Unaccustomed Physical Activity Research Articles

Sports-Statin Interaction: Ensuring Safe and Smart Synergy

Both sports (physical activity) and statins are recommended for the prevention and management of atherosclerotic cardiovasculardisease. The synergy that they create in risk reduction, however, may turn dysfunctional at times. Statin usage is associated witha risk of muscle-related conditions including myalgia, myositis and rhabdomyolysis. This risk is exacerbated by unaccustomedphysical activity, exercise or sports. The communication shares practical and pragmatic suggestions regarding the preventionand management of the potential sports-statin interactions that may occur. It also highlights the need to consider drug-lifestyleinteractions, apart from conventional drug-drug interactions.

Dorsal scapular displacement (flying scapula) in a heifer

AbstractDorsal scapular displacement, or flying scapula, is a rare condition characterised by sinking of the thorax between the forelimbs and protruding of the scapula above the thoracic vertebrae with the impression of a humpback appearance of the affected individual. The aetiology is still a matter of controversy. A 10‐month‐old heifer was presented with a history of sudden onset of gait abnormality and reluctance to stand and walk after being turned out to a spring pasture following the winter housing period. Clinical examinations revealed signs consistent with flying scapula. Whole‐blood selenium concentration and erythrocyte glutathione peroxidase activity were within the marginal status. Vitamin E level in serum was within the reference range. We proposed that the condition resulted from damage and bilateral rupture of the serratus ventralis muscle due to dystrophic myodegeneration in a selenium‐deficient individual exacerbated by walking long distances and unaccustomed physical activity after winter housing.

More than myalgia: An unusual presentation of exertional rhabdomyolysis

Exertional or exercise-induced rhabdomyolysis (ER) is a condition in which excessive and unaccustomed physical activity results in skeletal muscle damage. The ER is a relatively uncommon condition but can have very serious consequences such as acute renal failure, severe electrolyte abnormalities, acid base disturbances and death if not recognised and managed appropriately. The risk factors for rhabdomyolysis exist in our local setting, hence, it is paramount that healthcare practitioners (GPs) in our settings be made aware of ER, its prevention and symptoms. Cases of ER are often reported in sports men or women. Here, we report a case of a 33-year-old healthy female, with clinical and serological presentation, which is typical of ER following the commencement of a regimen of exercise to lose weight.

Evaluation of Clinical Outcomes in Hospitalized Patients With Exertional Rhabdomyolysis.

Exertional rhabdomyolysis (ER) is a medical condition in which excessive and unaccustomed physical activity results in skeletal muscle damage in otherwise healthy individuals. To assess the overall outcomes of patients who presented to the emergency department with ER. This retrospective study was conducted across 4 hospitals. The study included nonpregnant adults with no history of renal function impairment or myopathy disorder who had a diagnosis of ER in the emergency department setting. Medical records were reviewed for patient demographics, length of stay, complications, mechanism(s) of injury involved, impact of nutritional supplements, spectrum of creatine kinase (CK) responses, prevalence of hospital readmissions, and overall mortality. Of the 800 rhabdomyolysis cases identified during the 24-month study period, 41 were included in the study. The mean age was 29 years, and the patients were predominantly male (33 [80.5%]) and white (25 [61%]). The median length of stay was 2 days, and it correlated significantly with initial and peak CK levels (R=0.45, P=.004, and R=0.52, P<.001, respectively). Median initial and peak CK were noted to be 16,888 (range, 342-194,403) U/L and 18,534 (range, 342-287,565) U/L, respectively. Median discharge CK was 5287 (range, 10-61,617) U/L. The most commonly cited mechanism of injury was weight lifting (16 [39%]). In terms of overall outcomes, transient kidney injury was noted in 3 cases (7.4%), and no mortality was recorded during the admission or at 12 months of follow-up. Compartment syndrome or severe electrolyte abnormalities were not observed. There were only 2 uncomplicated readmissions (4.8%) due to high-intensity interval training. Hospitalized patients with ER without a history of renal impairment tend to have relatively low risks of complications and readmission.

