Other Ergogenic Aids

The application of a nutritional, physical, mechanical, psychologic, physiologic or

pharmacologic procedure or aid to improve physical work capacity

Discuss issues you should consider when evaluating evidence regarding a possible ergogenic aid

Creatine

Methylguanidine-acetic acid Naturally occurring most muscle tissue Synth by body – mainly liver and kidney –

transported via blood to muscle Normal intake ~2g/d (fish, red meat, trace

amnts plants) Broken down, same rate, to creatinine and

excreted in urine.

PCr

Provision of phosphate for ATP regeneration at start of high-intensity exercise.

PCr + ADP + H+ Cr + ATPcreatine kinase

Store limited – depleted within 5s supramaximal exercise

High PCr stores may reduce anaerobic glycolysis and lactic acid formation

Also potential for buffering H+

Cr supplementation

Harris et al., (1992) Cr monohydrate ↑ total muscle Cr 5g, 4-6x/d for several days Suggested could improve performance

Greenhaff et al., (1993) 20g.d for 5 days 6% improvement in repeated bouts of max knee

extension ~2/3 of studies different modes report +ve effects

– rest no effect (Williams et al., 1999)

Cr loading Generally 20g/d (4 x 5g) for 6 d

↑~25mmol/kg dw (~20% increase) Hultman et al., (1996) – after load – subsequent dose of 2g/d

maintenance for 35 d (otherwise levels declined) Similar results with 3g.d for 28 days Considerable individual variation – habitual diet? 160 mmol/kg dw appears to be max – only 20% of subjects

achieve this Co ingest with simple CHO ↑ uptake (Green et al., 1995,1996) Those who show largest increase also show largest performance

benefit (Casey et al., 1996)

Cr and weight gain

↑ 0.5 to 3.5kg BM (~1kg) Water retention (↑ intracellular osmolarity); anabolic effect? (Kreider et al., 1998)

↑BM not beneficial endurance Balsom et al. (1993) ↓ running performance PCr not limiting in endurance May benefit sprints in intermittent exercise eg.

Football (Cox et al., 2002, Mujika et al., 2000)

Cr and High-intensity exercise

~70% studies find improvements in strength, force production and torque

Balsom et al., (1993) significantly less fatigue in repeated sprints.

Cr and resistance training

Vandenberghe et al., (1997) - ↑max strength and FFM

Combination of Cr ingestion and strength training> strength training alone

Wagenmakers (1999) – suggest allows more repetitions in training and thus better training and anabolic effect

Anabolic effect may be due to cell swelling acting as an anabolic signal (Lang et al., 1998)

However, no studies show that Cr affects protein metabolism

Cr safety

No studies of detrimental health effects Anecdotal reports

GI disturbances, CV and muscular problems, nausea, vomiting, diarrhoea, kidney and liver function alterations, muscle cramps and elevated bp

Evidence incomplete Contamination supplements?

Cr safety

Recent case study 24-yr old ♂ acute renal failure, proteinuria Creatine + multiple other supplements Acute interstitial nephritis Thorsteinsdottir et al., (2006)

Buffers - bicarbonate Most imp extracellular buffer Na bicarbonate/Na citrate (less GI distress)/Na lactate –

ergogenic effect on middle distance events Buffers H+ and increases diffusion of H+ out of cells Goldfinch et al., (400m - 1988) Wilkes et al., (800m - 1983),

Matson and Tran (review - 1993) Increased peak power and total work in max cycling

(McNaughton et al., 1997, 2001) However controversial – other studies no effect Tiryaki and

Atterbom (600m – 1995);Horswill et al., (2 min sprints - 1998), Inbar et al., (Wingate, 1993)

Dosage? Duration of admin? Acute vs. chronic admin Tolerable dose – 300mg/kg bw

Recent studies

Douroudos et al., (2006) NaHCO3 0.5g.kg.d for 5d increased mean power in Wingate

Berger et al., (2006) NaHCO3 delays appearance of the slow component

Buffers - phosphate Dietary phosphate incorporated into

ATP, CP Thiamine pyrophosphate – coenzyme of carboxylase –

required for decarboxylation of pyruvic acid, keto acids, 2-oxoglutarate

Na phosphate (blood buffer) 2,3-disphosphoglycerate (DPG) – most research focussed

on this Number of studies ~4g.d-1 for 3-6 days increasing

VO2max, AT, exercise performance However other studies no effect. To date no conclusive evidence.

Glycerol

Capacity declines when dehydration >threshold

Threshold differs depending on temperature Body water loss < 1.8% in hot, < 3.2% in

temperate ambient conditions Prehydration may be beneficial when rate of

fluid consumption cannot limit BW loss to these levels

Glycerol Focus on role as hyperhydrating agent rather than fuel for exercise Improves water reabsorption (Wapnir et al., 1996), and retention

(Gleeson et al., 1986; Koenigsberg et al., 1995) Effect is independent of ADH and aldosterone Filtered by glomerulus, reabsorbed across tubular walls increasing

corticomedullary gradient for reabsorption of water Metabolised and excreted slowly so can work over extended period

of time Recent meta-analysis – improves endurance performance ~2.62%

(Goulet et al., 2007) Loading Protocols: 1-1.5 g glycerol.kg-1 BM consumed 2 hours pre-event in conjunction

with 25-35 ml fluid per kg (AIS, 2006) 1 – 1.2g glycerol.kg-1 BM with 26 ml fluid.kg-1 BM – taken during 60 -

90 min period, exercise to commence after bloated feelings subsided (Goulet et al., 2007)

Glycerol However…. A number of studies no effect on thermoregulation (Inder et al.,

1998, Latzka et al., 1997; 1998) Volume of water too low?

Significant side effects: Nausea, heartache, blurred vision, headaches, GI problems,

dizzy, light-header, bloated. Extra weight of fluid increase metabolic cost of exercise?

Ebert et al., (2007) dehydration (-2.5% BM) reduced TTE compared to euhydration (+0.3% BM)

↑risk hyponatraemia? Although [Na] decline, magnitude not sufficient to cause

hyponatraemia

http://www.ais.org.au/nutrition/SupProvision.asp