backend/calculations/body_metrics.py

@@ -223,6 +223,11 @@ def calculate_arm_28d_delta(profile_id: str) -> Optional[float]:
     return _calculate_circumference_delta(profile_id, 'c_arm', 28)
 
 
+def calculate_arm_relaxed_28d_delta(profile_id: str) -> Optional[float]:
+    """28-day relaxed arm circumference change (cm)."""
+    return _calculate_circumference_delta(profile_id, 'c_arm_relaxed', 28)
+
+
 def calculate_thigh_28d_delta(profile_id: str) -> Optional[float]:
     """Calculate 28-day thigh circumference change (cm)"""
     delta = _calculate_circumference_delta(profile_id, 'c_thigh', 28)

backend/data_layer/__init__.py

@@ -70,6 +70,7 @@ __all__ = [
     'calculate_hip_28d_delta',
     'calculate_chest_28d_delta',
     'calculate_arm_28d_delta',
+    'calculate_arm_relaxed_28d_delta',
     'calculate_thigh_28d_delta',
     'calculate_waist_hip_ratio',
     'calculate_recomposition_quadrant',

backend/data_layer/body_metrics.py

@@ -370,7 +370,8 @@ def get_circumference_summary_data(
             ('c_hip', 'Hüfte'),
             ('c_thigh', 'Oberschenkel'),
             ('c_calf', 'Wade'),
-            ('c_arm', 'Arm')
+            ('c_arm', 'Oberarm kontrahiert'),
+            ('c_arm_relaxed', 'Oberarm'),
         ]
 
         measurements = []
@@ -401,7 +402,7 @@ def get_circumference_summary_data(
                 })
 
         # Calculate confidence based on how many points we have
-        confidence = calculate_confidence(len(measurements), 8, "general")
+        confidence = calculate_confidence(len(measurements), 9, "general")
 
         if not measurements:
             return {
@@ -640,10 +641,15 @@ def calculate_chest_28d_delta(profile_id: str) -> Optional[float]:
 
 
 def calculate_arm_28d_delta(profile_id: str) -> Optional[float]:
-    """Calculate 28-day arm circumference change (cm)"""
+    """28-Tage-Delta Oberarm kontrahiert (c_arm), cm."""
     return _calculate_circumference_delta(profile_id, 'c_arm', 28)
 
 
+def calculate_arm_relaxed_28d_delta(profile_id: str) -> Optional[float]:
+    """28-Tage-Delta Oberarm entspannt (c_arm_relaxed), cm."""
+    return _calculate_circumference_delta(profile_id, 'c_arm_relaxed', 28)
+
+
 def calculate_thigh_28d_delta(profile_id: str) -> Optional[float]:
     """Calculate 28-day thigh circumference change (cm)"""
     delta = _calculate_circumference_delta(profile_id, 'c_thigh', 28)

backend/migrations/059_circumference_c_arm_relaxed.sql

@@ -0,0 +1,5 @@
+-- Zusätzlicher Umfang: Oberarm entspannt (c_arm = historisch / Oberarm kontrahiert)
+ALTER TABLE circumference_log ADD COLUMN IF NOT EXISTS c_arm_relaxed NUMERIC(5,2);
+
+COMMENT ON COLUMN circumference_log.c_arm IS 'Oberarmumfang kontrahiert/angespannt (bestehende Daten)';
+COMMENT ON COLUMN circumference_log.c_arm_relaxed IS 'Oberarmumfang entspannt';

backend/models.py

@@ -50,6 +50,7 @@ class CircumferenceEntry(BaseModel):
     c_thigh: Optional[float] = None
     c_calf: Optional[float] = None
     c_arm: Optional[float] = None
+    c_arm_relaxed: Optional[float] = None
     notes: Optional[str] = None
     photo_id: Optional[str] = None
 

backend/placeholder_registrations/body_metrics.py

@@ -18,9 +18,10 @@ Body Composition (5):
 - waist_hip_ratio
 - recomposition_quadrant
 
