diff --git a/src/fw/services/normal/activity/docs/index.md b/src/fw/services/normal/activity/docs/index.md
index 51f8c5a0..1feb3294 100644
--- a/src/fw/services/normal/activity/docs/index.md
+++ b/src/fw/services/normal/activity/docs/index.md
@@ -26,7 +26,7 @@ The spectral density of that same walk sample, showing the amount of energy pres
 
 _Note that the y axis on this plot is not simply Power, but rather “Power / Average Power”, where “Average Power” is the average power of that particular signal._
 
-![Spectral Density](spectial_density.png)
+![Spectral Density](spectral_density.png)
 
 You can see in the above spectral density plot that the dominant frequency in this example is 1Hz, corresponding to the 5 arm swings that occurred in these 5 seconds. 
 
diff --git a/src/fw/services/normal/activity/docs/spectial_density.png b/src/fw/services/normal/activity/docs/spectral_density.png
similarity index 100%
rename from src/fw/services/normal/activity/docs/spectial_density.png
rename to src/fw/services/normal/activity/docs/spectral_density.png