Table 1.
Human Spaceflight and Skeletal Muscle Adaptations.
| Author | Yr | Space Era | N (Gender) | Flight Duration | Exercise Countermeasures | Highlighted Adaptations |
|---|---|---|---|---|---|---|
| Thorton [24] | 1974 | Skylab2 | 3(M) | 28 d | Bicycle Erg | M.Volume (Girth Circ.): ↓4.5% Legs; Strength. (Isok): ↓20% Legs |
| Thorton [24] | 1974 | Skylab 3 | 3(M) | 59 d | Bicycle Erg., MK-I, MK-II | M.Volume (Girth Circ.): ↓5% Legs, Strength (Isok): ↓20% Legs |
| Thorton [24] | 1974 | Skylab 4 | 3(M) | 84 d | Bicycle Erg., MK-I, MK-II, Thorton Passive Treadmill | M.Volume (Girth Circ): ↓2% Legs, Strength. (Isok): ↓7% Legs |
| Leblanc [7] | 1995 | STS | 4(2M2W) | 8 d | Shuttle Erg | M.Volume (MRI):↓6.3%, Gastr, ↓3.9% Ant. Calf. ↓8.3% Ham, ↓6.0% Quad, ↓10.3% L.Back |
| Edgerton [12] | 1995 | STS | 8(5M3W) | 5–11 d | Shuttle Treadmill, LBNP | F. CSA: ↓11% type I &, ↓24% type II VL in 5 d, ↓16%–36% type II loss > type I in 11 d |
| Widrick [13] | 1999 | STS/Mir | 4(M) | 17 d | NR | F. Diam/: ↓8% in Sol. type I |
| Akima [6] | 2000 | STS | 3(?) | 9–16 d | NR | Volume (MRI): ↓5.6% to 15.4% KE, ↓8.6% to 14.1% KF, ↓8.4% to 15.9% PF |
| Leblanc [8] | 2000 | STS/Mir | 4(M) | 17 d | NR | Volume (MRI): ↓10% AE & IB, ↓5%–7% Quad & Psoas, ↓3% in Ham & AL |
| Leblanc [8] | 2000 | STS/Mir | 16(15M1W) | 115–197 d | NR | Volume (MRI): 14.6% AL, ↓16.9% Gast, ↓16.8% Sol, ↓10.1% Quad, ↓12.7% Ham, ↓15.9% IB, and ↓4.4% Psoas |
| Riley [25] | 2000 | STS | 4(M) | 17 d | NR | F: A Band ↓17% Filaments, ↑9% Short Filaments |
| Koryak [26] | 2001 | Mir | 7(M) | 6 mo | NR | Strength (Isom): ↓42% TS, Strength: (Evoked Forces): ↓26% Po TS, ↑15% Pt TS |
| Trappe [14] | 2001 | STS | 4(M) | 17 d | NR | F.CSA: ↓7.4% Type I Gast, ↓10.1 Type IIa Gast, ↓7.4 Type I Sol. ↔ Calf MVC or Force Velocity Relationship |
| Lambertz [27] | 2001 | Mir | 14(M) | 90–180 d | Cycle Erg., Treadmill | Strength (Isom): ↓2%–30% PF in 12 of 14 subjects |
| Narici [28] | 2003 | STS | 4(M) | 17 d | NR | M.CSA (Girth Circ.): ↓8% Calf., Strength (Evoked Forces) ↓24% Peak Twitch; ↓22% Tetanic Force at 50 Hz; ↓19.5% Specific Forces at 50 Hz of TS |
| Tesch [29] | 2005 | STS | 4(M) | 17 d | NR | M. CSA (MRI): ↓8% KE & Gluteal. Strength (Isom): ↓10% KE, Strength (Isok): ↓9% KE (CON), 11% KE (ECC) |
| Trappe [9] | 2009 | ISS | 9(?) | 6 mo | CEVIS, TVIS, VELO, iRED | M.Volume (MRI): ↓13% Calf, ↓15% Sol, ↓10% Gast. Calf Peak Power ↓32%, Force-Velocity ↓20%–29% across 30–300°/sec |
| Fitts [10] | 2010 | ISS | 9(?) | 6 mo | CEVIS, TVIS, VELO, iRED | F.CSA: ↓33% type 1 Sol > type II Sol > type I Gast. > type II Gas |
| Gopalakrishnan [30] | 2010 | ISS | 4(M) | 181 d | CEVIS, TVIS, VELO, iRED | M.Volume (MRI): ↓10 calf, ↓4 thigh |
| Smith [31] | 2012 | ISS | 8(6M2W) | 160 d | CEVIS, TVIS, iRED | Lean mass (DEXA): ↓2% total body |
| Smith [31] | 2012 | ISS | 5(3M2W) | 134 d | CVIS, TVIS, ARED | Lean mass (DEXA): ↑3% total body |
STS = Shuttle transport system, ISS = International space station, CEVIS = Cycle ergometer with isolation system, TVIS = Treadmill with isolation system, iRED = Interim resistive device, VELO = Russian velociped bicycle exercise device, MRI = Magnetic resonance imaging, CSA = Cross-sectional area, Pec/Lats = Pectoralis major/lattisimus dorsi, Gastr = Gastrocnemius, Ant = Anterior, Ham = Hamstring, Quad = Quadriceps, VL = Vastus lateralis, Sol. = Soleus, KF = Knee flexors, KE = Knee extensors, PF = Plantar flexors, IB = Intrinsic back, TS = Tricpes surea, Circ. = Circumference, Isok = Isokinetic, Isom = Isometric, Erg = Egometer, LBNP = Lower body negative pressure, F. = Fiber, M. = Muscle, Diam. = Diameter, CON = Concentric, ECC = Eccentric, MVC = Maximal voluntary contraction, d = Days, Yr. = Year, mo = months, M = Men, W = Women. NR = Not reported.