Archivio per ottobre, 2012

Wonderful Chamomile

Pubblicato: ottobre 31, 2012 in health, nutrition

 

Scientific Research
Drinking chamomile tea daily with meals may help prevent complications of diabetes, according to a study in the September 2008 “Journal of Agricultural and Food Chemistry.” Rats given a form of chamomile tea for three weeks saw levels of blood sugar fall by a quarter. A 2005 study in “Diabetes Research and Clinical Practice” also showed chamomile was able to reduce blood sugar without affecting insulin levels, while research in 2008 in the “Journal of Natural Medicine” found chamomile had a protective effect on pancreatic beta cells in reducing hyperglycemia-related oxidative stress.

http://www.livestrong.com/article/519090-chamomile-tea-for-diabetes/#ixzz2AsKvcBJ0

Studies

Potent hypoglycaemic activity of the aqueous extract of Chamaemelum nobile in normal and streptozotocin-induced diabetic rats.
Eddouks M, Lemhadri A, Zeggwagh NA, Michel JB.
SourceUFR: PNPE, BP 21, Errachidia, Morocco 52000. m.eddouks@caramail.com

Abstract
The purpose of this study was to investigate the effect of both a single dose and daily oral administration for 15 days of the aqueous extract of the aerial part of Chamaemelum nobile (C. nobile) at a dose of 20mg/kg body weight on blood glucose concentrations and basal insulin levels in normal and streptozotocin-induced diabetic rats (STZ). Single oral administration of C. nobile aqueous extract reduced blood glucose levels from 6.0 +/- 0.3 mmol/l to 4.9 +/- 0.09 mmol/l (P < 0.05) 6h after administration in normal rats and from 21.1 +/- 1.3 mmol/l to 14.5 +/- 0.9 mmol/l (P < 0.001) in STZ diabetic rats. Furthermore, blood glucose levels were decreased from 6.1 +/- 0.06 mmol/l to 4.6 +/- 0.17 mmol/l (P < 0.01) and from 21.1 +/- 1.31 mmol/l to 13.7 +/- 0.9 mmol/l (P < 0.01) in normal and STZ diabetic rats, respectively, after 15 days of treatment. Basal plasma insulin concentrations remain unchanged after treatment in both normal and STZ diabetic rats so the mechanism of this pharmacological activity seems to be independent of insulin secretion. We conclude that the aqueous extract of C. nobile exhibits a significant hypoglycaemic effect in normal and STZ diabetic rats without affecting basal plasma insulin concentrations and support, therefore, its traditional use by the Moroccan population.

Antihyperglycemic and antioxidative potential of Matricaria chamomilla L. in streptozotocin-induced diabetic rats.
Cemek M, Kaga S, Simsek N, Büyükokuroglu ME, Konuk M.
SourceDepartment of Chemistry (Biochemistry Division), Faculty of Sciences and Arts, Afyon Kocatepe University, Afyonkarahisar, Turkey.

Abstract
Plants with antidiabetic activities provide important sources for the development of new drugs in the treatment of diabetes mellitus. In the present study, we investigated possible antihyperglycemic and antioxidative activities of the aerial part of the Matricaria chamomilla L. ethanolic extract (MCE) in streptozotocin (STZ; 70 mg/kg, i.p.)-induced diabetic rats. The following groups were assigned; sham (did not receive any substance), STZ + distilled water (control), STZ + 5 mg/kg glibenclamide, STZ + 20 mg/kg MCE, STZ + 50 mg/kg MCE, STZ + 100 mg/kg MCE. Diabetic rats were treated for 14 days by gavage. Postprandial blood glucose levels, malondialdehyde, reduced glutathione (GSH), nitrate, nitrite, ascorbic acid, retinol, beta-carotene, superoxide dismutase, and catalase levels were measured, and immunohistochemical studies were performed in all of the groups. The obtained data showed that STZ resulted in oxidative stress and affected the antioxidant status. Treatment with different doses of MCE significantly reduced postprandial hyperglycemia and oxidative stress, and augmented the antioxidant system. In histological investigations, MCE treatment protected the majority of the pancreatic islet cells, with respect to the control group. As a result, MCE exhibited significant antihyperglycemic effect and protected beta-cells in STZ-diabetic rats, in a dose-dependent manner, and diminished the hyperglycemia-related oxidative stress.

Tea Polypehenols and some other herbals can be used as an all-natural alternative to carb and fat blocker tablets

 

Some Scientific Research supporting this.

Effects of tea polyphenols on the activities of alpha-amylase, pepsin, trypsin and lipase

Qiang He , a, , Yuanping Lva and Kai Yaoa
aCollege of Light Industry and Food Engineering, Sichuan University, Chengdu 610065, PR China
Received 30 November 2005;

Abstract
Tea polyphenols (TP) possess many beneficial properties, such as reducing the risk of cancer and heart diseases, and acting as natural antioxidants for the food industry. At the same time, tea polyphenols might inhibit digestive enzymes and reduce food digestibility. To explore this possible antinutritional property, the effects of tea polyphenols on the activity of four typical digestive enzymes were investigated. HPLC analysis of the tea polyphenols extracted from Chinese green tea indicated that their catechin content was 93.6% (w/w), and that the content of ester bond-containing polyphenols was more than 82%. Measurement of the interaction of gelatin with tea polyphenols was first carried out, in order to model enzyme protein-TP interaction. It proved that tea polyphenols were capable of binding and precipitating protein, suggesting a potential ability of TP to denature digestive enzymes. In addition, the inhibitory effects of tea polyphenols on alpha-amylase, pepsin, trypsin and lipase were studied. In the presence of 0.05 mg/ml tea polyphenols, the inhibition ratios of alpha-amylase, pepsin, trypsin and lipase were, respectively, 61%, 32%, 38% and 54%, suggesting that TP might possess antinutritional properties.

Sugar compositions, alpha-glucosidase inhibitory and amylase inhibitory activities of polysaccharides from leaves and flowers of Camellia sinensis obtained by different extraction methods.

Wang Y, Yang Z, Wei X.
Institute of Food Engineering, College of Life & Environment Science, Shanghai Normal University, 100 Guilin Rd, Shanghai 200234, PR China.

Abstract
The sugar compositions, alpha-glucosidase inhibitory and alpha-amylase inhibitory activities of polysaccharides from leaves and flowers of green tea (Camellia sinensis) obtained by hot water extraction (HWE), boiled water extraction (BWE) and enzymatic extraction (EE) were investigated. The yields, sugar contents and monosaccharide compositions of tea leaves polysaccharides (TLPS) and tea flower polysaccharides (TFPS) were all significantly affected by extraction methods. The contents of acidic polysaccharides (APS) extracted by BWE and EE were both much more than those by HWE. The yields of TLPS and TFPS were determined as EE>BWE>HWE. Enzyme and higher temperature could improve the contents of APS and yields of TLPS and TFPS. TLPS and TFPS were all mainly composed of Rha, Ara, Gal, Glu and GalA, very little molar contents of GluA, Xyl and Man. It seemed that enzyme extraction could be more conducive to increase the content of Ara, Gal and GaLA. The molecular weights of TFPS were larger than those of TLPS. The molecular weights of polysaccharides obtained by EE decreased. Proteins in tea leaves and tea flowers might be decomposed by EE by observing UV peaks and IR absorption. peaks. The alpha-glucosidase inhibitory and amylase inhibitory activities of TLPS and TFPS obtained by EE were lower than those by water extracted method. The inhibitory percentages of TLPS and TFPS against alpha-amylase were all lower than alpha-glucosidase for different extractions.

Evaluation of different teas against starch digestibility by mammalian glycosidases.

 

Koh LW, Wong LL, Loo YY, Kasapis S, Huang D.
Department of Chemistry, National University of Singapore, 3 Science Drive 3, Singapore 117543, Republic of Singapore.

Abstract
Current work investigated the ability of different tea (green, oolong and black teas) in inhibiting human salivary alpha-amylase (HSA) and mammalian alpha-glucosidase (AGH). The inhibitory profiles were correlated to their major polyphenol content (theaflavins and catechins). The fully fermented black tea was demonstrated to be most potent in inhibiting HSA and AGH (IC50 of 0.42 to 0.67 and 0.56 to 0.58 mg of tea leaves/mL respectively). Its capability in retarding the digestion of a real food system (rice noodle) was further elucidated with an in vitro digestion study. Results indicated that black tea was able to retard starch digestion moderately, thereby allowing a gradual reduction of sugar liberation. Polyphenolic profile analysis suggested that the oxidized catechins, theaflavins, may be responsible for its activity. We have found that refractive index (RI) measurement is a rapid, direct, and highly convenient method for quantifying the degree of enzymatic starch digestion and kinetics. The RI method has good linearity range, limit of detection (0.1596 mg/mL, maltose equivalent) and limit of quantitation (0.6312 mg/mL) and was successfully applied in our study.

Inhibitors of alpha-amylase from plants–a possibility to treat diabetes mellitus type II by phytotherapy?

 

 

Melzig MF, Funke I.
Institut für Pharmazie der Freien Universität Berlin, Berlin, Germany. melzig@zedat.fu-berlin.de

Abstract
Antidiabetics of plant origin are in common use. A proof of their effectiveness or their mode of action is often missing. The aim of this work was to review the knowledge about inhibitors of alpha-amylase from plants and to comment on the use in anti-diabetic treatment. Herbal alpha-amylase inhibitors are rarely described in the literature, nevertheless they have the ability to lower postprandial blood glucose level and should be used in the supplementary treatment of diabetes. Important constituents for the inhibitory activity against alpha-amylase are mainly polyphenolic compounds. There is a need for further clinical studies to establish a rational therapy with traditional herbal preparations, especially for the leaves from the blueberry, tamarind, lemon balm (Melissa Officinalis) and rosemary, the hulls from white kidney beans or green tea extract.

