Rucking & Military Fitness Glossary

A

ACFT (Army Combat Fitness Test)

The U.S. Army's fitness test from 2022 until it was replaced by the AFT on June 1, 2025. If you're looking for current standards, use the AFT calculator — the events and scoring tables changed between the two tests.

AFT (Army Fitness Test)

The Army's current official fitness test, effective June 2025. Five events — 3-rep max deadlift, hand-release push-up, sprint-drag-carry, plank, and a 2-mile run — each scored 0-100 points. See our AFT calculator.

ALICE Pack

All-Purpose Lightweight Individual Carrying Equipment — the U.S. military's external-frame rucksack system used from the Vietnam era into the 1990s, later succeeded by MOLLE. Still popular as a budget option; reviewed in our backpack buying guide.

Approach March Load

The weight a soldier carries while moving to initial contact with the enemy, heavier than a fighting load but lighter than a full sustainment load. See our military rucksack weight guide for how this compares to other load categories.

B

Bataan Memorial Death March

An annual marathon-distance (26.2-mile) memorial ruck event held in White Sands, New Mexico, honoring the World War II Bataan Death March survivors. Covered in our rucking events guide.

Battle Rattle

Informal military slang for a soldier's full combat equipment load — body armor, helmet, weapon, and gear — worn or carried together.

C

CFT (Combat Fitness Test)

The Marine Corps' combat-movement fitness test, alongside the PFT. Three events: Movement to Contact, Ammunition Can Lift, and Maneuver Under Fire. See our CFT calculator.

Combat Load

The total weight a service member carries into combat, including weapon, ammunition, body armor, and mission-essential equipment. See our military rucksack weight guide for real-world combat load figures.

D

Deadlift (3-Rep Max)

The first AFT event: lifting a hex-bar deadlift for 3 repetitions at the heaviest weight the Soldier can manage, testing lower-body and core strength. See our AFT calculator.

F

Fighting Load

The lightest standard military load category — weapon, ammunition, and immediate-fight essentials only, without a full rucksack. See our military rucksack weight guide.

Forced March

A ruck march conducted at a faster-than-normal pace, often under time pressure, to cover distance quickly while carrying a load. See our military ruck standards guide.

Foot March

The U.S. Army's official doctrinal term for a ruck march — see ATP 3-21.18, Foot Marches. Functionally the same as what's commonly called a "ruck march" or "rucking."

G

GORUCK

A gear brand and event organizer known for team-based endurance events built around rucking (Light, Tough, Heavy, and Selection, in increasing difficulty). See our rucking events guide and backpack reviews.

Grenade Throw (MANUF)

A target-accuracy component of the Marine Corps' Maneuver Under Fire event. A hit subtracts 5 seconds from the Marine's overall time; a miss adds 5 seconds. See our CFT calculator.

H

Hand-Release Push-Up (HRP)

A push-up variant where hands lift fully off the ground at the bottom of each rep, used on the Army AFT and as an option on the Marine Corps PFT, to prevent "bouncing" through a shortened range of motion.

Heart Rate Reserve (HRR)

The difference between your maximum and resting heart rate, used in the Karvonen method to calculate personalized training zones. See our Zone 2 rucking guide.

Hip Belt

The padded belt on a rucksack that transfers load onto the hips and pelvis rather than the shoulders. A properly fitted hip belt can carry roughly 70-80% of total pack weight. See our back pain and posture guide.

I

ILBE (Improved Load Bearing Equipment)

The Marine Corps' main rucksack and load-carriage system, introduced in the mid-2000s to replace older ALICE-based gear. Mentioned in our backpack buying guide.

K

Karvonen Method

A 1957 formula for calculating a target heart rate training zone using heart rate reserve rather than a flat percentage of max heart rate, making it more personalized to your own fitness level. See our Zone 2 rucking guide.

Keytel Formula

A 2005 heart-rate-based formula for estimating calories burned during exercise. Our calorie calculator shows this as an optional second estimate alongside the Pandolf equation.

L

Load Carriage

The general term for carrying weight (a pack, equipment, or both) while moving on foot — the broader category of physical activity that rucking and military foot marches both belong to.

