diff --git a/src/models/entities/RunnerGroup.ts b/src/models/entities/RunnerGroup.ts
index 5620aca..332bd33 100644
--- a/src/models/entities/RunnerGroup.ts
+++ b/src/models/entities/RunnerGroup.ts
@@ -51,6 +51,9 @@ export abstract class RunnerGroup {
   */
   @IsInt()
   public get distance(): number {
+    if (!this.runners || this.runners.length == 0) {
+      return 0;
+    }
     return this.runners.reduce((sum, current) => sum + current.distance, 0);
   }