Joint action in the transition from unperturbed walking to avoidance movements
| . | ThC joint . | . | . | CTr joint . | . | . | FTi joint . | . | . | ||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Action . | Inner . | Straight . | Outer . | Inner . | Straight . | Outer . | Inner . | Straight . | Outer . | ||||||
| Switch | 54 | 81.3 | 77.2 | 62.7 | 79.7 | 43.8 | 76.5 | 71.9 | 56.2 | ||||||
| Reinforce | 18 | 1.6 | 5.3 | 29.4 | 9.4 | 43.9 | 5.9 | 20.3 | 33.4 | ||||||
| Reduce | 28 | 17.2 | 17.6 | 7.9 | 11.0 | 12.3 | 17.6 | 7.9 | 10.6 | ||||||
| Motion component | Retraction | Levation | Flexion | ||||||||||||
| 82 | 76.6 | 79.0 | 86.3 | 89.1 | 80.7 | 80.4 | 89.1 | 87.7 | |||||||
| . | ThC joint . | . | . | CTr joint . | . | . | FTi joint . | . | . | ||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Action . | Inner . | Straight . | Outer . | Inner . | Straight . | Outer . | Inner . | Straight . | Outer . | ||||||
| Switch | 54 | 81.3 | 77.2 | 62.7 | 79.7 | 43.8 | 76.5 | 71.9 | 56.2 | ||||||
| Reinforce | 18 | 1.6 | 5.3 | 29.4 | 9.4 | 43.9 | 5.9 | 20.3 | 33.4 | ||||||
| Reduce | 28 | 17.2 | 17.6 | 7.9 | 11.0 | 12.3 | 17.6 | 7.9 | 10.6 | ||||||
| Motion component | Retraction | Levation | Flexion | ||||||||||||
| 82 | 76.6 | 79.0 | 86.3 | 89.1 | 80.7 | 80.4 | 89.1 | 87.7 | |||||||
Percentage of joint action of thorax-coxa (ThC) joint, coxa-trochanter(CTr) joint and femur-tibia (FTi) joint in three behavioural contexts: inner leg, straight walking and outer leg. Joint angle velocities were analysed before and after perturbation on a single-trial basis. All values indicate percentages of trials.
Of the three types of joint action defined, switching between two motion components occurred most frequently regardless of behavioural context and leg joint. Whereas switching clearly dominated in straight walking, it is less consistent in both curve-walking contexts. The avoidance movement context-independently comprised the motion components retraction, levation and flexion, each one in 77-89% of all trials.