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Dive into the research topics where Karl E. Friedl is active.

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Featured researches published by Karl E. Friedl.


Metabolism-clinical and Experimental | 1990

High-density lipoprotein cholesterol is not decreased if an aromatizable androgen is administered

Karl E. Friedl; Robert E. Jones; Stephen R. Plymate

We examined the influence of aromatization of testosterone on serum high-density lipoprotein cholesterol (HDL-C) and postheparin plasma hepatic triglyceride lipase activity (HTLA) in men. Eighteen healthy lean nonsmokers (ages, 20 to 33) were administered androgens in a weekly total dose of 280 mg for 12 weeks in one of three groups: testosterone enanthate (TE) (280 mg/wk intramuscularly [IM]); TE (280 mg/wk IM) + testolactone (TL) (250 mg orally [PO] four times daily); or methyltestosterone (MeT) (20 mg PO twice daily). Serum testosterone achieved steady state levels by 4 weeks with greater than 40 nmol/L (TE and TE + TL) and less than 15 nmol/L (MeT) while 17b-estradiol (E2) rose to greater than 250 pmol/L (TE) or remained below 70 pmol/L (TE + TL and MeT). LH fell to less than 5 U/L (TE and TE + TL) but remained unchanged with MeT. By 4 weeks, HDL-C had decreased significantly from 1.20 +/- 0.13 to 0.77 +/- 0.13 mmol/L (MeT), from 1.18 +/- 0.15 to 0.89 +/- 0.13 mmol/L (TE TL), and demonstrated no decrease in the TE group across the time course of the study. These changes were preceded by mean increases in HTLA of 102% (MeT) and 55% (TE + TL) over baseline, and no significant change with TE. The changes in HDL-C and HTLA returned to baseline within 2 weeks of steroid cessation. There were no changes in total cholesterol, triglycerides, or insulin in any group but, in the MeT group, apo AI levels decreased and low-density lipoprotein cholesterol (LDL-C) increased.(ABSTRACT TRUNCATED AT 250 WORDS)


The Physician and Sportsmedicine | 1988

Self-Reported Use of Anabolic-Androgenic Steroids by Elite Power Lifters.

Charles E. Yesalis; Richard T. Herrick; William E. Buckley; Karl E. Friedl; Diane Brannon; James E. Wright

In brief: Sixty-one athletes competed in the 1987 National Championship of the US Powerlifting Federation; all were surveyed to obtain information on anabolic-androgenic steroids regarding attitudes, patterns of use, and health effects. Of the 45 who responded to the survey, 15 admitted having used steroids. In a follow-up telephone interview of 20 of the competitors, 11 reported previous steroid use. The reason given most often for using steroids was improved athletic performance; the most common side effects reported were heightened libido, acne, and increased body hair. The small number of admitted users suggests that underreporting took place; this level of use probably represents the lower bound of steroid use among power lifters.


The Journal of Steroid Biochemistry and Molecular Biology | 1991

Comparison of the effects of high dose testosterone and 19-nortestosterone to a replacement dose of testosterone on strength and body composition in normal men ☆

Karl E. Friedl; Joseph R. Dettori; Charles J. Hannan; Troy Patience; Stephen R. Plymate

We examined the extent to which supraphysiological doses of androgen can modify body composition and strength in normally virilized men. In doubly blind tests, 30 healthy young men received testosterone enanthate (TE) or 19-nortestosterone decanoate (ND), at 100 mg/wk or 300 mg/wk for 6 weeks. The TE-100 mg/wk group served as replacement dose comparison, maintaining pretreatment serum testosterone levels, while keeping all subjects blinded to treatment, particularly through reduction in testicular volumes. Isokinetic strength measurements were made for the biceps brachii and quadriceps femoris muscle groups before treatment and 2-3 days after the 6th injection. Small improvements were noted in all groups but the changes were highly variable; a trend to greater and more consistent strength gain occurred in the TE-300 mg/wk group. There was no change in weight for TE-100 mg/wk but an average gain of 3 kg in each of the other groups. No changes in 4 skinfold thicknesses or in estimated percent body fat were observed. Of 15 circumferences, significant increases were observed only for men receiving TE-300 mg/wk (shoulders) and ND-300 mg/wk (shoulders and chest). The data suggest that high dose androgens increase body mass and may increase strength in normal men but, except for a consistent weight gain with greater than replacement doses, the detectable changes were highly variable and relatively small, especially in comparison to the significant alterations which were observed for other markers of androgen action.


Journal of Drug Education | 1989

Anabolic Steroid Use: Indications of Habituation among Adolescents.

