Exertional rhabdomyolysis: identification and evaluation of the athlete at risk for recurrence.

Exertional rhabdomyolysis (ER) is a common medical condition encountered by primary care and sports medicine providers. Although the majority of individuals with ER follow an expected and unremarkable clinical course without any adverse long-term sequelae or increased risk for recurrence, in others, the condition can serve as an 'unmasker' of an underlying condition that portends future risk. We present two cases of warfighters with a history of recurrent ER who presented to our facility for further evaluation and a return to duty determination.

Recurrent exertional rhabdomyolysis: coincidence, syndrome, or acquired myopathy?

The purposes of this report are to review and discuss the issue of recurrent exertional rhabdomyolysis (ER), the return to physical activity after ER, and the possible causes of recurrence, with special consideration to metabolic myopathies and the possibility of an acquired post-ER myopathy. We discuss the medical investigation required prior to return to physical activity after an episode of ER and suggest two possible mechanisms for recurrence of ER in the absence of a known cause: premature return to activity and an acquired post-ER muscular disorder. We also emphasize the need to create proper guidelines for return to physical activity after ER and, for further investigation, the possible mechanisms of ER recurrence in patients without a known metabolic myopathy.

Bone turnover markers do not predict stress fracture in elite combat recruits.

Background: With bone resorption rates greater than formation, stress fracture pathogenesis plausibly involves bone remodeling imbalance. If this is the case, one would anticipate serum levels of bone turnover markers would be higher in patients with stress fractures than in those without.

Questions/purposes: We therefore asked whether: (1) bone turnover markers differ between soldiers who will or will not have stress fractures during basic training; (2) bone turnover markers change during basic training; and (3) serial bone formation or bone resorption markers differ between subjects with and without stress fractures during basic training?

Methods: We performed serial determinations of serum bone formation (bone alkaline phosphatase [BAP] and procollagen type I amino-terminal propeptide [PINP]), and resorption (tartrate-resistant acid phosphatase [TRAP5b] and cross-linked collagen telopeptide [CTx]) biomarkers, measured at 2- to 4-week intervals (during 18 weeks) in 69 male soldiers in the Israeli Defense Forces during elite basic training.

Misdiagnosis of exertional heat stroke and improper medical treatment.

Exertional heat stroke (EHS) is the most complicated and dangerous amongst heat injuries that can lead to irreversible injury and even death. Early diagnosis and treatment are therefore crucial determinants of the patient's prognosis. The following case report depicts a soldier who presented primarily with confusion and behavioral changes during physical exercise and later lost consciousness.

Hypothermia following exertional heat stroke treatment.

Exertional heat stroke (EHS) is a life-threatening condition, which deteriorates rapidly. Immediate cooling treatment can, therefore, be life saving. Over the past two winters, we witnessed three cases of hypothermia resulting from treatment of suspected EHS.

Androgen receptor CAG repeat size is associated with stress fracture risk: a pilot study.

Background: Stress fractures commonly affect military recruits during basic training. Several lines of evidence suggest genetic factors are involved in stress fracture predisposition. As gender steroid hormone levels and activity have been implicated in affecting bone strength, one of the candidate genes likely to be involved is the androgen receptor gene.

Epidemiology of metatarsal stress fractures versus tibial and femoral stress fractures during elite training.

Background: The training of elite infantry recruits takes a year or more. Stress fractures are known to be endemic in their basic training and the clinical presentation of tibial, femoral, and metatarsal stress fractures are different. Stress fracture incidence during the subsequent progressively more demanding training is not known.

Hand immersion in cold water alleviating physiological strain and increasing tolerance to uncompensable heat stress.

The current study examines the use of hand immersion in cold water to alleviate physiological strain caused by exercising in a hot climate while wearing NBC protective garments. Seventeen heat acclimated subjects wearing a semi-permeable NBC protective garment and a light bulletproof vest were exposed to a 125 min exercise-heat stress (35 degrees C, 50% RH; 5 km/h, 5% incline). The heat stress exposure routine included 5 min rest in the chamber followed by two 50:10 min work-rest cycles.

Metabolic rate prediction by massless actigraphy for outdoor activities.

