in: Featured, Fitness, Health & Fitness

• Last updated: October 1, 2023

WWII Workout Week: The Importance of Physical Fitness

Vintage Soldiers doing Obstacle course Climing Wall.

In times of war, physical fitness becomes a matter of national vigilance and honor, only to invariably become a low priority during peace. This has been true in every age. When millions of Americans were called up to serve in the military during WWII, it quickly became clear that the advancement of modern civilization had left many men unfit for battle. While we bemoan our sedentary culture today, labor-saving devices and white collar work were already affecting the physical fitness of the nation’s men. One third of recruits were rejected for service over the course of the war, and fully one half of the first two million draftees failed to make the cut — 90% for medical and fitness reasons. Colonel Leonard G. Rowntree, medical director of the Selective Service, noted that “Many of the registrants were found to be pampered, soft, flabby, and in need of conditioning.”

Even amongst the men who made it in, it soon became clear that the basic training program then being utilized by the armed services was inadequate for getting soldiers ready for the rigors of the battlefield.

The military knew something had to be done to get recruits toughened up and combat ready. They appealed to high schools to incorporate more fitness classes and began a campaign to motivate young men to get in shape and to be ready to serve when the time came. They also sought to overhaul the physical training program recruits underwent during boot camp. In 1941, FM 21-20, a new physical training manual was released, but its program still wasn’t up to par. As men returned from combat, they encouraged the military to better prepare soldiers to thrive on the battlefield by increasing the intensity of the physical training they received before going overseas.

Physical Efficieency Matrix.

“Physical Efficiency Matrix,” FM 21-20, 1941

Health and fitness experts from colleges around the country were asked to conduct empirical studies on which tests best correlated to combat readiness, and which programs were most effective in increasing soldiers’ strength, endurance, and mobility. Their recommendations were implemented during the war, and then codified in a revised version of FM 21-20 in 1946. The new program was focused on progressively getting the soft and flabby up to speed and took a balanced approach that made “total military fitness” its goal. Rowntree declared the program was designed to produce “strength, endurance, stamina, special agilities, leadership, initiative, emotional stability, and the ‘will to win.’” The use of an obstacle course was introduced, and the program also emphasized the employment of fitness tests. Physical aptitude assessments were thought useful in identifying a man’s current status and areas of weakness, tracking progress, and introducing an element of competition into training that would motivate the men to beat their own scores and those of their peers.

I love reading through FM 21-20. The manual is full of a wide variety of interesting workouts, and offers both practical guidance on new exercises to try and inspiration on why to stay in shape and how to be a good leader as well. And it’s a surprisingly enjoyable read – especially for an old army field manual that’s almost 70 years old!

Each day this week we’ll be publishing excerpts from FM 21-20. First up is the manual’s introduction on the importance of physical fitness. While the language is obviously directed at a military audience, when you give it some thought, you’ll find many timeless parallels to civilian life today; even if you’re not about to storm the beaches of Normandy, there are many compelling reasons to stay strong.

The rest of the week, we’ll publish a different WWII-era workout each day. Maybe they’ll inspire you to try them wholesale, or perhaps they’ll just motivate you to work out, period. If you want to see how your current fitness stacks up to the GIs of old, you can find the FM 21-20 assessment test here.

Fm 21-20 army field manual Physical training.

FM 20-21: War Department Field Manual, 1946


PURPOSE AND SCOPE. This manual contains ready reference data for use in planning physical training programs for troops. The contents consist principally of brief descriptions and illustrations of various types of physical training activities. There are also suggestions on the planning and administration of physical training programs to fit various conditions and on effective physical fitness testing.


