diff --git a/rowers/dataprep.py b/rowers/dataprep.py
index 26684810..57c9d176 100644
--- a/rowers/dataprep.py
+++ b/rowers/dataprep.py
@@ -1053,14 +1053,22 @@ def checkbreakthrough(w, r):
         cpdf, delta, cpvalues = setcp(w)
         if not cpdf.empty:
             if workouttype in otwtypes:
-                res, btvalues, res2 = utils.isbreakthrough(
-                    delta, cpvalues, r.p0, r.p1, r.p2, r.p3, r.cpratio)
-                _ = update_rolling_cp(r, otwtypes, 'water')
+                try:
+                    res, btvalues, res2 = utils.isbreakthrough(
+                        delta, cpvalues, r.p0, r.p1, r.p2, r.p3, r.cpratio)
+                    _ = update_rolling_cp(r, otwtypes, 'water')
+                except ValueError:
+                    res = 0
+                    res2 = 0
 
             elif workouttype in otetypes:
-                res, btvalues, res2 = utils.isbreakthrough(
-                    delta, cpvalues, r.ep0, r.ep1, r.ep2, r.ep3, r.ecpratio)
-                _ = update_rolling_cp(r, otetypes, 'erg')
+                try:
+                    res, btvalues, res2 = utils.isbreakthrough(
+                        delta, cpvalues, r.ep0, r.ep1, r.ep2, r.ep3, r.ecpratio)
+                    _ = update_rolling_cp(r, otetypes, 'erg')
+                except ValueError:
+                    res = 0
+                    res2 = 0
             else:  # pragma: no cover
                 res = 0
                 res2 = 0