Purpose: In military scenarios, there is a need for a system that can enable identification of possible future injury during different activities that are considered to be physically strenuous. The purpose of the present study was to determine whether the use of an octagonal actigraph in conjunction with heart rate (fc) measurements could serve as an accurate method for metabolic rate estimation for different free-living activities in field settings.

Methods: Twenty young healthy volunteers (10 men, 22 +/- 3 years of age, and 10 women, 23 +/- 3 years of age) participated in this study.

The "golden hour" for heatstroke treatment.

Exertional heatstroke is a life-threatening event. It occurs mainly among the young healthy populations of athletes and soldiers. The severity of exertional heatstroke is directly correlated to the area under the temperature duration curve.

Hypothermia and local cold injuries in combat and non-combat situations--the Israeli experience.

Introduction: Cold weather has been recognized in the Israel Defense Forces (IDF) as a potential medical and operational threat to the soldier. Although regulations have been issued to cope with this situation, every year about 20 cases of hypothermia (T(core) < 35 degrees C) and peripheral cold injuries are reported.

Methods: This study was aimed at following cold weather injuries (CI) in the IDF in the period 1994-2001.

[Methods for core temperature measurements].

The measurement of core temperature is important for many clinical situations including heat illnesses, hypothermia, infections, sepsis, shock, hemorrhage, and exposure to chemical and biological agents. Currently, oral and rectal temperatures are clinically utilized for such measurements. However, oral measurements are not always possible and accurate whereas rectal measurements are not convenient in the field, are labor intensive, use fragile glassware containing mercury--an environmental contaminant, require sterilization and are not suited for mass casualties.

[Physiological aspects of women in combat].

Since military service is physically demanding, soldiers must maintain high levels of physical fitness for optimal performance of their duties. Women are at a physiological disadvantage when competing against men: they have a smaller muscle mass, more body fat, lower red blood cell counts, lower hemoglobin levels and smaller cardiac outputs. Women are slower and weaker than men and more prone to exercise-induced skeletal injuries.

Dantrolene and recovery from heat stroke.

Several authors have shown that dantrolene may be effective in the treatment of heat stroke patients. However, the scant data available are still controversial. The aim of this investigation was to establish an animal experimental model for studying the efficacy of this drug both as a prophylactic agent and as a means of hastening the cooling process after heat stroke.

Exertional heat stroke: a case series.

Unlabelled: Exertional heat stroke (EHS) is a state of extreme hyperthermia that occurs when excess heat that is generated by muscular exercise exceeds the body's ability to dissipate it at the same rate. EHS is thought to coincide with previously healthy, highly motivated, and relatively untrained individuals exerting in hot environments for long periods.

Purpose: To establish this notion, the present study was aimed to follow the trends in the incidence of EHS in the period 1988-1996.

Energy expenditure variations in soldiers performing military activities under cold and hot climate conditions.

This study assessed the energetic status of soldiers exposed to intense physical activities in cold and warm weather. Thirty subjects participated in a two-phase study group A (n = 18) in the winter phase and group B (n = 12) in the summer phase. Energy expenditure (EE) was measured by the doubly labeled water technique; after a single, oral dosing of 2H(2)18O, daily urine samples were collected for 12 successive days.

Insulin resistance in paraplegics--effect of one bout of acute exercise.

Insulin action was assessed in spinal cord injured (SCI) male individuals (n = 5) and compared to controls (C) (n = 5). Mean (+/-SD) age and body weight were 27.0 +/- 5.

Glucose polymer ingestion--effect on fluid balance and glycemic state during a 4-d march.

The effect of glucose-polymer solution on physical performance has been extensively studied under controlled laboratory conditions. The present study was conducted to investigate the influence of such beverages on fluid balance and on glycemic state during a moderate, prolonged field exercise. Forty-eight endurance trained, male subjects participated in the study.

The relationship between short-term antibiotic treatments and fatigue in healthy individuals.

Antibiotic treatment tends sometimes to result in sensations of fatigue and decreased physical performance. The effects of antibiotics were therefore studied in 50 healthy, male trainees, aged 18-25 years, assigned in a random, double-blind fashion to one of the following treatments: tetracycline, ampicillin, trimethoprim/sulphamethoxazole, placebo I and placebo II. Duration of treatment was five times the half-life of each agent and the placebo was matched accordingly.