Table 1.
Age-Related Changes in Grip Strength, Rotarod Performance, and Body Composition
| G1 | G2 | |||||||
|---|---|---|---|---|---|---|---|---|
| Age (months) | 4 | 7 | 12 | 15 | 18 | 21 | 24 | |
| Forelimb grip force (g) | M | 192.3 (11.0) | 172.2 (9.8) | 174.0 (7.0) | 159.0 (3.9) | 163.2 (5.5) | 150.6 (4.3) | 148.7 (5.8) |
| F | 177.4 (4.7) | 153.6 (7.2) | 169.0 (7.7) | 150.4 (7.4) | 144.6 (5.8) | 148.7 (5.0) | 153.1 (10.5) | |
| Hindlimb grip force (g) | M | 94.0 (5.3) | 154.2 (5.6) | 156.8 (10.1) | 171.0 (16.4) | 146.7 (6.7) | 145.0 (10.5) | 133.9 (7.7) |
| F | 83.2 (2.7) | 189.3 (11.0) | 200.3 (13.0) | 203.7 (9.6) | 147.9 (9.3) | 152.0 (6.1) | 128.4 (7.6) | |
| Rotarod time (s) | M | 69.0 (4.2) | 65.4 (6.0) | 61.1 (5.8) | 66.6 (6.4) | 57.5 (5.1) | 59.1 (4.6) | 58.8 (5.5) |
| F | 73.4 (3.0) | 68.1 (5.3) | 76.6 (6.0) | 73.4 (4.9) | 63.0 (5.2) | 64.0 (4.8) | 64.4 (4.9) | |
| Total body mass (g) | M | 31.2 (0.5) | 34.2 (0.5) | 39.0 (1.5) | 40.8 (1.6) | 42.5 (1.9) | 42.0 (2.0) | 41.5 (1.9) |
| F | 24.3 (0.6) | 27.7 (0.9) | 31.0 (1.3) | 32.8 (1.4) | 35.5 (1.8) | 34.0 (1.8) | 34.4 (1.9) | |
| Lean mass (g) | M | 26.6 (0.6)* | 27.4 (0.8) | 28.2 (0.7) | 28.6 (0.5) | 29.1 (0.7) | 29.1 (0.7) | 28.9 (0.6) |
| F | 19.9 (0.4)* | 20.6 (0.3) | 22.0 (0.6) | 22.6 (0.6) | 23.9 (0.7) | 23.3 (0.7) | 22.7 (0.7) | |
| Fat mass (g) | M | 1.2 (02)* | 2.1 (0.3) | 5.3 (0.9) | 6.5 (0.9) | 7.6 (1.1) | 7.1 (1.2) | 6.4 (1.1) |
| F | 2.4 (0.3)* | 3.6 (0.4) | 4.8 (0.7) | 5.4 (0.7) | 7.2 (1.0) | 5.9 (0.9) | 6.2 (1.0) | |
| Weekly food intake (g) | M | — | 28.9 (0.8) | — | 29.4 (0.9) | 29.0 (1.2) | 29.9 (1.3) | 30.7 (1.2) |
| F | — | 25.5 (0.1) | — | 26.3 (0.5) | 27.8 (1.0) | 26.2 (0.9) | 28.9 (1.1) | |
Notes: F = female; M = male. Weekly food intake was averaged over 3-month intervals from the time that measurement began. Baseline measures for G1 and G2 are not available as food intake was not tracked until the onset of the experiment. Values are means ± SEM.
*Measure performed at 5 months of age.