Biology subjects

Vanwanseele, B.

Publications and source records attributed to Vanwanseele, B..

3 recordsLinked to original sources

bioRxiv2020

Achilles tendon stiffness minimizes the energy cost in simulations of walking in older but not in young adults

Both Achilles tendon stiffness and walking patterns influence the energy cost of walking, but their relative contributions remain unclear. These independent contributions can only be investigated using simulations. We created models for 16 young (24{+/-}2 years) and 15 older (75{+/-}4 years) subjects, with individualized (using optimal parameter estimations) and generic triceps surae muscle-tendon parameters. We varied Achilles tendon stiffness and calculated the energy cost of walking. Both in young and older adults, Achilles tendon stiffness independently contributed to the energy cost of walking. However, overall, a 25% increase in Achilles tendon stiffness increased the triceps surae and whole-body energy cost of walking with approximately 7% and 1.5%, respectively. Therefore, the influence of Achilles tendon stiffness is rather limited. Walking patterns also independently contributed to the energy cost of walking because the plantarflexor (including, but not limited to the triceps surae) energy cost of walking was lower in older than in young adults. Hence, training interventions should probably rather target specific walking patterns than Achilles tendon stiffness to decrease the energy cost of walking. However, based on the results of previous experimental studies, we expected that the calculated hip extensor and whole-body energy cost of walking would be higher in older than in young adults. This was not confirmed in our results. Future research might therefore assess the contribution of the walking pattern to the energy cost of walking by individualizing maximal isometric muscle force and by using three-dimensional models of muscle contraction. Summary statementAchilles tendon stiffness and walking patterns independently contribute to the energy cost in simulations of walking in young and older adults. The influence of Achilles tendon stiffness is rather small.

physiology↗

bioRxiv2019

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

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

physiology↗

bioRxiv2019

Ultrasound-based optimal parameter estimation improves assessment of calf muscle-tendon interaction during walking

We present and evaluate a new approach to estimate calf muscle-tendon parameters and calculate calf muscle-tendon function during walking. We used motion analysis, ultrasound, and EMG data of the calf muscles collected in six young and six older adults during treadmill walking as inputs to a new optimal estimation algorithm. We used estimated parameters or scaled generic parameters in an existing approach to calculate muscle fiber lengths and activations. We calculated the fit with experimental data in terms of root mean squared differences (RMSD) and coefficients of determination (R2). We also calculated the calf muscle metabolic energy cost. RMSD between measured and calculated fiber lengths and activations decreased and R2 increased when estimating parameters compared to using scaled generic parameters. Moreover, R2 between measured and calculated gastrocnemius medialis fiber length and soleus activations increased by 19 % and 70 %, and calf muscle metabolic energy decreased by 25% when using estimated parameters compared to using scaled generic parameters at speeds not used for estimation. This new approach estimates calf muscle-tendon parameters in good accordance with values reported in literature. The approach improves calculations of calf muscle-tendon interaction during walking and highlights the importance of individualizing calf muscle-tendon parameters.

bioengineering↗