Habitual foot strike pattern does not affect simulated Triceps Surae muscle metabolic energy consumption during running

Abstract

7Foot strike pattern affects ankle joint work and Triceps Surae muscle-tendon dynamics during running. 8Whether these changes in muscle-tendon dynamics also affect Triceps Surae muscle energy 9 consumption is still unknown. In addition, as the Triceps Surae muscle accounts for a substantial 10 amount of the whole body metabolic energy consumption, changes in Triceps Surae energy 11 consumption may affect whole body metabolic energy consumption. However, direct measurements 12 of muscle metabolic energy consumption during dynamic movements is hard. Model-based 13 approaches can be used to estimate individual muscle and whole body metabolic energy consumption 14 based on Hill type muscle models. In this study, we use an integrated experimental and dynamic 15 optimization approach to compute muscle states (muscle forces, lengths, velocities, excitations and 16 activations) of 10 habitual mid-/forefoot striking and 9 habitual rearfoot striking runners while running 17 at 10 and 14 km/h. The Achilles tendon stiffness of the musculoskeletal model was adapted to fit 18 experimental ultrasound data of the Gastrocnemius medialis muscle during ground contact. Next, we 19 calculated Triceps Surae muscle and whole body metabolic energy consumption using four different 20 metabolic energy models provided in literature. Neither Triceps Surae metabolic energy consumption 21 (p > 0.35), nor whole body metabolic energy consumption (p > 0.14) was different between foot strike 22 patterns, regardless of the energy model used or running speed tested. Our results provide new 23 evidence that mid-/forefoot and rearfoot strike pattern are metabolically equivalent.

Evaluation of musculoskeletal models, scaling methods, and performance criteria for estimating muscle excitations and fiber lengths across walking speeds

“…All models assume the same MCV (10 OFL/s), activation time constant (10 ms), and deactivation time constant (40 ms) for all muscles, and PA was as per the original models. In addition, the non-linear tendon stiffness of gastrocnemius medialis, gastrocnemius lateralis, and soleus were set to 15 (nondimensionalized), according to ultrasound studies (Swinnen et al, 2019;Delabastita et al, 2020) that describe the Achilles tendon as highly compliant. Similarly, the non-linear tendon stiffness of vastus lateralis, vastus medialis, vastus intermedius, and rectus femoris was set to 20 (nondimensionalized), according to findings that modelling the Patellar tendon as highly compliant agrees better with experimental observations (Chleboun et al, 2007;Bohm et al, 2018), including muscle fiber operating range (Son et al, 2018).…”

“…Neuromusculoskeletal modeling enables the study of individual muscle-tendon unit (MTU) behavior, joint kinematics, dynamics, and neuromuscular control strategies by non-invasive means. Simulation studies have provided insights into the MTU mechanics in able-bodied individuals (Heintz and Gutierrez-Farewik, 2007;Hamner et al, 2010;Arnold et al, 2013;Swinnen et al, 2019;Delabastita et al, 2020), and in individuals with disabilities in unassisted motions (Krogt et al, 2016) and with the support of assistive devices (Lotti et al, 2020). A realistic representation of MTU behavior depends on adequately modeling skeletal anatomy and muscle architecture and decoding neuromuscular control.…”