Association between changes in serum bone metabolism markers and bone microarchitecture changes during basic combat training - The ARMI study.

Importance: U.S. Army Basic Combat Training (BCT) improves tibial volumetric bone mineral density (BMD) and structure in most, but not all soldiers.

Hypothalamic-pituitary-ovarian axis suppression is common among women during US Army Basic Combat Training.

Objective: Less than half of servicewomen report loss of menses during initial military training. However, self-reported menstrual status may not accurately reflect hypothalamic-pituitary-ovarian (HPO) axis suppression and may underestimate reproductive health consequences of military training. Our aim was to characterise HPO axis function during US Army Basic Combat Training (BCT) in non-hormonal contraceptive-using women and explore potential contributors to HPO axis suppression.

Exercise for optimizing bone health after hormone-induced increases in bone stiffness.

Hormones and mechanical loading co-regulate bone throughout the lifespan. In this review, we posit that times of increased hormonal influence on bone provide opportunities for exercise to optimize bone strength and prevent fragility. Examples include endogenous secretion of growth hormones and sex steroids that modulate adolescent growth and exogenous administration of osteoanabolic drugs like teriparatide, which increase bone stiffness, or its resistance to external forces.

Physiology of Health and Performance: Enabling Success of Women in Combat Arms Roles.

Introduction: The modern female soldier has yet to be fully characterized as she steps up to fill new combat roles that have only recently been opened to women. Both U.S.

Male Runners With Lower Energy Availability Have Impaired Skeletal Integrity Compared to Nonathletes.

Context: Female athletes, particularly runners, with insufficient caloric intake for their energy expenditure [low energy availability (EA) or relative energy deficiency] are at risk for impaired skeletal integrity. Data are lacking in male runners.

Objective: To determine whether male runners at risk for energy deficit have impaired bone mineral density (BMD), microarchitecture, and estimated strength.

Return to sport following low-risk and high-risk bone stress injuries: a systematic review and meta-analysis.

Objective: Bone stress injuries (BSIs) are classified in clinical practice as being at low- or high-risk for complication based on the injury location. However, this dichotomous approach has not been sufficiently validated. The purpose of this systematic review was to examine the prognostic role of injury location on return-to-sport (RTS) and treatment complications after BSI of the lower extremity and pelvis.

Unraveling the physiologic paradoxes that underlie exercise prescription for stress fracture prevention.

The effects of exercise on stress fracture risk are paradoxical. Exercise can promote both bone formation and resorption, which in turn, can reduce and increase risk of stress fractures, respectively. We review classic and current literature that suggests that the processes that underlie these responses to exercise are distinct.

Serum 25-Hydroxyvitamin D is Associated With Bone Microarchitecture and Strength in a Multiracial Cohort of Young Adults.

Purpose: To determine whether 25-hydroxyvitamin D (25-OH D) levels are associated with bone outcomes in a multiracial cohort of young adults.

Methods: This cross-sectional study included 165 participants (83 men, 82 women, 18-30 years of age) who self-identified as Asian, Black, or White. We measured bone microarchitecture and strength of the distal radius and tibia using high-resolution peripheral quantitative computed tomography.

Restrictive Eating and Prior Low-Energy Fractures Are Associated With History of Multiple Bone Stress Injuries.

Bone stress injuries (BSIs) are common among athletes and have high rates of recurrence. However, risk factors for multiple or recurrent BSIs remain understudied. Thus, we aimed to explore whether energy availability, menstrual function, measures of bone health, and a modified Female Athlete Triad Cumulative Risk Assessment (CRA) tool are associated with a history of multiple BSIs.

Bone stress injuries.

Bone stress injuries, including stress fractures, are overuse injuries that lead to substantial morbidity in active individuals. These injuries occur when excessive repetitive loads are introduced to a generally normal skeleton. Although the precise mechanisms for bone stress injuries are not completely understood, the prevailing theory is that an imbalance in bone metabolism favours microdamage accumulation over its removal and replacement with new bone via targeted remodelling.

Low energy availability surrogates associated with lower bone mineral density and bone stress injury site.

