Walking beyond preferred transition speed increases muscle activations with a shift from inverted pendulum to spring mass model in lower extremity

Shih, Yo; Chen, Yi Chun; Lee, Yin Shin; Chan, Michelle; Shiang, Tzyy Yuang

doi:10.1016/j.gaitpost.2016.01.003

Cited by 15 publications

(8 citation statements)

References 24 publications

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“…Indeed, muscle fiber composition of the TA in humans is rich in slow fibers in both superficial and deep area [52,53]. Shih et al [54] observed the PTS at 7.33 km·h -1 , and they found that only TA activity was greater during walking than running at that speed. These previous findings suggest that the TA must be the most sensitive for the gait change in erect bipedalism.…”

Section: Discussionmentioning

confidence: 99%

Muscle activities during walking and running at energetically optimal transition speed under normobaric hypoxia on gradient slopes

2017

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Energy cost of transport per unit distance (CoT; J·kg-1·km-1) displays a U-shaped fashion in walking and a linear fashion in running as a function of gait speed (v; km·h-1). There exists an intersection between U-shaped and linear CoT-v relationships, being termed energetically optimal transition speed (EOTS; km·h-1). Combined effects of gradient and moderate normobaric hypoxia (15.0% O2) were investigated when walking and running at the EOTS in fifteen young males. The CoT values were determined at eight walking speeds (2.4–7.3 km·h-1) and four running speeds (7.3–9.4 km·h-1) on level and gradient slopes (±5%) at normoxia and hypoxia. Since an alteration of tibialis anterior (TA) activity has been known as a trigger for gait transition, electromyogram was recorded from TA and its antagonists (gastrocnemius medialis (GM) and gastrocnemius lateralis (GL)) for about 30 steps during walking and running corresponding to the individual EOTS in each experimental condition. Mean power frequency (MPF; Hz) of each muscle was quantified to evaluate alterations of muscle fiber recruitment pattern. The EOTS was not significantly different between normoxia and hypoxia on any slopes (ranging from 7.412 to 7.679 km·h-1 at normoxia and 7.516 to 7.678 km·h-1 at hypoxia) due to upward shifts (enhanced metabolic rate) of both U-shaped and linear CoT-v relationships at hypoxia. GM, but not GL, activated more when switching from walking to running on level and gentle downhill slopes. Significant decreases in the muscular activity and/or MPF were observed only in the TA when switching the gait pattern. Taken together, the EOTS was not slowed by moderate hypoxia in the population of this study. Muscular activities of lower leg extremities and those muscle fiber recruitment patterns are dependent on the gradient when walking and running at the EOTS.

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Section: Discussionmentioning

confidence: 99%

Muscle activities during walking and running at energetically optimal transition speed under normobaric hypoxia on gradient slopes

2017

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“…The torque, position (joint angle) and displacement signals of each contraction were recorded to a computer connected to the isokinetic dynamometer. The raw data were filtered and smoothed, and peak torque was analyzed by the software of the Biodex Medical Systems, and the highest value of the three trials was used for subsequent analysis (Wang et al, 2014 ; Chen et al, 2015 ; Shih et al, 2016 ).…”

Section: Methodsmentioning

confidence: 99%

Influence of Maturation Status on Eccentric Exercise-Induced Muscle Damage and the Repeated Bout Effect in Females

Lin

Nosaka

et al. 2018

Front. Physiol.

