As tensions rise in Eastern Europe, the North Atlantic Treaty Organization has announced it is putting its defense of the continent on hold until the U.S. Army formally implements the Army Combat Fitness Test.

“While defending the western world from a resurgent and belligerent Russia is important, it is much more important that every soldier completes this holistic assessment of their physical fitness,” NATO Secretary General Jens Stoltenberg said. “We wouldn’t want someone defending Europe if they couldn’t do leg tucks.”

No other country or U.S. military service has plans to implement the ACFT. Experts say this puts NATO at a major strategic disadvantage. An Army with a fully operational ACFT is the only thing capable of fighting off an armored invasion of Ukraine.