We investigated the effect of carbohydrate and protein hydrolysate ingestion on whole-body and muscle protein synthesis during a combined endurance and resistance exercise session and subsequent ...overnight recovery. Twenty healthy men were studied in the evening after consuming a standardized diet throughout the day. Subjects participated in a 2-h exercise session during which beverages containing both carbohydrate (0.15 g·kg⁻¹·h⁻¹) and a protein hydrolysate (0.15 g·kg⁻¹·h⁻¹) (C+P, n = 10) or water only (W, n = 10) were ingested. Participants consumed 2 additional beverages during early recovery and remained overnight at the hospital. Continuous i.v. infusions with L-ring-¹³C₆-phenylalanine and L-ring-²H₂-tyrosine were applied and blood and muscle samples were collected to assess whole-body and muscle protein synthesis rates. During exercise, whole-body and muscle protein synthesis rates increased by 29 and 48% with protein and carbohydrate coingestion (P < 0.05). Fractional synthetic rates during exercise were 0.083 ± 0.011%/h in the C+P group and 0.056 ± 0.003%/h in the W group, (P < 0.05). During subsequent overnight recovery, whole-body protein synthesis was 19% greater in the C+P group than in the W group (P < 0.05). However, mean muscle protein synthesis rates during 9 h of overnight recovery did not differ between groups and were 0.056 ± 0.004%/h in the C+P group and 0.057 ± 0.004%/h in the W group (P = 0.89). We conclude that, even in a fed state, protein and carbohydrate supplementation stimulates muscle protein synthesis during exercise. Ingestion of protein with carbohydrate during and immediately after exercise improves whole-body protein synthesis but does not further augment muscle protein synthesis rates during 9 h of subsequent overnight recovery.
Resistance exercise has recently been shown to improve whole-body insulin sensitivity in healthy males. Whether this is accompanied by an exercise-induced decline in skeletal muscle glycogen and/or ...lipid content remains to be established. In the present study, we determined fibre-type-specific changes in skeletal muscle substrate content following a single resistance exercise session. After an overnight fast, eight untrained healthy lean males participated in a approximately 45 min resistance exercise session. Muscle biopsies were collected before, following cessation of exercise, and after 30 and 120 min of post-exercise recovery. Subjects remained fasted throughout the test. Conventional light and (immuno)fluorescence microscopy were applied to assess fibre-type-specific changes in intramyocellular triacylglycerol (IMTG) and glycogen content. A significant 27+/-7% net decline in IMTG content was observed in the type I muscle fibres (P<0.05), with no net changes in the type IIa and IIx fibres. Muscle glycogen content decreased with 23+/-6, 40+/-7 and 44+/-7% in the type I, IIa and IIx muscle fibres, respectively (P<0.05). Fibre-type-specific changes in intramyocellular lipid and/or glycogen content correlated well with muscle fibre-type oxidative capacity. During post-exercise recovery, type I muscle fibre lipid content returned to pre-exercise levels within 120 min. No changes in muscle glycogen content were observed during recovery. We conclude that intramyocellular lipid and glycogen stores are readily used during resistance exercise and this is likely associated with the reported increase in whole-body insulin sensitivity following resistance exercise.
Elite sport requires high training volumes. However, little is known about the relationship between training volume and performance development. This relationship appears to have an inverted U-shape. ...Short-term overtraining or overreaching is probably associated with insufficient metabolic recovery, resulting in a decline in ATP levels. Systemic overtraining or staleness is attributed to failure of the hypothalamus to cope with the total amount of stress. Clinically, a parasympathetic and sympathetic form has been distinguished. It is assumed that these two forms express different stages of staleness. No specific, simple, and reliable parameters are known to diagnose overreaching and overtraining in the earliest stage.
In contrast to the effect of nutritional intervention on postexercise muscle protein synthesis, little is known about the potential to modulate protein synthesis during exercise. This study ...investigates the effect of protein coingestion with carbohydrate on muscle protein synthesis during resistance-type exercise. Ten healthy males were studied in the evening after they consumed a standardized diet throughout the day. Subjects participated in two experiments in which they ingested either carbohydrate or carbohydrate with protein during a 2-h resistance exercise session. Subjects received a bolus of test drink before and every 15 min during exercise, providing 0.15 g x kg(-1) x h(-1) carbohydrate with (CHO + PRO) or without (CHO) 0.15 g x kg(-1) x h(-1) protein hydrolysate. Continuous intravenous infusions with l-ring-(13)C(6)phenylalanine and l-ring-(2)H(2)tyrosine were applied, and blood and muscle biopsies were collected to assess whole body and muscle protein synthesis rates during exercise. Protein coingestion lowered whole body protein breakdown rates by 8.4 +/- 3.6% (P = 0.066), compared with the ingestion of carbohydrate only, and augmented protein oxidation and synthesis rates by 77 +/- 17 and 33 +/- 3%, respectively (P < 0.01). As a consequence, whole body net protein balance was negative in CHO, whereas a positive net balance was achieved after the CHO + PRO treatment (-4.4 +/- 0.3 vs. 16.3 +/- 0.4 micromol phenylalanine x kg(-1) x h(-1), respectively; P < 0.01). In accordance, mixed muscle protein fractional synthetic rate was 49 +/- 22% higher after protein coingestion (0.088 +/- 0.012 and 0.060 +/- 0.004%/h in CHO + PRO vs. CHO treatment, respectively; P < 0.05). We conclude that, even in a fed state, protein coingestion stimulates whole body and muscle protein synthesis rates during resistance-type exercise.
