diff --git a/src/models/CertificateRunner.ts b/src/models/CertificateRunner.ts
index 937536e..a30b356 100644
--- a/src/models/CertificateRunner.ts
+++ b/src/models/CertificateRunner.ts
@@ -1,23 +1,16 @@
 import {
-    IsArray,
-    IsInt
+    IsArray
 } from "class-validator";
+import { DistanceDonation } from './DistanceDonation';
 import { Runner } from './Runner';
 
 /**
  * Defines the certificate runner class (from which the runner certificates get generated).
 */
 export class CertificateRunner extends Runner {
-
-    /**
-     * The total distance ran by the runner.
-     */
-    @IsInt()
-    distance: number;
-
     /**
      * Array containing all distance donations associated with the runner.
      */
     @IsArray()
-    distanceDonations: any[];
+    distanceDonations: DistanceDonation[];
 }
diff --git a/src/models/Runner.ts b/src/models/Runner.ts
index fec6235..826941a 100644
--- a/src/models/Runner.ts
+++ b/src/models/Runner.ts
@@ -38,4 +38,10 @@ export class Runner {
      */
     @IsObject()
     group: RunnerGroup;
+
+    /**
+     * The total distance ran by the runner.
+     */
+    @IsInt()
+    distance: number;
 }