diff --git a/train.py b/train.py
index d4bfc08d..9cd25a39 100644
--- a/train.py
+++ b/train.py
@@ -237,11 +237,15 @@ def train():
             imgs = imgs.to(device).float() / 255.0  # uint8 to float32, 0 - 255 to 0.0 - 1.0
             targets = targets.to(device)
 
-            # Hyperparameter burn-in
-            # n_burn = 100  # number of burn-in batches
-            # if ni < n_burn:
-            #     for x in optimizer.param_groups:
-            #         x['lr'] = x['initial_lr'] * (ni / n_burn) ** 4  # gain rises from 0 - 1
+            # Hyperparameter Burn-in
+            n_burn = 100  # number of burn-in batches
+            if ni <= n_burn:
+                g = (ni / n_burn) ** 4  # gain
+                for x in model.named_modules():
+                    if x[0].endswith('BatchNorm2d'):
+                        x[1].momentum = 1 - 0.9 * g  # momentum falls from 1 - 0.1
+                for x in optimizer.param_groups:
+                    x['lr'] = x['initial_lr'] * g  # gain rises from 0 - 1
 
             # Plot images with bounding boxes
             if ni < 1: