Spatiotemporal and Muscle Activation Adaptations During Overground Walking in Response to Lower Body Added Mass

Author(s):  
Vinayak Vijayan ◽  
Shanpu Fang ◽  
Timothy Reissman ◽  
Allison L. Kinney ◽  
Megan E. Reissman
2018 ◽  
Vol 50 (5S) ◽  
pp. 487
Author(s):  
Adam Korak ◽  
Max R. Paquette ◽  
Dana K. Fuller ◽  
Jennifer L. Caputo ◽  
John M. Coons

2016 ◽  
Vol 16 (8) ◽  
pp. 1130-1136
Author(s):  
Misha Murtagh ◽  
Darrell Brooks ◽  
Jonathan Sinclair ◽  
Stephen Atkins

Author(s):  
Vasilios Koronas ◽  
Nikolaos Koutlianos

Tennis is one of the most popular individual sports all over the world. Strength and trained muscles are required for a player in order to achieve a good backhand, forehand, volley or flat stroke. Especially while playing tennis are many kinds of muscles involved, including the lower body muscles, trunk muscles and upper body muscles. The purpose of this review is to present the activated muscles in the basic tennis movements of forehand and backhand and to improve the knowledge about their role in order to help tennis players and coaches to enhance their tennis performance and to reduce risk of injury. To support the present review, data were gathered from library and network databases using keywords such as tennis, muscles, forehand, and backhand for publications between 2015 and 2019. Overall, thirty-five references were detected and used. The literature showed that forehand and backhand drives are strokes that involve muscles not only of the upper limbs but also a series of more complex movements that start with the feet and end with the swinging of the tennis racket. The insight for the action of the muscles in tennis should be utilized in tennis players so as to better understand the muscular function which takes part in specific tennis movements and has a greater performance. In addition, this knowledge is considered strongly beneficial for the coaches and the favourable building of the training process.


2004 ◽  
Vol 18 (3) ◽  
pp. 154-160 ◽  
Author(s):  
Michelle L. Harris-Love ◽  
Richard F. Macko ◽  
Jill Whitall ◽  
Larry W. Forrester

Author(s):  
Smit Soni ◽  
Anouk Lamontagne

Abstract Background Conventional treadmills are widely used for gait retraining in rehabilitation setting. Their usefulness for training more complex locomotor tasks, however, remains limited given that they do not allow changing the speed nor the direction of walking which are essential walking adaptations for efficient and safe community ambulation. These drawbacks can be addressed by using a self-pace omnidirectional treadmill, as those recently developed by the gaming industry, which allows speed changes and locomotor movements in any direction. The extent to which these treadmills yield a walking pattern that is similar to overground walking, however, is yet to be determined. Methods The objective of this study was to compare spatiotemporal parameters, body kinematics and lower limb muscle activation of healthy young individuals walking at different speeds (slow, comfortable, fast) on a low-cost non-motorized omnidirectional treadmill with and without virtual reality (VR) vs. overground. Results Results obtained from 12 young healthy individuals (18–29 years) showed that participants achieved slower speed on the treadmill compared to overground. On the treadmill, faster walking speeds were achieved by a mere increase in cadence, as opposed to a combined increase in cadence and step length when walking overground. At matched speed, enhanced stance phase knee flexion, reduced late stance ankle plantarflexion, as well as enhanced activation amplitudes of hip extensors in late stance and hip extensors in early swing were observed. The addition of VR to treadmill walking had little or no effect of walking outcomes. Collectively, results show that the omnidirectional treadmill yields a different walking pattern and lead to different adaptations to speed compared to overground walking. We suggest that these alterations are mainly driven by the reduced shear forces between the weight bearing foot and supporting surface and a perceived threat to balance on the omnidirectional treadmill. Conclusion Since such treadmills are likely to be used for prolonged periods of time by gamers or patients undergoing physical rehabilitation, further research should aim at determining the impact of repeated exposure on gait biomechanics and lower limb musculoskeletal integrity.


2009 ◽  
Vol 4 (1) ◽  
pp. 84-96 ◽  
Author(s):  
William P. Ebben

Purpose:The purpose of this study was to evaluate differences in hamstring activation during lower body resistance training exercises. This study also sought to assess differences in hamstring-to-quadriceps muscle activation ratios and gender differences therein.Methods:A randomized repeated measures design was used to compare six resistance training exercises that are commonly believed to train the hamstrings, including the squat, seated leg curl, stiff leg dead lift, single leg stiff leg dead lift, good morning, and Russian curl. Subjects included 34 college athletes. Outcome measures included the biceps femoris (H) and rectus femoris (Q) electromyography (EMG) and the H-to-Q EMG ratio, for each exercise.Results:Main effects were found for the H (P < 0.001) and Q (P < 0.001). Post hoc analysis identified the specific differences between exercises. In addition, main effects were found for the H-to-Q ratio when analyzed for all subjects (P < 0.001). Further analysis revealed that women achieved between 53.9 to 89.5% of the H-to-Q activation ratios of men, for the exercises assessed. In a separate analysis of strength matched women and men, women achieved between 35.9 to 76.0% of the H-to-Q ratios of men, for these exercises.Conclusions:Hamstring resistance training exercises offer differing degrees of H and Q activation and ratios. Women compared with men, are less able to activate the hamstrings and/or more able to activate the quadriceps. Women may require disproportionately greater training for the hamstrings compared with the quadriceps.


2021 ◽  
Vol 92 (7) ◽  
pp. 570-578
Author(s):  
Logan Kluis ◽  
Nathan Keller ◽  
Hedan Bai ◽  
Narahari Iyengar ◽  
Robert Shepherd ◽  
...  

INTRODUCTION: Current spacesuits are cumbersome and metabolically expensive. The use of robotic actuators could improve extravehicular activity performance. We propose a novel method to quantify the benefit of robotic actuators during planetary ambulation.METHODS: Using the OpenSim framework, we completed a biomechanical analysis of three walking conditions: unsuited, suited with the extravehicular mobility unit (EMU) spacesuit (represented as external joint torques applied to human joints), and suited with the EMU and assisted by robotic actuators capable of producing up to 10 Nm of torque. For each scenario, we calculated the inverse kinematics and inverse dynamics of the lower body joints (hip, knee, and ankle). We also determined the activation of muscles and robotic actuators (when present). Finally, from inverse dynamics and muscle activation results, the metabolic cost of one gait cycle was calculated in all three conditions.RESULTS: The moments of lower body joints increased due to the increased resistance to movement from the spacesuit. The additional torque increased the overall metabolic cost by 85 compared to the unsuited condition. The assistive robotic actuators were able to reduce the metabolic cost induced by EMU resistance by 15.DISCUSSION: Our model indicates that the majority of metabolic cost reduction can be attributed to the actuators located at the hip. The robotic actuators reduced metabolic cost similar to that of modern-day actuators used to improve walking. During a Mars mission, the actuators could save one crewmember up to 100,000 kilocal on one 539-d planetary expedition.Kluis L, Keller N, Bai H, Iyengar N, Shepherd R, Diaz-Artiles A. Reducing metabolic cost during planetary ambulation using robotic actuation. Aerosp Med Hum Perform. 2021; 92(7):570578.


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