Amino acid profile during exercise and training in Standardbreds.

The objective of this study is to assess the influence of acute exercise, training and intensified training on the plasma amino acid profile. In a 32-week longitudinal study using 10 Standardbred horses, training was divided into four phases, including a phase of intensified training for five horses. At the end of each phase, a standardized exercise test, SET, was performed. Plasma amino acid concentrations before and after each SET were measured. Training significantly reduced mean plasma aspartic acid concentration, whereas exercise significantly increased the plasma concentrations of alanine, taurine, methionine, leucine, tyrosine and phenylalanine and reduced the plasma concentrations of glycine, ornithine, glutamine, citrulline and serine. Normally and intensified trained horses differed not significantly. It is concluded that amino acids should not be regarded as limiting training performance in Standardbreds except for aspartic acid which is the most likely candidate for supplementation.

The incidence and severity of gastric ulceration does not increase in overtrained Standardbred horses.

REASONS FOR PERFORMING STUDY: Gastric ulceration can be caused by different pathophysiological mechanisms including dietary factors, psychological stress and exercise. Overtraining is a medical syndrome in performance horses associated with altered hormone levels, altered feed intake, altered behaviour and decreased performance. These components might lead to a higher incidence of gastric ulceration in overtrained horses. OBJECTIVES: To investigate whether the incidence of gastric ulceration is increased in overtrained compared to control horses. METHODS: A longitudinal training study with twelve 1.5 years old Standardbred horses was performed on a treadmill for a total of 32 weeks. Training was divided into 4 periods: (1) acclimatisation (2) training (3) intensified training, and (4) detraining. In period 3, the horses were randomly divided into 2 groups: control (C) and intensified trained group (IT). At the end of each period, gastroscopy was performed in conscious horses after withholding feed for 12 h and water for 6 h using a 3.5 m video gastroendoscope. Lesion scores were assigned to areas of the stomach and graded 1-4. Logistic regression was used for statistical calculations. RESULTS: Evaluation of the stomach revealed only minor changes (grades 1 or 2) on each occasion. There were no significant differences in gastric lesion scores between groups or periods. Most lesions (70%) were found around the minor curvature. After detraining no lesions (0%) were found in contrast to periods 1 (40%, P = 0.056), 2 (30%) and 3 (30%). CONCLUSIONS: Experimentally-induced overtraining does not increase the incidence of gastric ulceration in normally fed Standardbred horses and detraining appears to reduce gastric ulceration.

Normal function of the hypothalamic-pituitary growth axis in three dwarf Friesian foals.

Serial blood samples were collected from three dwarf Friesian foals to examine their endogenous growth hormone (GH) profiles, and the integrity of the GH-insulin-like growth factor-1 (IGF-1) axis was tested in one of them by examining its responses to the administration of GH-releasing hormone (GHRH) and to 10 days of treatment with recombinant equine GH. The basal serum concentrations of IGF-1 in the three dwarf foals were compared with those in nine age-matched normal foals. All the dwarf foals secreted endogenous GH. Stimulation with 7.0 microg/kg GHRH led to a 1400 per cent increase in plasma GH concentration in the dwarf foal tested, and 10 daily subcutaneous treatments with 20 microg/kg recombinant equine GH led to a 100 per cent increase in its serum IGF-1 concentration. The basal serum concentrations of IGF-1 in the dwarf foals were not significantly different from those of the normal foals.

Overtrained horses alter their resting pulsatile growth hormone secretion.

The influence of intensified and reduced training on nocturnal growth hormone (GH) secretion and elimination dynamics was studied in young (1.5 yr) Standardbred geldings to detect potential markers indicative for early overtraining. Ten horses trained on a treadmill for 32 wk in age-, breed-, and gender-matched fixed pairs. Training was divided into four phases (4, 18, 6, and 4 wk, respectively): 1) habituation to high-speed treadmill trotting, 2) normal training, in which speed and duration of training sessions were gradually increased, 3) in this phase, the horses were divided into 2 groups: control (C) and intensified trained (IT) group. In IT, training intensity, duration, and frequency were further increased, whereas in control these remained unaltered, and 4) reduced training (RT). At the end of phases 2, 3, and 4, blood was sampled overnight every 5 min for 8 h for assessment of GH secretory dynamics using pulse detection, deconvolution analysis, and approximate entropy (ApEn). Intensified training induced overtraining (performance decreased by 19% compared with C), which was associated with an increase in concentration peaks number (3.6 vs. 2.0, respectively), a smaller peak secretion pattern with a prolonged half-life (15.2 vs. 7.3 min, respectively), and an increased ApEn (0.89 vs. 0.49, respectively). RT did not lead to full recovery for the overtrained horses. The increased irregularity of nocturnal GH pulsatility pattern is indicative of a loss of coordinated control of GH regulation. Longer phases of somatostatin withdrawal are hypothesized to be the underlying mechanism for the observed changes in GH pulsatility pattern.

Long-standing, insulin-treated type 2 diabetes patients with complications respond well to short-term resistance and interval exercise training.

OBJECTIVE: To determine the feasibility and the benefits of combined resistance and interval exercise training on phenotype characteristics and skeletal muscle function in deconditioned, type 2 diabetes (T2D) patients with polyneuropathy. DESIGN: Short-term, single-arm intervention trial. METHODS: Eleven male T2D patients (age: 59.1+/-7.5 years; body mass index: 32.2+/-4.0 kg/m2) performed progressive resistance and interval exercise training thrice a week for 10 weeks. Besides primary diabetes outcome measures, muscle strength (MUST), maximal workload capacity (Wmax), whole-body peak oxygen uptake (VO2peak) and muscle oxidative capacity (MUOX), intramyocellular lipid (IMCL) and glycogen (IMCG) storage, and systemic inflammation markers were determined before and after training. Daily exogenous insulin requirements (EIR) and historic individualized EIR were gathered and analysed. RESULTS: MUST and Wmax increased with 17% (90% confidence intervals 9-24%) and 14% (6-21) respectively. Furthermore, mean arterial blood pressure declined with 5.5 mmHg (-9.7 to -1.4). EIR dropped with 5.0 IU/d (-11.5 to 1.5) compared with baseline. A decline of respectively -0.7 mmol/l (-2.9 to 1.5) and -147 micromol/l (-296 to 2) in fasting plasma glucose and non-esterified fatty acids concentrations were observed following the intervention, but these were not accompanied by changes in VO2peak, MUOX, IMCL or IMCG, and blood glycolysated haemoglobin, adiponectin, tumor necrosis factor-alpha and/or cholesterol concentrations. CONCLUSION: Short-term resistance and interval exercise training is feasible in deconditioned T2D patients with polyneuropathy and accompanied by moderate improvements in muscle function and blood pressure. Such a specific exercise regimen may provide a better framework for future exercise intervention programmes in the treatment of deconditioned T2D patients.

Hormonal responses to acute exercise, training and overtraining. A review with emphasis on the horse.

Overtraining is an imbalance between training and recovery leading to symptoms associated with a neuroendocrine dysbalance called the overtraining syndrome, a disease characterized by behavioral, emotional and physical symptoms similar with depression. Although the prevalence of overtraining is high in human and equine athletes, at present no sensitive and specific test is available to prevent or diagnose overtraining. Nowadays, it is believed that combination of different (hormonal) parameters appear to be the best indicators of overtraining. Therefore, this review provides a summary of previous literature examining the response of the hypothalamic-pituitary-adrenal (HPA) axis and the growth hormone-insulin-like growth factor-I (GH-IGF-I) axis to acute and chronic exercise as well as overtraining in humans and horses. The exercise induced hormonal responses seem to be equal for the equine as well as the human athlete, which makes comparisons possible. Repeated bouts of exercise are suggested to provide a way to detect subtle changes in hormonal responses in the individual athlete, which may make them an important tool in detecting early overtraining. This should be combined with corticotropin releasing hormone (CRH) stimulation tests and basal ACTH and GH pulsatility determination. Further research is needed to establish the correct training intensity and rest period for the exercise test in equines.

