Risk factors of acute and overuse musculoskeletal injuries among young conscripts: a population-based cohort study.

BACKGROUND: Military service in Finland is compulsory for all male citizens and annually about 80% of 19-year-old men enter into the service. The elevated risk for many chronic diseases and loss of function among those who are inactive and unfit can be often detected already in youth. On the other hand, activity-induced injuries among young are true public health issue. The purpose of the present prospective cohort follow-up study was to evaluate predictive associations between acute or overuse injuries and their various intrinsic risk factors. METHODS: Four successive cohorts of conscripts who formed a representative sample of Finnish young men were followed for 6 months. At the beginning of the service, the risk factors of injuries were measured and recorded and then the acute and overuse injuries treated at the garrison clinic were identified. Predictive associations between injuries and their risk factors were examined by multivariate Cox's proportional hazard models. RESULTS: Of the 1411 participants, 27% sustained an acute injury and 51% suffered from overuse injury. Concerning acute injuries, highest risk for severe injuries were detected among conscripts with low fitness level in both the standing long-jump and push-up tests (hazard rate, HR=5.9; 95% CI: 1.6‒21.3). A history of good degree in school sports was not a protective factor against acute injuries. High waist circumference and, on the other hand, being underweight according to BMI increased the HR for overuse injuries. Brisk leisure time physical activity before military entry was a protective factor against overuse injuries. Poor result in Cooper's test was a warning signal of elevated risk of overuse injuries. CONCLUSION: We confirmed previous findings that low level of physical fitness is predictor for musculoskeletal injuries during intensive physical training. The U-shaped relationship between body composition and overuse injuries was noticed indicating that both obesity and underweight are risk factors for overuse injuries. Persons with excellent sports skills according to their earlier degrees in school sports had similar HR for acute injuries than those with poorer degrees. This indicates that school-age sports skills and fitness do not carry far and therefore preventive programmes are needed to prevent activity-induced injuries.

Neuromuscular exercise and counseling decrease absenteeism due to low back pain in young conscripts: a randomized, population-based primary prevention study.

STUDY DESIGN: Controlled intervention with group randomization. OBJECTIVE: To investigate the effectiveness of a 6-month neuromuscular exercise and counseling program for reducing the incidence of low back pain (LBP) and disability in young conscripts, with a healthy back at the beginning of their compulsory military service. SUMMARY OF BACKGROUND DATA: Basic military training is physically demanding on the back and requires adequate physical fitness. LBP causes significant morbidity and absence from military service. METHODS: Participants were conscripts of 4 successive age cohorts (n = 1409). In the prestudy year, before adoption of the intervention, 2 successive cohorts of conscripts of 4 companies (n = 719) were followed prospectively for 6 months to study the baseline incidence of different categories of LBP. In the intervention year, conscripts (n = 690) of 2 new cohorts of the same companies (intervention group: antitank, engineer; control group: signal, mortar) were followed for 6 months. The intervention program aimed to improve conscripts' control of their lumbar neutral zone and specifically to avoid full lumbar flexion in all daily tasks. RESULTS: Total number and incidence of off-duty days due to LBP were significantly decreased in the intervention companies compared with controls (adjusted hazard ratio = 0.42, 95% confidence interval = 0.18-0.94, P = 0.035). The number of LBP cases, number of health clinic visits due to LBP, and number of the most severe cases showed a similar decreasing trend but without statistical significance. CONCLUSION: These findings provide evidence that exercise and education to improve control of the lumbar neutral zone have a prophylactic effect on LPB-related off-duty service days in the military environment when implemented as part of military service among young healthy men.

Predictors of low back pain in physically active conscripts with special emphasis on muscular fitness.

