Post on 12-Sep-2020
Nutritional Challenges for High Performance Athletics
Peter W.R. LemonThe University of Western Ontario
Factors Affecting Dietary Needs
• exercise type/intensity/duration• continuous vs intermittent• rest/recovery time between sessions• degree of adaptation (training)• environment• age• gender
Nutrients Known to be Important• energy intake
60
80
100
120
140
160
180
200
Ener
gy In
take
(% o
f se
dent
ary
cont
rol)
Men Women
Activity & Energy Intake
SwimRunBodyBXC-SkiWt liftWresB DanceBasketGym
455
460
465
470
475
2000
m
Erg
omet
er
Tim
e (s
ec)
Performance with/without 940kJ/d Supplement in Elite Female Rowers
Day 0Day 19
Day 0 472.4 463.3Day 19 467 461.4
Protein Fat
P<0.05 d0 vs d19(n=8/treatment)*
* *Bachman, Talyor, Lemon, 2000
*
Lemon, 1998
Nutrients Known to be Important• CHO intake
10
10.25
10.5
10.75
11
Tim
e (m
in)
Time Trial Following 50 min@ 80% Aerobic max, n=8
10.9 10.2Placebo CHO
*P<0.05
Below et al (1995)
6.4% faster
Chronic CHO Intake & Performance
0
50
100
150
200
50 150Muscle Glycogen (mmol/kg)
Tim
e to
Exh
aust
ion
(75%
Aer
obic
Max
)
Bergstrom et al (1967)
Low CHO (5% energy)
High CHO(82% energy)
*P<0.05
Nutrients Known to be Important• fluid intake
Controversial topics
• protein• fat• vitamins/minerals• creatine• variety of others, ie., glutamine, ribose,
HMB, prohormones, ephedrine, caffeine, CLA, etc
• other questions, ie., timing of nutrient relative to training sessions, etc
0
50
100
150
200
250
Whole Body Protein Synthesis (mg/kg/h)
0.9 1.4 2.4
Protein Intake (g/kg/d)
Protein Intake & Protein SynthesisSedentary ControlsStrength Athletes
Tarnopolosky et al (1992)
*P<0.05
Protein?
Post-ex Amino Acids Ingestion increases protein synthesis!
Effects on Strength & Size? - yes
Leg Press Endurance- Reps at 80% of 1-RM
0
10
20
30
40
50
60PrePost
Pre 10.0 7.7 11.9Post 40.0 23.9 29.8
Protein+CR Protein CR
** **P<0.05
mean+SD
*
Creatine and protein may enhancemuscle strength/size gains with training!
Whole Body Lean Mass (kg)
63656769717375777981
PrePost
Pre 68.1 66.4 69.0Post 70.8 67.6 70.7
Protein+CR Protein CR
*
P<0.05*
**
mean+SD
Beneficial for aged, muscle disease, etc?
Challenge(s)?• several– athletes: what product(s) to take?– scientists: provide the objective data to clarify picture• but traditional funding inadequate!
– industry: credibility – regulators: quality control, safety
• solutions ?????– partnership - science and industry (% of sales)– benefits ????• equip more laboratories• unbiased data collection; more speculative research• answers, new product ideas, and enhance credibility/
marketability of products by verifying applicability of theory