Substrate source utilisation in long-term diagnosed type 2 diabetes patients at rest, and during exercise and subsequent recovery.

AIMS/HYPOTHESIS: Disturbances in substrate source metabolism and, more particularly, in fatty acid metabolism, play an important role in the aetiology and progression of type 2 diabetes. However, data on substrate source utilisation in type 2 diabetes are inconclusive. METHODS: [U-(13)C]palmitate and [6,6-(2)H(2)]glucose tracers were used to assess plasma NEFA and glucose oxidation rates and to estimate the use of muscle- and/or lipoprotein-derived triacylglycerol and muscle glycogen. Subjects were ten male patients who had a long-term (7 +/- 1 years) diagnosis of type 2 diabetes and were overweight, and ten matched healthy, male control subjects. Muscle biopsy samples were collected before and after exercise to assess muscle fibre type-specific intramyocellular lipid and glycogen content. RESULTS: At rest and during exercise, the diabetes patients had greater values than the controls for palmitate rate of appearance (Ra) (rest, 2.46 +/- 0.18 and 1.85 +/- 0.20 respectively; exercise, 3.71 +/- 0.36 and 2.84 +/- 0.20 micromol kg(-1) min(-1)) and rate of disappearance (Rd) (rest, 2.45 +/- 0.18 and 1.83 +/- 0.20; exercise, 3.64 +/- 0.35 and 2.80 +/- 0.20 micromol kg(-1) min(-1) respectively). This was accompanied by significantly higher fat oxidation rates at rest and during recovery in the diabetes patients (rest, 0.11 +/- 0.01 in diabetes patients and 0.09 +/- 0.01 in controls; recovery, 0.13 +/- 0.01 and 0.11 +/- 0.01 g/min respectively), despite significantly greater plasma glucose Ra, Rd and circulating plasma glucose concentrations. Furthermore, exercise significantly lowered plasma glucose concentrations in the diabetes patients, as a result of increased blood glucose disposal. CONCLUSION: This study demonstrates that substrate source utilisation in long-term-diagnosed type 2 diabetes patients, in whom compensatory hyperinsulinaemia is no longer present, shifts towards an increase in whole-body fat oxidation rate and is accompanied by disturbances in fat and carbohydrate handling.

The effect of long-term exercise on glucose metabolism and peripheral insulin sensitivity in standardbred horses.

REASONS FOR PERFORMING STUDY: To study the possible long-term effect of improved glucose tolerance in horses after long-term training, as the impact of exercise training on glucose metabolism is still unclear in the equine species. It is not known whether there is a direct long-term effect of training or if the measurable effect on glucose metabolism is the residual effect of the last exercise session. OBJECTIVES: To determine the chronic effect on glucose metabolism and peripheral insulin sensitivity of long-term training in horses by use of the euglycaemic hyperinsulinaemic clamp technique. METHODS: Eleven Standardbred horses were acclimatised to running on the high-speed treadmill for 4 weeks (Phase 1) followed by training for 18 weeks with an alternating endurance (approximately 60% HRmax) high intensity training programme (approximately 80% HRmax) (Phase 2). Training frequency was 4 days/week. At the end of Phase 1, a euglycaemic hyperinsulinaemic clamp was performed 72 h after the last bout of exercise in all horses. At the end of Phase 2, the horses were clamped 24 h or 72 h after the last bout of exercise. RESULTS: Glucose metabolism rate did not change significantly after 18 weeks of training, measured 72 h after the last exercise bout (0.018 +/- 0.009 and 0.022 +/- 0.006 mmol/kg bwt/min, respectively). Peripheral insulin sensitivity also did not change significantly following training (7.6 +/- 5.7 x 10(-6) and 8.0 +/- 3.1 x 10(-6), respectively). The same measurements 24 h after the last bout of exercise showed no significant differences. CONCLUSIONS: Results indicated that long-term training in Standardbreds neither changed glucose metabolism or insulin sensitivity 72 h after the last bout of exercise. POTENTIAL RELEVANCE: The fact that the beneficial effect of increased insulin sensitivity after acute exercise diminishes quickly in horses and no long-term effects on insulin sensitivity after chronic exercise have as yet been found in horses, implies that exercise should be performed on a regular basis in horses to retain the beneficial effect of improved insulin sensitivity.