BACKGROUND CONTEXT: Association between low physical fitness and low back pain (LBP) is contradictory in previous studies. PURPOSE: The objective of the present prospective cohort study was to investigate the predictive associations of various intrinsic risk factors in young conscripts for LBP, with special attention to physical fitness. STUDY DESIGN: A prospective cohort study. PATIENT SAMPLE: A representative sample of Finnish male conscripts. In Finland, military service is compulsory for male citizens and 90% of young men enter into the service. OUTCOME MEASURES: Incidence of LBP and recurrent LBP prompting a visit at the garrison health clinic during 6-month military training. METHODS: Four successive cohorts of 18- to 28-year-old male conscripts (N=982) were followed for 6 months. Conscripts with incidence of LBP were identified and treated at the garrison clinic. Predictive associations between intrinsic risk factors and LBP were examined using multivariate Cox proportional hazard models. RESULTS: The cumulative incidence of LBP was 16%, the incidence rate being 1.2 (95% confidence interval [CI], 1.0-1.4) per 1,000 person-days. Conscripts with low educational level had increased risk for incidence of LBP (hazard ratio [HR], 1.6; 95% CI, 1.1-2.3). Conscripts with low dynamic trunk muscle endurance and low aerobic endurance simultaneously (ie, having coimpairment) at baseline also had an increased risk for incidence of LBP. The strongest risk factor was coimpairment of trunk muscular endurance in tests of back lift and push-up (HR, 2.8; 95% CI, 1.4-5.9). CONCLUSIONS: The increased risk for LBP was observed among young men who had a low educational level and poor fitness level in both muscular and aerobic performance.

Low physical fitness is a strong predictor of health problems among young men: a follow-up study of 1411 male conscripts.

BACKGROUND: Military service in Finland is compulsory for male citizens and annually about 90% of 19-year-old men enter into the service. Approximately 15% of them are discharged due to medical reasons constituting a group of young men who are at risk of being marginalised in society. The purpose of the study was to evaluate predictive associations between medical discharge from the compulsory military service and various intrinsic risk factors, including socio-economic, health, health behavior, and physical fitness outcomes. METHODS: We followed four successive cohorts of conscripts who formed a representative sample of Finnish young men (18-28 years old, median age 19 yrs) for 6 months. To exclude injuries and illnesses originating before the onset of service, conscripts discharged from the service at the medical screenings during the 2-week run-in period were excluded from the analyses. Data regarding medical discharge were charted from computerised patient records. Predictive associations between medical discharge and intrinsic risk factors were examined using multivariate Cox's proportional hazard models. RESULTS: Of 1411 participants, 9.4% (n = 133) were discharged prematurely for medical reasons, mainly musculoskeletal (44%, n = 59) and mental and behavioral (29%, n = 39) disorders. Low levels of physical fitness assessed with a 12-min running test (hazard ratio [HR] 3.3; 95% confidence interval [CI]: 1.7-6.4), poor school success (HR 4.6; 95% CI: 2.0-11.0), poor self-assessed health (HR 2.8; 95% CI: 1.6-5.2), and not belonging to a sports club (HR 4.9; 95% CI: 1.2-11.6) were most strongly associated with medical discharge in a graded manner. The present results highlight the need for an improved pre-enlistment examination and provide a new means of identifying young persons with a high risk for discharge. CONCLUSIONS: The majority of the observed risk factors are modifiable. Thus preventive measures and programs could be implemented. The findings suggest that increasing both aerobic and muscular fitness is a desirable goal in a pre-training program before entering military service. Attention to appropriate waist circumference and strategies addressing psychological well-being may strengthen the preventive program. Optimally the effectiveness of these programs should be tested in randomized controlled intervention studies.

Neuromuscular training with injury prevention counselling to decrease the risk of acute musculoskeletal injury in young men during military service: a population-based, randomised study.

BACKGROUND: The rapidly increasing number of activity-induced musculoskeletal injuries among adolescents and young adults is currently a true public health burden. The objective of this study was to investigate whether a neuromuscular training programme with injury prevention counselling is effective in preventing acute musculoskeletal injuries in young men during military service. METHODS: The trial design was a population-based, randomised study. Two successive cohorts of male conscripts in four companies of one brigade in the Finnish Defence Forces were first followed prospectively for one 6-month term to determine the baseline incidence of injury. After this period, two new successive cohorts in the same four companies were randomised into two groups and followed prospectively for 6 months. Military service is compulsory for about 90% of 19-year-old Finnish men annually, who comprised the cohort in this study. This randomised, controlled trial included 968 conscripts comprising 501 conscripts in the intervention group and 467 conscripts in the control group. A neuromuscular training programme was used to enhance conscripts' motor skills and body control, and an educational injury prevention programme was used to increase knowledge and awareness of acute musculoskeletal injuries. The main outcome measures were acute injuries of the lower and upper limbs. RESULTS: In the intervention groups, the risk for acute ankle injury decreased significantly compared to control groups (adjusted hazards ratio (HR) = 0.34, 95% confidence interval (95% CI) = 0.15 to 0.78, P = 0.011). This risk decline was observed in conscripts with low as well as moderate to high baseline fitness levels. In the latter group of conscripts, the risk of upper-extremity injuries also decreased significantly (adjusted HR = 0.37, 95% CI 0.14 to 0.99, P = 0.047). In addition, the intervention groups tended to have less time loss due to injuries (adjusted HR = 0.55, 95% CI 0.29 to 1.04). CONCLUSIONS: A neuromuscular training and injury prevention counselling programme was effective in preventing acute ankle and upper-extremity injuries in young male army conscripts. A similar programme could be useful for all young individuals by initiating a regular exercise routine. TRIAL REGISTRATION: ClinicalTrials.gov identifier number NCT00595816.