Charles E. Yesalis; Andrea Streit; Judith R. Vicary; Karl E. Friedl; Diane Brannon; William E. Buckley

The use of anabolic steroids (AS) by adolescent males is argued to be more widespread than currently acknowledged. Although the long-term physiological and psychological ramifications of use are not well established, current research and anecdotal information suggest that there is reason for concern. In addition, very little is known about the attitudes and behaviors of these adolescent AS users. While the debate concerning the physiological versus the psychological dependence liability of various drugs continues to evolve, there seems to be a consensus that drug dependence is not a per se phenomenon and that the characteristics of dependence differ in accordance with the drug being used. The following article attempts to identify characteristics of the adolescent male AS user and suggests that AS use does have a dependence potential. The AS user population was found to be significantly different from nonusers in several areas such as self-perceptions of health and strength, interest in controlling AS use, and perceptions of peer AS use. The AS user group was also found to contain several subgroups (heavy users [≥ 5 cycles] versus other users, and those who initiated use prior to age sixteen who reported significantly different attitudes and/or behaviors. These differences suggest that prevention efforts will have to focus on different motivations for AS use.


Medicine and Science in Sports and Exercise | 1994

Loss of muscle mass is poorly reflected in grip strength performance in healthy young men

Michael J. Johnson; Karl E. Friedl; Peter N. Frykman; Robert J. Moore

Isometric maximal handgrip strength (GSmax) has been used as an expedient test of overall muscle strength and index of fat-free mass (FFM). We tested this relationship in 55 fit young men undergoing high rates of FFM loss in an 8.5-wk military training course involving multiple stressors including nutritionally uncomplicated energy deficit. GSmax was measured by a hand dynamometer interfaced with a computer providing visual feedback; another strength test, measuring dynamic strength of larger muscle groups (Cleansim), was also performed. GSmax did not change (530 +/- 57 vs 529 +/- 63 N) in the face of a 15.6% loss of body weight (12.1 +/- 3.4 (SD) kg), including 6.9% loss of FFM (4.6 +/- 2.6 kg), but Cleansim decremented significantly (77.4 +/- 9.6 to 58.7 +/- 8.9 kg) and changes were significantly correlated with delta FFM for GSmax (r = 0.31) and Cleansim (r = 0.49). We conclude that GSmax is not a good representation of changes in total FFM in healthy young men even though it appears to be useful in more severely catabolic patients with extreme losses of FFM and in pubertal boys making large gains in FFM. Other aspects of physical performance are clearly affected by high rates of weight loss, as demonstrated by decrements in the Cleansim and its stronger relationship to delta FFM.


Medicine and Science in Sports and Exercise | 2008

Stress fracture and military medical readiness: bridging basic and applied research.

Karl E. Friedl; Rachel K. Evans; Daniel S. Moran

PURPOSE Military recruits and distance runners share a special risk of stress fracture injury. Recent efforts by US and Israeli military-sponsored researchers have uncovered important mechanisms and practical low-cost interventions. This article summarizes key findings relevant to prevention of stress fracture, including simple strategies to identify and to mitigate risk. METHODS Published research supported through the Bone Health and Military Medical Readiness research program and related military bone research was analyzed for contributions to preventing stress fracture in military recruits and optimizing bone health. RESULTS Thousands of military recruits helped test hypotheses about predictors of risk, safer exercise regimens, and rest, nutrition, gait training, and technology interventions to reduce stress fracture risk. Concurrent cellular, animal, and human laboratory studies were used to systematically investigate mechanisms of mechanical forces acting on bone and interactions through muscle, hormonal and genetic influences, and metabolism. The iterative and sometimes simultaneous process of basic discovery and field testing produced new knowledge that will provide safer science-based physical training. DISCUSSION Human training studies evaluating effects on bone require special commitment from investigators and funders due to volunteer compliance and attrition challenges. The findings from multiple studies indicate that measures of bone elasticity, fragility, and geometry are as important as bone mineral density in predicting fracture risk, with applications for new measurement technologies. Risk may be reduced by high intakes of calcium, vitamin D, and possibly protein (e.g., milk products). Prostaglandin E2, insulin-like growth factor 1, and estrogens are important mediators of osteogenesis, indicating reasons to limit the use of certain drugs (e.g., ibuprofen), to avoid excessive food restriction, and to treat hypogonadism. Abnormal gait may be a correctable risk factor. Brief daily vibration may stimulate bone mineral accretion similar to weight-bearing exercise. Genetic factors contribute importantly to bone quality, affecting fracture susceptibility and providing new insights into fracture healing and tissue reengineering.


Wilderness & Environmental Medicine | 2003

Effects of a 3-Month Endurance Event on Physical Performance and Body Composition: The G2 Trans-Greenland Expedition

Peter N. Frykman; Everett A. Harman; Per Kristian Opstad; Reed W. Hoyt; James P. DeLany; Karl E. Friedl

OBJECTIVE Prolonged physical exertion with inadequate time for recuperation may result in an overtraining phenomenon characterized by reduced physical strength and endurance capacity. We tested the hypothesis that highly motivated men pushed to the limits of their endurance capacity for 3 months would suffer physical breakdown characterized by loss of lean mass and reduced physical performance capacity. METHODS Two well-trained men (VO2max > 60 mL/kg/min), aged 25 years, completed an unsupported, 2928-km, south-to-north ski trek across Greenland in 86 days. The trek involved ski marching, typically for 9 h/d, pulling sleds initially containing 150 kg and a high-fat (60%) energy-dense diet of 25.1 MJ/d. Body composition and physical performance data were collected 14 days before and 4 days after the trek. RESULTS Energy expenditure based on doubly labeled water during three 2-week periods ranged from 28.3 and 34.6 MJ/d in rugged terrain to 14.6 and 16.1 MJ/d during travel on flat terrain for subjects 1 and 2, respectively. Both men lost weight, completing the trek with low-normal fat stores (approximately 13% body fat). The lighter man gained 0.6 kg lean mass, while the heavier man lost 1.4 kg lean mass and a larger amount of fat weight (7.0 kg). Most performance measures showed trivial changes within the errors of measurement and test reproducibility, indicating no loss of endurance capacity, but anaerobic tests (Wingate and vertical jump) were markedly reduced. Markers of metabolic status, including oral glucose tolerance tests, indicated no functional impairments. CONCLUSIONS Although the number of subjects was limited, this observational study demonstrated that well-trained and experienced long-distance ski trekkers who eat an adequate high-calorie diet can perform endurance treks in severe cold, with little or no loss of lean mass and physical capability.


The Physician and Sportsmedicine | 1989

Self-Treatment of Gynecomastia in Bodybuilders Who Use Anabolic Steroids.

Karl E. Friedl; Charles E. Yesalis

In brief: Gynecomastia is a cruel irony for bodybuilders who use steroids in hope of perfecting their somatotype. These athletes and their advisers perpetuate locker-room theories about which drugs to use to avoid this widely acknowledged feminizing effect. This paper presents four case reports of bodybuilders whose self-administered drug programs resulted in gynecomastia. These examples illustrate treatment strategies bodybuilders have advocated for the prevention and self-treatment of gynecomastia, which include the use of tamoxifen, mesterolone, and human chorionic gonadotropin. In fact, the recommended treatment is complete cessation of drugs. By dispelling unfounded treatment methods, physicians might help to discourage these athletes from such drug use.


Current Opinion in Clinical Nutrition and Metabolic Care | 2006

Field studies of exercise and food deprivation.

Reed W. Hoyt; Karl E. Friedl

Purpose of reviewThe increase in obesity in developed societies drives interest in the interplay of energy intake, metabolic energy expenditure, and body energy stores. A better understanding of energy management in physically active and undernourished humans should help guide strategies to manage obesity safely and effectively. This review focuses on field studies of men and women engaged in prolonged strenuous activities, ranging from ranger training to extreme expeditions. Recent findingsAlthough scientifically unconventional and limited, field studies of exercise and food deprivation have yielded interesting findings: 4–5% body fat is the normal lower limit to fat reserves in physically active underfed young adult men, and in response to exercise and underfeeding, women used more fat mass and less fat-free mass to meet metabolic fuel requirements. SummaryField studies have shown that fat energy reserves in young adult men can be estimated as percentage body fat minus 5%, and initial body fat mass has a significant positive influence on fat oxidation rates per kilogram of fat-free mass during rapid weight loss associated with underfeeding and exercise. Data logging pedometers, activity monitors, global positioning systems, and wireless body and personal-area networks promise to make it easier to study and care for free-living humans.


Fertility and Sterility | 1990

Serum lipids and lipoproteins in continuous or cyclic medroxyprogesterone acetate treatment in postmenopausal women treated with conjugated estrogens

Michael K. Yancey; Stephen R. Plymate; I. Keith Stone; Karl E. Friedl; James Wright

This study evaluates effects on serum lipids of continuous or sequential progestogens for hormonal replacement in women. Subjects received either a cyclic regimen of replacement (0.625 mg/d of conjugated equine estrogens (Es) for 25 days/month and 10 mg medroxyprogesterone acetate [MPA] for the last 13 days of E) or 0.625 mg/d E along with either 5 or 10 mg MPA (Provera, Upjohn Company, Kalamazoo, MI). Study parameters were measured over a 24-week period. No differences in total cholesterol, high-density lipoprotein (HDL) cholesterol, triglycerides, apolipoproteins I and II, sex hormone-binding globulin, or serum MPA levels were noted between the sequential and 5 mg continuous group. The 10 mg MPA group did not have an increase in HDL or decrease in low-density lipoprotein as did the other groups.

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Reed W. Hoyt

United States Army Research Institute of Environmental Medicine

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Bradley C. Nindl

United States Army Research Institute of Environmental Medicine

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Charles E. Yesalis

Pennsylvania State University

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Marilyn A. Sharp

United States Army Research Institute of Environmental Medicine

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Robert J. Moore

Louisiana State University

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Adam W Potter

United States Army Research Institute of Environmental Medicine

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Peter N. Frykman

United States Army Research Institute of Environmental Medicine

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