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Table 2 Summary of Relevant Literature Pertaining to Nutrient Timing and Exercise

From: Nutrient Administration and Resistance Training

AUTHORS/REFERENCE SUBJECTS SUPPLEMENT/DOSAGE TIME OF ADMINISTRATION TYPE OF EX. SAMPLES MAJOR OUTCOMES
Biolo et al. 1997[47] 6 untrained males - Infusion of balanced AA mixture (0.15 g·kg-1·h-1 for 3 h) Two conditions:
- REST
- Post-ex.
- Leg resistance exercise routine - Muscle biopsies
- Arteriovenous blood samples for 3 h post-ex.
- PRO synthesis post-ex. > rest
- AA transport increased 30–100% post-ex. compared to rest- PRO intake immediately post-ex. may be more anabolic than other times
Kobayashi et al. 2003[30] 10 normal Yorkshire swine Continuous infusion of a mixed AA solution Infusion began 2 h into dialysis and for remaining 2 h NONE - A/V samples and biopsies were taken throughout entire protocol. - Signal to change [AA] was plasma [AA]
- Decrease in PRO synthesis led to decrease in eIF2B activation
- Intramuscular [AA] did not change
Bohe et al. 2003[59] - 21 healthy subjects (11 M, 10 F)
- 29 ± 2 yrs
- Mixed AA infusion at varying rates (44–261 mg AA·kg-1·h-1) Study attempted to determine any dose-response relationship to PRO synthesis NONE - A/V blood samples pre-infusion and for next 6.5 h
- 4 biopsies at 30, 180, 240 and 390 min.
- Myofibrillar, sarcoplasmic, and mitochondrial PRO synthesis was similar
- PRO synthesis is regulated by extracellular [EAA] and becomes saturated at high concentrations.
- A dose-dependent relationship exists between [AA] and PRO synthesis.
Bohe et al. 2001[58] 6 (5 M, 1 F) normal, healthy adults - Infusion (162 mg·kg-1·h-1) of mixed AA 6 h infusion period at constant rate NONE - A/V blood samples over 9 h
- Muscle biopsies to determine AA incorporation
- PRO synthesis increase ~2.8× basal value within 2 h of infusion
- PRO synthesis then declined rapidly
- AA availability may be limited by transport of AA into muscle
Paddon-Jones et al. 2003[45] 12 healthy male and females Two conditions:
- Saline infusion + 15 g EAA solution
- 27 h cortisol infusion + 15 g EAA solution
- Measurements were taken pre- and post-consumption of EAA solution. NONE - A/V blood before and after EAA ingestion.
- 3 biopsies were taken (pre-/post-infusion, supplement consumption)
- Cortisol increased arterial, venous and muscle intracellular AA concentrations.
- EAAs improved muscle protein anabolism during acute hypercortisolemia and may help minimize muscle loss following debilitating injury.
Levenhagen et al. 2002[65] 5 M, 5 F tested 3× with 4 week wash-out Oral doses of:
- Placebo (P)
- 8 g CHO + 3 g fat (SUPP)
- 8 g CHO + 3 g fat + 10 g PRO (SUPP+PRO)
Immediately after exercise 60-min. cycling @ 60% max VO2 and 180 min recovery period. - Blood every 15 min. before ex.
- Arterial and venous blood every 30 min. post-ex. for 180 min.
- In compared to NO or SUPP, SUPP + PRO resulted in a net uptake of EAA and increase in leg and whole-body protein synthesis
- AA are more important than energy for post-ex. repair and growth.
Levenhagen et al. 2001[56] 5 M, 5 F 10 g PRO + 8 g CHO + 3 g Fat Oral administration immediate or 3 h post-ex. 60 min cycling @ 60% max VO2 - Blood every 15 min. before ex.
- Arterial and venous blood every 30 min. post-ex. For 180 min.
- Early intake of a nutrient supplement enhances greater accretion of whole body and leg protein compared to late ingestion.
Tarnopolsky et al. 1997[66] 8 M, 8 F trained endurance athletes 3 groups:
- Placebo (PLA)
- CHO (1 g/kg)
- CHO (0.75 g/kg) + PRO (0.1 g/kg) + Fat (0.02 g/kg)
Two oral doses of each supplement:
- Immediately post-ex.
- 1 h post-ex.
- 90 min. cycle ergometer at 65% max VO2 - Blood samples were given pre-ex., during ex. And 3 h and 4 h post-ex.
- 3 post-ex biopsies (immediate, 1 h 4 h)
- Glucose and insulin increased in both trials post-ex w/no gender effect
- Glycogen resynthesis increased in both trials vs. PLA w/no gender effect
Borsheim et al. 2004[52] 16 (10 M, 6 F) recreationally active subjects Two conditions:
- 100 g CHO
- Placebo (PLA) solution
Oral ingestion at 1 h post-ex. - Leg press (10 × 8 reps) @ 80% 1 Rmprior to 4 h bed rest
- 2 min. rest between sets
- Arteriovenous blood every ~20 min. for 4 h post-ex.
- 4 biopsies (1 pre/3 post-ex.)