Aetiology and risk factors of musculoskeletal disorders in physically active conscripts: a follow-up study in the Finnish Defence Forces.

BACKGROUND: Musculoskeletal disorders (MSDs) are the main reason for morbidity during military training. MSDs commonly result in functional impairment leading to premature discharge from military service and disabilities requiring long-term rehabilitation. The purpose of the study was to examine associations between various risk factors and MSDs with special attention to the physical fitness of the conscripts. METHODS: Two successive cohorts of 18 to 28-year-old male conscripts (N = 944, median age 19) were followed for six months. MSDs, including overuse and acute injuries, treated at the garrison clinic were identified and analysed. Associations between MSDs and risk factors were examined by multivariate Cox's proportional hazard models. RESULTS: During the six-month follow-up of two successive cohorts there were 1629 MSDs and 2879 health clinic visits due to MSDs in 944 persons. The event-based incidence rate for MSD was 10.5 (95% confidence interval (CI): 10.0-11.1) per 1000 person-days. Most MSDs were in the lower extremities (65%) followed by the back (18%). The strongest baseline factors associated with MSDs were poor result in the combined outcome of a 12-minute running test and back lift test (hazard ratio (HR) 2.9; 95% CI: 1.9-4.6), high waist circumference (HR 1.7; 95% CI: 1.3-2.2), high body mass index (HR 1.8; 95% CI: 1.3-2.4), poor result in a 12-minute running test (HR 1.6; 95% CI: 1.2-2.2), earlier musculoskeletal symptoms (HR 1.7; 95% CI: 1.3-2.1) and poor school success (educational level and grades combined; HR 2.0; 95% CI: 1.3-3.0). In addition, risk factors of long-term MSDs (>or=10 service days lost due to one or several MSDs) were analysed: poor result in a 12-minute running test, earlier musculoskeletal symptoms, high waist circumference, high body mass index, not belonging to a sports club and poor result in the combined outcome of the 12-minute running test and standing long jump test were strongly associated with long-term MSDs. CONCLUSIONS: The majority of the observed risk factors are modifiable and favourable for future interventions. An appropriate intervention based on the present study would improve both aerobic and muscular fitness prior to conscript training. Attention to appropriate waist circumference and body mass index would strengthen the intervention. Effective results from well-planned randomised controlled studies are needed before initiating large-scale prevention programmes in a military environment.

Musculoskeletal disorders in physically active conscripts: a one-year follow-up study in the Finnish Defence Forces.

BACKGROUND: Musculoskeletal disorders (MSDs) are an important cause for morbidity in military service. They result in disabilities needing long-term rehabilitation and functional impairment leading to premature discharge from military service. The purpose of the study was to investigate the incidence and nature of MSDs in Finnish conscripts. METHODS: Two successive arrivals of 18-28-yr-old male conscripts (N = 955, median age 19) were followed for six months. MSDs, including overuse and acute injuries, treated at the garrison clinic were identified and analysed. RESULTS: During the 12-month study period there were 437 outpatient clinic visits in 955 persons. The occurrence rate was 33% during 6-month service while the event-based incidence was 3.3 per 1000 person-days. Occurrence peaked in summer months. The most common types of MSDs were low back pain (LBP, 20%), lower limb overuse injuries (16%) and sprains or strains (13%). Disorders mostly occurred in combat training in combat gear (40%) and during marching on foot or bicycle (28%). Overuse-related MSDs were more prevalent (66%) than traumatic ones (34%). One-third (34%) of the MSDs were recurrent and 66% were new ones. Disorders of the back and the knee were most frequently recurrent conditions (44% for both). Fractures, knee ligament ruptures, dislocations and muscle strains accounted for the highest number of service days lost. Twenty-four (2.5%) out of 955 conscripts were prematurely discharged due to MSDs. CONCLUSION: Preventive measures during military service should be targeted at decreasing low back pain and lower limb overuse injuries, because these inflict the largest burden of MSDs and tend to have a chronic nature.