-Circumference Deltas (5):
+Circumference Deltas (6):
 - waist_28d_delta
-- arm_28d_delta
+- arm_28d_delta (Oberarm kontrahiert, c_arm)
+- arm_relaxed_28d_delta (Oberarm entspannt, c_arm_relaxed)
 - chest_28d_delta
 - hip_28d_delta
 - thigh_28d_delta
@@ -1033,14 +1034,14 @@ def register_body_metrics():
 
     arm_28d_delta_metadata = PlaceholderMetadata(
         key="arm_28d_delta",
-        description="Armumfang Änderung 28d (cm)",
+        description="Oberarm kontrahiert (c_arm): Umfangs-Änderung 28d (cm)",
         resolver_function="_safe_float('arm_28d_delta', decimals=1)",
         data_layer_function="calculate_arm_28d_delta",
         semantic_contract=(
-            "Liefert die Veränderung des Armumfangs in Zentimetern über 28 Tage. "
-            "Positive Werte bedeuten Zunahme, negative Werte Reduktion."
+            "Veränderung des kontrahierten/angespannten Oberarmumfangs (Spalte c_arm) in cm über 28 Tage. "
+            "Entspricht historischen Einträgen „Arm“ vor Einführung des zweiten Messpunkts."
         ),
-        business_meaning="Ergänzender Umfangsindikator für detaillierte Körperentwicklungsanalysen",
+        business_meaning="Arm-Umfang unter Anspannung (z. B. leicht gebeugter Arm, Bizeps leicht aktiv)",
         unit="cm",
         example_output="+0.6",
         **circumference_delta_common
@@ -1054,6 +1055,30 @@ def register_body_metrics():
     arm_28d_delta_metadata.set_evidence("example_output", EvidenceType.DRAFT_DERIVED)
     register_placeholder(arm_28d_delta_metadata)
 
+    # ── arm_relaxed_28d_delta ────────────────────────────────────────────────
+
+    arm_relaxed_28d_delta_metadata = PlaceholderMetadata(
+        key="arm_relaxed_28d_delta",
+        description="Oberarm entspannt (c_arm_relaxed): Umfangs-Änderung 28d (cm)",
+        resolver_function="_safe_float('arm_relaxed_28d_delta', decimals=1)",
+        data_layer_function="calculate_arm_relaxed_28d_delta",
+        semantic_contract=(
+            "Veränderung des entspannten Oberarmumfangs (Spalte c_arm_relaxed) in cm über 28 Tage."
+        ),
+        business_meaning="Arm-Umfang bei locker hängendem Arm ohne zusätzliche Muskelanspannung",
+        unit="cm",
+        example_output="+0.3",
+        **circumference_delta_common
+    )
+    arm_relaxed_28d_delta_metadata.evidence.update(circ_delta_evidence)
+    arm_relaxed_28d_delta_metadata.set_evidence("resolver_function", EvidenceType.CODE_DERIVED)
+    arm_relaxed_28d_delta_metadata.set_evidence("data_layer_function", EvidenceType.CODE_DERIVED)
+    arm_relaxed_28d_delta_metadata.set_evidence("semantic_contract", EvidenceType.DRAFT_DERIVED)
+    arm_relaxed_28d_delta_metadata.set_evidence("business_meaning", EvidenceType.DRAFT_DERIVED)
+    arm_relaxed_28d_delta_metadata.set_evidence("unit", EvidenceType.CODE_DERIVED)
+    arm_relaxed_28d_delta_metadata.set_evidence("example_output", EvidenceType.DRAFT_DERIVED)
+    register_placeholder(arm_relaxed_28d_delta_metadata)
+
     # ── chest_28d_delta ──────────────────────────────────────────────────────
 
