{"id":"2145b1cf-88d3-5bb3-a806-8f227f8d8080","stable_key":"b3c3f45a-50fb-5b79-98d7-5e5228df00db:cold-cwi-blunts-hypertrophy","predicate":"reduces","statement":"Strength and muscle mass increased more with active recovery than with cold water immersion, with isokinetic work up 19%, type II fibre cross-sectional area up 17% and myonuclei per fibre up 26% in the active recovery group but not the immersion group.","claim_class":"observational","status":"source_derived_draft","evidence_grade":"ungraded","direction":"negative","is_public":true,"mechanism_event_id":"632ae638-af7f-546e-9eb3-db3196c1fa9c","mechanism_event_label":"Twelve weeks of plunging after lifting left people smaller and weaker than not plunging.","subject":{"id":"96a7dff2-caf4-51c1-93c4-c9ed08c05c9a","slug":"cold-water-immersion","display_name":"Cold water immersion","entity_type_key":"drug"},"object":{"id":"dcb80669-6981-57a6-b6e7-b8b18ac2ba61","slug":"muscle-hypertrophy","display_name":"Skeletal muscle fibre hypertrophy","entity_type_key":"cellular_process"},"evidence_count":1,"mechanism_event":{"id":"632ae638-af7f-546e-9eb3-db3196c1fa9c","stable_key":"b3c3f45a-50fb-5b79-98d7-5e5228df00db:cold-cwi-blunts-hypertrophy-event","event_type":"observed_intervention","label":"Twelve weeks of plunging after lifting left people smaller and weaker than not plunging.","description":"Strength and muscle mass increased more with active recovery than with cold water immersion, with isokinetic work up 19%, type II fibre cross-sectional area up 17% and myonuclei per fibre up 26% in the active recovery group but not the immersion group.","status":"provisional","compartment":null,"participants":[{"entity":{"id":"f8868e74-0596-516b-b9f8-e9bce977e5bc","slug":"muscle-fiber-area","display_name":"Skeletal-muscle fiber cross-sectional area","entity_type_key":"cellular_process"},"role":"measured_property","stoichiometry":null,"state_label":"","sequence_order":0,"notes":""},{"entity":{"id":"2dff91a1-bdc1-550c-82cc-e8d63132b7a5","slug":"myonuclei-per-fibre","display_name":"Number of myonuclei per muscle fibre","entity_type_key":"cellular_process"},"role":"measured_property","stoichiometry":null,"state_label":"","sequence_order":1,"notes":""},{"entity":{"id":"1392689d-e3eb-58fe-9f1d-ea0e426c5b13","slug":"skeletal-muscle-strength","display_name":"Skeletal muscle strength","entity_type_key":"cellular_process"},"role":"affected_outcome","stoichiometry":null,"state_label":"","sequence_order":2,"notes":""},{"entity":{"id":"96a7dff2-caf4-51c1-93c4-c9ed08c05c9a","slug":"cold-water-immersion","display_name":"Cold water immersion","entity_type_key":"drug"},"role":"subject","stoichiometry":null,"state_label":"","sequence_order":3,"notes":""},{"entity":{"id":"dcb80669-6981-57a6-b6e7-b8b18ac2ba61","slug":"muscle-hypertrophy","display_name":"Skeletal muscle fibre hypertrophy","entity_type_key":"cellular_process"},"role":"target","stoichiometry":null,"state_label":"","sequence_order":4,"notes":""}]},"contexts":[{"dimension":"evidence_span","value_text":"{\"source_cache\": \"artifacts/cold-research/26174323.abstract.txt\", \"locator\": \"Indexed abstract; zero-based, end-exclusive Unicode character offsets\", \"file_sha256\": \"91eff53ecc4779637af3d6fd47a67892729e3a896fdc8738f69d1c7936b4787d\", \"start_char\": 0, \"end_char\": 1595, \"text_sha256\": \"91eff53ecc4779637af3d6fd47a67892729e3a896fdc8738f69d1c7936b4787d\"}","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"experimental_model","value_text":"Twelve weeks of strength training in 21 men with immersion or active recovery, plus a biopsy study in nine men","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"exposure","value_text":"10 minutes of cold water immersion after each training session, twice weekly for 12 weeks","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"limitations","value_text":"A randomised training study with muscle biopsies. It measures long-term adaptation rather than acute recovery, which is why it can disagree with the soreness literature without contradicting it.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"nutrient_topic","value_text":"Cold water immersion research collection; topical membership is not evidence of a direct clinical effect, and a therapeutic exposure is not a dietary intake.","comparator":null,"unit":null,"notes":"","entity":{"slug":"cold-water-immersion","display_name":"Cold water immersion","entity_type_key":"drug"}},{"dimension":"organism","value_text":"Human","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"plain_language","value_text":"Twelve weeks of plunging after lifting left people smaller and weaker than not plunging.