Inhibition of adipose tissue lipolysis increases intramuscular lipid use in type 2 diabetic patients.

AIMS/HYPOTHESIS: In the present study, we investigated the consequences of adipose tissue lipolytic inhibition on skeletal muscle substrate use in type 2 diabetic patients. MATERIALS AND METHODS: We studied ten type 2 diabetic patients under the following conditions: (1) at rest; (2) during 60 min of cycling exercise at 50% of maximal workload capacity and subsequent recovery. Studies were done under normal, fasting conditions (control trial: CON) and following administration of a nicotinic acid analogue (low plasma non-esterified fatty acid trial: LFA). Continuous [U-13C]palmitate and [6,6 -2H2]glucose infusions were applied to quantify plasma NEFA and glucose oxidation rates, and to estimate intramuscular triacylglycerol (IMTG) and glycogen use. Muscle biopsies were collected before and after exercise to determine net changes in lipid and glycogen content specific to muscle fibre type. RESULTS: Following administration of the nicotinic acid analogue (Acipimox), the plasma NEFA rate of appearance was effectively reduced, resulting in lower NEFA concentrations in the LFA trial (p<0.001). Plasma NEFA oxidation rates were substantially reduced at rest, during exercise and subsequent recovery in the LFA trial. The lower plasma NEFA oxidation rates were compensated by an increase in IMTG and endogenous carbohydrate use (p<0.05). Plasma glucose disposal rates did not differ between trials. In accordance with the tracer data, a greater net decline in type I muscle fibre lipid content was observed following exercise in the LFA trial (p<0.05). CONCLUSIONS/INTERPRETATION: This study shows that plasma NEFA availability regulates IMTG use, and that adipose tissue lipolytic inhibition, in combination with exercise, could be an effective means of augmenting intramuscular lipid and glycogen use in type 2 diabetic patients in an overnight fasted state.

Physiological, biochemical and psychological markers of strenuous training-induced fatigue.

The purpose of the study was to investigate whether severe fatigue, possibly leading to overreaching, could be diagnosed at an early stage by a combination of parameters. Seven well-trained male subjects (age [mean +/- SD]: 25.3 +/- 4.7 yr; body mass: 76 +/- 6.6 kg; VO2max: 61.1 +/- 7 ml.kg(-1).min(-1)) increased their training load by doubling their training volume and increasing the intensity by 15 % over a period of two weeks. Before and after this intensified training period subjects underwent a series of tests including a maximal incremental cycle ergometer test (Wmax) with continuous ventilatory measurements and blood lactate values, time trial, basal blood parameter tests (red and white blood profile), hormones [growth hormone (GH), insulin-like growth factor 1(IGF-1), adreno-corticotropic hormone (ACTH), cortisol], neuro-endocrine stress test [short insulin tolerance test (SITT), combined anterior pituitary test (CAPT) and exercise], a shortened Profile of Mood State (POMS), the estimated rate of perceived exertion (RPE) and a cognitive reaction time test. The intensified training period resulted in a significant increase of the training load (p <0.01), training monotony (p <0.01) and training strain (p <0.01). The RPE during training increased significantly (p <0.01) during the intensified training period. Total mood score obtained from the POMS tended to increase (p=0.06), reflecting an increase in worse mood state. A novel finding was that reaction times increased significantly, indicating that overreaching might adversely affect speed of information processing by the brain, especially for the most difficult conditions. After the intensified training period, neither changes in exercise-induced plasma hormone values, nor SITT values were observed. During the CAPT only cortisol showed a significant decrease after the intensified training period. Hemoglobin showed a significant decrease after the intensified training period whereas hematocrit, red blood cell count (RBC) and MCV tended to decrease. The intensified training had no effect on physical performance (Wmax or time trial), maximal blood lactate, maximal heart rate and white blood cell profile. The most sensitive parameters for detecting overreaching are reaction time performance (indicative for cognitive brain functioning), RPE and to a lesser extend the shortened POMS. This strongly suggests, that central fatigue precedes peripheral fatigue. All other systems,including the neuro-endocrine, are more robust and react most likely at a later stage in exhaustive training periods.

