The majority of reported injuries among military populations are injuries due to cumulative repetitive microtrauma — overuse injuries. Plantar pressure measurement is a simple tool to analyse lower limb biomechanics through the assessment of forces applied to the foot. This study aimed to determine the relation between peak plantar pressure and lower extremity overuse. Sixty-six active-duty infantry male soldiers, with mean age 29.7 years (range 22–40 years), and mean service time 5.2 years (range 1–15 years) participated. The highest peak plantar pressure (PPP) at the forefoot occurred at the hallux (cases: 50.82 n/cm2, SD = 38.84; control: 34.39 n/cm2, SD= 28.03) and 3rd metatarsal head (cases: 54.40 n/cm2, SD = 33.83; control: 49.16 n/cm2, SD=28.87). The study demonstrated elevated PPP among cases. Statistically significant results were found at the hallux (χ2(1) = 6.8; p = 0.01), medial heel (χ2(1) = 5.18; p = 0.02) and lateral heel (χ2(1) = 12.12; p < 0.01) regions. The results show that plantar pressure assessment could be used as a useful screening tool for early lower extremity overuse injury detection.

Background High rates of musculoskeletal injuries such as plantar fasciitis and stress fractures have been observed among physically active military personnel. During service time, infantry soldiers use issued boots daily that should fit well and provide comfort to prevent injuries and decrease lower extremity pain effectively. The association of military boot comfort with overuse injuries remains unclear. This study investigates the relationship between the chosen military boot size, perceived boot comfort and lower leg overuse injury. Methods During the cross-sectional study, 227 (males, n = 213; females, n = 14) active-duty infantry soldiers at a mean age of 29.5 years old, and with an average service time of 7.2 years were assessed for a history of overuse injury, footprint length, appropriate shoe size, and footwear comfort. Males with a history of overuse injury (n = 32) and non-injured age-matched controls (n = 34) were selected for detailed testing and establishing the possible relationship between footwear comfort and lower leg overuse injury. Results No relationship was found between footwear comfort and a history of lower leg overuse injury. N = 38 (57.6%) of study subjects were wearing an inappropriate shoe size daily. Inappropriate shoe size usage affected footwear comfort ratings significantly. Conclusions Study results showed that improper boot size was significantly related to comfort ratings but was not associated with a history of lower leg overuse injury.

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Background A high incidence of lower leg overuse injury has been observed among military populations. Footwear usage could be promising in reducing the risk of injury from overuse of the lower extremities. The purposeof this study was to identify possible gait-related risk factors for lower leg overuse injurieswhen walking barefoot and in military boots. Methods Cases (n=32) were active-duty infantry soldiers from Latvian Land Forces with a history of overuse injury during the last 6 months of service before entering the study. During the study period, the cases recovered completely from the injury, did not report any functional limits, and were able to participate in all kinds of physical activities. Controls (n=32) of the same age and gender were free of injury in the same time period. Study subjects were instructed to walk on a 5-meter walkway in the gait laboratory. Rearfoot eversion, ankle plantar/dorsiflexion and stride time, length and variability were evaluated for barefoot and shod conditions. Results Gait-related parameters during shod and barefoot conditions differ in both groups. The barefoot stride time and the stride time variability were statistically different between cases and controls. No significant differences were found for stride length and stride time variability among groups. Conditional regression analysis showed that stride time variability during barefoot gait statistically significantly predicted the risk oflower leg overuse injury. ROC analysis showed an AUC of 0.77 (p<0.001; 95% CI 0.648-0.883), a sensitivity of 56%, and aspecificity of 88%, with an optimal cut-off value for stride time variability of 1.95%. Conclusions The risk of injury was independent of thegait-related characteristics during shod gait. Stride time variability has low sensitivity, but if the variability value during the barefoot walk is less than 1.95%, it can be considered a negative risk factor for lower leg overuse injury among infantry soldiers. Trial registration Not applicable.

Musculoskeletal injury is the leading cause of disability among different military populations that results in socioeconomic burden and negatively affects military readiness. Study aim was to describe self-reported musculoskeletal injuries among Latvian infantry soldiers during one-year period. Survey-based cross-sectional study was carried out. Data was assessed using survey about injuries that occurred in one-year period during annual medical check-up. Musculoskeletal injuries were classified according to body regions as it is in Barell injury matrix and by injury type – acute or overuse. Study results showed in one-year injury incidence rate was 867.8 cases per 1000 person-years (95% CI 824.8 – 913.0) with total 197 musculoskeletal injuries reported among active duty infantry soldiers. Typical acute injuries were superficial contusion injuries (n=24), fractures (n=21), joint dislocations (n=21) and sprains (n=29). Typical overuse diagnoses were lower back pain (n=42), patellofemoral pain syndrome (n=11), medial tibial stress syndrome (n=9), plantar fasciitis (n=8). Present study showed high incidence of overuse back injuries and overuse and acute lower leg injuries. Mostly of reported injuries could be classified as preventable and should be reduced through injury reduction programmes.