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"primary_references","value_text":"[cold-p26174323] Post-exercise cold water immersion attenuates acute anabolic signalling and long-term adaptations in muscle to strength training. (2015). https://pubmed.ncbi.nlm.nih.gov/26174323/ DOI: 10.1113/jp270570","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"tissue_or_cell_type","value_text":"Skeletal muscle","comparator":null,"unit":null,"notes":"","entity":null}],"evidence":[{"id":"818ed118-b4ab-56f9-9be6-90782531e8d2","evidence_kind":"source_excerpt","locator":"Lines 806-817","start_line":806,"end_line":817,"excerpt":"### cold-cwi-blunts-hypertrophy\nStrength and muscle mass increased more with active recovery than with cold water immersion, with isokinetic work up 19%, type II fibre cross-sectional area up 17% and myonuclei per fibre up 26% in the active recovery group but not the immersion group.\nCondition category: normal\nnutrient_topic: Cold water immersion research collection; topical membership is not evidence of a direct clinical effect, and a therapeutic exposure is not a dietary intake.\nplain_language: Twelve weeks of plunging after lifting left people smaller and weaker than not plunging.\norganism: Human\ntissue_or_cell_type: Skeletal muscle\nexperimental_model: Twelve weeks of strength training in 21 men with immersion or active recovery, plus a biopsy study in nine men\nlimitations: A randomised training study with muscle biopsies. It measures long-term adaptation rather than acute recovery, which is why it can disagree with the soreness literature without contradicting it.\nexposure: 10 minutes of cold water immersion after each training session, twice weekly for 12 weeks\nevidence_span: {\"source_cache\": \"artifacts/cold-research/26174323.abstract.txt\", \"locator\": \"Indexed abstract; zero-based, end-exclusive Unicode character offsets\", \"file_sha256\": \"91eff53ecc4779637af3d6fd47a67892729e3a896fdc8738f69d1c7936b4787d\", \"start_char\": 0, \"end_char\": 1595, \"text_sha256\": \"91eff53ecc4779637af3d6fd47a67892729e3a896fdc8738f69d1c7936b4787d\"}\n[cold-p26174323] Post-exercise cold water immersion attenuates acute anabolic signalling and long-term adaptations in muscle to strength training. (2015). https://pubmed.ncbi.nlm.nih.gov/26174323/ DOI: 10.1113/jp270570","model_system":"Twelve weeks of strength training in 21 men with immersion or active recovery, plus a biopsy study in nine men","directness":"author_interpretation","verification_status":"source_derived_draft","notes":"Exact curation-document quotation, not publisher quotation. Study references: [cold-p26174323] Post-exercise cold water immersion attenuates acute anabolic signalling and long-term adaptations in muscle to strength training. (2015). https://pubmed.ncbi.nlm.nih.gov/26174323/ DOI: 10.1113/jp270570","relationship":"supports","weight":1.0,"link_notes":"","source":{"id":"feeccadc-1392-573e-a0b5-0939ee5de6e2","stable_key":"import-b3c3f45a-50fb-5b79-98d7-5e5228df00db","title":"Cold water immersion: cold sensing, heat production, the catecholamine axis and what repeated exposure changes (2026-09-19)","document_type":"imported_text","citation_label":"AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text.","file_path":"","sha256":"557f074d372c49c502c34e648651aff7ebf2c8816305d2d2f08e338a7e96a5f0","revision_id":"ecc19e8d-40db-5b5d-b98e-0507f645976c","review_status":"unverified_draft","notes":""}}],"relations":[],"conflicts":[{"id":"37816a62-c117-5f5c-8508-0ec6e75b192f","title":"Does cold water immersion after resistance training cost strength, or only fibre size?","kind":"contradiction","status":"open","why":"Two randomised training studies agree that post-exercise immersion attenuates type II fibre hypertrophy and blunts anabolic signalling. They disagree on whether strength follows: a twelve-week study found strength and muscle mass increased more with active recovery, while a seven-week whole-body study found one-repetition maximum leg press improvements similar between groups despite attenuated fibre growth. Training duration, exercise selection, the comparison condition (active versus passive recovery) and the strength test differ between them. Which difference accounts for the disagreement is not established.","resolution":"Unresolved; needs review.","created_at":"2026-09-20 