Changes in tibial bone microarchitecture in female recruits in response to 8 weeks of U.S. Army Basic Combat Training.

U.S. Army Basic Combat Training (BCT) is a physically-demanding program at the start of military service. Whereas animal studies have shown that increased mechanical loading rapidly alters bone structure, there is limited evidence of changes in bone density and structure in humans exposed to a brief period of unaccustomed physical activity. We aimed to characterize changes in tibial bone density and microarchitecture and serum-based biochemical markers of bone metabolism in female recruits as a result of 8 weeks of BCT. We collected high-resolution peripheral quantitative computed tomographic images of the distal tibial metaphysis and diaphysis (4% and 30% of tibia length from the distal growth plate, respectively) and serum markers of bone metabolism before and after BCT. Linear mixed models were used to estimate the mean difference for each outcome from pre- to post-BCT, while controlling for race/ethnicity, age, and body mass index. 91 female BCT recruits volunteered and completed this observational study (age = 21.5 ± 3.3 yrs). At the distal tibial metaphysis, cortical thickness, trabecular thickness, trabecular number, bone volume/total volume, and total and trabecular volumetric bone density (vBMD) increased significantly by 1-2% (all p < 0.05) over the BCT period, whereas trabecular separation, cortical tissue mineral density (TMD), and cortical vBMD decreased significantly by 0.3-1.0% (all p < 0.05). At the tibial diaphysis, cortical vBMD and cortical TMD decreased significantly (both -0.7%, p < 0.001). Bone strength, estimated by micro finite element analysis, increased by 2.5% and 0.7% at the distal tibial metaphysis and diaphysis, respectively (both p < 0.05). Among the biochemical markers of bone metabolism, sclerostin decreased (-5.7%), whereas bone alkaline phosphatase, C-telopeptide cross-links of type 1 collagen, tartrate-resistance acid phosphatase, and 25(OH)D increased by 10-28% (all p < 0.05). BCT leads to improvements in trabecular bone microarchitecture and increases in serum bone formation markers indicative of new bone formation, as well as increases in serum bone resorption markers and decreases in cortical vBMD consistent with intracortical remodeling. Together, these results demonstrate specific changes in trabecular and cortical bone density and microarchitecture following 8 weeks of unaccustomed physical activity in women.

The Risk of Cardiovascular Events During Leisure Time Activities at Altitude

Annually, more than 100 million tourists are attracted by the mountainous areas around the world. On the one hand, leisure time activities at altitude may well contribute to the well-established beneficial effects of exercise; on the other hand, these activities are also associated with a relatively high risk of death. Sudden cardiac death (SCD) is the most frequent cause of nontraumatic death in males older than 34 years at altitude during leisure time activities such as downhill skiing and hiking. Whereas prior myocardial infarction is the most important risk factor for SCD, particularly relevant in downhill skiers, the unusual physical activity during the first days at altitude and the prolonged abstinence from food and fluid intake during exercise at altitude are the most important triggers. Unaccustomed physical activity seems more likely to trigger SCD than altitude per se. The detection of subjects at risk, evidence-based therapy, and advice on adequate behavior during the altitude sojourn will help to prevent SCD and to increase the health benefits generated by mountaineering activities.

Acute Myocarditis Associated with Clozapine

A case of acute myocarditis associated with the commencement of clozapine is described, highlighting the onset, course and possible contributing factors. There is an urgent need to raise awareness about this potentially fatal complication of clozapine use. A 20-year-old male with schizophrenia developed a sudden onset of myocarditis after commencement of clozapine. The patient recovered with intensive medical support. The symptoms occurred around 2 weeks after starting clozapine in an inpatient setting. Possible contributing factors may have been concomitant antidepressant use and unaccustomed physical activity. Myocarditis is an increasingly recognized complication associated with the use of clozapine. It can be fatal if not recognized and treated early. Considering that clozapine remains the gold standard in treatment of resistant psychosis, there is an urgent need to raise awareness among medical and paramedical staff involved in the care of these patients. There are also implications for recommendations and regulations regarding the use of clozapine.

Exercise and Acute Cardiovascular Events

Habitual physical activity reduces coronary heart disease events, but vigorous activity can also acutely and transiently increase the risk of sudden cardiac death and acute myocardial infarction in susceptible persons. This scientific statement discusses the potential cardiovascular complications of exercise, their pathological substrate, and their incidence and suggests strategies to reduce these complications. Exercise-associated acute cardiac events generally occur in individuals with structural cardiac disease. Hereditary or congenital cardiovascular abnormalities are predominantly responsible for cardiac events among young individuals, whereas atherosclerotic disease is primarily responsible for these events in adults. The absolute rate of exercise-related sudden cardiac death varies with the prevalence of disease in the study population. The incidence of both acute myocardial infarction and sudden death is greatest in the habitually least physically active individuals. No strategies have been adequately studied to evaluate their ability to reduce exercise-related acute cardiovascular events. Maintaining physical fitness through regular physical activity may help to reduce events because a disproportionate number of events occur in least physically active subjects performing unaccustomed physical activity. Other strategies, such as screening patients before participation in exercise, excluding high-risk patients from certain activities, promptly evaluating possible prodromal symptoms, training fitness personnel for emergencies, and encouraging patients to avoid high-risk activities, appear prudent but have not been systematically evaluated.

Exercise and Acute Cardiovascular Events

Habitual physical activity reduces coronary heart disease events, but vigorous activity can also acutely and transiently increase the risk of sudden cardiac death and acute myocardial infarction in susceptible persons. This scientific statement discusses the potential cardiovascular complications of exercise, their pathological substrate, and their incidence and suggests strategies to reduce these complications. Exercise-associated acute cardiac events generally occur in individuals with structural cardiac disease. Hereditary or congenital cardiovascular abnormalities are predominantly responsible for cardiac events among young individuals, whereas atherosclerotic disease is primarily responsible for these events in adults. The absolute rate of exercise-related sudden cardiac death varies with the prevalence of disease in the study population. The incidence of both acute myocardial infarction and sudden death is greatest in the habitually least physically active individuals. No strategies have been adequately studied to evaluate their ability to reduce exercise-related acute cardiovascular events. Maintaining physical fitness through regular physical activity may help to reduce events because a disproportionate number of events occur in least physically active subjects performing unaccustomed physical activity. Other strategies, such as screening patients before participation in exercise, excluding high-risk patients from certain activities, promptly evaluating possible prodromal symptoms, training fitness personnel for emergencies, and encouraging patients to avoid high-risk activities, appear prudent but have not been systematically evaluated.

Metabolic Consequences of Exercise-Induced Muscle Damage

Exercise-induced muscle damage (EIMD) is commonly experienced following either a bout of unaccustomed physical activity or following physical activity of greater than normal duration or intensity. The mechanistic factor responsible for the initiation of EIMD is not known; however, it is hypothesised to be either mechanical or metabolic in nature. The mechanical stress hypothesis states that EIMD is the result of physical stress upon the muscle fibre. In contrast, the metabolic stress model predicts that EIMD is the result of metabolic deficiencies, possibly through the decreased action of Ca(2+)-adenosine triphosphatase. Irrespective of the cause of the damage, EIMD has a number of profound metabolic effects. The most notable metabolic effects of EIMD are decreased insulin sensitivity, prolonged glycogen depletion and an increase in metabolic rate both at rest and during exercise. Based on current knowledge regarding the effects that various types of damaging exercise have on muscle metabolism, a new model for the initiation of EIMD is proposed. This model states that damage initiation may be either metabolic or mechanical, or a combination of both, depending on the mode, intensity and duration of exercise and the training status of the individual.

Youth Football: Heat Stress and Injury Risk

Michael F. Bergeron, Ph.D., FACSM (Co-Chair)Douglas B. McKeag, M.D., FACSM (Co-Chair)Douglas J. Casa, Ph.D., ATC, FACSMPriscilla M. Clarkson, Ph.D., FACSMRandall W. Dick, FACSME. Randy Eichner, M.D., FACSMCraig A. Horswill, Ph.D., FACSMAnthony C. Luke, M.D., MPHFrederick Mueller, Ph.D., FACSMThayne A. Munce, Ph.D.William O. Roberts, M.D., FACSMThomas W. Rowland, M.D., FACSM

Early Treatment Of Exercise Induced Muscle Damage With Meloxicam Affects Muscle Cell Membrane Permeability

Exercise induced muscle damage occurs after unaccustomed physical activity, resulting in stiff, painful muscles with impaired function. Conventional non-steroidal anti-inflammatory agents are often ingested prior to, or after exercise to treat these symptoms. PURPOSE To determine the effects of the cox-2 selective agent meloxicam (M), on symptoms of exercise induced muscle damage and plasma creatine kinase [CK] activity. METHODS: Forty five healthy males were recruited for a double-blind placebo controlled trial and were then randomly assigned to treatment with either M 15mg immediately before (ME) or 48 hrs after induced injury (ML) or a placebo (P) and monitored for a total of 168 hours. Muscle injury was induced in their non-dominant arms using an eccentric exercise protocol. The dominant arm, which did not do any exercise was the control. RESULTS Subjects in all three groups experienced severe pain (2.5 +2.2 units; 2.3 + 2.1 units; 2.4+2.5 units vs. control P < 0.001) following the eccentric exercise. After 24 hours the difference in elbow joint angle between control and exercised arm, of all three groups had increased significantly (7.0 + 6.5°; 4.3 + 3.4°; 2.7 +2.7°; ME, ML and P; P <0.05), possibly as a consequence of elbow flexor muscles shortening. Peak [CK] was higher at 72 hr in ME (2540 +4230 U.L−1) compared to ML (671 + 953 U.L−1) and P (675 + 1002 U.L−1; P < 0.05 vs pre exercise control). M was well tolerated by the subjects in both groups without any adverse effects. CONCLUSIONS These data show that symptoms of exercise induced skeletal muscle damage are not positively influenced by ME or ML. Indeed, it appears that ingestion of M immediately preceding injury seems to affect muscle cell membrane permeability resulting in higher peak [CK]. These findings have important implications to athletes who ingest anti-inflammatory agents before exercising in an attempt to decrease skeletal muscle injury.

Electro-membrane microcurrent therapy reduces signs and symptoms of muscle damage

LAMBERT, M. I., P. MARCUS, T. BURGESS, and T. D. NOAKES. Electro-membrane microcurrent therapy reduces signs and symptoms of muscle damage. Med. Sci. Sports Exerc., Vol. 34, No. 4, pp. 602–607, 2002. Purpose Delayed onset muscle soreness (DOMS) occurs after unaccustomed physical activity or competitive sport, resulting in stiff, painful muscles with impaired function. Acustat® electro-membrane microcurrent therapy has been used to treat postoperative pain and soft tissue injury; however, its efficacy in reducing symptoms of muscle damage is not known. Methods Thirty healthy men were recruited for a double-blind, placebo-controlled trial. The muscles of their nondominant arms were damaged using an eccentric-exercise protocol. Subjects were then randomly assigned to treatment with either Acustat or a matching placebo membrane for 96 h and monitored for a total of 168 h. Results Subjects in both groups experienced severe pain and swelling of the elbow flexors after the eccentric exercise. After 24 h, the elbow joint angle of the placebo group had increased significantly more than those in the Acustat group (13.7 ± 8.9° vs 7.5 ± 5.5°; placebo vs Acustat, P < 0.05), possibly as a consequence of the elbow flexor muscles shortening. For the first 48 h after exercise, maximum voluntary contraction of the elbow flexor muscles was significantly impaired in the placebo group by up to 25% (P < 0.05), whereas muscle function was unchanged in the Acustat group. Peak plasma creatine kinase activity was also lower in the Acustat group (peak = 777 ± 1438 U·L−1) versus the placebo group (peak = 1918 ± 2067 U·L−1; (P < 0.05). The membranes were well tolerated by the subjects in both groups without any adverse effects. Conclusion These data show that treatment of muscle damage with Acustat electro-membrane microcurrent therapy reduces the severity of the symptoms. The mechanisms of action are unknown but are likely related to maintenance of intracellular Ca2+ homeostasis after muscle damaging exercise.

