Association Between Altered Hip Extension and Kinetic Gait Variables

Area of Science:

• Biomechanics
• Gait Analysis
• Rehabilitation Science

Background:

• Kinematic and kinetic variables are closely related during walking.
• Understanding how isolated kinematic changes affect kinetic outcomes is crucial for gait rehabilitation.
• Current knowledge on the specific relationship between altering a single kinematic variable and subsequent kinetic changes is limited.

Purpose of the Study:

• To investigate the relationship between isolated hip extension alterations and changes in kinetic outcome measures during treadmill walking.
• To determine if modifying hip extension influences key kinetic parameters such as propulsive impulse and ankle power.

Main Methods:

• Ten healthy individuals walked on an instrumented split-belt treadmill with motion capture.
• Participants walked at five randomized cadences (self-selected, ±10%, ±20%) while treadmill speed remained constant.
• Hip extension and kinetic outcomes were calculated for each cadence to assess alterations.

Main Results:

• Altering hip extension by changing cadence led to significant changes in kinetic outcomes.
• Hip extension alterations strongly correlated with changes in propulsive impulse (r = 0.852, P < 0.001).
• Significant correlations were also found with peak ankle power (r = 0.473, P = 0.002) and ankle plantarflexion work (r = 0.762, P < 0.001).

Conclusions:

• Kinetic outcomes in walking are highly adaptable in response to kinematic gait modifications.
• Targeting hip extension during gait can effectively alter kinetic parameters.
• This provides a potential strategy for improving motor output in gait rehabilitation by optimizing limb positioning.