An extract of black, green, and mulberry teas causes malabsorption of carbohydrate but not of triacylglycerol in healthy volunteers.

Zhong L, Furne JK, Levitt MD.
NatureGen Inc, San Diego, CA, Minneapolis, MN 55417, USA.
Comment in:
” Am J Clin Nutr. 2007 Apr;85(4):1164.

Abstract

BACKGROUND: In vitro studies suggest that extracts of black, green, and mulberry teas could interfere with carbohydrate and triacylglycerol absorption via their ability to inhibit alpha-amylase, alpha-glucosidase, sodium-glucose transporters, and pancreatic lipase.

OBJECTIVE: We measured breath hydrogen and 13CO2 to investigate the ability of an extract of black, green, and mulberry tea leaves to induce malabsorption of carbohydrate and triacylglycerol in healthy volunteers.

DESIGN: In a crossover design, healthy adult volunteers randomly ingested test meals with a placebo beverage or a preparation containing an extract of black (0.1 g), green (0.1 g), and mulberry (1.0 g) teas. One test meal contained 50 g carbohydrate as white rice, 10 g butter, and 0.2 g [13C]triolein, and the beverages contained 10 g sucrose. The calorie content of the second test meal consisted entirely of lipid (30 g olive oil and 0.2 g [13C]triolein). Breath-hydrogen and 13CO2 concentrations were assessed hourly for 8 h, and symptoms were rated on a linear scale.

RESULTS: With the carbohydrate-containing meal, the tea extract resulted in a highly significant increase in breath-hydrogen concentrations, which indicated appreciable carbohydrate malabsorption. A comparison of hydrogen excretion after the carbohydrate-containing meal with that after the nonabsorbable disaccharide lactulose suggested that the tea extract induced malabsorption of 25% of the carbohydrate. The tea extract did not cause triacylglycerol malabsorption or any significant increase in symptoms.

CONCLUSION: This study provides the basis for additional experiments to determine whether the tea extract has clinical utility for the treatment of obesity or diabetes.

Targeting adipose tissue

Pubblicato: ottobre 31, 2012 in health

Targeting adipose tissue
Bodo Haas, Paul Schlinkert, Peter Mayer and Niels Eckstein

Diabetology & Metabolic Syndrome 2012, 4:43 doi:10.1186/1758-5996-4-43 Published: 27 October 2012
Abstract (provisional)
Two different types of adipose tissues can be found in humans enabling them to respond to starvation and cold: white adipose tissue (WAT) is generally known and stores excess energy in the form of triacylglycerol (TG), insulates against cold, and serves as a mechanical cushion. Brown adipose tissue (BAT) helps newborns to cope with cold. BAT has the capacity to uncouple the mitochondrial respiratory chain, thereby generating heat rather than adenosine triphosphate (ATP). The previously widely held view was that BAT disappears rapidly after birth and is no longer present in adult humans. Using positron emission tomography (PET), however, it was recently shown that metabolically active BAT occurs in defined regions and scattered in WAT of the adult and possibly has an influence on whole-body energy homeostasis. In obese individuals adipose tissue is at the center of metabolic syndrome. Targeting of WAT by thiazolidinediones (TZDs), activators of peroxisome proliferator-activated receptor gamma (PPARgamma) a ‘master’ regulator of fat cell biology, is a current therapy for the treatment of type 2 diabetes. Since its unique capacity to increase energy consumption of the body and to dissipate surplus energy as heat, BAT offers new perspectives as a therapeutic target for the treatment of obesity and associated diseases such as type 2 diabetes and metabolic syndrome. Recent discoveries of new signaling pathways of BAT development give rise to new therapeutic possibilities in order to influence BAT content and activity.

 

http://www.dmsjournal.com/content/4/1/43/abstract

Avvertenza: Il presente documento rappresenta la mia personale esperienza con questa strategia nutrizionale. Il presente documento non sostituisce i dettami della comunita’ medica e non vuole fornire consigli nutrizionali di competenza a Dietisti e Dietologi. Consultate sempre il Vostro medico se decidete di seguire anche in parte i suggerimenti riportati nel presente articolo. Il presente documento non deve essere usato per il trattamento e la prevenzione di malattie.