Effects of androgenic-anabolic steroids on apolipoproteins and lipoprotein (a).

OBJECTIVES: To investigate the effects of two different regimens of androgenic-anabolic steroid (AAS) administration on serum lipid and lipoproteins, and recovery of these variables after drug cessation, as indicators of the risk for cardiovascular disease in healthy male strength athletes. METHODS: In a non-blinded study (study 1) serum lipoproteins and lipids were assessed in 19 subjects who self administered AASs for eight or 14 weeks, and in 16 non-using volunteers. In a randomised double blind, placebo controlled design, the effects of intramuscular administration of nandrolone decanoate (200 mg/week) for eight weeks on the same variables in 16 bodybuilders were studied (study 2). Fasting serum concentrations of total cholesterol, triglycerides, HDL-cholesterol (HDL-C), HDL2-cholesterol (HDL2-C), HDL3-cholesterol (HDL3-C), apolipoprotein A1 (Apo-A1), apolipoprotein B (Apo-B), and lipoprotein (a) (Lp(a)) were determined. RESULTS: In study 1 AAS administration led to decreases in serum concentrations of HDL-C (from 1.08 (0.30) to 0.43 (0.22) mmol/l), HDL2-C (from 0.21 (0.18) to 0.05 (0.03) mmol/l), HDL3-C (from 0.87 (0.24) to 0.40 (0.20) mmol/l, and Apo-A1 (from 1.41 (0.27) to 0.71 (0.34) g/l), whereas Apo-B increased from 0.96 (0.13) to 1.32 (0.28) g/l. Serum Lp(a) declined from 189 (315) to 32 (63) U/l. Total cholesterol and triglycerides did not change significantly. Alterations after eight and 14 weeks of AAS administration were comparable. No changes occurred in the controls. Six weeks after AAS cessation, serum HDL-C, HDL2-C, Apo-A1, Apo-B, and Lp(a) had still not returned to baseline concentrations. Administration of AAS for 14 weeks was associated with slower recovery to pretreatment concentrations than administration for eight weeks. In study 2, nandrolone decanoate did not influence serum triglycerides, total cholesterol, HDL-C, HDL2-C, HDL3-C, Apo-A1, and Apo-B concentrations after four and eight weeks of intervention, nor six weeks after withdrawal. However, Lp(a) concentrations decreased significantly from 103 (68) to 65 (44) U/l in the nandrolone decanoate group, and in the placebo group a smaller reduction from 245 (245) to 201 (194) U/l was observed. Six weeks after the intervention period, Lp(a) concentrations had returned to baseline values in both groups. CONCLUSIONS: Self administration of several AASs simultaneously for eight or 14 weeks produces comparable profound unfavourable effects on lipids and lipoproteins, leading to an increased atherogenic lipid profile, despite a beneficial effect on Lp(a) concentration. The changes persist after AAS withdrawal, and normalisation depends on the duration of the drug abuse. Eight weeks of administration of nandrolone decanoate does not affect lipid and lipoprotein concentrations, although it may selectively reduce Lp(a) concentrations. The effect of this on atherogenesis remains to be established.

