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Effect of Time and Direction Preparation on Ankle Muscle Response During Backward Translation of a Support Surface in Stance

Masakazu Matsuoka, Hiroshi Kunimura, and Koichi Hiraoka

gastrocnemius muscle ( Diener, Horak, & Nashner, 1988 ; Horak, Diener, & Nashner, 1989 ; Horak & Nashner, 1986 ; Nardone et al., 1990 ). The middle-latency response is mediated by Group II afferents ( Grey, Ladouceur, Andersen, Nielsen, & Sinkjær, 2001 ; Schieppati & Nardone, 1997 ). The latency of the long

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Relationship Between Gastrocnemius Muscle Length and Overhead Squat Movement Compensations Among Active-Duty Firefighters

Thomas J. Sherriff, Kyle T. Ebersole, and David J. Cornell

Key Points ▸ Firefighters display a variety of movement compensations during an overhead squat. ▸ Restricted gastrocnemius muscle length is associated with the movement efficiency of firefighters. ▸ Interventions to lengthen gastrocnemius musculature should be utilized among these tactical athletes

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An Isovelocity Dynamometer Method to Determine Monoarticular and Biarticular Muscle Parameters

Filipe Conceição, Mark A. King, Maurice R. Yeadon, Martin G.C. Lewis, and Stephanie E. Forrester

This study aimed to determine whether subject-specific individual muscle models for the ankle plantar flexors could be obtained from single joint isometric and isovelocity maximum torque measurements in combination with a model of plantar flexion. Maximum plantar flexion torque measurements were taken on one subject at six knee angles spanning full flexion to full extension. A planar three-segment (foot, shank and thigh), two-muscle (soleus and gastrocnemius) model of plantar flexion was developed. Seven parameters per muscle were determined by minimizing a weighted root mean square difference (wRMSD) between the model output and the experimental torque data. Valid individual muscle models were obtained using experimental data from only two knee angles giving a wRMSD score of 16 N m, with values ranging from 11 to 17 N m for each of the six knee angles. The robustness of the methodology was confirmed through repeating the optimization with perturbed experimental torques (±20%) and segment lengths (±10%) resulting in wRMSD scores of between 13 and 20 N m. Hence, good representations of maximum torque can be achieved from subject-specific individual muscle models determined from single joint maximum torque measurements. The proposed methodology could be applied to muscle-driven models of human movement with the potential to improve their validity.

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Estimation of Passive Ankle Joint Moment during Standing and Walking

Tetsuro Muraoka, Tadashi Muramatsu, Daisuke Takeshita, Hiroaki Kanehisa, and Tetsuo Fukunaga

This study estimated the passive ankle joint moment during standing and walking initiation and its contribution to total ankle joint moment during that time. The decrement of passive joint moment due to muscle fascicle shortening upon contraction was taken into account. Muscle fascicle length in the medial gastrocnemius, which was assumed to represent muscle fascicle length in plantarflexors, was measured using ultrasonography during standing, walking initiation, and cyclical slow passive ankle joint motion. Total ankle joint moment during standing and walking initiation was calculated from ground reaction forces and joint kinematics. Passive ankle joint moment during the cyclical ankle joint motion was measured via a dynamometer. Passive ankle joint moment during standing and at the time (Tp) when the MG muscle-tendon complex length was longest in the stance phase during walking initiation were 2.3 and 5.4 Nm, respectively. The muscle fascicle shortened by 2.9 mm during standing compared with the length at rest, which decreased the contribution of passive joint moment from 19.9% to 17.4%. The muscle fascicle shortened by 4.3 mm at Tp compared with the length at rest, which decreased the contribution of passive joint moment from 8.0% to 5.8%. These findings suggest that (a) passive ankle joint moment plays an important role during standing and walking initiation even in view of the decrement of passive joint moment due to muscle fascicle shortening upon muscle contraction, and (b) muscle fascicle shortening upon muscle contraction must be taken into account when estimating passive joint moment during movements.