- CHO ingestion improved PRO balance after RE
- Effect, however, was minor and delayed compared with ingestion of AA
Roy et al. 2000[67] 10 young (19–21 y), healthy males - Placebo (PLC)
- CHO (1 g/kg)
- CHO/PRO/Fat (1 g/kg)
Immediately post-ex and 1 h post-ex. - 9 resistance training exercises
- 3 sets @ 80% 1 RM
- Arterial/venous blood samples every ~20 min. post-ex.
- 24 h urine
- Nonoxidative leucine disposal (marker of protein synthesis) was increased 4 h for CHO/PRO/Fat and CHO immediately and 1 h following resistance training.
Tipton et al. 2001[3] 3 M, 3 F completed one PRE and POST session EAC: 6 g EAA + 35 g CHO
PLA: Sweetened water
PRE: EAC solution pre-ex.
POST: EAC solution post-ex.
- Leg press and leg ext. 8–10 sets × 8 reps @ 80% 1 RM
- 2 min. rest between sets
- 16 venous and arterial blood samples pre-, during and post-ex. Over 180 min.
- Muscle biopsies @ -60, 0, 60 and 120 min.
- AA delivery increased w/ex. And 2 h post-ex. In both trials
- PRO synthesis increased compared to post
- PRE AA uptake was increased 160% more than in POST
- EAC promoted positive N balance in both trials
Borsheim et al. 2004[57] 8 subjects participated in both trials Oral doses of:
- 77.4 g CHO + 17.5 g Whey + 4.9 g AA (PAAC)
- 100 g CHO (P)
1 h post-exercise - Resistance exercise - Femoral artery, vein and muscle biopsies were collected for 3 h post-ex. - PAAC caused an immediate increase and a delayed increase in protein balance
- PAAC stimulated a greater increase in PRO synthesis vs. CHO after resistance training.
Tipton et al. 1999[54] 3 M, 3 F Three solutions:
- 40 g CHO (PLA)
- 40 g mixed AA
- 40 g EAA
- Continual (100 mL) consumption every 15–20 min. from 1 h post-ex. To 4 h post-ex. - Leg Press (5 × 10 reps @ 75% 1 RM)
- Squat, leg curls/ext. (4 × 8 reps @ 75% 1 RM
- Arteriovenous blood at -120, 30, 220, 260 and 270 min.
- Muscle biopsy was taken at 270 min.
- Both MAA and EAA increased net protein balance
- No difference in protein balance between MAA and EAA suggests no need for NEAA to cause protein synthesis
Tipton et al. 2003[60] 4 F, 3 M Two conditions:
- REST
- REST + EAA+ EX
- 15 g EAA solution before and after exercise session - 8 × 8 reps @ 80% 1 RM
- 2 min. rest between sets
- Five biopsies and A/V blood samples were taken throughout entire 24 h protocol. - AA exchange (ES – REST) @ 3 h and 24 h was not different
- Acute response of muscle to EAA intake + EX is additive to rest and thus reflects 24 h response.
Tipton et al. 2004[62] 23 healthy untrained young males and females Three conditions:
- Placebo (PLA)
- Casein (CAS)
- Whey protein (WP)
1 h post-ex. - Leg ext. 10 × 8 reps @ 80% 1 RM
- 2 min. rest between sets
- Femoral A/V blood samples for 3 h post-ex.
- 4 biopsies (pre-, 1 h, 2 h, 5 h post-ex.)
- Both WP and CAS increased PRO balance to promote PRO synthesis
- AA uptake was increased after exercise in both groups
Ratamess et al. 2003[37] 17 resistance-trained men Two conditions:
- Placebo (PLA)
- AA supplementation
- Immediately post-workout when training
- Mornings of no training
- 4 d/wk RE program for 4 wks
- 2 wk high-intensity phases
- Strength, power and endurance were determined at end of week - Reduction in strength and power was attenuated by AA supplementation
- High intensity, moderate volume RE is effective to increase strength and power.
Rasmussen et al. 2000[51] 3 M, 3 F in postabsorptive state and recreationally active - Placebo drink (PLA)
- EAA+CHO drink (35 g CHO+6 g EAA)
Two conditions:
- PLA 1 h post-ex + EAA+CHO 3 h post-ex
- EAA+CHO 1 h post-ex. + PLA 3 h post-ex.
- 8–10 sets × 8 reps @ 80% 1 RM
- 2 min. rest between sets
- 11 arteriovenous blood over 7 h time span.
- Muscle biopsies at 45 min, 2 h and 4 h post-ex.
- No change in PLA
- EAA+CHO increased PRO balance and PRO SYN 1 h and 3 h post-ex.
- No increase in PS and PRO balance at 3 h vs. 1 h with both > than pre-ex.
Miller et al. 2003[53] 6 M, 4 F - CHO alone
- AA alone
- CHO + mixed AAs (MIX)*
*50% EAA according to wt.
- Two drinks at 1 h and 2 h post-ex.
- Infusion was started 1 h prior to exercise and continue 4 h post-ex.
- 8–10 sets × 10 reps of leg press and leg ext. @ 75% 1 RM
- 2 min. rest between sets
- Biopsies at 30, 90, 150 and 210 min. post-ex.