CARB-UP GUIDELINES (Part 4/6)
Rel 3.1 del 30th Oct 2012
By Athletime © 2012-10-30 https://athletime.wordpress.com

Management della Leptina

Il CARB-UP puo’ essere anche uno strumento per rinormalizzare i livelli di leptina che sono bassi quando si esegue un regime low-carb con restrizione calorica e quando il grasso corporeo e’ molto basso.

leptin effects

 

In sintesi la Leptina:

Riduce il consumo energetico dai cibi;
Incrementa la lipolisi (ossidzione di grasso);
Decrementa la lipogenesi(produzione di grasso);
Riduce l’appetito;
Migliora la sensibilita’ ll’insulina.

L’aumento di leptina circolante si ottiene quando le cellule grasse rilevano l’entrata di glucosio. Le cellule grasse sono come le altre cellule con la sola differenza che sono specializzate nella sintesi e nel deposito di grassi. Parte del glucosio riversato nel corpo con il CARB-UP day verra’ sequestrato dalle cellule grasse le quali inizieranno a produrre Leptina.
In tal senso avremo una ipertrofia sarcoplasmatica delle cellule grasse benefica ai fini della produzione di Leptina. Gli adipociti non stanno sintetizzando altro grasso poiche’ questo e’ un processo molto piu’ complesso che coinvolge fegato, sistema linfatico, etc…
La leptina e’ anche un potente modulatore del cAMK.
La Leptina sembra essere positivamente correlata anche con gli EFA. Quindi assumere EFA nei giorni che precedono il CARB-UP puo’ provocare una cascata di eventi favorevoli tra i quali:

Disciplina di controllo durante il Carb-UP per l’attenuazione della fame.
Miglioramento della sensibilit’a all’insulina ed alla Leptina.

leptin levels3

 

Glucose Uptake Enhancers

Alcune sostanze con meccanismi insulino-simili (cioe’ mimano le funzioni dell’insulina) oppure insulino-tropici (cioe’ aumentano il rilascio di insulina a parita’ di zuccher ingeriti), possono migliorare la qualita del carb-up.
Tra le sostanza insulino-simili possiamo citare la Cannella e l’Acido Lipoico. Tra le sostanze insulino-tropiche possiamo citare il Fieno greco ed alcune classi di aminoacidi come la glutammina.

cannella

 

La sensibilita’ all’insulina puo’ essere migliorata anche in altre maniere. Il consumo di piccolissime quantita’ di fruttosio o di cacao possono attivare il cosidetto second-meal effect vale a dire una migliorata sensibilita’ insulinica a partire dal pasto successivo. Gli EFA migliorano la sensibilita’ all’insulina a lungo termine aumentando la permeabilita’ delle memrane cellulari.
Anche l’aceto o il succo di limone sono stati associati ad un miglioramento dell’uptake di glucosio attraverso un meccanismo di miglioramento della sensibilita’ all’insulina.

Lipoic-acid-3D-vdW

Creatina
La creatina e’ stata correlata ad un miglioramento delle prestazioni in regime anaerobico o aerobico-lattacido. L’up-take di creatina e’ migliorato dalla presenza di insulina e quindi dagli zuccheri. Il periodo del Carb-UP puo’ essere un buon momento per un carico di creatina. Personalmente ho avuto fastidiosissimi crampi durante i Carb-UP con assunzione di Creatina. Il carico di creatina ritarda tra l’altro la deplezione delle riserve di ATP-PCr e questo puo’ essere uno svantaggio quando con il training si cerca di forzare la biologia cellulare in uno stato di basso contenuto energetico necessario all’attivazione del AMPk per l’avvio del processo di lipoburning.

creatinaeATP

Effetto dell’adrenalina sull’up-take di glucosio


La resintesi di glicogeno insulino-indipendente come e’ il caso di contrazioni da workout non sembra essere influenzata dalla presenza di adrenalina. Il meccanismo insulino-dipendente lo e’ fortemente. Il massimo rate di resintesi si ha in presenza di un protocollo che preveda training ed una successiva fase insulino dipendentente. In figura le parti in nero sono quelle relative alla presenza di adrenalina. Morale: bevande eccitanti come caffee, the ed altro dovrebbero essere evitate durante la fase di carb-up per massimizzare il tasso di resintesi. Questo e’ sempre piu’ vero via via che il carb-up evolve nel tempo quando la finestra anabolica si chiude e dobbiamo affidarci unicamente a mecanismi insulino-dipendenti.

uptakenhancers

Contributo dell’attivita’ di endurance sulla deplezione di glicogeno

endurance

Flavours Progression

E’ consigliabile sempre procedere partendo da sapori ed aromi deboli e via via che si assumono altri pasti eventualmente ricorrere a sapori e condimenti più forti. Esempio: condimenti quali aceto balsamico, ketchup ed altro è consigliabile che siano assunti ai pasti successivi al primo od ai primi due.

flavours

 

End of CARB-UP GUIDELINES (Part 4/6)
Rel 3.1 del 30th Oct 2012
By Athletime © 2012-10-30 https://athletime.wordpress.com

Avvertenza: Il presente documento rappresenta la mia personale esperienza con questa strategia nutrizionale. Il presente documento non sostituisce i dettami della comunita’ medica e non vuole fornire consigli nutrizionali di competenza a Dietisti e Dietologi. Consultate sempre il Vostro medico se decidete di seguire anche in parte i suggerimenti riportati nel presente articolo. Il presente documento non deve essere usato per il trattamento e la prevenzione di malattie.

