diff --git a/glm/gtx/easing.hpp b/glm/gtx/easing.hpp
index 83cbc4db..b0d20afc 100644
--- a/glm/gtx/easing.hpp
+++ b/glm/gtx/easing.hpp
@@ -171,29 +171,41 @@ namespace glm{
 	template <typename genType>
 	GLM_FUNC_DECL genType elasticEaseInOut(genType const & a);
 
-	/// @param o Optional overshoot modifier
 	/// @see gtx_easing
 	template <typename genType>
-	GLM_FUNC_DECL genType backEaseIn(genType const & a, genType const & o = 1.70158f);
+	GLM_FUNC_DECL genType backEaseIn(genType const& a);
+
+	/// @see gtx_easing
+	template <typename genType>
+	GLM_FUNC_DECL genType backEaseOut(genType const& a);
+
+	/// @see gtx_easing
+	template <typename genType>
+	GLM_FUNC_DECL genType backEaseInOut(genType const& a);
 
 	/// @param o Optional overshoot modifier
 	/// @see gtx_easing
 	template <typename genType>
-	GLM_FUNC_DECL genType backEaseOut(genType const & a, genType const & o = 1.70158f);
+	GLM_FUNC_DECL genType backEaseIn(genType const& a, genType const& o);
 
 	/// @param o Optional overshoot modifier
 	/// @see gtx_easing
 	template <typename genType>
-	GLM_FUNC_DECL genType backEaseInOut(genType const & a, genType const & o = 1.70158f);
+	GLM_FUNC_DECL genType backEaseOut(genType const& a, genType const& o);
+
+	/// @param o Optional overshoot modifier
+	/// @see gtx_easing
+	template <typename genType>
+	GLM_FUNC_DECL genType backEaseInOut(genType const& a, genType const& o);
 
 	template <typename genType>
-	GLM_FUNC_DECL genType bounceEaseIn(genType const & a);
+	GLM_FUNC_DECL genType bounceEaseIn(genType const& a);
 
 	template <typename genType>
-	GLM_FUNC_DECL genType bounceEaseOut(genType const & a);
+	GLM_FUNC_DECL genType bounceEaseOut(genType const& a);
 
 	template <typename genType>
-	GLM_FUNC_DECL genType bounceEaseInOut(genType const & a, genType);
+	GLM_FUNC_DECL genType bounceEaseInOut(genType const& a, genType);
 
 	/// @}
 }//namespace glm
diff --git a/glm/gtx/easing.inl b/glm/gtx/easing.inl
index 984e4a9e..4ea32c59 100644
--- a/glm/gtx/easing.inl
+++ b/glm/gtx/easing.inl
@@ -361,6 +361,24 @@ namespace glm{
 		}
 	}
 
+	template <typename genType>
+	GLM_FUNC_QUALIFIER genType backEaseIn(genType const& a)
+	{
+		return backEaseIn(a, static_cast<genType>(1.70158));
+	}
+
+	template <typename genType>
+	GLM_FUNC_QUALIFIER genType backEaseOut(genType const& a)
+	{
+		return backEaseOut(a, static_cast<genType>(1.70158));
+	}
+
+	template <typename genType>
+	GLM_FUNC_QUALIFIER genType backEaseInOut(genType const& a)
+	{
+		return backEaseInOut(a, static_cast<genType>(1.70158));
+	}
+
 	template <typename genType>
 	GLM_FUNC_QUALIFIER genType bounceEaseOut(genType const& a)
 	{
diff --git a/test/gtx/gtx_easing.cpp b/test/gtx/gtx_easing.cpp
index 90455811..79e6661a 100644
--- a/test/gtx/gtx_easing.cpp
+++ b/test/gtx/gtx_easing.cpp
@@ -13,39 +13,39 @@ namespace
 		T r;
 
 		r = glm::linearInterpolation(a);
-		//
+
 		r = glm::quadraticEaseIn(a);
 		r = glm::quadraticEaseOut(a);
 		r = glm::quadraticEaseInOut(a);
-		//
+
 		r = glm::cubicEaseIn(a);
 		r = glm::cubicEaseOut(a);
 		r = glm::cubicEaseInOut(a);
-		//
+
 		r = glm::quarticEaseIn(a);
 		r = glm::quarticEaseOut(a);
 		r = glm::quinticEaseInOut(a);
-		//
+
 		r = glm::sineEaseIn(a);
 		r = glm::sineEaseOut(a);
 		r = glm::sineEaseInOut(a);
-		//
+
 		r = glm::circularEaseIn(a);
 		r = glm::circularEaseOut(a);
 		r = glm::circularEaseInOut(a);
-		//
+
 		r = glm::exponentialEaseIn(a);;
 		r = glm::exponentialEaseOut(a);
 		r = glm::exponentialEaseInOut(a);
-		//
+
 		r = glm::elasticEaseIn(a);
 		r = glm::elasticEaseOut(a);
 		r = glm::elasticEaseInOut(a);
-		//
+
 		r = glm::backEaseIn(a);
 		r = glm::backEaseOut(a);
 		r = glm::backEaseInOut(a);
-		//
+
 		r = glm::bounceEaseIn(a);;
 		r = glm::bounceEaseOut(a);
 		r = glm::bounceEaseInOut(a);