Using contemporary stable-isotope methodology and fluorescence microscopy, we assessed the impact of carbohydrate supplementation on whole-body and fiber-type-specific intramyocellular ...triacylglycerol (IMTG) and glycogen use during prolonged endurance exercise. Ten endurance-trained male subjects were studied twice during 3 h of cycling at 63 +/- 4% of maximal O(2) uptake with either glucose ingestion (CHO trial; 0.7 g CHO kg(-1) h(-1)) or without (CON placebo trial; water only). Continuous infusions with U-(13)C palmitate and 6,6-(2)H(2) glucose were applied to quantify plasma free fatty acids (FFA) and glucose oxidation rates and to estimate intramyocellular lipid and glycogen use. Before and after exercise, muscle biopsy samples were taken to quantify fiber-type-specific IMTG and glycogen content. Plasma glucose rate of appearance (R (a)) and carbohydrate oxidation rates were substantially greater in the CHO vs CON trial. Carbohydrate supplementation resulted in a lower muscle glycogen use during the first hour of exercise in the CHO vs CON trial, resulting in a 38 +/- 19 and 57 +/- 22% decreased utilization in type I and II muscle-fiber glycogen content, respectively. In the CHO trial, both plasma FFA R (a) and subsequent plasma FFA concentrations were lower, resulting in a 34 +/- 12% reduction in plasma FFA oxidation rates during exercise (P < 0.05). Carbohydrate intake did not augment IMTG utilization, as fluorescence microscopy revealed a 76 +/- 21 and 78 +/- 22% reduction in type I muscle-fiber lipid content in the CHO and CON trial, respectively. We conclude that carbohydrate supplementation during prolonged cycling exercise does not modulate IMTG use but spares muscle glycogen use during the initial stages of exercise in endurance-trained men.
Samenvatting
ProstaatKankerStichting.nl
(PKS) heeft tijdens een symposium haar visie op de toekomst van de prostaatkankerzorg gepresenteerd. Een visie vanuit het perspectief van de patiënt, waarbij ...kwaliteitscriteria leidend zijn. Alle prostaatkankerpatiënten moeten gelijkwaardige toegang krijgen tot ‘state-of-the-art’-prostaatkankerzorg; de best mogelijke behandeling met goede oncologische resultaten en zo min mogelijk bijwerkingen die de kwaliteit van leven beïnvloeden. Voor optimale prostaatkankerzorg is voldoende volume van patiënten en staf, (sub)specialisatie en een goede infrastructuur van belang. Verdergaande concentratie van de huidige prostaatkankerzorg is hiervoor nodig, uitgevoerd binnen een beperkt aantal expertcentra, eventueel aangevuld met partnerziekenhuizen. Expertcentra worden gekenmerkt door systematische samenwerking, transparant werken aan verbetering van uitkomsten, wetenschappelijk onderzoek, innovatie, samen beslissen en het meten en bespreken van patiëntervaringen.
To assess possible ergogenic properties of corticosteroid administration.
A balanced, double-blind, placebo-controlled design was used.
28 well-trained cyclists and rowers.
4 weeks' daily inhalation ...of 800 microg budesonide or placebo.
The subjects performed three incremental cycle ergometer tests until exhaustion, before and after 2 and 4 weeks of placebo or budesonide administration, to measure maximal power output (W(max)). Once a week they filled in a profile of mood state (POMS) questionnaire.
There was no significant difference in W(max) between the placebo (376 (SD 25) W) and the corticosteroid group (375 (36) W) during the preintervention test, and there were no significant changes in either group after 2 and 4 weeks of intervention. No effect of the intervention on mood state was found.
4 weeks of corticosteroid or placebo inhalation in healthy, well-trained athletes did not affect maximal power output or mood state. Hence no ergogenic properties of 4 weeks' corticosteroid administration could be demonstrated, which corroborates previous studies of short-term corticosteroid administration.
The impact of exercise on blood glucose homeostasis has not been assessed in long-standing type 2 diabetes patients receiving exogenous insulin treatment.
