Presentation on theme: "Presentations – sort. LAST LECTURE WE TALKED ABOUT DIETARY WATER IN SPORTS TODAY WE WILL TALK ABOUT SUPPLEMENTS."— Presentation transcript:
Presentations – sort
LAST LECTURE WE TALKED ABOUT DIETARY WATER IN SPORTS TODAY WE WILL TALK ABOUT SUPPLEMENTS
Lecture 17 SUPPLEMENTS
OUTLINE OF LECTURE 17 INTRODUCTION CRITERIA FOR SUPPLEMENT USE SUPPLEMENTS-EVALUATION-DO THEY REALLY WORK? SUPPLEMENTS-IDENTIFIED AND USES IN: -ANAEROBIC -INTERVAL -AEROBIC SUPPLEMENTS-ARE THEY WORTH IT?
SUPPLEMENTS INTRODUCTION long history of chemical use to try and boost performance not all of these chemicals are from food doping-ethics in theory the best athlete is a product of genes, coaching, sports dietitian direction(good diet), training
Criteria for supplements Are they safe, effective, legal and have effects superior to a proper diet? If legal (or not illegal?) then how know if they are safe and effective and indeed safe and effective at what dose and at what timing and in conjunction with which diet, which training and with which drugs the athlete may be taking? Just because something is natural that does not make it legal, safe, effective and have effects superior to a good diet.
Supplement evaluation- how to know if they really work Clear hypothesis? Study on cells, muscle, animals or humans? Claims for a population based on basis of population based in study? External variables controlled? Placebo controlled? Adequate techniques? Trials randomised? Cross-over design used? Random assignment to groups? Statistics? Other studies confirm? In peer reviewed journals?
Supplement evaluation- how to know if they really work Hypothesis 1. A tentative explanation for an observation, phenomenon, or scientific problem that can be tested by further investigation. 2. Something taken to be true for the purpose of argument or investigation; an assumption.
Supplement evaluation- how to know if they really work Clear Hypothesis Clear hypothesis-two caffeine tablets delivering a total dose of 200 mg of caffeine and taken 1 hour before a 100 metre sprint will decrease time to sprint the 100 metres in males and females aged 19-25.
Supplement evaluation- how to know if they really work Unclear hypothesis-caffeine tablets improve sprint performance.
Supplement evaluation- how to know if they really work Study on cells, muscle, animals or humans? Cell culture, whole muscle preparations, and animals are not whole humans
Supplement evaluation- how to know if they really work Claims for a population based on basis of population based in study? What works well in one population eg marathoners may not work well in sprinters Must compare apples with apples and not apples with oranges
Supplement evaluation- how to know if they really work External variables controlled? Only difference between the groups can be the agent (active or placebo) used Placebo and active agent must look the same, taste the same, and in no way be distinguishable from one another –why?
Supplement evaluation- how to know if they really work Placebo controlled? If prior knowledge or expectations of what one is receiving then this can affect performance-how? Single and double blinding
Supplement evaluation- how to know if they really work adequate techniques used? is there normally a lot of day to day variability in the outcome measure(s)(eg endurance) -sufficient sensitivity of instruments?-small differences that could explain winning may not be able to be detected
Supplement evaluation- how to know if they really work Trials randomised? -someone not associated with trial is given subject names and numbers which are then randomised by computer to receive placebo or treatment administering an active agent to people you know are faster does not show that the active agent causes improved performance
Supplement evaluation- how to know if they really work Cross-over design used? Advantages- better control and can use small numbers to meet power requirement Power requirement – enough subjects in each group to be 100 percent sure that you are 95 percent positive Parallel design- randomised controlled trial – what this does to power requirement
Supplement evaluation- how to know if they really work Random assignment to groups? - computer assignment better-never allow self selection- eg those most motivated to lose weight would choose active agent believed to cause weight loss - in other words this causes bias in the results
Supplement evaluation- how to know if they really work Statistics? -the wrong statistics applied gives the wrong answer -also must control for multiple comparisons being done
Supplement evaluation- how to know if they really work Other studies confirm? If the result is important others will attempt to repeat it
Supplement evaluation- how to know if they really work in peer reviewed journals? Peer review process -can be great in theory but can be lousy in practice -conflicts of interest eg somebody’s friend does the review -politics -stealing of data
NOW ONTO INDIVIDUAL NUTRITIONAL SUPPLEMENTS
Androstenedione -supposedly anabolic ie builds muscle for eg 100 metre sprinting -does not work
Bee Pollen -rich in vitamins, minerals and amino Acids and on that basis Alleged to: improve endurance reduce free radical damage control weight increase longevity prevent asthma -all false
