diff --git a/backend/routers/clubs.py b/backend/routers/clubs.py
index 7507709..bca67e9 100644
--- a/backend/routers/clubs.py
+++ b/backend/routers/clubs.py
@@ -5,6 +5,7 @@ Handles CRUD operations for clubs, divisions, and training groups.
 """
 from typing import Any, List, Optional
 from fastapi import APIRouter, HTTPException, Depends, Query
+from psycopg2.extras import Json
 
 from db import get_db, get_cursor, r2d
 from tenant_context import TenantContext, get_tenant_context
@@ -39,6 +40,33 @@ def _optional_int(value: Any) -> Optional[int]:
     return i if i > 0 else None
 
 
+def _normalize_co_trainer_ids(val: Any) -> List[int]:
+    """Listen von Profil-IDs für JSONB; ungültige Einträge werden verworfen."""
+    if val is None:
+        raw: List[Any] = []
+    elif isinstance(val, list):
+        raw = val
+    else:
+        raw = []
+    out: List[int] = []
+    seen = set()
+    for x in raw:
+        try:
+            i = int(x)
+        except (TypeError, ValueError):
+            continue
+        if i <= 0 or i in seen:
+            continue
+        seen.add(i)
+        out.append(i)
+    return out
+
+
+def _co_trainer_ids_jsonb(val: Any) -> Json:
+    """psycopg2: reine list/dict für JSONB → ProgrammingError ohne Json()."""
+    return Json(_normalize_co_trainer_ids(val))
+
+
 # ── List Clubs ────────────────────────────────────────────────────────
 @router.get("/clubs")
 def list_clubs(
@@ -609,8 +637,7 @@ def create_training_group(data: dict, tenant: TenantContext = Depends(get_tenant
         trainer_id = _optional_int(raw_tid)
 
     division_id = _optional_int(data.get("division_id"))
-    co_raw = data.get("co_trainer_ids")
-    co_trainer_ids = [] if co_raw is None else co_raw
+    co_json = _co_trainer_ids_jsonb(data.get("co_trainer_ids"))
 
     with get_db() as conn:
         cur = get_cursor(conn)
@@ -633,7 +660,7 @@ def create_training_group(data: dict, tenant: TenantContext = Depends(get_tenant
             ) VALUES (
                 %s, %s, %s, %s, %s, %s,
                 %s, %s, %s, %s,
-                %s, %s, %s
+                %s, %s::jsonb, %s
             ) RETURNING id
         """,
             (
@@ -648,7 +675,7 @@ def create_training_group(data: dict, tenant: TenantContext = Depends(get_tenant
                 _blank_to_none(data.get("time_end")),
                 _blank_to_none(data.get("location")),
                 trainer_id,
-                co_trainer_ids,
+                co_json,
                 data.get("status") or "active",
             ),
         )
@@ -689,9 +716,7 @@ def update_training_group(group_id: int, data: dict, tenant: TenantContext = Dep
         if not allowed:
             raise HTTPException(403, "Keine Berechtigung")
 
-        co_upd = data.get("co_trainer_ids")
-        if co_upd is None:
-            co_upd = []
+        co_json = _co_trainer_ids_jsonb(data.get("co_trainer_ids"))
 
         cur.execute(
             """
@@ -706,7 +731,7 @@ def update_training_group(group_id: int, data: dict, tenant: TenantContext = Dep
                 time_end = %s,
                 location = %s,
                 trainer_id = %s,
-                co_trainer_ids = %s,
+                co_trainer_ids = %s::jsonb,
                 status = %s,
                 updated_at = NOW()
             WHERE id = %s
@@ -722,7 +747,7 @@ def update_training_group(group_id: int, data: dict, tenant: TenantContext = Dep
                 _blank_to_none(data.get("time_end")),
                 _blank_to_none(data.get("location")),
                 _optional_int(data.get("trainer_id")),
-                co_upd,
+                co_json,
                 data.get("status") or "active",
                 group_id,
             ),