Table 2.
Estimated marginal means and mean differences (95% confidence interval lower and upper limits) for ΔF, peak discharge rates, and recruitment thresholds before and after control or handgrip conditions in young and older adults and for soleus and tibialis anterior
| ΔF (pps) | Peak discharge rates (pps) | Recruitment threshold (% of peak torque) | |
|---|---|---|---|
| Older adults – soleus | |||
| Before control | 1.81 (1.44, 2.17) | 8.75 (8.17, 9.32) | 8.11 (6.92, 9.30) |
| After control | 1.73 (1.36, 2.09) | 8.62 (8.05, 9.20) | 8.39 (7.20, 9.57) |
| After – before control | −0.08 (−0.37, 0.21) | −0.13 (−0.39, 0.14) | 0.28 (−0.76, 1.31) |
| Before handgrip | 2.02 (1.66, 2.39) | 8.54 (7.96, 9.12) | 8.66 (7.47, 9.85) |
| After handgrip | 2.41 (2.04, 2.77) | 9.00 (8.42, 9.57) | 9.01 (7.82, 10.20) |
| After – before handgrip | 0.39 (0.10, 0.67) | 0.46 (0.20, 0.72) | 0.35 (−0.68, 1.38) |
| Young adults – soleus | |||
| Before control | 2.64 (2.21, 3.08) | 10.65 (9.95, 11.36) | 9.20 (7.79, 10.61) |
| After control | 2.53 (2.09, 2.96) | 10.75 (10.04, 11.45) | 9.03 (7.62, 10.45) |
| After – before control | −0.12 (−0.44, 0.20) | 0.10 (−0.19. 0.39) | −0.17 (−1.31, 0.98) |
| Before handgrip | 2.60 (2.15, 3.06) | 10.57 (9.85, 11.28) | 9.54 (8.06, 11.02) |
| After handgrip | 2.96 (2.51, 3.41) | 10.91 (10.20, 11.63) | 8.42 (6.94, 9.90) |
| After – before handgrip | 0.35 (−0.04, 0.74) | 0.34 (−0.01, 0.70) | −1.12 (−2.51, 0.28) |
| Older adults – tibialis anterior | |||
| Before control | 2.92 (2.44, 3.40) | 12.14 (11.09, 13.19) | 10.39 (8.94, 11.84) |
| After control | 2.79 (2.31, 3.26) | 11.89 (10.84, 12.95) | 10.88 (9.43, 12.33) |
| After – before control | −0.13 (−0.39, 0.13) | −0.25 (−0.60, 0.10) | 0.49 (−0.17, 1.15) |
| Before handgrip | 2.95 (2.47, 3.44) | 12.04 (10.98, 13.10) | 9.71 (8.24, 11.18) |
| After handgrip | 3.36 (2.88, 3.85) | 12.22 (11.16, 13.28) | 11.36 (9.88, 12.83) |
| After – before handgrip | 0.41 (0.10, 0.72) | 0.18 (−0.23, 0.59) | 1.65 (0.80, 2.49) |
| Young adults – tibialis anterior | |||
| Before control | 4.18 (3.71, 4.66) | 14.75 (13.71, 15.79) | 11.36 (9.91, 12.80) |
| After control | 4.21 (3.74, 4.69) | 14.71 (13.67, 15.75) | 10.79 (9.34, 12.23) |
| After – before control | 0.03 (−0.25, 0.30) | −0.04 (−0.41, 0.33) | −0.57 (−1.29, 0.15) |
| Before handgrip | 4.18 (3.70, 4.66) | 14.12 (13.08, 15.17) | 11.56 (10.10, 13.02) |
| After handgrip | 4.59 (4.10, 5.07) | 14.66 (13.62, 15.75) | 11.05 (9.59, 12.51) |
| After – before handgrip | 0.41 (0.10, 0.71) | 0.53 (0.12, 0.94) | −0.51 (−1.31, 0.29) |