To study the effects of an acute bout of ...exercise on the subsequent 24-h blood glucose excursions under free-living conditions in insulin-treated type 2 diabetes patients.
Eleven male type 2 diabetes patients (59 +/- 2 yr) performed an acute bout of exercise. One day before the exercise bout, a continuous glucose monitoring system (GlucoDay, A. Menarini Diagnostics) was inserted subcutaneously in the periumbilical region. The glucose sensor continuously measured glucose concentrations in the dialysate during a 48-h period.
The prevalence of hyperglycemic glucose excursions was reduced by 39% during a 24-h period (equivalent to 3 h) after an acute bout of exercise (P < 0.05). Average glucose concentrations 24 h before and after the exercise bout did not differ (NS). Mean dialysate glucose concentrations and the prevalence of hyperglycemic periods correlated strongly with baseline blood HbA1c concentrations (Pearson's R = 0.69, P < 0.05).
An acute bout of exercise effectively reduces the prevalence of hyperglycemia during a 24-h period under free-living conditions in long-standing type 2 diabetes patients on exogenous insulin therapy.
To determine (1) whether use of an ankle-foot orthosis (AFO) by patients with ankle dorsiflexor paresis leads to decreased muscle activity, immediately or 6 weeks after AFO use, and (2) whether this ...decrease (if present) differs between healthy and paretic subjects.
Cross-sectional and longitudinal randomized case-control study.
Rehabilitation research center in the Netherlands.
Fourteen healthy persons and 29 patients with foot drop.
Muscle activity was measured by surface electromyography. Electromyographic reproducibility was tested in 14 healthy volunteers walking with and without AFO. Acute changes in muscle activity from AFO use were compared between the 14 healthy persons and the 29 patients with foot drop. Adaptation effects of AFO use after 6 weeks were studied in 29 patients, randomly chosen 16 of whom had started using an AFO at the first measurement.
Amount of change in mean rectified electromyographic activity (delta value) between walking with and without AFO. Follow-up measurements were conducted after 3 and 6 weeks.
Correlation coefficients, reflecting within-subject reproducibility, varied between.68 and.96 (mean,.86). In patients and healthy subjects, tibialis anterior muscle activity decreased by 7% and 20% (P = .01, P = .04), respectively, when using an AFO. In patients, this decrease was measured in the overall activity during the gait cycle; in healthy subjects, it was measured in the first 15% of the gait cycle. Overall electromyographic activity did not change during 6 weeks; delta values per muscle did not change during follow-up in the AFO group.
AFO use immediately reduced muscle activity of the ankle dorsiflexors. However, using an AFO for 6 weeks did not lead to a generally lower electromyographic activity level nor did the amount of activity reduction accumulate in comparison with patients who did not use an AFO. It is, therefore, safe to use an AFO, even with recently paretic patients.
BACKGROUND: Some strength athletes use androgenic-anabolic steroids (AAS) to improve body dimensions, though the drugs' long- and short-term effects have not been definitively established.
OBJECTIVE: ...This study sought to investigate the short- and long-term effects of AAS self-administration on body dimensions and total and regional body composition.
DESIGN: This prospective, unblinded study involved 35 experienced male strength athletes: 19 AAS users (drugs were self-administered) and 16 nonuser controls engaged in their usual training regimens. At baseline, 8 weeks, and 6 weeks after AAS withdrawal (for AAS users) circumferences were measured at 10 sites, and skinfolds measured at 8 sites. To assess differences in AAS regimens, 9 subjects took AAS for 8 weeks (short-AAS) and 10 athletes took AA S for 12 to 16 weeks (long-AAS). Body composition and anthropometry were assessed at baseline, at the end of AAS use, and 6 weeks later. Lean body mass (LBM) was calculated from body weight and percentage fat. Total and regional body composition was measured by dual-energy x-ray absorptiometry.
RESULTS: AAS use increased users' body weight by 4.4 kg and LBM by 4.5 kg, and produced increases in several circumferences. Percentage of fat decreased (17.0% to 16.0%), but fat mass remained unchanged. Changes persisted 6 weeks after drug withdrawal but were not less than those taken at 8 weeks. Bone-free lean mass of all regional body parts increased in subjects taking AAS, but fat mass was unaffected. Short- and long-term AAS users did not differ in any parameter measured at 8 weeks or after drug withdrawal.
CONCLUSION: In AAS users, 8 weeks of self-administered AAS increased body weight, lean body mass, and limb circumferences, but decreased percentage fat compared with controls. Changes remained 6 weeks after drug withdrawal, though for some measurements only partially. AAS stimulated the bone-free lean mass of all body parts, but it did not affect fat mass. Short-term and long-term AAS administration produced comparable effects.
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