Plasma leptin and energy expenditure during prolonged, moderate intensity, treadmill exercise.

Zaccaria M, Ermolao A, Brugin E, Bergamin M.

leptin

 

Source

Sports Medicine Unit, Department of Medicine, University of Padova, Italy.

Abstract

Background: Current literature shows conflicting results regarding the possible direct role of exercise on leptin concentrations, mainly because of a non-homogeneous level of energy expenditure (EE) and the lack of standardization of energy balance. Aim: The aim of the study was to evaluate the effect of exercise duration and its corresponding EE on leptin levels, during prolonged treadmill exercise, in a well-controlled laboratory setting. Materials and methods: Seven young trained males underwent a 4-hour treadmill exercise. The starting intensity was set at 65% of maximal oxygen consumption. At the start of the test and throughout the exercise, venous blood samples were drawn for the assays of leptin, glucose, free fatty acids (FFA), cortisol, epinephrine (E) and norepinephrine (NE). Hourly and total EE was monitored with gas analysis. Results: Plasma leptin levels decreased from 1.10±0.15 to 0.85±0.26 µg/L (p<0.01) at the end of the exercise, reaching a significant reduction already after the second hour. FFA and cortisol showed a progressive significant increase, while glucose didn’t significantly change throughout the test. Plasma E and NE significantly increased at all sampling times compared to basal values (48.1±30.3 to 352.3±187.7 pg/mL, p<0.001 and 238.1±118.9 to 1798.7±413.5 pg/mL, p<0.001). The random-effects model for panel data analysis showed negative correlation between leptin, NE and the values of progressive EE (r2=0.745, p<0.05). Conclusions: Our data demonstrate that, during a prolonged moderate intensity exercise, leptin decrease is significantly related to the total EE. Further, NE concentrations seem to play an important role on the inhibition of leptin secretion.

leptin2

http://www.ncbi.nlm.nih.gov/pubmed/23095336?dopt=Abstract

Australian Protocol for Carb Loading…..

Pubblicato: ottobre 27, 2012 in nutrition

 

carbs

 