     chest_28d_delta_metadata = PlaceholderMetadata(

backend/placeholder_resolver.py

@@ -749,7 +749,8 @@ _SAFE_FLOAT_NONE_REASON: Dict[str, str] = {
     "waist_28d_delta": "Taillen-Delta 28 Tage nicht berechenbar (zwei auswertbare Messungen nötig)",
     "hip_28d_delta": "Hüft-Delta 28 Tage nicht berechenbar",
     "chest_28d_delta": "Brust-Delta 28 Tage nicht berechenbar",
-    "arm_28d_delta": "Arm-Delta 28 Tage nicht berechenbar",
+    "arm_28d_delta": "Oberarm kontrahiert: Delta 28 Tage nicht berechenbar",
+    "arm_relaxed_28d_delta": "Oberarm entspannt: Delta 28 Tage nicht berechenbar",
     "thigh_28d_delta": "Oberschenkel-Delta 28 Tage nicht berechenbar",
     "waist_hip_ratio": "Taille-Hüfte-Verhältnis nicht berechenbar",
     "energy_balance_7d": (
@@ -913,6 +914,7 @@ def _safe_float(func_name: str, profile_id: str, decimals: int = 1) -> str:
             'hip_28d_delta': body_metrics.calculate_hip_28d_delta,
             'chest_28d_delta': body_metrics.calculate_chest_28d_delta,
             'arm_28d_delta': body_metrics.calculate_arm_28d_delta,
+            'arm_relaxed_28d_delta': body_metrics.calculate_arm_relaxed_28d_delta,
             'thigh_28d_delta': body_metrics.calculate_thigh_28d_delta,
             'waist_hip_ratio': body_metrics.calculate_waist_hip_ratio,
             'energy_balance_7d': nutrition_metrics.calculate_energy_balance_7d,
@@ -1556,6 +1558,7 @@ PLACEHOLDER_MAP: Dict[str, Callable[[str], str]] = {
     '{{hip_28d_delta}}': lambda pid: _safe_float('hip_28d_delta', pid),
     '{{chest_28d_delta}}': lambda pid: _safe_float('chest_28d_delta', pid),
     '{{arm_28d_delta}}': lambda pid: _safe_float('arm_28d_delta', pid),
+    '{{arm_relaxed_28d_delta}}': lambda pid: _safe_float('arm_relaxed_28d_delta', pid),
     '{{thigh_28d_delta}}': lambda pid: _safe_float('thigh_28d_delta', pid),
     '{{waist_hip_ratio}}': lambda pid: _safe_float('waist_hip_ratio', pid, decimals=3),
     '{{recomposition_quadrant}}': lambda pid: _safe_str('recomposition_quadrant', pid),
@@ -1785,7 +1788,7 @@ def get_available_placeholders(categories: Optional[List[str]] = None) -> Dict[s
             '{{weight_7d_median}}', '{{weight_28d_slope}}', '{{weight_90d_slope}}',
             '{{fm_28d_change}}', '{{lbm_28d_change}}',
             '{{waist_28d_delta}}', '{{hip_28d_delta}}', '{{chest_28d_delta}}',
-            '{{arm_28d_delta}}', '{{thigh_28d_delta}}',
+            '{{arm_28d_delta}}', '{{arm_relaxed_28d_delta}}', '{{thigh_28d_delta}}',
             '{{waist_hip_ratio}}', '{{recomposition_quadrant}}',
             '{{body_progress_score}}',
         ],

backend/routers/circumference.py

@@ -67,10 +67,10 @@ def upsert_circ(e: CircumferenceEntry, x_profile_id: Optional[str]=Header(defaul
             # INSERT new entry
             eid = str(uuid.uuid4())
             cur.execute("""INSERT INTO circumference_log
-                (id,profile_id,date,c_neck,c_chest,c_waist,c_belly,c_hip,c_thigh,c_calf,c_arm,notes,photo_id,created)
-                VALUES (%s,%s,%s,%s,%s,%s,%s,%s,%s,%s,%s,%s,%s,CURRENT_TIMESTAMP)""",
+                (id,profile_id,date,c_neck,c_chest,c_waist,c_belly,c_hip,c_thigh,c_calf,c_arm,c_arm_relaxed,notes,photo_id,created)
+                VALUES (%s,%s,%s,%s,%s,%s,%s,%s,%s,%s,%s,%s,%s,%s,CURRENT_TIMESTAMP)""",
                 (eid,pid,d['date'],d['c_neck'],d['c_chest'],d['c_waist'],d['c_belly'],
-                 d['c_hip'],d['c_thigh'],d['c_calf'],d['c_arm'],d['notes'],d['photo_id']))
+                 d['c_hip'],d['c_thigh'],d['c_calf'],d['c_arm'],d.get('c_arm_relaxed'),d['notes'],d['photo_id']))
 