Total fitness for war includes technical fitness, mental and emotional fitness, and physical fitness. All of these attributes of total military fitness must be combined in the well trained soldier. If any are lacking, the soldier’s combat effectiveness suffers proportionately. Without technical fitness a soldier lacks the knowledge and skill to fight; without mental and emotional fitness he lacks the incentive and desire to fight; without physical fitness he lacks the strength and stamina to fight.


a. Military leaders have always recognized that the effectiveness of fighting men depends to a large degree upon their physical condition. War places a great premium upon the strength, stamina, agility, and coordination of the soldier because victory and his life are so often dependent upon them. Warfare is a grueling ordeal for soldiers and makes many severe physical demands upon them. To march long distances with full pack, weapons, and ammunition through rugged country and to fight effectively upon arriving at the area of combat; to drive fast-moving tanks and motor vehicles over rough terrain; to make assaults and to run and crawl for long distances, to jump into and out of fox holes, craters, and trenches, and over obstacles; to lift and carry heavy objects; to keep going for many hours without sleep or rest — all these activities of warfare and many others require superbly conditioned troops.

b. The fact that warfare has become mechanized has accentuated rather than minimized the importance of physical fitness. Soldiers must still perform most of the arduous tasks which fighting men for thousands of years have had to do. There are always places where mechanized units cannot maneuver, tasks which they cannot accomplish, and situations in which equipment becomes disabled. Furthermore, the machines are no better than the men operating them. Every new advance in the speed, maneuverability, striking power, durability, and destructiveness of our machines must be accompanied by a corresponding improvement in the quality and fitness of their operators.

c. Physical fitness is important from another point of view. A close relationship exists between physical fitness and mental and emotional fitness or morale. Fatigue, weakness, lack of stamina, and physical exhaustion are usually associated with a low state of morale. The rugged, tough, well-conditioned soldier has a feeling of fitness and confidence, and he is much less susceptible to many of the factors which undermine morale.


a. Freedom from disease and defect. Freedom from anatomical defect or disease, the discovery and treatment of which are functions of the medical department, is the first requirement of physical fitness. Physiological soundness, however, does not in itself constitute physical fitness; it is merely the foundation upon which physical fitness is built. Before a soldier is fit for combat operations good health and the absence of handicapping defects must be supplemented by strength, endurance, agility and coordination.

b. Strength.

(1) Every soldier must have sufficient strength for the heaviest tasks he may encounter in routine and emergency activities. Arduous military duties require a considerable degree of leg, back, abdominal and arm and shoulder girdle strength.

(2) Muscles increase in size and strength with regular and strenuous exercise. They atrophy and grow weaker when not exercised. Strength is best developed in muscles when their power of contracting is challenged by maximum loads. The closer a muscle works to its capacity load, the greater will be its development of strength. Strenuous conditioning exercises, rifle and log exercises, weight lifting, wrestling, and sprint running are excellent strength-developing activities.

c. Endurance. Every soldier needs enough endurance to go through the most rigorous day without undue fatigue and to complete the most strenuous duty to which he may be assigned. There are two types of endurance:

(1) Muscular endurance. This type of endurance permits an individual to continue strenuous activity for many hours without undue fatigue. The soldier needs muscular endurance to make long marches, to keep going for hours on end, and to perform the fatiguing duties of battle. Muscular endurance is characterized by a greater than average amount of muscular strength and an enriched blood capillary network within the muscles. This network makes it possible for the blood stream to deliver increased amounts of oxygen and nutrition to the muscle mass, and to carry away waste products more rapidly. The kinds of exercise needed to build up muscular endurance are the same as those indicated under strength.

(2) Circulo-respiratory endurance. This type of endurance is required for prolonged activity at more than normal speed, such as long distance running. The soldier needs circulo-respiratory endurance when he must cover a considerable distance at great speed. It is composed of muscular endurance plus an increased efficiency in the functioning of the heart, vascular system, and lungs. Running is the best way to develop circulo-respiratory endurance.

d. Agility. Agility is characterized by an ability to change direction and the position of the body in space with great rapidity. It enables the soldier to fall to the ground or leap to his feet quickly; it makes him a fraction of a second faster at ducking into a fox hole or into a trench under sudden machine gun fire; it is of great value in hand-to-hand fighting. This important constituent of physical fitness is best developed by conditioning exercises which require extensive and rapid changes of position, and by such activities as tumbling, sports and games and combative activities.

e. Coordination. Coordination is the ability to integrate all parts of the body into efficient, purposeful effort. In the well coordinated individual, superfluous movements are eliminated, precision and accuracy are increased, energy is conserved, and endurance increased.