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This study compared changes in indirect muscle damage markers, proprioception and arterial stiffness after elbow flexor eccentric exercise between pre-pubescent (9–10 y), pubescent (14–15 y), and post-pubescent (20–24 y) healthy, untrained females (n = 13/group). The maturation of the participants was confirmed by the hand bone age. All participants performed two bouts of 30 sub-maximal eccentric contractions (EC1, EC2) using a dumbbell set at 60% of pre-exercise maximal voluntary isometric elbow flexion strength at 90°. Changes in maximal voluntary concentric contraction (MVC) torque, muscle soreness (SOR), plasma creatine kinase activity, proprioception (position sense, joint reaction angle) and arterial stiffness (carotid-femoral pulse-wave velocity: cfPWV) before to 5 days after EC1 and EC2 were compared among groups by a mixed-design two-way ANOVA. Pre-exercise MVC torque and cfPWV were smaller (P < 0.05) for the pre-pubescent (MVC: 10.0 ± 0.9 Nm, cfPWV: 903 ± 60 cm/s) and the pubescent (14.3 ± 1.1 Nm, 967 ± 61 cm/s) than the post-pubescent (19.1 ± 1.4 Nm, 1,103 ± 73 cm/s). Changes in all variables after EC1 were smaller (P < 0.05) for the pre-pubescent (e.g., MVC at 1 d post-exercise: −10 ± 6%, peak SOR: 5 ± 2 mm) than the pubescent (−15 ± 9%, 12 ± 6 mm) and the post-pubescent (−25 ± 7%, 19 ± 13 mm). After EC2, changes in all variables were smaller (P < 0.05) than those after EC1 for all groups (e.g., MVC at 1 d post-exercise, pre-pubescent: −4 ± 6%, pubescent: −9 ± 4%, post-pubescent: −14 ± 5%; peak SOR: 3 ± 2, 7 ± 3, 11 ± 6 mm), but the magnitude of the repeated bout effect was not different (P > 0.05) among the groups. These results show that the extents of muscle damage, and proprioception and arterial stiffness changes after eccentric exercise are greater at later stages of maturation, but the repeated bout effect is not affected by maturation.

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“…Participants were verbally encouraged to generate maximal force for 3 s, with a 45-s rest, and this was repeated three times. The peak value during the 3-s contraction was recorded, and the highest value of the three peak values was used for further analysis (17)(18)(19).…”

Section: Dependent Variablesmentioning

confidence: 99%

Contralateral Effects by Unilateral Eccentric versus Concentric Resistance Training

Tseng

Nosaka

Tseng

et al. 2019

Medicine &Amp; Science in Sports &Amp; Exercise

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Purpose: Unilateral resistance training increases muscle strength of the contralateral homologous muscle by the cross-education effect. Muscle damage induced by second eccentric exercise bout is attenuated, even when it is performed by the contralateral limb. The present study compared the effects of unilateral eccentric training (ET) and concentric training (CT) of the elbow flexors (EF) on maximal voluntary isometric contraction (MVC) strength and muscle damage of the contralateral untrained EF. Methods: Young men were placed into ET, CT, ipsilateral repeated bout (IL-RB), and contralateral repeated bout (CL-RB) groups (n = 12 per group). The ET and CT groups performed unilateral EF training consisting of five sets of six eccentric and concentric contractions, respectively, once a week for 5 wk by increasing the intensity from 10% to 100% of MVC, followed by 30 maximal eccentric contractions (30MaxEC) of the opposite EF 1 wk later. The IL-RB group performed two bouts of 30MaxEC separated by 2 wk using the nondominant arm, and CL-RB group performed two bouts of 30MaxEC with a different arm for each bout in 1-wk apart. Results: The MVC increased (P < 0.05) greater for the trained (19% ± 8%) and untrained (11% ± 5%) arms in ET when compared with those in CT (10% ± 6%, 5% ± 2%). The magnitude of changes in muscle damage markers was reduced by 71% ± 19% after the second than the first bout for IL-RB group, and by 48% ± 21% for CL-RB group. Eccentric training and CT attenuated the magnitude by 58% ± 25% and 13% ± 13%, respectively, and the protective effect of ET was greater (P < 0.05) than CL-RB, but smaller (P < 0.05) than IL-RB. Conclusions: These results showed that cross-education effect was stronger for ET than CT, and progressive ET produced greater contralateral muscle damage protective effect than a single eccentric exercise bout.

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Walking beyond preferred transition speed increases muscle activations with a shift from inverted pendulum to spring mass model in lower extremity

Cited by 15 publications

References 24 publications

Muscle activities during walking and running at energetically optimal transition speed under normobaric hypoxia on gradient slopes

Muscle activities during walking and running at energetically optimal transition speed under normobaric hypoxia on gradient slopes

Influence of Maturation Status on Eccentric Exercise-Induced Muscle Damage and the Repeated Bout Effect in Females

Contralateral Effects by Unilateral Eccentric versus Concentric Resistance Training

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