             # Phase 2: Increment usage counter (only for new entries)
             increment_feature_usage(pid, 'circumference_entries')

backend/routers/exportdata.py

@@ -312,14 +312,38 @@ Datumsformat: YYYY-MM-DD
             cur.execute("SELECT id, date, weight, note, source, created FROM weight_log WHERE profile_id=%s ORDER BY date", (pid,))
             write_csv(zf, "weight.csv", [r2d(r) for r in cur.fetchall()], ['id','date','weight','note','source','created'])
 
-            cur.execute("SELECT id, date, c_waist, c_hip, c_chest, c_neck, c_arm, c_thigh, c_calf, notes, created FROM circumference_log WHERE profile_id=%s ORDER BY date", (pid,))
+            cur.execute(
+                "SELECT id, date, c_waist, c_hip, c_chest, c_neck, c_arm, c_arm_relaxed, c_thigh, c_calf, notes, created FROM circumference_log WHERE profile_id=%s ORDER BY date",
+                (pid,),
+            )
             rows = [r2d(r) for r in cur.fetchall()]
             for r in rows:
                 r['waist'] = r.pop('c_waist', None); r['hip'] = r.pop('c_hip', None)
                 r['chest'] = r.pop('c_chest', None); r['neck'] = r.pop('c_neck', None)
-                r['upper_arm'] = r.pop('c_arm', None); r['thigh'] = r.pop('c_thigh', None)
+                r['upper_arm_contracted'] = r.pop('c_arm', None)
+                r['upper_arm_relaxed'] = r.pop('c_arm_relaxed', None)
+                r['thigh'] = r.pop('c_thigh', None)
                 r['calf'] = r.pop('c_calf', None); r['forearm'] = None; r['note'] = r.pop('notes', None)
-            write_csv(zf, "circumferences.csv", rows, ['id','date','waist','hip','chest','neck','upper_arm','thigh','calf','forearm','note','created'])
+            write_csv(
+                zf,
+                "circumferences.csv",
+                rows,
+                [
+                    'id',
+                    'date',
+                    'waist',
+                    'hip',
+                    'chest',
+                    'neck',
+                    'upper_arm_contracted',
+                    'upper_arm_relaxed',
+                    'thigh',
+                    'calf',
+                    'forearm',
+                    'note',
+                    'created',
+                ],
+            )
 
             cur.execute("SELECT id, date, sf_chest, sf_abdomen, sf_thigh, sf_triceps, sf_subscap, sf_suprailiac, sf_axilla, sf_method, body_fat_pct, notes, created FROM caliper_log WHERE profile_id=%s ORDER BY date", (pid,))
             rows = [r2d(r) for r in cur.fetchall()]

backend/routers/importdata.py

@@ -112,12 +112,17 @@ async def import_zip(
                         csv_data = zf.read('data/circumferences.csv').decode('utf-8-sig')
                         reader = csv.DictReader(io.StringIO(csv_data), delimiter=';')
                         for row in reader:
+                            _ua_contr = (
+                                row.get('upper_arm_contracted')
+                                or row.get('upper_arm')
+                            )
+                            _ua_rel = row.get('upper_arm_relaxed')
                             cur.execute("""
                                 INSERT INTO circumference_log (
                                     profile_id, date, c_waist, c_hip, c_chest, c_neck,
-                                    c_arm, c_thigh, c_calf, notes, created
+                                    c_arm, c_arm_relaxed, c_thigh, c_calf, notes, created
                                 )
-                                VALUES (%s, %s, %s, %s, %s, %s, %s, %s, %s, %s, %s)
+                                VALUES (%s, %s, %s, %s, %s, %s, %s, %s, %s, %s, %s, %s)
                                 ON CONFLICT (profile_id, date) DO NOTHING
                             """, (
                                 pid,
@@ -126,7 +131,8 @@ async def import_zip(
                                 float(row['hip']) if row.get('hip') else None,
                                 float(row['chest']) if row.get('chest') else None,
                                 float(row['neck']) if row.get('neck') else None,
-                                float(row['upper_arm']) if row.get('upper_arm') else None,
+                                float(_ua_contr) if _ua_contr not in (None, '') else None,
+                                float(_ua_rel) if _ua_rel not in (None, '') else None,
                                 float(row['thigh']) if row.get('thigh') else None,
                                 float(row['calf']) if row.get('calf') else None,
                                 row.get('note', ''),

