diff --git a/src/python/pose_format/utils/normalization_3d.py b/src/python/pose_format/utils/normalization_3d.py
index e7e9d80..0ea6632 100644
--- a/src/python/pose_format/utils/normalization_3d.py
+++ b/src/python/pose_format/utils/normalization_3d.py
@@ -2,7 +2,6 @@
 
 import numpy as np
 import numpy.ma as ma
-from scipy.spatial.transform import Rotation
 
 from pose_format.pose_header import PoseNormalizationInfo
 
@@ -136,8 +135,15 @@ def rotate(self, pose: ma.masked_array, angle: np.ndarray) -> ma.masked_array:
         ma.masked_array
             rotated pose
         """
-        r = Rotation.from_euler('z', -angle[..., np.newaxis], degrees=True)  # Clockwise rotation
-        rotated = np.einsum('...ij,...kj->...ik', pose, r.as_matrix()).reshape(pose.shape)
+        theta = np.radians(-angle)  # Clockwise rotation
+        cos, sin = np.cos(theta), np.sin(theta)
+        rotation_matrix = np.zeros((*theta.shape, 3, 3))
+        rotation_matrix[..., 0, 0] = cos
+        rotation_matrix[..., 0, 1] = -sin
+        rotation_matrix[..., 1, 0] = sin
+        rotation_matrix[..., 1, 1] = cos
+        rotation_matrix[..., 2, 2] = 1
+        rotated = np.einsum('...ij,...kj->...ik', pose, rotation_matrix).reshape(pose.shape)
         return ma.masked_array(rotated, pose.mask)
 
     def scale(self, pose: ma.masked_array) -> ma.masked_array:
diff --git a/src/python/pyproject.toml b/src/python/pyproject.toml
index 5bcd451..1ed2684 100644
--- a/src/python/pyproject.toml
+++ b/src/python/pyproject.toml
@@ -11,7 +11,6 @@ authors = [
 ]
 dependencies = [
     "numpy",
-    "scipy",
     "tqdm",
     "simple-video-utils",
 ]
@@ -21,6 +20,7 @@ requires-python = ">= 3.8"
 dev = [
     "pylint",
     "pytest",
+    "scipy",
     "opencv-python",
     "vidgear",
     "mediapipe<0.10.30",