- Arteriovenous blood for 4 h post-ex.
- Combined effects of CHO Å after resistance exercise is equivalent to their independent effects.
- Prior intake of AA+CHO does not diminish metabolic response to a second comparable dose 1 h later.
Borsheim et al. 2002[1] 3 M, 3 F recreationally active - 6 g Essential amino acids (EAA) - Two oral doses of 6 g EAA at 1 h and 2 h post-ex - 8–10 sets × 10 reps of leg press and leg ext. @ 80% 1 RM
- 2 min. rest between sets
- 4 muscle biopsies were provided post-ex
- Femoral artery and venous blood samples ~every 20 min. for 4 h post-ex
- PRO balance increased in response to both drinks and decreased when [AA] returned to basal levels
- Non-essential AA are not necessary for increasing PRO balance
- PRO synthesis is dose-dependent of [EAA]
Boirie et al. 1997[68] 16 young (24 ± 4 yrs) healthy subjects Five conditions:
- 30 g whey
- 43 g casein (equal [Leu])
- 30 g unlabeled whey
- 43 g unlabeled casein
- 30 g unlabeled casein
- Feeding Trial
- No exercise
- All conditions were ingested at same time
NONE - A/V blood samples for entire 7 h time period - CAS had prolonged plateau of high [AA] inhibiting PRO breakdown by 34%
- WP caused dramatic increase in [AA] causing 68% increase in PRO synthesis
- Speed of PRO digestion and AA absorption have major effect on protein synthesis.
Dangin et al. 2003[69] - 9 elderly (72 ± 1 yrs)
- 6 young (24 ± 1 yrs)
- Casein protein (CAS)
- Isonitrogenous whey w/CAS (WPiC)
- Isonitrogenous whey w/leucine (WPiL)
- Feeding Trial
- No exercise
NONE - A/V blood samples
- Muscle biopsies
- Whey digested faster than CAS
- PRO breakdown was not different
- PRO synthesis was highest with WP vs. CAS irrespective of age
Dangin et al. 2001[70] 22 healthy young males (25 ± 1 yrs) - 30 g casein
- 30 g free AA mimic casein
- 30 g whey
- Repeated small doses of whey
- Feeding Trial
- No exercise
NONE - A/V blood samples for entire 7 h time period - "Fast" meals (whey and free AA) caused strong, rapid increase of [AA]
- Moderate increase in [AA] with "slow" meals and stayed elevated longer
- 7 h Leu balance was higher after slow vs. fast meals
Volpi et al. 1998[71] (71 ± 2 yrs) - Infusion of an AA mixture - Postabsorptive vs. Infusion state NONE - Muscle PRO synthesis and breakdown
- A/V blood
- Muscle biopsies
- Muscle PRO synthesis increased in response to AA infusion
- Muscle PRO breakdown did not change thus increasing PRO balance.
Paddon-Jones et al. 2004[72] - 6 Young (34 ± 4 yrs)
- 7 Older (67 ± 2 yrs)
- One single oral dose of 15 g EAA solution - Pre-/post-supplementation measures were taken. NONE - A/V blood samples and muscle biopsies were taken for 3 h pre- and 4 h post-supplementation - EAA increased PRO synthesis in both young and old
- Increase in [AA] was slower in elderly subjects but remained elevated for a longer period.
- No overall diff. in PRO synthesis between young and old.
Esmarck et al. 2001[55] 13 M older individuals (74.1 ± 1 yr) - Liquid supplement (10 g PRO + 7 g CHO + 3 g fat) - Immediately post training session (P0)
- 2 h post training session (P2)
- 12 week RE program (3×/week) - Body comp. (DEXA)
- Hypertrophy via MRI, and muscle biopsies
- Isokinetic strength
- P0 > P2 for cross-sect. area and mean fiber area
- Similar change in strength
- Immediate protein supplementation post-ex. promotes more growth in elderly males
Volpi et al. 2000[73] 4 M, 1 F young (30 ± 3 yrs)
4 M, 1 F elderly (72 ± 1 yrs)
- Resting or basal phase
- 40 g glucose + 40 g mixed AA
Subjects completed a:
- 300 min. resting period
- 180 min. supplement period
NONE - AV samples every 10 min. last 60 min.
- 4 biopsies in 480 min.
- AA turnover was similar in young and old.
- PRO synthesis with high [AA] and [insulin] was blunted in elderly compared to young.
Volpi et al. 2003[74] 14 elderly adults (70 ± 2 yrs) - 18 g EAA
- 40 g Mixed AA (18 g EAA+22 g NEAA)
Small oral boluses every 10 min. for 3 h NONE Protein metabolism was measured via:
- A/V blood
- Muscle biopsies
- AA balance increased in similar amounts from resting in both conditions
- EAA are responsible for PRO synthesis in elderly
Andersen et al. 2005[63]   - Isoenergetic CHO vs. PRO - Before and after RE
- Morning on non-training days
14-week RE program - Muscle cross-sectional area
- Strength
- PRO increased Type I/II fibers more than CHO
- Squat jump height increased in PRO vs. CHO