diff --git a/interface/resources/avatar/avatar-animation_withIKNode.json b/interface/resources/avatar/avatar-animation_withIKNode.json
index 04ed593755..13c102a5f1 100644
--- a/interface/resources/avatar/avatar-animation_withIKNode.json
+++ b/interface/resources/avatar/avatar-animation_withIKNode.json
@@ -193,7 +193,9 @@
                                                                                     "alphaVar": "splineIKAlpha",
                                                                                     "enabledVar": "splineIKEnabled",
                                                                                     "endEffectorRotationVarVar": "splineIKRotationVar",
-                                                                                    "endEffectorPositionVarVar": "splineIKPositionVar"
+                                                                                    "endEffectorPositionVarVar": "splineIKPositionVar",
+                                                                                    "primaryFlexCoefficients": "1, 0.5, 0.25, 0.2, 0.1",
+                                                                                    "secondaryFlexCoefficients": "1.0, 0.5, 0.25"
                                                                                 },
                                                                                 "children": [
                                                                                     {
diff --git a/libraries/animation/src/AnimNodeLoader.cpp b/libraries/animation/src/AnimNodeLoader.cpp
index ebe9dbe3ba..c5d17e8884 100644
--- a/libraries/animation/src/AnimNodeLoader.cpp
+++ b/libraries/animation/src/AnimNodeLoader.cpp
@@ -596,12 +596,15 @@ static AnimNode::Pointer loadSplineIKNode(const QJsonObject& jsonObj, const QStr
     READ_STRING(enabledVar, jsonObj, id, jsonUrl, nullptr);
     READ_STRING(endEffectorRotationVarVar, jsonObj, id, jsonUrl, nullptr);
     READ_STRING(endEffectorPositionVarVar, jsonObj, id, jsonUrl, nullptr);
+    READ_STRING(primaryFlexCoefficients, jsonObj, id, jsonUrl, nullptr);
+    READ_STRING(secondaryFlexCoefficients, jsonObj, id, jsonUrl, nullptr);
 
     auto node = std::make_shared<AnimSplineIK>(id, alpha, enabled, interpDuration,
         baseJointName, tipJointName,
         alphaVar, enabledVar, endEffectorRotationVarVar, endEffectorPositionVarVar, 
         basePositionVar, baseRotationVar, 
-        tipPositionVar, tipRotationVar, secondaryTargetJointName, secondaryTargetPositionVar, secondaryTargetRotationVar);
+        tipPositionVar, tipRotationVar, secondaryTargetJointName, secondaryTargetPositionVar, 
+        secondaryTargetRotationVar, primaryFlexCoefficients, secondaryFlexCoefficients);
     return node;
 }
 
diff --git a/libraries/animation/src/AnimSplineIK.cpp b/libraries/animation/src/AnimSplineIK.cpp
index bb3ec654f5..658fa2cf6a 100644
--- a/libraries/animation/src/AnimSplineIK.cpp
+++ b/libraries/animation/src/AnimSplineIK.cpp
@@ -28,7 +28,9 @@ AnimSplineIK::AnimSplineIK(const QString& id, float alpha, bool enabled, float i
     const QString& tipRotationVar,
     const QString& secondaryTargetJointName,
     const QString& secondaryTargetPositionVar,
-    const QString& secondaryTargetRotationVar) :
+    const QString& secondaryTargetRotationVar,
+    const QString& primaryFlexCoefficients,
+    const QString& secondaryFlexCoefficients) :
     AnimNode(AnimNode::Type::SplineIK, id),
     _alpha(alpha),
     _enabled(enabled),
@@ -47,8 +49,25 @@ AnimSplineIK::AnimSplineIK(const QString& id, float alpha, bool enabled, float i
     _tipRotationVar(tipRotationVar),
     _secondaryTargetJointName(secondaryTargetJointName),
     _secondaryTargetPositionVar(secondaryTargetPositionVar),
-    _secondaryTargetRotationVar(secondaryTargetRotationVar) 
+    _secondaryTargetRotationVar(secondaryTargetRotationVar)
 {
+    
+    QStringList flexCoefficientsValues = primaryFlexCoefficients.split(',', QString::SkipEmptyParts);
+    for (int i = 0; i < flexCoefficientsValues.size(); i++) {
+        if (i < MAX_NUMBER_FLEX_VARIABLES) {
+            qCDebug(animation) << "flex value " << flexCoefficientsValues[i].toDouble();
+            _primaryFlexCoefficients[i] = (float)flexCoefficientsValues[i].toDouble();
+        }
+    }
+    _numPrimaryFlexCoefficients = std::min(flexCoefficientsValues.size(), MAX_NUMBER_FLEX_VARIABLES);
+    QStringList secondaryFlexCoefficientsValues = secondaryFlexCoefficients.split(',', QString::SkipEmptyParts);
+    for (int i = 0; i < secondaryFlexCoefficientsValues.size(); i++) {
+        if (i < MAX_NUMBER_FLEX_VARIABLES) {
+            qCDebug(animation) << "secondaryflex value " << secondaryFlexCoefficientsValues[i].toDouble();
+            _secondaryFlexCoefficients[i] = (float)secondaryFlexCoefficientsValues[i].toDouble();
+        }
+    }
+    _numSecondaryFlexCoefficients = std::min(secondaryFlexCoefficientsValues.size(), MAX_NUMBER_FLEX_VARIABLES);
 
