Relationship between running economy and mechanical characteristics of triceps surae assessed with tensiomyography: A pilot study

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Tensiomyography (TMG) is a non-invasive technique commonly used for evaluating muscle properties
in highly trained athletes. The aim of our study was to evaluate the mechanical characteristics of m. triceps
surae in competitive runners through TMG measurement and analyze if there was a relationship with
running economy (RE). Nine male runners completed the study (mean±SD: age 40.4±9.0 years, body height
176.2±4.9 cm, body mass 70.7±9.4 kg, 10-km time 39.8±5.9 min, VO2peak 56.9 ± 6.5 mL kg-1 min-1). Each
subject visited the lab on two occasions with 72h of rest between the trials. On the first day, an incremental
test was performed to determine their ventilatory thresholds and peak oxygen consumption. On the second
day, RE was evaluated on a treadmill at the velocity of their first ventilatory threshold (VT1), and mechanical
characteristics of the soleus and gastrocnemius muscles were analyzed with TMG. Significant differences
were found between the economic and non-economic runners in m. soleus in delayed time (Td), contraction
time (Tc), and maximal radial displacement of the muscle belly (Dm). Also, significant differences were
found in contraction time (Tc) in medium calf (MC) and in half relaxation time (Tr) in lateral twin (LT). The
main finding of our study was that the runners with better RE showed greater stiffness in the triceps surae
muscles, an aspect that seems to be associated with better performance in athlete runners.