Kinematic effects on the lower limb caused by urban terrain cross-slopes.

Greater eversion was required at the upslope limb ankle for cross-slopes greater than 2°.

• Sixteen participants (nine female) walked on level, 2°, 4°, 6°, 8°, and 10° cross-slopes at self-selected pace (1.12 ± 0.09 ms-1).
• Ankle, knee, and hip joint angles were analysed at midstance.
• The upslope limb required progressively greater eversion as slope angle increased beyond 2°.
• Participants were found to use the end range of motion of their ankles in these commonplace urban settings.

Greater inversion was required at the downslope limb ankle for cross-slopes greater than 4°.

• The downslope limb (the limb in the lower position relative to the other) required greater inversion for slopes over 4°.
• This inversion requirement at the downslope ankle reflects asymmetric adaptation to the cross-sloped surface.
• Ankle joint angles were measured at midstance across all slope conditions.
• These findings suggest that reduced ankle mobility may impede ambulation over cross-sloped surfaces commonly encountered in urban environments.

Males and females exhibited different hip kinematics when walking on a cross-sloped surface.

• Sex differences were observed specifically at the hip joint rather than uniformly across all joints.
• Nine of the sixteen participants were female.
• The nature of sex differences in hip kinematics was identified as a distinct factor in cross-slope gait adaptation.
• Slope angle, speed, and sex were all identified as variables resulting in differences in gait pattern on a cross-sloped surface.

Ankle dorsi- and plantarflexion changed with walking speed when on a cross-sloped surface.

• Walking speed effects on ankle kinematics were assessed at the 10° cross-slope condition repeated at self-selected slow (0.81 ± 0.14 ms-1), self-selected (1.12 ± 0.09 ms-1), and fast (1.43 ± 0.14 ms-1) paces.
• Both dorsiflexion and plantarflexion at the ankle were affected by walking speed on the cross-sloped surface.
• Speed-related changes in ankle kinematics were specific to cross-slope conditions.
• This finding indicates that walking speed is an important variable when considering gait adaptations on cross-sloped terrain.

Cross-sloped surfaces commonly found in urban environments push walkers to the end range of ankle motion, which may impede mobility for populations with reduced ankle mobility.

• The cross-slope conditions tested (2°–10°) are encountered every day in urban environments.
• People were found to use the end range of motion of their ankles even at moderate urban cross-slopes.
• This is identified as a potential impediment to mobility for populations with reduced ankle mobility, such as those with lower limb pathologies.
• The authors suggest ambulation over cross-sloped surfaces may be an important task to consider in future designs of interventions for the lower limb.