CORRELATION OF MUSCLE DAMAGE AND ACUTE PHASE REACTION AFTER AN ULTRAMARATHON: EFFECT OF DICLOFENAC 679

Unaccustomed physical activity induces muscle damage which is reflected by elevated serum levels of myoglobin (Myo), creatine kinase (CK), and aspartate-aminotransferase (ASAT). An acute phase reaction, e.g. an elevation of C-reactive protein (CRP), is known to occur with heavy exercise. To influence this reaction some authors recommend non-steroidal antirheumatic drugs like Diclofenac. 16 experienced male participants of the Swiss Alpine Marathon Davos (67 km, altitude difference 2300 m, average running time 8.5 h) received Diclofenac orally (75 mg Voltaren® SR 24, 12, and 1 h pre-race), while 11 additional male subjects served as controls. Myo, CK, ASAT, and CRP were measured 1 day pre-race, at the start, at the finish, 2 h, 1 day, and 2 days after the race. A significant elevation in all parameters occurred immediately after the race (Wilcoxon ranksum test). There was no difference between treated and non-treated group (Mann-Whitney U-test). The Myo level peaked at the finish (814 μg/L; 95% CI, 759-869), whereas CK, ASAT, and CRP levels peaked 1 day after the race (6601 U/L, 4342-8860; 211 U/L, 160-262; 26 mg/L, 22-30). In the control group, the Myo value at the finish was correlated with the 1 day post-race CRP level (Spearman r=0.68, p=0.03). Further, CK and ASAT correlated significantly with the 1 day post-race CRP level at the finish, 1 and 2 days post-race (r>0.65, p<0.04). In contrast, no such correlation was found in the Diclofenac treated group. Diclofenac did not change the elevation of the analyzed parameters, but might have interfered with the regulation of muscle damage and/or the acute phase reaction.

Stress fractures. An analysis of 250 consecutive cases.

STRESS, fatigue, boot, cough, and march fractures are some of the more common synonyms for a particular type of fracture which occurs in individuals with seemingly normal form and structure of bone, but an apparent susceptibility to development of fractures under conditions of unaccustomed stress and physical activity. Stress fractures are relatively infrequent in average radiological practice. The usual roentgen appearance offers no special diagnostic challenge, but of particular concern is the fact that certain of the clinical and radiographic features of stress fractures may on occasion mimic malignant bone tumors (5). The large military training facility affords a most unique opportunity to definitively study this problem. This is due to the large number of reasonably healthy young males sub jected to vigorous training conditions, which for most participants fulfill the criteria for unaccustomed physical activity. This report concerns our analysis of 250 fatigue fractures of bone encountered in 219 patients over an arbitrary ten-month period at one of the largest troop-training centers within the United States. All patients studied were otherwise healthy young males without underlying abnormality of bone, and serial roentgenograms were available for analysis in all cases. Clinical Findings In our selected population of military trainees, the onset of clinical findings was generally during the first two weeks of basic training, frequently occurring during the first several days. In those patients suitable for retrospective study of originally negative roentgenograms, symptoms preceded the onset of positive radiographic findings by from one to several weeks. The most common presenting symptom was pain, which was usually described initially as an aching or soreness. However, the pain and discomfort invariably became progressively more intense with the passage of time. Although a few patients felt that light activity alleviated their symptoms, the consensus was that more intense physical activity aggravated pain and discomfort. Positive physical findings included localized tenderness, swelling, and discoloration. A limping gait was invariably present when the stress fracture occurred in the lower extremity. A frequent finding later in the course of healing of metatarsal stress fractures was the presence of a palpable mass, due to the formation of exuberant callus. Radiographic Findings Retrospective analysis of these 250 stress fractures suggested to us that the initial roentgen features could be categorized into one of four basic patterns. The dominant pattern depended not only upon the bone involved, but also upon the period in the evolution of the process when roentgenograms were first obtained. These four patterns were: TYPE I: Fracture line only demonstrable, with no evidence of endosteal callus or periosteal reaction