If you can work out a way to boost your muscle glycogen to supra-normal levels, your performances in athletic events lasting longer than about 60 minutes will be much improved. Glycogen is a key fuel during such exertions, but a basic problem is that, unlike fat, glycogen cannot be stored in your body in relatively limitless amounts. In addition, the glycogen in your muscles is quite rapidly depleted during fairly intense exercise, so that muscles begin to notice a shortage of glycogen after 60-90 minutes of activity. Yes, they can call on fat to provide fuel for further contractions and force production, but fat supports a lower intensity of exercise, and thus movement speed drops. This is why athletes who do a poor job of muscular glycogen replenishment before lengthy workouts, games or races usually slow down after 60 minutes, while their glycogen-loaded counterparts continue to work at the same intensity. So, the key question is: how do you make sure that you are amply glycogen-loaded? Once it became clear in the 1960s that glycogen was especially important during exercise lasting longer than an hour, Swedish scientists began to work at a furious pace to answer this question. A Swede named Ahlborg developed a protocol in which athletes performed a bout of very strenuous exercise and then consumed a high-carbohydrate diet for a period of three days while training normally (1). It worked! Athletes in the Ahlborg study boosted muscle glycogen above 150 mmol.kg-1 wet weight (‘normal’ levels are about 80-120).
There was just one problem, though – that strenuous bout of exercise. Usually, athletes want to be especially glycogen-loaded for a big race, and the notion of carrying out a very strenuous exertion lasting longer than an hour just three days before a big competition (in order to stimulate high rates of glycogen synthesis) was troublesome. Such efforts could interfere with tapering and could produce wear and tear on muscles which were frantically trying to heal themselves before a major event. Another problem also became apparent: athletes sometimes overloaded themselves during their three-day carb-fests. Instead of feeling unusually energetic, they ended up being bloated and sluggish on race day. The Ahlborg plan just wouldn’t do! Ahlborg’s colleague, a fellow Swede named Bergstrom, developed a slightly different plan. Bergstrom advised athletes to first engage in a rugged bout of strenuous exercise, then consume a high-fat, low-carbohydrate diet for three days (to really drive glycogen levels down), then undertake strenuous exercise again (just to make sure that muscle-glycogen levels were really low), and finally feast on carbohydrates for the seemingly magical period of three days, while training very lightly. This technique also succeeded in magnifying muscle glycogen concentrations.
The perils of strenuous exercise bouts before a major event
Again there were problems, however. Specifically, Bergie had failed to take into account the fact that two bouts of very strenuous, glycogen-depleting exercise during the week before a very important competition might be a bad idea. In addition, the three initial days of high-fat, low-carb eating left athletes irritable and less than super-confident. Finally, the three-day carbohydrate festival at the end of the Bergstrom protocol again left many athletes feeling gigantic and slow, rather than sleek and fast. Mike Sherman of Ohio State entered these troubled waters in the early 1980s with a very sensible and seemingly more practical plan for glycogen loading.
Addressing the paradox of recommending strenuous exercise during the week before a major event, Sherman’s stratagem called for no heavy exertion, and in fact allowed decreasing amounts of exercise on consecutive days. In Sherman’s six-day plan, athletes ingested a routine, ‘mixed’ (modest carbohydrate content) diet for three days and then stoked up on carbs for the next three days. Like the techniques developed by Ahlborg and Bergstrom, the Sherman stratagem ‘worked’, producing muscle glycogen levels above 150 mmol.kg-1 wet weight. However, the overall plan once again left many athletes feeling sluggish, and many individuals did not particularly want to cut back on training uniformly and relentlessly during their tapering periods, preferring to alternate days of doing almost nothing with days of performing modest amounts of quality work. In addition, many athletes wisely questioned the necessity of the initial three days of mixed-diet eating, and so Sherman’s plan was modified to consist of just the three days of high-carb eating, accompanied by successively lighter workouts.
Unafraid to enter this controversy, my own US newsletter Running Research News has for the past 10 years been recommending routine high-carbohydrate consumption (in the form of about four grams of carbohydrate per pound of body weight per day) for endurance athletes. This recommendation is based on research carried out by Clyde Williams and colleagues at Loughborough University, showing that endurance athletes engaged in serious training who consume less carbohydrate than this often end up gradually depleting their muscle glycogen stores, leading to lower-quality workouts and poorer performances. Our position has been that, if this strategy leads to routinely high levels of muscle glycogen, there is no special need to try to ram more carbs home shortly before races and extreme workouts. The reduced training employed in these times will allow extra glycogen synthesis to occur in muscles, and the chronically carb-rich diet will furnish the carbs necessary to get the job done.
Admittedly, though, the RRN plan is not without its own perils: for one thing, 4g of carbohydrate per pound of body weight per day has been shown to be a bit rich for some athletes, especially those who have previously restricted their calorie and carb intake. These athletes, many of whom may routinely take in just 2g per pound per day (we have even documented one quite successful athlete who was trying to get by with 1g!), may gain weight and feel extremely lethargic if they make a quantum leap to our ideal of 4g/lb/day.
So what’s the answer? Is there a simple, quick way to maximise muscle glycogen levels without fuss, extended periods of unusual eating or disruption of normal training?
In a word, yes! Thanks to research carried out at the Department of Human Movement and Exercise Science at the University of Western Australia, we now have such a plan (4). This plan takes just a day, and it produces incredibly high muscle glycogen levels!
Intensity and glycogen synthesis
The Western Australia work pivots around one key concept: very high intensities of exercise actually stimulate higher rates of muscle glycogen synthesis than moderate intensities of exercise carried out for prolonged periods. Naturally, athletes have been a little afraid to engage in very high-intensity exercise during their tapering, glycogen-loading periods, but the Australian researchers asked, quite reasonably: what if the intense exercise is just long enough to dramatically kick-start glycogen synthesis – but not so long as to interfere with tapering and recovery? In their ingenious plan, the Australians settled on a very short duration of intense exercise – just three minutes! Could such a brief period of exertion carry the broad load of heavy carbohydrate loading on its apparently puny shoulders? To find out, the Australians worked with seven healthy, endurance-trained male subjects. The athletes averaged 22 years of age, trained about 10 hours per week, possessed max aerobic capacities of around 56 ml.kg-1.min-1, and normally consumed about 6.6 grams of carbohydrate per kg of lean body mass per day (e.g. 3g of carbs per pound of lean body mass per day and 2.55g of carbs per pound of body weight per day).

carbs2

 