03:49:50","record_type":"conflict","display_label":"Recorded conflict","record_url":"/conflicts/37816a62-c117-5f5c-8508-0ec6e75b192f","sides":[{"conflict_id":"37816a62-c117-5f5c-8508-0ec6e75b192f","ordinal":0,"label":"Twelve weeks of plunging after lifting left people smaller and weaker than not plunging.","revision_id":"ecc19e8d-40db-5b5d-b98e-0507f645976c","start_line":806,"end_line":817,"quote":"### cold-cwi-blunts-hypertrophy\nStrength and muscle mass increased more with active recovery than with cold water immersion, with isokinetic work up 19%, type II fibre cross-sectional area up 17% and myonuclei per fibre up 26% in the active recovery group but not the immersion group.\nCondition category: normal\nnutrient_topic: Cold water immersion research collection; topical membership is not evidence of a direct clinical effect, and a therapeutic exposure is not a dietary intake.\nplain_language: Twelve weeks of plunging after lifting left people smaller and weaker than not plunging.\norganism: Human\ntissue_or_cell_type: Skeletal muscle\nexperimental_model: Twelve weeks of strength training in 21 men with immersion or active recovery, plus a biopsy study in nine men\nlimitations: A randomised training study with muscle biopsies. It measures long-term adaptation rather than acute recovery, which is why it can disagree with the soreness literature without contradicting it.\nexposure: 10 minutes of cold water immersion after each training session, twice weekly for 12 weeks\nevidence_span: {\"source_cache\": \"artifacts/cold-research/26174323.abstract.txt\", \"locator\": \"Indexed abstract; zero-based, end-exclusive Unicode character offsets\", \"file_sha256\": \"91eff53ecc4779637af3d6fd47a67892729e3a896fdc8738f69d1c7936b4787d\", \"start_char\": 0, \"end_char\": 1595, \"text_sha256\": \"91eff53ecc4779637af3d6fd47a67892729e3a896fdc8738f69d1c7936b4787d\"}\n[cold-p26174323] Post-exercise cold water immersion attenuates acute anabolic signalling and long-term adaptations in muscle to strength training. (2015). https://pubmed.ncbi.nlm.nih.gov/26174323/ DOI: 10.1113/jp270570","source_key":"import-b3c3f45a-50fb-5b79-98d7-5e5228df00db","source_title":"Cold water immersion: cold sensing, heat production, the catecholamine axis and what repeated exposure changes (2026-09-19)","claim_ids":["2145b1cf-88d3-5bb3-a806-8f227f8d8080"]},{"conflict_id":"37816a62-c117-5f5c-8508-0ec6e75b192f","ordinal":1,"label":"Here the cold cost fibre size but not the weight people could lift.","revision_id":"ecc19e8d-40db-5b5d-b98e-0507f645976c","start_line":832,"end_line":843,"quote":"### cold-cwi-strength-preserved\nImprovements in one-repetition maximum leg press were similar between immersion and control groups, whereas increases in type II muscle fibre cross-sectional area were attenuated with immersion.\nCondition category: normal\nnutrient_topic: Cold water immersion research collection; topical membership is not evidence of a direct clinical effect, and a therapeutic exposure is not a dietary intake.\nplain_language: Here the cold cost fibre size but not the weight people could lift.\norganism: Human\ntissue_or_cell_type: Skeletal muscle\nexperimental_model: Sixteen men completing seven weeks of whole-body resistance training with immersion or passive recovery\nlimitations: A second training study with molecular endpoints. It reproduces the fibre-size result but not the strength result, which is the disagreement recorded in this collection.\nexposure: 15 minutes at 10 degrees C after each session, three days a week for seven weeks\nevidence_span: {\"source_cache\": \"artifacts/cold-research/31513450.abstract.txt\", \"locator\": \"Indexed abstract; zero-based, end-exclusive Unicode character offsets\", \"file_sha256\": \"f39d3b6bef4879805e7aab7b14df67921ac12765af5d4466836936039ad7a872\", \"start_char\": 0, \"end_char\": 2195, \"text_sha256\": \"f39d3b6bef4879805e7aab7b14df67921ac12765af5d4466836936039ad7a872\"}\n[cold-p31513450] Cold water immersion attenuates anabolic signaling and skeletal muscle fiber hypertrophy, but not strength gain, following whole-body resistance training. (2019). https://pubmed.ncbi.nlm.nih.gov/31513450/ DOI: 10.1152/japplphysiol.00127.2019","source_key":"import-b3c3f45a-50fb-5b79-98d7-5e5228df00db","source_title":"Cold water immersion: cold sensing, heat production, the catecholamine axis and what repeated exposure changes (2026-09-19)","claim_ids":["c22ad7be-db0b-5acd-b205-ec0fd0381390"]}]}],"corrections":[],"research":null}