buoyancy. Reduced immobility can reflect stimulation or panic-like activity rather than a selective antidepressant-like effect.
Data capture
Store animal ID, cylinder dimensions, water depth, water temperature, session duration, scoring epoch, immobility time, swimming time, climbing time, latency, water-change schedule, and exclusion notes.
Confound checks
- Water temperature, depth, cylinder diameter, or lighting differs between animals.
- Prior forced swim exposure, handling, or stress history changes behavior.
- Drug effects on locomotion, thermoregulation, arousal, or motor ability.
- Scorer threshold differs for floating, paddling, climbing, or diving.
- Body weight, coat condition, sex, strain, and age alter buoyancy or fatigue.
Reporting checklist
- Ethics-approved protocol, cylinder dimensions, water depth, temperature, and session length.
- Scoring epoch, immobility definition, manual or automated method, and blinding.
- Swimming, climbing, latency to immobility, total immobility, and exclusion rules.
- Drug or treatment timing, prior swim exposure, handling, and stress timeline.
- Post-test drying, warming, recovery monitoring, and humane endpoints.
- Companion endpoints such as open-field distance, sucrose preference, body weight, or tail suspension.
References
Evidence notes
Endpoint pages should cite the method literature behind the scored value and keep high-specificity protocol claims qualified unless the source supports them.
Related workflow paths
Endpoint articles link to adjacent products, software workflows, and sibling endpoints where the connection is useful and already routable.
Forced swim immobility calculator
Summarize immobility, swimming, climbing, latency, and bout timing.
Distance traveled endpoint
Use locomotor activity to check whether immobility changes reflect motor suppression.
Sucrose preference test calculator
Pair stress-coping data with a natural reward intake endpoint when appropriate.
