Tibial Compression During Activities of Daily Living in Young and Older Adults
Authors: Walker Elijah Miles 
Published: March 2023

Introduction: Stress fracture, particularly in the tibia, is a growing concern among older adults (greater than 65 years).
Older adults may have inherent stress fracture risk from ageing-related changes to their musculoskeletal system. Specifically, older adults
reduced ankle neuromuscular function may impair their ability to attenuate repetitive compressive forces experienced during daily locomotor
tasks and increase the likelihood of suffering bone damage from decreased bone tissue elasticity. Yet, it is currently unknown if older adults
exhibit greater tibial compression than their younger counterparts during locomotor tasks. Purpose: This study sought to
quantify tibial compression for older and younger adults when walking and negotiating stairs and determine whether tibial compression is
related to specific ankle biomechanics. Methods: 13 young (ages 18-25 years) and 13 older (greater than 65 years) adults had
tibial compression, and ankle joint stiffness and biomechanics (peak joint angle and moment) quantified during an overground walk, and stair
ascent and descent tasks. Statistical Analysis: Maximum and impulse of tibial compression, ankle joint stiffness, and peak of
stance (0-100%) ankle flexion joint angle and moment were submitted to an independent t-test to assess the difference between young and older
adults during each task. Then, correlation analysis determined the relation between tibial compression and ankle biomechanics for all
participants, as well as the young and older adults. Results: Neither tibial compression (maximum and impulse), nor ankle biomechanics
(joint stiffness, moment, and angle) differed between young and older adults (all: p > 0.05) during the walk and stair ascent tasks.
However, older adults exhibited ~15% smaller maximum tibial compression (p = 0.004) and ~10% peak ankle joint moment (p = 0.037) compared
to young adults during the stair descent. Peak ankle flexion moment exhibited a moderate to strong relation with maximum tibial compression
during each task (overground walk: r = -0.69 ± 0.26; stair descent: r = -0.48 ± 0.32; stair ascent: r = -0.72 ± 0.25, respectively). Yet,
older adults typically exhibited stronger relation between ankle biomechanics and tibial compression than their younger counterparts.
Specifically, older adults exhibited a moderate linear relation between ankle joint stiffness and peak ankle joint moment with impulse
of tibial compression during the walk (r = 0.44 ± 0.48 and r = -0.47 ± 0.47), and peak ankle joint moment with maximum tibial compression
(r = -0.48 ± 0.47) during stair descent task; whereas young adults exhibited a weak relation between the same ankle biomechanical and tibial
compression measures (r = 0.23, -0.20, and - 0.27, respectively) during the walk and stair descent tasks. Conclusion: Older adults
exhibited a substantial, albeit statistically insignificant, 3% to 10% increase in impulse of tibial compression compared to young adults.
The elevated compression impulse may place larger compressive forces on older adult’s tibia, increasing likelihood of bone microdamage
accumulation and stress fracture development. Yet, despite exhibiting a stronger relation between ankle biomechanics and tibial compression
than their younger counterparts, there was not a specific alteration in older adults’ ankle biomechanics that may predict the substantial
change in their tibial compression