Norwegian conscripts undergoing basic military training. Scand J .... largest number of acute injuries, like sprains and strains ... Both acute and overuse inju- ... Concussion. 4. 0.3. 0.3 ..... ment of an ambulatory recorder for evaluation of muscle.
Copyright 0 Munksgaard 1996
Scand J M e d Sci Sports 1996: 6: 186-191
Scandinuoiun J o u r n a l of M E D I C I N E & SCIENCE I N SPORTS 1SSN 0905-7188
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Epidemiology of musculoskeletal injuries among Norwegian conscripts undergoing basic military training Heir T, Glomsaker P. Epidemiology of musculoskeletal injuries among Norwegian conscripts undergoing basic military training. Scand J Med Sci Sports 1996: 6: 186-191.0 Munksgaard, 1996 Compulsory military service entails a change in the patterns of physical activity of many conscripts, and an accompanying risk of musculoskeletal injury. The present study was carried out to determine the incidence and types of musculoskeletal injury among Norwegian conscripts, and their consequences in the form of sick leave and discharge from the service. The study population consisted of 6488 conscripts in all, drawn from the Army, the Air Force and the Navy. They were monitored through an initial 6-10-week period of basic military and physical training. Every injury for which a conscript had to consult a doctor was registered. Slightly more than every fourth Army, every fifth Air Force and every eighth Navy conscript suffered one or more injuries during basic training. Incidence rates for the Army, Air Force and Navy respectively were 15.3, 13.4 and 9.3 injuries per 100 conscript-months. The sites of the majority of the injuries were in the lower limbs (63%). The most common types of injury were low back pain; overuse knee injuries; Achilles tendinitis; sprains of joint capsules or ligaments; and periostitis or compartment syndromes of lower leg. In the doctors' opinions, contributory or triggering causes of the injuries could be attributed to organized service activities in 67% of the cases. The number of days of partial or total sick leave as a result of injury amounted to 3.4% and 0.2% respectively of the total basic training period. Of Army, Air Force and Navy conscripts, 23%, 16% and 11% respectively had sick leave. Injury was also the direct cause of the discharge of 2.1% of the Army conscripts and 0.1% of the Air Force and Navy conscripts. The results of the study show that musculoskeletal injuries occur frequently during basic training and that injuries contribute to lost training time.
Physical strength and endurance are held to be important elements of military preparedness (1). The armed forces therefore attach great importance to physical training and exercises in sporting and military skills, of which physical activity forms a part (1). For many people, the transition from civilian to military life means a change in their patterns of physical activity. Unaccustomed forms of movement and a general increase in the level of activity predispose to musculoskeletal injuries (2, 3 ) . Studies from several countries thus show frequent occurrences of such injuries among military recruits (47), but also considerable differences between countries. We are not aware of similar epidemiological studies that have been published from any of the
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T. Heir, P. Glomsaker Institute of Military Issues, Norwegian University of Sport and Physical Education, Oslo, Norway
Key words: musculoskeletal injuries; overuse injuries; physical activity; physical training; military personnel; recruits Trond Heir, Norwegian University of Sport and Physical Education, Postboks 4014 Ulleval Hageby, N-0806 Oslo, Norway Accepted for publication October 6, 1995
Nordic countries. The purpose of the present study was therefore to map the incidence of musculoskeletal injuries among Norwegian conscripts. We also wished to highlight to activities of presumptively high injury risk, and to document such possible consequences of injuries as burdens on the health services, loss of training time, and the discharge of conscripts who are unable to complete their service.
Material and methods Study population The recruitment of servicemen to the Norwegian armed forces is based on the principle of compulsory military service for all males. Service begins
Injuries in military recruits with a period of basic military and physical training. During the 1988-1992 period, 92-93% of the male population was found to be fit for service when meeting for the conscription board (8). Before entry a further 5% was classified as unfit, 44.5% dropped out because of conscientious objection and a final 4-5% was transferred to the civil defence (National Service Administration, personal communication). Conscripts at Sessvollmoen (the Army), Gardermoen (the Air Force) and Madla (the Navy) were chosen as the study population. All conscripts serving at one of the three training camps in the space of a calendar year (1990-91) were included in the study. The total was 6488 individuals, of whom 2379 were in the Army, 1516 in the Air Force, and 2593 in the Navy. The conscripts were from 18 to 30 years of age (median 20, 92% within the 19-22 age range). Voluntarily enlisted women made up 1.0% of the population. The basic training period was from 8 to 10 weeks in the Army and Air Force, and from 6 to 8 weeks in the Navy. The dates of entry and transfer or discharge of every serviceman were registered and formed the basis for the calculation of the total time at risk, which was 11 695 conscript-months. Physical activity
The training programmes at each of the three training camps included 4 h a week of basic physical training, of which roughly half was effective training. In addition, the Army and the Air Force included 1 and 2 h per week of march training, and 2 and 1-2 h per week of infantry running, respectively. Each service included 2-3 h per week of close order drill. The Air Force also had 1-2 h and the Army 34 h per week of open order and battle technique. The total physical strain is estimated to have been highest in the Army and lowest in the Navy. Registration of injuries
An injury was defined as a pain, inflammation or functional disorder that (a) involved the musculoskeletal or soft tissues; (b) was serious enough for the conscript to seek and obtain a medical consultation; and (c) could have occurred entirely or in part as a consequence of an external trauma or strain sustained during the period of basic training. Injuries were registered by doctors (unit medical officers and conscripted doctors) attached to the training camps. Instruction aimed at standardizing methods of examination, diagnosis and registration routines was given continuously at central meetings and on visits to the units. An experienced specialist in physical medicine was engaged in the instruction.
An injury registration card was routinely inserted in the medical records of all conscripts joining a unit. For every consultation concerning an injury, the doctor entered the date, whether the injury had been registered previously, the diagnosis and anatomical site, the tentative aetiology, measures and treatment if any, and the number of days of full or partial sick leave that was prescribed. The doctor also registered whether there were objective indications of injury and to what extent he found the existence of pain or a functional disorder credible. The diagnosis was specified in the doctor’s own words and given a code number from a list in which different diagnoses were grouped in 22 categories on the basis of experience from a similar study (9) and terminology from ICD-9 (10). In the event of more than one consultation for the same injury, the injury only counted once. If the diagnosis was changed, the most recently registered diagnosis was used. Analysis of data
Population characteristics were described by contingency tables. Incidence rates were expressed as injuries per 100 or 1000 conscript-months. Relative risks with 95% confidence intervals were calculated using a model of injuries per subject and time at risk, assuming a model with constant intensity of injuries (1 1). Statistical comparisons between groups were made using a chi-square test based on the same model (11). The test was two-tailed, and differences were considered significant if P