Androgenic anabolic steroid use and severe hypothalamic-pituitary dysfunction: a case study.

The data of the present case demonstrate that the abuse of androgenic anabolic steroids (AAS) may lead to serious health effects. Although most clinical attention is usually directed towards peripheral side effects, the most serious central side effect, hypothalamic-pituitary-dysfunction, is often overlooked in severe cases. Although this latter central side-effect usually recovers spontaneously when AAS intake is discontinued, the present case shows that spontaneous recovery does not always take place. We suggest that hypothalamic-pituitary dysfunction should always be considered in the differential diagnosis in athletes seen with typical presentation of anabolic steroid use. In order to regain normal hypothalamic-pituitary function, supraphysiological doses of 200 microg LH-RH should be considered when the physiological challenge test with LH-RH (50 microg) fails to show an acceptable response.

Diminished performance on response-selection tasks in Type 2 diabetes.

Comparisons of visual perception, response-selection, and response-execution performance were made between Type 2 diabetes mellitus patients and a matched nondiabetic control group. 10 well-controlled male patients with Type 2 diabetes without diabetic complications (M age 58 yr.) and an age and IQ-matched non-diabetic control group consisting of 13 male healthy volunteers (M age 57 yr.) were included. Significant differences were found only between the two groups on response-selection performance, which concerns the selection and preparation of an appropriate motor action.

Substrate utilization in non-obese Type II diabetic patients at rest and during exercise.

Recently, we observed that impairments exist in skeletal muscle free fatty acid (FFA) utilization during exercise in obese subjects with Type II diabetes. The main objective of the present study was to investigate whether plasma FFA oxidation is impaired during exercise in non-obese Type II diabetic patients. Stable isotope tracers of palmitate and glucose were infused for 2 h at rest and 1h of bicycle exercise at 40% peak oxygen consumption ( V*O(2)max) in volunteers with Type II diabetes and a healthy control group. At rest, plasma FFA oxidation was not significantly different between subjects with Type II diabetes and control subjects (2.13+/-0.51 versus 1.93+/-0.54 micromol.kg(-1).min(-1) respectively). During exercise, Type II diabetic patients and control subjects had similar rates of total fat [Type II diabetes, 9.62+/-1.84 micromol.kg(-1).min(-1); control, 12.08+/-4.59 micromol.kg(-1).min(-1); not significant (NS)] and glucose oxidation (Type II diabetes, 44.24+/-10.36 micromol.kg(-1).min(-1); control, 57.37+/-14.54 micromol.kg(-1).min(-1); NS). No aberrations were present in plasma FFA uptake [rate of disappearance ( Rd ); Type II diabetes, 11.78+/-4.82; control, 10.84+/-3.39; NS] and oxidation rates (Type II diabetes 8.10+/-1.44; control 8.00+/-3.12, NS) in Type II diabetic patients; triacylglycerol-derived fatty acid oxidation was 2.6-fold lower in Type II diabetic patients than in control subjects, but this difference was not statistically significant. Muscle glycogen oxidation was lower in diabetes patients than in control subjects (Type II diabetes, 25.16+/-13.82 micromol.kg(-1).min(-1); control, 42.04+/-10.58 micromol.kg(-1).min(-1); P <0.05) and plasma glucose contributed more to energy expenditure in Type II diabetes (26+/-3% in diabetic versus 15+/-2% in control, P <0.05). We conclude that plasma FFA oxidation is not impaired during exercise in non-obese Type II diabetic patients. The data confirm that Type II diabetes is a heterogeneous disease, and that the adaptation at the substrate level differs between obese and non-obese patients and may contribute to differences in the final appearance of the various phenotypes.

Red blood cell profile of elite olympic distance triathletes. A three-year follow-up.