Background: Exercise is an osteogenic stimulus that should increase bone mineral density (BMD) and protect against injury. However, some female athletes have lower BMD and increased bone stress injury (BSI) risk. Impaired bone health seen in athletes may be explained by low energy availability as described by concepts of Relative Energy Deficiency in Sport (RED-S) and Female Athlete Triad (Triad).

Impact loading in female runners with single and multiple bone stress injuries during fresh and exerted conditions.

Background: Bone stress injuries (BSIs) are common in female runners, and recurrent BSI rates are high. Previous work suggests an association between higher impact loading during running and tibial BSI. However, it is unknown whether impact loading and fatigue-related loading changes discriminate women with a history of multiple BSIs.

Impact of Low Energy Availability on Skeletal Health in Physically Active Adults.

For decades researchers reported that pre-menopausal women who engage in extensive endurance exercise and have menstrual dysfunction can develop low bone mineral density (BMD) or osteoporosis. More recently, low energy availability has been recognized as the initiating factor for low BMD in these women. Furthermore, the relationship between low energy availability and poor skeletal health is not exclusive to women engaging in endurance exercise.

Physical Activity, Menstrual History, and Bone Microarchitecture in Female Athletes with Multiple Bone Stress Injuries.

Purpose: To determine differences in health and physical activity history, bone density, microarchitecture, and strength among female athletes with a history of multiple BSI, athletes with ≤1 BSI, and nonathletes.

Methods: We enrolled 101 women (age, 18-32 yr) for this cross-sectional study: nonathlete controls (n = 17) and athletes with a history of ≥3 BSIs (n = 21) or ≤1 BSI (n = 63). We collected subjects' health and training history and measured bone microarchitecture of the distal tibia via high-resolution peripheral quantitative computed tomography (HR-pQCT) and areal bone mineral density of the hip and spine by dual-energy X-ray absorptiometry.

Changes in Volumetric Bone Mineral Density Over 12 Months After a Tibial Bone Stress Injury Diagnosis: Implications for Return to Sports and Military Duty.

Background: Bone stress injuries (BSIs) occur in up to 20% of runners and military personnel. Typically, after a period of unloading and gradual return to weightbearing activities, athletes return to unrestricted sports participation or military duty approximately 4 to 14 weeks after a BSI diagnosis, depending on the injury location and severity. However, the time course of the recovery of the bone's mechanical competence is not well-characterized, and reinjury rates are high.

Bone geometry and lower extremity bone stress injuries in male runners.

Unlabelled: Bone stress injuries (BSI) are common among distance runners and research investigations examining risk factors for BSI among men are limited. Therefore, investigations are needed to determine if men with a history of BSI have skeletal properties that may heighten BSI incidence.

Objectives: To analyze differences in bone density, bone geometry, and estimates of bone strength in male runners with and without a BSI history.

Skeletal loading score is associated with bone microarchitecture in young adults.

Unlabelled: Physical activity that involves high strain magnitudes and high rates of loading is reported to be most effective in eliciting an osteogenic bone response. Whether a history of participation in osteogenic activities during youth, as well as current participation in osteogenic activities, contributes to young adult bone microarchitecture and strength is unknown.

Purpose: We determined the association between a new skeletal loading (SkL) score reflecting physical activity from age 11 to adulthood, the bone specific physical activity questionnaire (BPAQ) and bone microarchitecture in young Black and White men and women.

A prospective field study of U.S. Army trainees to identify the physiological bases and key factors influencing musculoskeletal injuries: a study protocol.

Background: Musculoskeletal injuries (MSKIs) are common in military trainees and present a considerable threat to occupational fitness, deployability, and overall military readiness. Despite the negative effects of MSKIs on military readiness, comprehensive evaluations of the key known and possible risk factors for MSKIs are lacking. The U.

Regional Changes in Density and Microarchitecture in the Ultradistal Tibia of Female Recruits After U.S. Army Basic Combat Training.

Musculoskeletal injuries, such as stress fracture, are responsible for over 10-million lost-duty days among U.S. Army Soldiers.