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Effect of Gastrocnemius Kinesio Taping on Countermovement Jump Performance and Vertical Stiffness Following Muscle Fatigue

Sahar Boozari, Mohammad Ali Sanjari, Ali Amiri, and Ismail Ebrahimi Takamjani

CMJ involves the stretch-shortening cycle and is a functional test to assess lower-extremity performance. 12 Previous studies on the effects of KT during CMJ have used different methods of KT application on different muscles. 5 , 6 , 8 – 11 Among the muscles involved in CMJ, the gastrocnemius has a

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The Effects of Ankle Restriction on the Multijoint Coordination of Vertical Jumping

Hiroshi Arakawa, Akinori Nagano, Dean C. Hay, and Hiroaki Kanehisa

The current study aimed to investigate the effect of ankle restriction on the coordination of vertical jumping and discuss the influence of energy transfer through m. gastrocnemius on the multijoint movement. Eight participants performed two types of vertical jumps: a normal squat jump, and a squat jump with restricted ankle joint movement. Mechanical outputs were calculated using an inverse dynamics analysis. Custom-made shoes were used to restrict plantar flexion, resulting in significantly (P < .001) reduced maximum power and work at the ankle joint to below 2% and 3%, while maintaining natural range of motion at the hip and knee. Based on the comparison between the two types of jumps, we determined that the ankle restriction increased (P < .001) the power (827 ± 346 W vs. 1276 ± 326 W) and work (92 ± 34 J vs. 144 ± 36 J) at the knee joint. A large part of the enhanced output at the knee is assumed to be due to ankle restriction, which results in the nullification of energy transport via m. gastrocnemius; that is, reduced contribution of the energy transfer with ankle restriction appeared as augmentation at the knee joint.

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Muscle–Tendon Behavior and Kinetics in Gastrocnemius Medialis During Forefoot and Rearfoot Strike Running

Tomonari Takeshita, Hiroaki Noro, Keiichiro Hata, Taira Yoshida, Tetsuo Fukunaga, and Toshio Yanagiya

gastrocnemius medialis (GM) while running was higher in RFS runners rather than in FFS runners. In addition, Suzuki et al 16 demonstrated that GM fascicle length was longer in the RFS than the FFS throughout the gait cycle. While the difference in muscle–tendon kinematics has been investigated between the FFS

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Muscle Preactivation Control: Simulation of Ankle Joint Adjustments at Touchdown During Running on Uneven Ground

Roy Müller, Tobias Siebert, and Reinhard Blickhan

In locomotion, humans have to deal with irregularities in the ground. When they encounter uneven terrain with changes in vertical height, they adjust the geometry of their legs. Recent investigations have shown that the preactivation of the gastrocnemius muscle (GM) correlates with the ankle angle at touchdown, but it is as of yet unclear why these adjustments were achieved by the GM and not by the preactivation of the tibialis anterior (TA). To examine the differences between TA regulation and GM regulation regarding (1) ankle angle adjustment and (2) joint stiffness, we used a three-segment musculoskeletal model with two antagonistic muscles (GM, TA). During the GM regulation, the ankle angle was adjusted from 121° to 109° (dorsiflexion) by a 41% decrease in the GM activation. During the TA regulation, the activation of TA must be increased by about 52%. In addition, we found that the ankle stiffness was most sensitive to changes in activation of the GM and decreased by about 20% while adjusting the angle. In contrast, the ankle stiffness remains similar when using TA regulation. Thus, the GM regulation is more adequate for adjustment in the ankle joint, enabling sufficient regulation of angle and stiffness.

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Effects of the Functional Heel Drop Exercise on the Muscle Architecture of the Gastrocnemius

Diego Alonso-Fernandez, Yaiza Taboada-Iglesias, Tania García-Remeseiro, and Águeda Gutiérrez-Sánchez

proven in this preventive and rehabilitative aspect, but its effects on muscle architecture have not yet been studied. Therefore, our purpose was to assess the effects that the HDE may have on FL, PA, and MT of the lateral gastrocnemius (LG) and medial gastrocnemius (MG) muscles, due to the high

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Acute Effects of Gastrocnemius/Soleus Self-Myofascial Release Versus Dynamic Stretching on Closed-Chain Dorsiflexion

Kimberly Somers, Dustin Aune, Anthony Horten, James Kim, and Julia Rogers

elongation of equal parts of both tendon and muscle fascicles, whereas post stretching ROM gains were secondary to changes in elastic properties of the gastrocnemius muscle rather than the tendon. During self-myofascial release, pressure, undulation, movement, and friction are applied to muscle tissue