The purpose of this study was to monitor general and individual changes in hematological variables during long-term endurance training, detraining and altitude training in elite Olympic distance triathletes. Over a period of three years, a total of 102 blood samples were collected in eleven (7-male and 4 female) elite Olympic distance triathletes (mean +/- SD; age = 26.4 +/- 5.1 yr; VO(2) max = 67.9 +/- 6.6 ml/min/kg) for determination of hemoglobin (Hb), hematocrit (Hct), red blood cell count (RBC), Mean corpuscular hemoglobin (MCH), Mean corpuscular hemoglobin content (MCHC), Mean corpuscular volume (MCV) and plasma ferritin. The data were pooled and divided into three periods; off-season, training season and race season. Blood samples obtained before and after altitude training were analyzed separately. Of all measured variables only RBC showed a significant decrease (p < 0.05) during the race season compared to the training season. Hematological values below the lower limit of the normal range were found in 46 % of the athletes during the off-season. This percentage increased from 55 % during the training season to 72 % of the athletes during the race season. Hemoglobin and ferritin values were most frequently below the normal range. There was a weak correlation between Hb levels and VO(2) max obtained during maximal cycling (r = 0.084) and running (r = 0.137) tests. Unlike training at 1500 m and 1850 m, training at an altitude of 2600 m for three weeks showed significant increases in Hb (+ 10 %; p < 0.05), Hct (+ 11 %; p < 0.05) and MCV (+ 5 %; p < 0.05). Long-term endurance training does not largely alter hematological status. However, regular screening of hematological variables is desirable as many athletes have values near or below the lower limit of the normal range. The data obtained from altitude training suggest that a minimum altitude (>2000 m) is necessary to alter hematological status.

Misuse of androgenic-anabolic steroids and human deltoid muscle fibers: differences between polydrug regimens and single drug administration.

The objective of this investigation was to study the effects of androgenic-anabolic steroid (AAS) misuse on deltoid muscle fiber characteristics in experienced, male strength-trained athletes. In a double-blind study, 15 volunteers were administered nandrolone decanoate (ND) for 8 weeks (200 mg/week, intramuscularly). In an additional study, 12 subjects self-administered various AASs at supratherapeutic dosages (AAS group), while 7 non-users served as controls. In all subjects, a percutaneous needle biopsy sample of the deltoid muscle was obtained at baseline and after 8 weeks. Muscle sections were pre-incubated at pH 4.4, stained with adenosine triphosphatase and analyzed morphometrically. In each biopsy sample, at least 150 fibers were classified for "gray level" and "lesser fiber diameter" to determine the mean fiber size, the sizes of type I and type II fibers, and the fiber type distribution. ND administration did not seem to affect any of those parameters. In the AAS group, mean muscle fiber size (+ 12.6%), and the size of type I (+ 10.8%) and type II (+ 14.6%) muscle fibers increased. The fiber type distribution remained unaltered. We conclude that polydrug regimens of AAS misuse at supratherapeutic dosages increased the size of deltoid muscle fibers (especially type II fibers) in experienced strength-trained athletes, while ND at a therapeutic intramuscular dose of 200 mg did not exert any effect.

A reduction in training volume and intensity for 21 days does not impair performance in cyclists.

