Sternum drop during trip recovery differs between the laboratory and real world - An exploratory pilot study

Area of Science:

• Biomechanics
• Gerontology
• Human Movement Science

Background:

• Trips and falls are a significant concern for older adults, impacting mobility and independence.
• Understanding the biomechanics of balance recovery after tripping is crucial for developing effective fall prevention strategies.
• Previous research has primarily focused on laboratory-induced trips, with limited data on real-world tripping events.

Purpose of the Study:

• To compare sternum drop, a key indicator of balance recovery, between lab-induced trips and naturally occurring real-world trips in community-dwelling older adults.
• To investigate the kinematic differences in sternum drop during balance recovery in controlled versus uncontrolled environments.

Main Methods:

• Twenty community-dwelling older adults (mean age 71.8 years) participated in the study.
• Participants wore three inertial measurement units (IMUs) and a voice recorder for three weeks to capture real-world trips.
• A laboratory session involved inducing two trips per participant to measure sternum drop using the same IMUs.

Main Results:

• Sternum drop was significantly smaller (p < 0.001) and less variable (p < 0.001) during real-world trips compared to all lab-induced trips.
• When considering only lab-induced trips that resulted in recovery, sternum drop did not differ significantly (p = 0.163), but remained less variable (p < 0.001).
• No significant association was found between sternum drop in real-world trips and lab-induced trips (R² = 0.005, p = 0.757).

Conclusions:

• The differences observed are likely due to the faster gait speed and higher obstacle in the lab protocol compared to real-world conditions.
• While modifying lab protocols may improve agreement with real-world data, it could reduce the effectiveness in identifying fall-related factors.
• Further research is warranted to elucidate the relationship between laboratory and real-world tripping kinematics and to improve the ecological validity of fall-related laboratory studies.