Influence of M. tibialis anterior fatigue on the walk-to-run and run-to-walk transition in non-steady state locomotion

Abstract

The purpose of this study was to examine the influence of muscular fatigue of tibialis anterior (TA) on the walk-to-run transition (WRT) and run-to-walk transition (RWT) when speed is altered at different constant accelerations (a = 0.01, 0.07 and 0.05 m s À2 ). Twenty women (height: 168.9 AE 3.36 cm) performed WRTs and RWTs on a motor-driven treadmill, before and after a protocol inducing muscular fatigue of the TA.WRT-speed decreased after TA fatigue whereas RWT-speed did not change except during the intermediate deceleration. Integrated EMG (iEMG) of the activity burst of TA around heel contact was examined in the last steps before transition, the transition step and the first steps after transition. iEMG increased before WRT, then decreased after transition to running. In the RWT the opposite was observed: iEMG increased after RWT, then decreased with decreasing walking speed. After inducing fatigue in the TA, there was a decrease in iEMG in the WRT whereas no influence of fatigue was found on iEMG in the RWT.As a result of TA fatigue, WRT occurred at a lower speed, probably to avoid over-exertion of the TA. This indicates that the TA is a likely determinant of WRT as previously reported. The RWT, on the other hand, was not altered following TA fatigue, which would indicate that WRT and RWT are determined by different factors. #

Preferred gait and walk–run transition speeds in ostriches measured using GPS-IMU sensors

“…The walk-run and run-walk transition distribution of ostriches exhibited gait-transition hysteresis, and such directional effects on the preferred gait-transition speed cannot be explained by steady-state CoT curves. A similar gait-transition hysteresis has been observed in humans (Thorstensson and Roberthson, 1987;Mohler et al, 2007), and human studies suggest that neural processing and fatigue factors probably influence gait-transition speeds (Mohler et al, 2007;Segers et al, 2007). Thus, while gait transitions of ostriches occur near the energetically optimum speeds (Fig.…”

Respostas cardiorrespiratórias e perceptivas para as mesmas velocidades de caminhada e corrida

“…In both forms of perception, there was a greater value during walking than during running, at a speed above the WRTS, corroborating the data observed for HR and ventilatory variables. At all speeds, the local perception had higher scores than the general perception during walking, suggesting a strong influence of peripheral factors on this form of locomotion 3,5 . Above the WRTS, VO 2 , HR and VE responses were higher during walking than during running, possibly due to an increased recruitment of the muscles of the trunk and upper limbs with the increase in speed in this form of locomotion, also increasing the eccentric work for carrying out the movement 5 .…”

“…At all speeds, the local perception had higher scores than the general perception during walking, suggesting a strong influence of peripheral factors on this form of locomotion 3,5 . Above the WRTS, VO 2 , HR and VE responses were higher during walking than during running, possibly due to an increased recruitment of the muscles of the trunk and upper limbs with the increase in speed in this form of locomotion, also increasing the eccentric work for carrying out the movement 5 . There may be a relationship between the local perception of greater effort and the greater increase in cardiorespiratory variables.…”

“…The answer to this question is far from settled [2][3][4][5][6] . Whatever the mechanism responsible for the WRTS, the knowledge of the physiological responses to walking and running, at a speed near the WRTS can provide important data for the prescription for aerobic exercise in healthy subjects and in patients with cardiovascular diseases.…”

Distancia recorrida y costo fisiológico según el nivel socioeconómico y género durante la prueba de caminata en seis minutos en adultos mayores autovalentes de la ciudad de Talca

“…En consecuencia, la VAV contempló particularmente una SSF >2/10 y <7/10, en tanto que el porcentaje de frecuencia cardiaca de reserva utilizada (%FCRu) fue >40% y <70%. Complementariamente se indicó al participante ejecutar una adecuada coordinación de la respiración 32 y tolerar la fatiga periférica generada por la musculatura dorsiflexora de tobillo 33 . Datos fuera de la VAV condicionaron el fin y la repetición posterior de la prueba.…”