OBJECTIVES: (a) To investigate the effects of reduced training on physical condition and performance in well trained cyclists; (b) to study whether an intermittent exercise programme would maintain physiological training adaptations more effectively than a continuous exercise programme during a period of reduced training. METHODS: Twelve male cyclists participated in a 21 day training programme and were divided into two training groups. One group (age 25.3 (7) years; weight 73.3 (5.7) kg; VO(2)MAX 58.6 (4.5) ml/kg/min; means (SD)) underwent a continuous endurance exercise training programme (CT) whereas the second group (age 22.8 (3.5) years; weight 74.1 (7.0) kg; VO(2)MAX 59.7 (6.7) ml/kg/min) followed an intermittent endurance exercise training programme (IT). During this reduced training period, both groups trained for two hours a day, three days a week. RESULTS: Neither group showed changes in maximal workload (WMAX) (4.6 (0.5) v 4.8 (0.5) W/kg and 4.6 (0.5) v 4.7 (0.6) W/kg for the CT and IT group respectively) and VO(2)MAX (58.6 (4.5) v 60.1 (5.8) ml/kg/min and 59.7 (6.7) v 58.8 (7.5) ml/kg/min for the CT and IT group respectively). During the submaximal steady state exercise test, substrate use and heart rate remained unchanged after reduced training. CONCLUSIONS: These results indicate that well trained cyclists who reduce training intensity and volume for 21 days can maintain physiological adaptations, as measured during submaximal and maximal exercise. An intermittent training regimen has no advantage over a continuous training regimen during a detraining period.

Uncoupling protein 3 content is decreased in skeletal muscle of patients with type 2 diabetes.

Recently, a role for uncoupling protein-3 (UCP3) in carbohydrate metabolism and in type 2 diabetes has been suggested. Mice overexpressing UCP3 in skeletal muscle showed reduced fasting plasma glucose levels, improved glucose tolerance after an oral glucose load, and reduced fasting plasma insulin levels. However, data regarding the expression of UCP3 in patients with type 2 diabetes is inconsistent, and so far, there have been no reports of UCP3 protein content. Here we compared, for the first time, the protein levels of UCP3 in vastus lateralis muscle in 14 male type 2 diabetic patients (age 49.8 +/- 2.1 years; BMI 27.2 +/- 1.2 kg/m(2); mean +/- SE) with 16 male control subjects (age 48.0 +/- 1.9 years; BMI 23.4 +/- 0.6 kg/m(2)). We found that UCP3 protein levels were twice as low in patients with type 2 diabetes compared with control subjects (117 +/- 16 vs. 58 +/- 12 AU; P = 0.007). There was no correlation between UCP3 content and BMI. In conclusion, UCP3 content is lower in type 2 diabetic patients compared with healthy control subjects. These results are consistent with a role for UCP3 in glucose homeostasis and suggest a role for UCP3 in type 2 diabetes.

[Long-term intensive athletic training; few adverse effects on later physical health]. / Langdurige intensieve fysieke sportbeoefening: weinig nadelige late gevolgen voor de gezondheid.

In general, physical activity benefits health. However, long-term intensive physical training may have detrimental effects on the health of some individuals. In cyclists, changes in the femoral arteries may occur leading to stenoses that are manifested in claudication type symptoms. Some endurance athletes may experience atrial fibrillations that are possibly related to long-term physical training. Older athletes only have an increased risk of osteoarthritis in joints that have suffered injuries. Menstrual disturbances and premature osteoporosis may occur in women as a consequence of intensive physical training. However, the risk for these adverse consequences of long-term physical training is small.

Validation of a computerized metabolic measurement system (Oxycon-Pro) during low and high intensity exercise.

The aim of the study was to validate a new, fast metabolic measurement system (the Oxycon-Pro) during low and high exercise intensities against the Douglas bag method. For this purpose twelve highly trained subjects performed an incremental cycle ergometer test. In the third minute of each exercise step simultaneous measurements of the Douglas bag and the Oxycon-Pro were performed. No significant differences between the Oxycon-Pro and the Douglas bag measurements for minute ventilation (VE), oxygen uptake (VO2) and carbon dioxide expiration (VCO2) were found. Bland and Altman analysis of validity demonstrated minimal bias and low standard deviations. In conclusion, the results show that the Oxycon-Pro is a valid apparatus for determination of minute ventilation (VE), oxygen uptake (VO2) and carbon dioxide expiration (VCO2) during low as well as during maximal exercise intensities. Unlike with the Douglas bag method, this fast metabolic measurement system can be used for accurate and quick determination of ventilatory variables during exercise.