diff --git a/rowers/datautils.py b/rowers/datautils.py
index 0be51d35..376c8d2d 100644
--- a/rowers/datautils.py
+++ b/rowers/datautils.py
@@ -180,7 +180,7 @@ def getmaxwattinterval(tt,ww,i):
             if testres:
                 deltat = 1.0e-3*(t_0-t_1)
                 wmax = w_roll.ix[indexmax]
-                if wmax > 800:
+                if wmax > 800 or wmax > 800/(5.0e04*deltat):
                     wmax = 0
             else:
                 wmax = 0