Beta alanine and carnosine Beta alanine synthesised in body to carnosine Carnosine is a buffer against intracellular acid- eg lactic acid Eg 400 metre sprinting- some success
HMB-beta hydroxy beta methylbutyrate -metabolite of leucine in the body -consumption of HMB alleged to build lean (muscle mass) and hence increase strength- not a sure thing-not everyone agrees
Fig. 12-7, p. 392
Boron alleged to increase muscle mass in strength athletes-no evidence of such
Caffeine -improve high intensity exercise (near 100 % VO2 max lasting for 3-8 minutes) decreases sprint times- 6 mg/kg bw)-not all studies agree -endurance exercise- endurance improved with 1-9 mg/kg bw-most but not all studies agree with this
Fig. 12-7, p. 392
L-Carnitine What does the L mean? transports fatty acids into the mitochondria for catabolism via Krebs cycle-does not work for endurance exercise Slimming agent- does not work
Fig. 12-7, p. 392
Choline -role of acetylcholine-neurotransmitter -depleted during endurance (32 km) running-report -improves endurance running performance in at least one study but this was not universally found -no grounds for universal recommendation
38 Chromium -some say it is a fat burner and a muscle builder- -no solid evidence to support this claim
Coenzyme Q10 -part of the electron transport chain -said to improve VO2 max and increase energy and stamina but no real evidence to support this -may increase free radical production -nothing really to support its use
40 Creatine -part of creatine phosphate -during intense maximal exercise (anaerobic) it contributes significantly production of ATP -roughly 67 percent of studies in favour with 33 percent against benefits
Fig. 12-7, p. 392
47 Creatine Most success in anaerobic Less so in interval No real success in endurance (aerobic)
48 DHEA -supposed muscle builder -irrelevant as IOC banned with zero tolerance
49 Fish oil -cell deformability and theoretical improved oxygen delivery -still hypothetical
50 Ginseng No evidence to suggest that ergogenic aid
51 Glycerol -only a small contributor to gluconeogenesis- so no real help -pre-exercise hyper-hydration -draws water into extracellular space -decreases urination -if sufficient water ingestion there is indication of reduced heat stress -no real proof of increased endurance yet
Fig. 12-7, p. 392
53 Inosine -converted to a molecule in the body that helps release oxygen but no improvement in endurance or interval -said to increase ATP but no improvement in sprinting or interval or endurance
54 Lactate salts and polylactate -heart fuel -no indication that these 2 improve performance
55 Lecithin contains choline and phosphorous no evidence of it being ergogenic We have lots of it to begin with
56 Medium chain triacylglycerol -6-10 carbon fatty acids (6-12 in other books) -more easily digested and absorbed than LCTs But- next slide-small contribution to energy and does not affect glycogen breakdown -therefore not ergogenic
Fig. 12-7, p. 392
58 Pangamic Acid supposedly reduces lactate and increases maximal oxygen uptake both claims false FDA prohibits sale as dietary supplement or drug
59 Phosphatidylserine part of cell membranes no demonstrated ergogenic effect
60 Phosphorous -part of ATP and CrP -many studies-no indication of improved performance in endurance activities
61 Pyruvate and Dihydroxyacetone (DHA) part of glycolysis which they supposedly speed up controversial in endurance as to whether improved performance
62 Sodium bicarbonate buffer- pH control-lactate improved performance with sodium bicarbonate for anaerobic sports optimal dose is 300 mg/kg b.w. 1-2 hours before event
Fig. 12-7, p. 392
64 Sodium bicarbonate but get diarrhea, cramping, bloating at this optimal dose
65 Sodium citrate -increased efflux of ions from cell -improved pH -300-500 mg/kg b.w. -best for anaerobic -same problems as with bicarb- cramping, diarrhea, bloating
66 Vanadium supposed improved glucose transport into cells but does not work in athlete therefore not ergogenic
SUPPLEMENTS ARE THEY WORTH IT? REMEMBER!! Are you informed about all the ingredients in the product? (If you are unsure of what you are consuming, you should not take that particular product.) Do you know if the product is safe (from a short- and long-term health perspective)? A product that is promoted as "natural" is not guaranteed to be safe. Does the product contain any banned or restricted substances from the WADA list? (If you are unsure of what you are consuming, you should not take that particular product.) Have you sought professional advice from medical, physiological and/or nutritional experts? Is your training plan optimal (in terms of nutrition, recovery, and mental and physical preparation)? COST OF SUPPLEMENTS?!!
71 SUPPLEMENTS –are they worth it? Contaminants Beware the internet and even some shops on the ground ephedrine-stimulant-appetite control -banned by IOC strychnine-stimulant-banned by IOC various steroids that can lead to a positive steroid drug test
SUMMARY OF LECTURE 17 INTRODUCTION CRITERIA FOR SUPPLEMENT USE SUPPLEMENTS-EVALUATION-DO THEY REALLY WORK? SUPPLEMENTS-IDENTIFIED AND USES IN: -ANAEROBIC -INTERVAL -AEROBIC SUPPLEMENTS-ARE THEY WORTH IT?