 }
 
@@ -145,8 +164,11 @@ const AnimPoseVec& AnimSplineIK::evaluate(const AnimVariantMap& animVars, const
 
         target.setPose(rotation, translation);
         target.setWeight(weight);
+
+   
+
         const float* flexCoefficients = new float[5]{ 1.0f, 0.5f, 0.25f, 0.2f, 0.1f };
-        target.setFlexCoefficients(5, flexCoefficients);
+        target.setFlexCoefficients(_numPrimaryFlexCoefficients, _primaryFlexCoefficients);
     }
 
     AnimChain jointChain;
@@ -182,7 +204,7 @@ const AnimPoseVec& AnimSplineIK::evaluate(const AnimVariantMap& animVars, const
         secondaryTarget.setWeight(weight2);
         
         const float* flexCoefficients2 = new float[3]{ 1.0f, 0.5f, 0.25f };
-        secondaryTarget.setFlexCoefficients(3, flexCoefficients2);
+        secondaryTarget.setFlexCoefficients(_numSecondaryFlexCoefficients, _secondaryFlexCoefficients);
     }
     
     AnimChain secondaryJointChain;
diff --git a/libraries/animation/src/AnimSplineIK.h b/libraries/animation/src/AnimSplineIK.h
index d4dbb85a9e..e00b5a5b04 100644
--- a/libraries/animation/src/AnimSplineIK.h
+++ b/libraries/animation/src/AnimSplineIK.h
@@ -26,7 +26,9 @@ public:
         const QString& tipPositionVar, const QString& tipRotationVar,
         const QString& secondaryTargetJointName,
         const QString& secondaryTargetPositionVar,
-        const QString& secondaryTargetRotationVar);
+        const QString& secondaryTargetRotationVar,
+        const QString& primaryFlexCoefficients,
+        const QString& secondaryFlexCoefficients);
 
 	virtual ~AnimSplineIK() override;
     virtual const AnimPoseVec& evaluate(const AnimVariantMap& animVars, const AnimContext& context, float dt, AnimVariantMap& triggersOut) override;
@@ -65,6 +67,14 @@ protected:
     QString _tipRotationVar;
     QString _secondaryTargetPositionVar;
     QString _secondaryTargetRotationVar;
+    //QString _primaryFlexCoefficients;
+    //QString _secondaryFlexCoefficients;
+
+    static const int MAX_NUMBER_FLEX_VARIABLES = 10;
+    float _primaryFlexCoefficients[MAX_NUMBER_FLEX_VARIABLES];
+    float _secondaryFlexCoefficients[MAX_NUMBER_FLEX_VARIABLES];
+    int _numPrimaryFlexCoefficients { 0 };
+    int _numSecondaryFlexCoefficients { 0 };
 
     int _baseParentJointIndex { -1 };
     int _baseJointIndex { -1 };