Such intakes of carbs are fairly routine among endurance athletes, and thus the Australians had created a nice test of whether their one-day plan could really dramatically bolster muscle glycogen contents in typical athletes. On the morning the one-day high-carb diet commenced, the athletes had muscle biopsies performed on their quadriceps muscles (to assess glycogen levels), carried out a five-minute warm-up on a cycle ergometer, and then blasted through a sustained 150-second sprint on the ergometer at a very high intensity of 130% VO2max. At the end of this sprint, the athletes – without a second of hesitation – embarked on an all-out 30s sprint. Lactate levels at the end of this three-minute period of intense work soared to 21.9 mM/litre!
When carbo windows are open widest
Following a cool-down, each subject began the 24-hour high-carb eating plan, during which they ingested 12g of relatively high-glycaemic-index carbs per kg of lean body mass (e.g. 5.45g per pound of lean body mass and 4.6g per pound of body weight, just above the RRN recommendation). Crucially, the ingestion of carbohydrate was initiated within 20 minutes of the end of the exercise. (Remember that your muscles’ carbo ‘windows’ are open widest shortly after a bout of exercise ends; by two hours-or-so after exercise, they are open just a crack.) The participants ate high-carb foods they liked, including pasta, bread and rice but they also poured in extra carbohydrate in the form of the maltodextrose-rich drink Polycose, produced by Ross Laboratories in Columbus, Ohio. Indeed, about 80% of the carbs ingested over the 24-hour period came from this drink. The energy ingested as fat and protein, by contrast, was marginal – less than 10% of the caloric total for the day.
On the morning after the exercise and initiation of the carbo-loading regime, a second quadriceps muscle biopsy was taken. This revealed incredibly high levels of muscle glycogen; the mean glycogen concentration in the quads, which had been just 109 mmol.kg-1 wet weight before the trial, soared to 198.2 – an 82-% increase – afterwards! Analysis revealed that both slow and fast-twitch muscle fibres did an equally fantastic job of storing super concentrations of glycogen. The Australian plan was a real winner! It is the fastest glycogen-loading plan ever reported in the scientific literature. It also produces end glycogen concentrations (~198 mmol.kg-1 wet weight) which are extraordinarily high – considerably higher than the 131-153 readings often reported after three or even six days of traditional carbo-loading.
Preventing dips in muscle glycogen
The Australian research has several practical implications. If you are training strenuously, you need to worry about preventing dips in your day-to-day muscle glycogen levels. One way to do that is to routinely consume a high-carb diet, but another strategy – based on the Australian findings – would be to add in about three minutes of intense exercise near the end of many of your easy-to-moderate-intensity workouts. Such short periods of high-intensity work should not increase your risk of injury or burn-out, should enhance your fitness and should kick-start the post-workout glycogen-synthesis process, helping to ensure that you will have enough glycogen in your muscles for the next day’s workout. Of course, if your workout is already intense, there is no need to add anything to it.
This recommendation to slip in three minutes of intense stuff near the end of an easy workout may seem a bit bizarre, but it may well prove to be an exceedingly good strategy. Bear in mind that after fairly prolonged exercise consisting of only moderate-intensity work, it usually takes about 24 hours for muscle glycogen stores to return to pre-exercise levels, even when a high-carb diet is followed (6). The true glycogen-loading following such exercise does not really occur until the second and third days afterwards. By contrast, with the Aussie three-minute plan, super-loading occurs within the first 24 hours. Thus, it may be much easier to build – rather than merely maintain – muscle glycogen concentrations when a pinch of high intensity is added to workouts, and for some athletes the intensity may actually mean boosting glycogen levels back up to performance-enhancing levels (if they have been slogging away for a while with too-low levels of carbohydrate in their muscles). Note, too, how wonderfully well the Australian plan would work for a marathon runner (or other endurance athlete getting ready for a competition lasting longer than an hour). The athlete could follow his normal diet during the week leading up to the race, with no risk of bloating, lethargy, heaviness or gastric discomfort, and training could be tapered appropriately. The day before the big race, he could warm up, go hard for three minutes and then begin consuming large quantities of carbs. He should feel great – and have about 200 mmol.kg-1 wet weight in his leg muscles at the start line the following morning. He might even find his overall running fitness inched up a notch. Worried about three minutes of very hard running the day before the marathon? Perhaps it might cause your hamstrings to twitch a bit on race day? Don’t worry: you can carry out the 24-hour plan two – or even three – days before your major event and still go to the start line with supra-normal concentrations of glycogen in your muscles. Research has shown that once such concentrations are achieved, they can be maintained for a couple of days, providing athletes eat normal amounts of carbohydrate and do not carry out much exercise. Since you will be tapering, you won’t be doing much exercise, so all should be well. Here, then, is your guide to carbo-loading Aussie-style:
1. Start eating carbs as soon as possible after you finish your exercise.
2. Consume high-glycaemic-index foods during your 24-hour period, and don’t be afraid to include high-carb drinks like Polycose. Foods that count as high-glycaemic-index items (with glycaemic-index values above 60) include the following: croissants, crumpets, banana or apricot muffins, pancakes, waffles, scones, cranberry-juice cocktail, Gatorade, bagels, baguettes, bread stuffing, oat bread, white bread, flatbread, cornflakes, Pop Tarts, Raisin Bran, Special K, cornmeal, boiled sweet corn, couscous, most crackers and crispbreads, rice cakes, chocolate ice cream, apricots in syrup, dried dates, dried figs, papaya, raisins, watermelon, fruit bars, a plain pizza with cheese and tomato sauce, kugel, gnocchi, udon noodles, jelly beans, black-bean soup, split-pea soup, broad beans, parsnips, swede, most baked potatoes (especially if baked without fat), most boiled potatoes, mashed potatoes, and tapioca. You’ll need to read box labels and use nutritional charts to determine how much carbohydrate you are really taking in during your 24-hour period; remember that you are aiming for about 4.6g of carbohydrate per pound of body weight. If you fret about consuming high-glycaemic-index foods, bear in mind that many of the foods consumed heavily and regularly by élite Kenyan runners have very high glycaemic indices. For example, maize-meal porridge checks in with a glycemic index of 109. (The standard – glucose – is set at 100, which means that maize-meal porridge gets glucose into the bloodstream more quickly than glucose itself!) Another popular Kenyan breakfast item – millet-flour porridge – has a similarly whopping glycaemic index of 107. Kenyan rice – a true staple of the Kenyan runners’ diet – has an eye-popping glycaemic index of 112, and cornmeal – used to create the ubiquitous Kenyan national dish, ugali, has an index of about 70. Kenyan ‘wholemeal’ wheat flour checks in at 87, and chapati, a flat wheat bread settles for 66.
3. Once you have completed your warm-up, three-minute burst and cool down, do not exercise again during the next 24 hours as this will damp down your muscles’ glycogen-synthesis rate.
4. Don’t be afraid of the lactate you will inevitably generate during your three-minute surge. Remember that lactate does you no harm; in fact, there is evidence that the lactate itself may spur the increased rate of glycogen synthesis which occurs after intense exercise.
5. The Aussie plan allows you to relax! If work or other pressures have kept you from carbo-loading as much as you would like before a major race, you can still do a tremendous job of stocking up on muscle glycogen during the last 24 hours before your event.
6. Make sure you try out the Aussie regime a couple of times in training before you use it in competition. (By trying it out, I mean using the warm-up, three-minute burst, cool-down and 24-hour carb-eating scheme, followed by a long run afterwards.) There should be no major side effects associated with the plan, but you should at least prepare your body for it. If the regime doesn’t seem to be working well, try using the 24-hour plan two days before your long workouts or races, while carrying out little exercise and eating normally the day before the event. This intervening day may allow you to recover from your three-minute blast, without reducing your muscle glycogen concentrations.

