Effects of resistance exercise combined with essential amino acid supplementation and energy deficit on markers of skeletal muscle atrophy and regeneration during bed rest and active recovery.
Study Goal
The researchers aimed to determine the effects of EAA supplementation, with or without resistance training, on molecular changes in skeletal muscle during bed rest (simulating spaceflight) and recovery.
Results Summary
EAA alone was the least protective against muscle loss, while resistance training combined with EAA showed better outcomes. EAA supplementation led to increased myostatin during bed rest and upregulated certain muscle-related transcripts during recovery, but satellite cell counts remained unchanged.
Population
31 men aged 31-55 years subjected to an 8 ± 6% energy deficit.
Effective Dosage
Not specified in the abstract.
Duration
28-day bed rest followed by 14-day recovery.
Interactions
None mentioned
| Intervention | Direction | Endpoint | Population | Dosage | Impact | Claim # |
|---|---|---|---|---|---|---|
essential amino acid (EAA) supplementation without resistance training | increase | myostatin transcript levels | men (31-55 years) subjected to an 8 ± 6% energy deficit during bed rest | twofold | increased | #1 |
essential amino acid (EAA) supplementation and resistance training with decreased energy intake | increase | insulin-like growth factor-1 (IGF-1) mRNA | men (31-55 years) subjected to an 8 ± 6% energy deficit during recovery | - | increased | #2 |
essential amino acid (EAA) supplementation without resistance training | increase | Pax7 transcripts | men (31-55 years) subjected to an 8 ± 6% energy deficit during recovery | - | increased | #3 |
essential amino acid (EAA) supplementation without resistance training | increase | MyoD transcripts | men (31-55 years) subjected to an 8 ± 6% energy deficit during recovery | - | increased | #4 |
essential amino acid (EAA) supplementation without resistance training | increase | myogenin transcripts | men (31-55 years) subjected to an 8 ± 6% energy deficit during recovery | - | increased | #5 |
essential amino acid (EAA) supplementation without resistance training | increase | MRF4 transcripts | men (31-55 years) subjected to an 8 ± 6% energy deficit during recovery | - | increased | #6 |
essential amino acid (EAA) supplementation without resistance training | decrease | MAFbx transcripts | men (31-55 years) subjected to an 8 ± 6% energy deficit | twofold | decreased | #7 |
essential amino acid (EAA) supplementation 3 h after resistance training | decrease | MAFbx transcripts | men (31-55 years) subjected to an 8 ± 6% energy deficit | twofold | decreased | #8 |
essential amino acid (EAA) supplementation and resistance training with decreased energy intake | no change | satellite cells | men (31-55 years) subjected to an 8 ± 6% energy deficit during bed rest or recovery | - | did not change | #9 |
Spaceflight and bed rest (BR) lead to muscle atrophy. This study assessed the effect of essential amino acid (EAA) supplementation and resistance training with decreased energy intake on molecular changes in skeletal muscle after 28-day BR and 14-day recovery. Thirty-one men (31-55 years) subjected to an 8 ± 6% energy deficit were randomized to receive EAA without resistance training (AA, n = 7), or EAA 3 h after (RT, n = 12) or 5 min before (AART, n = 12) resistance training. During BR, myostatin transcript levels increased twofold in the AA group. During recovery, insulin-like growth factor-1 (IGF-1) mRNA increased in all groups, whereas Pax7, MyoD, myogenin, and MRF4 transcripts increased in AA only (all P < 0.05). MAFbx transcripts decreased twofold with AA and RT. Satellite cells did not change during BR or recovery. This suggests that EAA alone is the least protective countermeasure to muscle loss, and several molecular mechanisms are proposed by which exercise attenuates muscle atrophy during BR with energy deficit.