Walking Stability and Kinematic Variability Following Motor Fatigue Induced by Incline Treadmill Walking.

Area of Science:

• Biomechanics
• Human Movement Science
• Sports Medicine

Background:

• Detecting motor fatigue is vital for preventing injuries and over-exertion during physical activities.
• Previous research on fatigue indices often uses motion capture or wearable sensors, but fatigue induction methods can alter movement patterns.
• The impact of different fatigue induction methods on gait dynamics requires further investigation.

Purpose of the Study:

• To compare the effects of whole-body motor fatigue (incline treadmill walking) versus localized leg and ankle fatigue on gait stability and variability.
• To analyze changes in dynamic margins of stability (MOS), spatiotemporal gait parameters, kinematic variability, and local dynamic stability (LDEs) after different fatigue protocols.
• To determine which fatigue induction method results in greater alterations in gait characteristics.

Main Methods:

• Twenty healthy young adults participated in the study.
• Gait was analyzed at 1.25 m/s before (PRE) and after (POST) two distinct fatigue protocols: whole-body and localized.
• Key gait parameters including dynamic margins of stability (MOS), spatiotemporal measures, kinematic variability, and short-term local divergence exponents (LDEs) of trunk movement were computed and compared using POST-to-PRE ratios.

Main Results:

• Localized fatigue led to significant increases in mean step width, mean mediolateral MOS, knee joint angle variability, and peak mediolateral center of mass velocity compared to whole-body fatigue.
• Whole-body fatigue resulted in a significant reduction in short-term LDE values for anterior-posterior trunk motion, indicating enhanced local dynamic stability.
• The study found that localized fatigue had a more pronounced effect on gait variability and stability metrics than whole-body fatigue.

Conclusions:

• The method used to induce motor fatigue significantly influences gait stability and variability.
• Localized fatigue appears to have a greater detrimental impact on gait variability and stability compared to whole-body fatigue.
• These findings highlight the importance of considering the specific fatigue induction method when assessing gait changes and developing injury prevention strategies.