Sudden turns and stops while walking: kinematic sources of age and gender differences

Area of Science:

• Biomechanics
• Gerontology
• Human Movement Science

Background:

• Significant age and gender disparities exist in the ability of healthy individuals to suddenly stop or turn to avoid gait path obstacles.
• Previous research identified these differences in young and older adults, prompting further investigation into the underlying kinematic factors.

Purpose of the Study:

• To quantify how age and gender differences in response kinematics influence the total time required to suddenly arrest forward momentum.
• To determine the specific kinematic parameters contributing to age- and gender-related differences in necessary response time (NRT).

Main Methods:

• Measured four kinematic parameters of forward abdominal movement: duration of the first response phase (T1), acceleration (A1), and decelerations (D2, D3).
• Constructed a three-line-segment velocity history to predict NRT differences based on measured kinematic variations.
• Analyzed age- and gender-group means for these kinematic measures and their impact on NRT.

Main Results:

• Increased T1 duration was the primary factor contributing to the age-related difference in NRT.
• For older males, higher A1 values contributed significantly; for older females, smaller D2 values were a major factor.
• In older adults, gender differences in D2 almost entirely explained the NRT gender disparity in both sudden stops and turns.

Conclusions:

• The extended first response phase (T1) largely accounts for older adults' longer NRT compared to younger individuals.
• Older females exhibit longer NRT than young adults and older males due to substantially smaller decelerations (D2) in the second response phase.
• These kinematic differences may stem from age- and gender-related variations in the rapid development of lower extremity joint torque strength.