Analysis of Potential Muscular Determinants of the Preferred Walk-Run Transition Speed in Human Gait

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Abstract

The spontaneous transition from walking to running as walking speed increases is an intriguing neuromotor phenomenon that consistently occurs near 2 m/s in humans. Despite investigations of various metabolic and biomechanical factors, the determinants of the transition have remained elusive. However, no study has investigated the potential influence of intrinsic muscle properties and fiber-tendon interactions as potential determinants. The overall objective of this research was to use a forward dynamical simulation framework in three studies to identify the potential influence of these muscular determinants on the preferred walk-run transition speed (PTS).

In the first study, individual muscle force production was examined as walking speed increased to assess the influence of intrinsic muscle properties on the PTS. The simulation data showed that of all the major lower-extremity muscle groups examined, the ankle plantar flexors were the only muscles to show a decrease in force production, despite an increase in activation, as walking speed approached the PTS. The force reduction was attributed to adverse contractile conditions. Considering the importance of the plantar flexors to providing body support and forward progression, the impaired force generation was deemed an important determinant of the PTS.

In the second study, individual muscle contributions to body support and forward progression in walking and running at the PTS were quantified to clarify differences in muscle function between the two gait modes. The most distinctive difference was the reduced soleus contribution to forward progression in running. All other muscle groups performed similarly between the two gait modes.

In the third study, individual muscle fiber and tendon mechanical work was quantified to examine whether there existed an energetic advantage during walking and running above and below the PTS. The total muscle fiber work was found to be higher in running than walking below the PTS, and higher in walking than running above the PTS. In addition, tendon elasticity utilization was lower in running below the PTS than in running above the PTS. These results highlight the advantages of each gait mode and suggest why walking below the PTS and running above the PTS are the preferred gaits.

Cited Works (18)

Year	Entry
1987	Ker RF, Bennett MB, Bibby SR, Kester RC, Alexander RM. The spring in the arch of the human foot. Nature. January 8, 1987;325(6100):147-149.
2003	Thelen DG, Anderson FC, Delp SL. Generating dynamic simulations of movement using computed muscle control. J Biomech. March 2003;36(3):321-328.
2001	Neptune RR, Kautz SA, Zajac FE. Contributions of the individual ankle plantar flexors to support, forward progression and swing initiation during walking. J Biomech. November 2001;34(11):1387-1398.
1990	Winter DA. Biomechanics and Motor Control of Human Movement. 2nd ed. New York, NY: Inc., John Wiley & Sons; 1990.
1989	Yamaguchi GT, Zajac FE. A planar model of the knee joint to characterize the knee extensor mechanism. J Biomech. 1989;22(1):1-10.
1990	Hof AL. Effects of muscle elasticity in walking and running. In: Winters JM, Woo SL-Y, eds. Multiple Muscle Systems: Biomechanics and Movement Organization. New York, NY: Springer-Verlag; 1990:591-607.
1997	Raasch CC, Zajac FE, Ma B, Levine WS. Muscle coordination of maximum-speed pedaling. J Biomech. June 1997;30(6):595-602.
1997	Roberts TJ, Marsh RL, Weyand PG, Taylor CR. Muscular force in running turkeys: work, the economy of minimizing. Science. February 21, 1997;275(5303):1113-1115.
1996	Fregly BJ, Zajac FE. A state-space analysis of mechanical energy generation, absorption, and transfer during pedaling. J Biomech. January 1996;29(1):81-90.
1989	Zajac FE. Muscle and tendon: properties, models, scaling, and application to biomechanics and motor control. Crit Rev Biomed Eng. 1989;17(4):359-411.
1987	Davy DT, Audu ML. A dynamic optimization technique for predicting muscle forces in the swing phase of gait. J Biomech. 1987;20(2):187-201.
2004	Neptune RR, Zajac FE, Kautz SA. Muscle force redistributes segmental power for body progression during walking. Gait Post. April 2004;19(2):194-205.
1994	Goffe WL, Ferrier GD, Rogers J. Global optimization of statistical functions with simulated annealing. J Econom. January–February 1994;60:65-99.
2000	Neptune RR, Wright IC, van den Bogert AJ. A method for numerical simulation of single limb ground contact events: application to heel-toe running. Comput Methods Biomech Biomed Eng. 2000;3(4):321-334.
1990	Delp SL. Surgery Simulation: A Computer Graphics System to Analyze and Design Musculoskeletal Reconstructions of the Lower Limb [PhD thesis]. Stanford University; August 1990.
1983	Wickiewicz TL, Roy RR, Powell PL, Edgerton VR. Muscle architecture of the human lower limb. Clin Orthop Relat Res. October 1983;179:275-283.
1999	Anderson FC III. A Dynamic Optimization Solution for a Complete Cycle of Normal Gait [PhD thesis]. University of Texas at Austin; December 1999.
1997	Stefanyshyn DJ, Nigg BM. Mechanical energy contribution of the metatarsophalangeal joint to running and sprinting. J Biomech. November–December 1997;30(11-12):1081-1085.