LBE (Load-Bearing Equipment)

General military term for the harnesses, vests, and belts used to carry gear on the body, separate from the main rucksack.

M

MANUF (Maneuver Under Fire)

A timed Marine Corps CFT event combining sprinting, crawling, a casualty drag/carry, an ammo can carry, and a grenade throw. See our CFT calculator.

MOLLE (Modular Lightweight Load-carrying Equipment)

The webbing and attachment system used on most modern military packs and vests, allowing pouches and accessories to be added or rearranged. Succeeded the older ALICE system. See our backpack buying guide.

MTC (Movement to Contact)

An 880-yard sprint event on the Marine Corps CFT, simulating closing the distance to enemy contact. See our CFT calculator.

N

Norwegian Foot March

A demanding foot march standard adopted from the Norwegian military, requiring roughly 18.6 miles (30 km) carrying a weighted pack and rifle within a strict time limit, worn as a badge by those who complete it under U.S. military programs that offer it.

P

Pandolf Equation

A 1977 U.S. Army load-carriage formula (Pandolf, Givoni & Goldman) that estimates metabolic energy cost from body weight, load weight, walking speed, and terrain. The core calculation behind our rucking calorie calculator.

Pace

Your speed expressed as time per unit distance (minutes per mile), the inverse of speed in mph. See our rucking pace guide.

PFT (Physical Fitness Test)

The Marine Corps' general fitness test, alongside the CFT. Three events: a choice of pull-ups or push-ups, the plank, and a 3-mile run. See our PFT calculator.

PFRA (Physical Fitness and Readiness Assessment)

The Air Force's fitness test, effective March 2026, replacing the previous three-component assessment. Four weighted components including body composition. See our PFRA pass/fail checker.

Plank (Forearm)

A core-endurance hold used on the Army AFT, Marine Corps PFT, Navy PRT, and Air Force PFRA — maintaining a straight-body position supported on forearms and toes for as long as possible.

PRT (Physical Readiness Test)

The Navy's fitness test: push-ups, the forearm plank, and a cardio event (usually the 1.5-mile run). Scored in discrete categories from Probationary to Outstanding rather than a continuous point scale. See our PRT calculator.

R

Ranger School

The U.S. Army's premier leadership and small-unit tactics course, with demanding ruck march requirements throughout. See our Ranger ruck standards guide.

RASP (Ranger Assessment and Selection Program)

The selection course for soldiers seeking to join a Ranger battalion, including a graded 12-mile ruck march. See our Ranger ruck standards guide.

Ruck / Rucking

Walking or marching with a weighted pack (a "ruck") for fitness or military training. The core activity this entire site is built around — start with our rucking calculator.

Ruck March

A march covering a set distance while carrying a weighted rucksack, often against a time standard. See our military ruck standards guide for requirements by branch.

Ruck Plate

A flat, rigid weight (steel or urethane-coated) designed to sit against the back inside a rucksack, a common alternative to sandbags or water for adding training weight. See our essential gear guide.

S

SFAS (Special Forces Assessment and Selection)

The multi-week selection course for soldiers seeking to join Army Special Forces, including a long culminating ruck march. See our Special Forces ruck standards guide.

Sprint-Drag-Carry (SDC)

An AFT event combining a sprint, a weighted sled drag, a lateral shuffle, and a loaded carry, testing anaerobic power and work capacity. See our AFT calculator.

Sustainment Load

The heaviest standard military load category, including everything needed to operate independently for an extended period — the full rucksack loadout. See our military rucksack weight guide.

V

VO2 Max

The maximum rate at which your body can use oxygen during intense exercise, a standard marker of aerobic fitness. Zone 2 training is one approach to improving it over time. See our Zone 2 rucking guide.

W

WHtR (Waist-to-Height Ratio)

A body composition measurement (waist circumference divided by height) used by the Air Force's PFRA as part of its fitness score. See our PFRA checker.

Z

Zone 2

A low-intensity "easy aerobic" heart-rate training zone, roughly 60-70% of max heart rate, where the body relies mostly on fat and oxygen for energy. Building time in this zone improves aerobic base. See our Zone 2 rucking guide.