| Summary: | The aim of this study was to investigate how the anterior and posterior muscles in
the shank (Tibialis Anterior, Gastrocnemius Lateralis and Medialis), influence the level
of minimum toe clearance (MTC). With aging, MTC deteriorates thus, greatly increasing
the probability of falling or tripping. This could result in injury or even death. For this study,
muscle activity retention taping (MART) was used on young adults, which is an accepted
method of simulating a poor MTC—found in elderly gait. The subject’s muscle activation
was measured using surface electromyography (SEMG), and the kinematic parameters
(MTC, knee and ankle joint angles) were measured using an optical motion capture
system. Our results indicate that MART produces significant reductions in MTC (P <
α), knee flexion (P < α) and ankle dorsiflexion (P < α), as expected. However, the muscle
activity increased significantly, contrary to the expected result (elderly individuals should
have lower muscle activity). This was due to the subject’s muscle conditions (healthy and
strong), hence the muscles worked harder to counteract the external restriction. Yet, the
significant change in muscle activity (due to MART) proves that the shank muscles do play
an important role in determining the level of MTC. The Tibialis Anterior had the highest
overall muscle activation, making it the primary muscle active during the swing phase.
With aging, the shank muscles (specifically the Tibialis Anterior) would weaken and stiffen,
coupled with a reduced joint range of motion. Thus, ankle-drop would increase—leading
to a reduction in MTC.
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