The physical fitness required of the soldier can be acquired only through physical training. The performance of purely military exercises such as drill and marching, is not alone sufficient to bring the soldier up to the desired standard of physical fitness. Experience has demonstrated that few recruits enter the Army physically fit for the arduous duties ahead of them. The softening influences of our modern machine civilization make the problem of conditioning men more important than ever before. Within the Army itself labor-saving devices and mechanized equipment exert the same debilitating effect. If troops are to be brought up to the desired standard of physical fitness, a well-conceived plan of physical training must be an integral part of every-training program. In no other way will the soldier be adequately prepared for the strenuous duties associated with military service.


a. If there is a proper concept of physical fitness, the physical training program will be directed toward the total conditioning of all the men. Since physical fitness includes strength, endurance, agility and coordination, it is apparent that no one activity is sufficient for its full development. Marching is a splendid conditioning activity, but it alone is not sufficient for the conditioning of troops because it does not adequately develop abdominal, arm and shoulder girdle strength, agility, coordination, or the type of endurance which is called for in running. Supplementary exercises are required if total physical conditioning is to be achieved.

b. The quality of a unit is determined by the over-all picture of physical condition and total military fitness of all its members. It is more important that all men in a unit receive the benefits of a balanced and well directed program of physical training than that a few members achieve record performances. The physical training program, therefore, is directed toward the total conditioning of all men.

OBJECTIVES OF THE PHYSICAL TRAINING PROGRAM. The primary purpose of a physical training program is to develop and maintain a high level of physical fitness among the troops. However, while attaining this fundamental purpose, other valuable outcomes may be obtained.

a. It is possible to develop through physical training many basic military skills which are essential to personal safety or to effective performance in combat operations. Swimming, running, jumping, vaulting, climbing, crawling, both with and without equipment are basic skills which should be taught to or further developed in all soldiers. Maneuverability, alertness, and ability to anticipate may be the means of saving a soldier’s life and these can be developed through boxing, wrestling, and· other competitive activities.

b. Teamwork, aggressiveness, confidence, resourcefulness, a will to win, unit solidarity, and the ability to think and act quickly under pressure are other valuable products of the well conducted program of physical training.

c. Recreation is another important objective of physical training provided it can be accomplished without sacrificing the physical fitness value of the program. Interesting and enjoyable physical activities not only provide a desirable diversion in the daily routine, but they also motivate men to participate more enthusiastically in the total physical training program.


a. The low level of physical fitness of most recruits now entering service makes it necessary to devote more time to their conditioning than was formerly required. A daily period of at least 1 hour (1.5 hours is recommended when training schedules permit) is required for this purpose until the troops acquire satisfactory condition. This will usually take from 10 to 15 weeks, depending upon the condition of the men at the outset. Once attained, a high level of fitness can be maintained on a somewhat reduced daily schedule when necessary, provided the time allotted for this purpose is properly used.

b. It is the unit commander’s responsibility to ascertain that the time allotted to physical training is effectively used for that purpose. The complexities of modern warfare require so much technical training that all too frequently there is a tendency to subordinate physical training to other training activities. The utilization of physical training time for other training activities, or for routine military duties, is an unsound and unwise practice.


a. Mental and Emotional Health.

(1) Physical health cannot be dissociated from mental and emotional health. Ill health is almost as often due to conditions of the mind and emotions resulting in bodily ailment as it is due to purely physical causes. Therefore, some consideration must be given to mental and emotional as well as physical hygiene.

(2) A healthy state of mind is characterized by cheerfulness, confidence and interest. An unhealthy state of mind is characterized by indifference, discouragement, worry, and a feeling of inferiority which may be due to lack of success or progress. Physical training can help to develop healthy mental states if:

(a) The instructor is a worthy example to his men.
(b) The instructor has an understanding, fair, and sympathetic attitude.
(c) Work is interesting and varied.
(d) Work is arranged to result in gradual and progressive development.
(e) Individual physiological differences are considered.

b. Personal Habits. Proper personal habits, such as cleanliness, proper eating, rest, and elimination should be stressed during instruction in physical training. The matter of a well-balanced diet is of particular importance. Many men increase their weight to such an extent that their physical condition is impaired. Proper diet is as important as exercise in improving the physical condition of men who are considerably overweight.

Read the Entire Series

Conditioning Exercises

Related Posts