diff --git a/src/models/entities/Runner.ts b/src/models/entities/Runner.ts
index 1c509d6..5c51c11 100644
--- a/src/models/entities/Runner.ts
+++ b/src/models/entities/Runner.ts
@@ -18,7 +18,7 @@ export class Runner extends Participant {
    * Can be a runner team or organisation.
    */
   @IsNotEmpty()
-  @ManyToOne(() => RunnerGroup, group => group.runners, { nullable: false })
+  @ManyToOne(() => RunnerGroup, group => group.runners)
   group: RunnerGroup;
 
   /**