Table 1 Summary of literature pertaining to protein metabolism response to resistance exercise

Biolo et al. 1995[49]

10 (9 M, 1 F) healthy volunteers (19–52 yrs)

NONE

- A/V blood samples

- Muscle biopsies

- AA infusion can validly quantify many important aspects of PRO synthesis, breakdown and AA transport.

Biolo et al. 1995[11]

5 M young (24 ± 2 yrs), healthy males

- Leg Press (5 × 10 reps @ 75% 1 RM)

- Squat, leg curls/ext. (4 × 8 reps @ 75% 1 RM

- PRO synthesis, PRO breakdown and AA transport were determined at rest and 3 h post-ex.

- PRO synthesis and PRO breakdown are increased after resistance exercise

- Post-ex. increase of AA transport may contribute to PRO synthesis

Tipton et al. 1996[17]

7 collegiate female swimmers

Four conditions:

- Resting (R)

- Intense swimming (S)

- Resistance ex. (RE)

- Swim + resistance ex. (SRE)

- 5 h testing period

- 4 blood samples at 4 h and 5 h post-ex.

- 2 biopsies at 1 h and 5 h post-ex.

- No difference in PRO breakdown for all conditions

- PRO synthesis increased after SRE vs. R

- Combined SRE increases PRO synthesis above resting levels in female swimmers.

Phillips et al. 1997[12]

8 (4 M, 4 F) untrained individuals

- 8 × 8 concentric or eccentric reps @ 80% 1 RM

- A/V blood at 120, 180, 210, 240, 260, 280 and 300 min.

- Biopsies were taken at 120, 280 and 300 min.

- Increased synthesis rate at all time points (3 h: 112%, 24 h: 65%, 48 h: 34%).

- Increased breakdown rate at 3 h (31%) and 24 h (18%), but no diff. at 48 h.

- Resistance exercise resulted in increases in protein balance that persisted for up to 48 h and is independent of type of muscle contractions.

Phillips et al. 1999[15]

Trained subjects (6) vs. untrained subjects (6)

- 10 × 8 eccentric reps @ 120% 1 RM

- One leg exercised while other was control

- Femoral A/V blood samples

- Femoral muscle biopsies

- Exercise increased both PRO synthesis and breakdown

- Training status diminishes the response of PRO synthesis and breakdown

Hasten et al. 2000[24]

7 healthy young (23–32 y) and 7 elder (78–84 y) subjects

2 week weight lifting program (3 × 8–12 reps @ 60–90% 1 RM)

14 h infusion to determine incorporation of protein into vastus lateralis

- MHC and mixed protein after training increased in young (88% and 121%) and older (105 and 182%) compared to baseline

- Older people retain capacity to increase MHC

Phillips et al. 2002[19]

19 young (23.7 ± 3.2 yrs), untrained, healthy, male subjects

- 8 week RE program (6 d/week)

- During testing, one leg acted as control

- A/V blood samples and muscle biopsies after acute, initial bouts of RE and after 6 weeks of training

- RE increases PRO balance in both legs but more so in exercised leg

- Regular training attenuates increase in PRO synthesis

Pitkanen et al. 2003[9]

12 healthy, physically active males

- 50 min. bout of lower-body RE

- 3 × 10 reps @ 80% 1 RM w/1–1.5 min. rest

- A/V blood samples were provided throughout entire 5 h protocol

- Biopsies were provided 1 h post-ex. and 3.5 h post-ex.

- Protein net balance is negative and similar between groups

- RES induces an increase in MPS and breakdown at 195 min. but not by 60 min. post-ex.

Sheffield-Moore et al. 2004[14]

- 6 older M

(69 ± 1 yrs)

- 6 younger M (29 ± 2 yrs)

- 45 min. treadmill walking @ ~40% peak VO₂

- Femoral biopsies and A/V blood samples at -10, 60 and 180 min. post-ex.

- Protein synthesis and breakdown increased in both groups after exercise

- Older individuals had increased protein breakdown compared to younger individuals

Durham et al. 2004[64]

7 (5 M, 2 F) were studied at rest and after exercise

- Leg press (8 × 10 reps @ 75% 1 RM) and Leg ext. (8 × 8 reps @ 80% 1 RM)

- Femoral A/V blood and biopsies were obtained at rest and immediately after exercise.

- Lower body RE increases glucose uptake and lactate release

- PRO synthesis is not elevated during a bout of RE