Table 2. Task performance variables of AMD participants, older visual normals and young visual normals in the two different conditions (mean ± SD).
| Variables | AMD participants (n = 8) | Older visual normals (n = 8) | Young visual normals (n = 8) | ANOVA | |||
|---|---|---|---|---|---|---|---|
| No-pressure | Time-pressure | No-pressure | Time-pressure | No-pressure | Time-pressure | ||
| Total performance time (s) | 10.0 (2.0) | 7.8 (1.8) | 8.7 (1.9) | 6.5 (1.7) | 7.0 (0.5) | 5.2 (0.7) | G, C |
| Normalised peak ground reaction forces | |||||||
| Peak vertical ground reaction force (% body mass) | 101 (3) | 102 (3) | 104 (8) | 104 (10) | 106 (4) | 116 (13) | G |
| Peak AP ground reaction force (% body mass) | −16 (6) | −15 (3) | −16 (6) | −21 (5) | −21 (4) | −29 (5) | G, C, GxC |
| Peak ML ground reaction force (% body mass) | 6 (1) | 7 (1) | 6 (2) | 6 (1) | 6 (0) | 8 (2) | ns |
| Loading rates | |||||||
| Loading rate in vertical direction (N/s) | 2,128 (508) | 2,224 (554) | 2,107 (764) | 3,642 (1,401) | 3,011 (510) | 4,515 (1,560) | G, C, GxC |
| Loading rate in AP direction (N/s) | −560 (365) | −461 (284) | −431 (347) | −878 (423) | −665 (195) | −1,334 (719) | G, C, GxC |
| Loading rate in ML direction (N/s) | 151 (76) | 134 (49) | 146 (100) | 197 (65) | 177 (49) | 308 (150) | G, C, GxC |
| Temporal variables | |||||||
| Double support phase prior to step-up (s) | 0.19 (0.04) | 0.13 (0.03) | 0.19 (0.06) | 0.12 (0.05) | 0.14 (0.03) | 0.06 (0.03) | G, C |
| Single support phase during step-up lead foot (s) | 0.42 (0.07) | 0.38 (0.05) | 0.45 (0.03) | 0.39 (0.03) | 0.41 (0.03) | 0.41 (0.12) | C |
| Double support phase during step-up (s) | 0.32 (0.09) | 0.26 (0.09) | 0.33 (0.13) | 0.22 (0.09) | 0.23 (0.04) | 0.12 (0.03) | G, C |
| Single support phase during step-up trail foot (s) | 0.31 (0.04) | 0.29 (0.03) | 0.34 (0.03) | 0.31 (0.05) | 0.32 (0.03) | 0.30 (0.05) | C |
| Balance control single support phase | |||||||
| CoP displacement in AP direction (cm) | 2.7 (2.2) | 2.3 (1.0) | 1.9 (1.0) | 3.6 (2.1) | 2.2 (1.0) | 5.0 (1.7) | C, GxC |
| CoP displacement in ML direction (cm) | 3.2 (1.6) | 1.8 (1.4) | 1.0 (0.6) | 1.6 (1.0) | 1.4 (1.1) | 1.5 (0.7) | G, GxC |
| Centre-of-pressure velocity in AP direction (cm/s) | 8.6 (5.8) | 8.6 (4.1) | 5.8 (2.7) | 12.0 (6.5) | 7.1 (3.3) | 17.6 (5.2) | C, GxC |
| Centre-of-pressure velocity in ML direction (cm/s) | 11.5 (6.5) | 6.4 (5.4) | 3.3 (2.4) | 5.4 (3.6) | 4.6 (4.1) | 5.4 (2.1) | G, GxC |
Note:
AP, anterior-posterior; CoP, centre-of-pressure; ML, medial-lateral; G, significant group effect (p < 0.05); C, significant condition effect (p < 0.05); GxC, significant group by condition interaction (p < 0.05); ns, no significant effect.