backend/schema.sql

@@ -104,6 +104,7 @@ CREATE TABLE IF NOT EXISTS circumference_log (
     c_thigh     NUMERIC(5,2),
     c_calf      NUMERIC(5,2),
     c_arm       NUMERIC(5,2),
+    c_arm_relaxed NUMERIC(5,2),
     notes       TEXT,
     photo_id    UUID,
     created     TIMESTAMP WITH TIME ZONE DEFAULT CURRENT_TIMESTAMP

frontend/src/pages/CircumScreen.jsx

@@ -6,10 +6,10 @@ import { CIRCUMFERENCE_POINTS } from '../utils/guideData'
 import UsageBadge from '../components/UsageBadge'
 import dayjs from 'dayjs'
 
-const FIELDS = ['c_neck','c_chest','c_waist','c_belly','c_hip','c_thigh','c_calf','c_arm']
-const LABELS = {c_neck:'Hals',c_chest:'Brust',c_waist:'Taille',c_belly:'Bauch',c_hip:'Hüfte',c_thigh:'Oberschenkel',c_calf:'Wade',c_arm:'Oberarm'}
+const FIELDS = ['c_neck','c_chest','c_waist','c_belly','c_hip','c_thigh','c_calf','c_arm','c_arm_relaxed']
+const LABELS = {c_neck:'Hals',c_chest:'Brust',c_waist:'Taille',c_belly:'Bauch',c_hip:'Hüfte',c_thigh:'Oberschenkel',c_calf:'Wade',c_arm:'Oberarm kontrahiert',c_arm_relaxed:'Oberarm'}
 
-function empty() { return {date:dayjs().format('YYYY-MM-DD'), c_neck:'',c_chest:'',c_waist:'',c_belly:'',c_hip:'',c_thigh:'',c_calf:'',c_arm:'',notes:'',photo_id:''} }
+function empty() { return {date:dayjs().format('YYYY-MM-DD'), c_neck:'',c_chest:'',c_waist:'',c_belly:'',c_hip:'',c_thigh:'',c_calf:'',c_arm:'',c_arm_relaxed:'',notes:'',photo_id:''} }
 
 export default function CircumScreen() {
   const [entries, setEntries] = useState([])

frontend/src/pages/MeasureWizard.jsx

@@ -387,7 +387,7 @@ export default function MeasureWizard() {
           <div>
             <div style={{fontSize:16,fontWeight:600}}>Umfänge messen</div>
             <div style={{fontSize:12,color:'var(--text3)',marginTop:2}}>
-              8 Messpunkte · Hals, Brust, Taille, Bauch, Hüfte, Oberschenkel, Wade, Oberarm
+              9 Messpunkte · inkl. Oberarm kontrahiert + Oberarm entspannt
             </div>
           </div>
           <ChevronRight size={20} style={{marginLeft:'auto',color:'var(--text3)'}}/>

frontend/src/pages/NewMeasurement.jsx

@@ -53,7 +53,7 @@ export default function NewMeasurement() {
     date: dayjs().format('YYYY-MM-DD'),
     weight: null,
     c_neck:null, c_chest:null, c_waist:null, c_belly:null,
-    c_hip:null, c_thigh:null, c_calf:null, c_arm:null,
+    c_hip:null, c_thigh:null, c_calf:null, c_arm:null, c_arm_relaxed:null,
     sf_method:'jackson3',
     sf_chest:null, sf_axilla:null, sf_triceps:null, sf_subscap:null,
     sf_suprailiac:null, sf_abdomen:null, sf_thigh:null,
@@ -132,7 +132,7 @@ export default function NewMeasurement() {
 