Foot Striking comparison

Pubblicato: ottobre 21, 2012 in Uncategorized

Effects of Foot Strike on Low Back Posture, Shock Attenuation, and Comfort in Running.

Delgado TL, Kubera-Shelton E, Robb RR, Hickman R, Wallmann HW, Dufek JS.

Source

1School of Allied Health Sciences, University of Nevada, Las Vegas, NV 2Doctor of Physical Therapy Program, Western Kentucky University, Bowling Green, KY.

Abstract

PURPOSE:

Barefoot running (BF) is gaining popularity in the running community. Biomechanical changes occur with BF, especially when initial contact changes from rearfoot strike (RFS) to forefoot strike (FFS). Changes in lumbar spine range of motion (ROM), particularly involving lumbar lordosis, have been associated with increased low back pain (LBP). However, it is not known if changing from RFS to FFS affects lumbar lordosis or LBP. The purpose of this study was to determine if a change from RFS to FFS would change lumbar lordosis, influence shock attenuation, or change comfort levels in healthy recreational/experienced runners.

METHODS:

Forty-three subjects performed a warm up on the treadmill where a self-selected foot strike pattern was determined. Instructions on running RFS/FFS were taught and two conditions were examined. Each condition consisted of 90 s of BF with RFS or FFS; order randomly assigned. A comfort questionnaire was completed after both conditions. Fifteen consecutive strides from each condition were extracted for analyses.

RESULTS:

Statistically significant differences between FFS and RFS shock attenuation (p<0.001), peak leg acceleration (p<0.001), and overall lumbar ROM (p=0.045) were found. There were no statistically significant differences between FFS and RFS in lumbar extension or lumbar flexion. There was a statistically significant difference between FFS and RFS for comfort/discomfort of the comfort questionnaire (p=.007). There were no statistically significant differences between other questions or the average of all questions.

CONCLUSIONS:

Change in foot strike from RFS to FFS decreased overall ROM in the lumbar spine but did not make a difference in flexion or extension in which the lumbar spine is positioned. Shock attenuation was greater in RFS. RFS was perceived a more comfortable running pattern.
http://www.ncbi.nlm.nih.gov/pubmed/23073217?dopt=Abstract