       {/* Umfänge */}
       <Section title="Umfänge" open={openSections.circum} onToggle={()=>toggle('circum')}
-        hint="Hals, Brust, Taille, Bauch, Hüfte, Oberschenkel, Wade, Oberarm">
+        hint="Hals, Brust, Taille, Bauch, Hüfte, Oberschenkel, Wade, Oberarm (kontrahiert + entspannt)">
         {CIRCUMFERENCE_POINTS.map(p => (
           <NumInput key={p.id} label={p.label}
             guideText={p.where.length > 50 ? p.where.substring(0,48)+'…' : p.where}

frontend/src/utils/calc.js

@@ -228,11 +228,16 @@ export const CIRCUMFERENCE_GUIDE = [
     posture:'Aufrecht, Gewicht gleichmäßig verteilt',
     how:'Waagerecht, Muskel entspannt',
     tip:'Morgens messen – abends schwellen Beine durch Wassereinlagerungen an' },
-  { id:'c_arm',   name:'Oberarm',      color:'#1D9E75',
+  { id:'c_arm',   name:'Oberarm kontrahiert', color:'#1D9E75',
     where:'Dickste Stelle, Mitte zwischen Schultergelenk und Ellenbogen',
-    posture:'Arm locker hängen lassen und entspannen',
+    posture:'Ellenbogen leicht gebeugt, Bizeps leicht angespannt',
     how:'Waagerecht, senkrecht zur Längsachse',
-    tip:'Immer denselben Arm (rechts); auch angespannt messen und notieren' },
+    tip:'Bestehende Messreihen = kontrahiert' },
+  { id:'c_arm_relaxed', name:'Oberarm', color:'#2E7D57',
+    where:'Gleiche Stelle wie kontrahiert',
+    posture:'Arm locker hängen, ohne Anspannung',
+    how:'Waagerecht',
+    tip:'Entspannte Messung für Vergleich zur Kontraktionsmessung' },
 ]
 
 export const CALIPER_GUIDE = {

frontend/src/utils/guideData.js

@@ -50,11 +50,18 @@ export const CIRCUMFERENCE_POINTS = [
     tip: 'Morgens messen – gegen Abend schwellen Beine durch Wassereinlagerungen an'
   },
   {
-    id: 'c_arm', label: 'Oberarm', color: '#1D9E75',
+    id: 'c_arm', label: 'Oberarm kontrahiert', color: '#1D9E75',
     where: 'An der dicksten Stelle des Oberarms – Mitte zwischen Schultergelenk und Ellenbogen',
-    posture: 'Arm locker hängen lassen und entspannen',
-    how: 'Waagerecht anlegen, senkrecht zur Längsachse des Arms',
-    tip: 'Immer denselben Arm messen (meist rechts) – beide Werte notieren (entspannt & angespannt)'
+    posture: 'Ellenbogen leicht gebeugt, Bizeps leicht anspannen (wie leichter „Kraft-Griff“)',
+    how: 'Waagerecht anlegen, Maßband ohne Luftspalt, nicht einschneidend',
+    tip: 'Historische Einträge beziehen sich auf diesen Wert (angespannter Arm)'
+  },
+  {
+    id: 'c_arm_relaxed', label: 'Oberarm', color: '#2E7D57',
+    where: 'Gleiche Stelle wie beim kontrahierten Messpunkt – dickste Stelle, Mitte Oberarm',
+    posture: 'Arm locker und gerade hängen lassen, Schulter entspannt, kein Spannen',
+    how: 'Waagerecht anlegen; vorher tief einatmen und normal ausatmen, dann messen',
+    tip: 'Typischer „Alltags“-Umfang ohne extra Muskelanspannung'
   },
 ]