Search results for "Muscle force"
showing 10 items of 18 documents
Constant Power Solution of Hill’s Equation
2019
This book deals with constant power solution of Hill’s equation. This book covers key areas of muscle mechanics; muscle force; muscle power; force-velocity relationship; Hill’s equation; arm movement; leg movement etc. This book contains various materials suitable for students, researchers and academicians of this area.
Decreased motor unit firing rate and force control in older men
2006
Introduction Ageing is related to muscle atrophy that leads to decreases in muscle force. The largest changes are found in fast muscle fibres and fast force production, reducing the capability to recover from sudden balance disturbances. Also ageing-related decrease in force control has been found, as indicated by an increase in force fluctuations and motor unit (MU) firing variability (Galganski et al. 1993). Possibly due to differences in measurement protocols and muscles, the results concerning the effects of ageing on motor unit firing rate are, however, somewhat contradictory (for review, see Roos et al. 1997). The purpose of the present study was to investigate the age-related changes…
Walking and Running Require Greater Effort from the Ankle than the Knee Extensor Muscles.
2016
The knee and ankle extensors as human primary antigravity muscle groups are of utmost importance in a wide range of locomotor activities. Yet, we know surprisingly little about how these muscle groups work, and specifically, how close to their maximal capacities they function across different modes and intensity of locomotion. Therefore, to advance our understanding of locomotor constraints, we determined and compared relative operating efforts of the knee and ankle extensors during walking, running, and sprinting.Using an inverse dynamics biomechanical analysis, the muscle forces of the knee and ankle extensors during walking (1.6 m·s), running (4.1 m·s), and sprinting (9.3 m·s) were quant…
Bilaterale Acetabulumfrakturen der vorderen Pfeiler und Wirbelkörperfraktur nach alkoholinduziertem Krampfanfall
1996
The case of a 54-year-old male with a compression fracture of the T 12 vertebral body and a bilateral anterior column fracture of the acetabulum is presented. The origin of this rare combination of fractures is explained by the action of the patient's own muscle force on bone of very poor quality. The treatment of these lesions is comparable to the treatment of similar fractures in bone of normal quality.
Neuromuscular adaptations to combined strength and endurance training: order and time-of-day
2017
AbstractThe present study examined the effects of 24 weeks of morning vs. evening same-session combined strength (S) and endurance (E) training on neuromuscular and endurance performance. Fifty-one men were assigned to the morning (m) or evening (e) training group, where S preceded E or vice versa (SEm, ESm, SEe and ESe), or to the control group. Isometric force, voluntary activation, EMG and peak wattage during the maximal cycling test were measured. Training time did not significantly affect the adaptations. Therefore, data are presented for SEm+e (SEm+SEe) and ESm+e (ESm+ESe). In the morning, no order specific gains were observed in neuromuscular performance. In the evening, the changes …
Aging of the musculoskeletal system: How the loss of estrogen impacts muscle strength.
2019
Skeletal muscle weakness occurs with aging and in females this is compounded by the loss of estrogen with ovarian failure. Estrogen deficiency mediates decrements in muscle strength from both inadequate preservation of skeletal muscle mass and decrements in the quality of the remaining skeletal muscle. Processes and components of skeletal muscle that are affected by estrogens are beginning to be identified. This review focuses on mechanisms that contribute to the loss of muscle force generation when estrogen is low in females, and conversely the maintenance of strength by estrogen. Evidence is accumulating that estrogen deficiency induces apoptosis in skeletal muscle contributing to loss of…
99 Muscle-tendon Properties During Recovery From Complete Achilles Tendon Rupture – A Case Study
2014
Introduction Achilles tendon is the most common tendon to suffer for complete rupture. Physically active young adults are often treated with surgery. Most of the patients do not suffer from activity limitations after injury 3 but performance level is often significantly decreased. 1,2 The purpose of this study was to follow recovery of Achilles tendon and triceps surae muscles after complete Achilles tendon rupture and subsequent surgery. This study served as a pilot phase for future research project. Methods Three subjects were recruited to this pilot phase of the study. Subjects were first time measured 2 to 8 months after injury and followed 6 to 8 months. Plantarflexion strength was mea…
Tensiomyography reliability and prediction of changes in muscle force following heavy eccentric strength exercise using muscle mechanical properties
2015
AbstractThe current study involved the completion of two distinct experiments. Experiment 1 analyzed the inter-day reliability of tensiomyography (TMG) muscle mechanical properties based on the amplitude of the muscle belly radial deformation, the time it takes to occur, and its velocity under maximal and submaximal stimuli, in the muscles rectus femoris, biceps femoris, and gastrocnemius lateralis, from 20 male sport students. Experiment 2 investigated whether changes in maximal voluntary isometric contraction (MVIC) could be predicted based on changes in TMG properties following 24 h after different squat training protocols (MS = multiple sets; DS = drop sets; EO = eccentric overload; FW …
Deadlift muscle force and activation under stable and unstable conditions.
2010
The objective of this study was to compare the production of force and paraspinal muscle activity between deadlifts carried out in a standard way and with different instability devices (Bosu and T-Bow). Deadlifts involve the performance of muscle activities with dynamic and isometric characteristics. Thirty-one subjects participated voluntarily in the study. Initially, they performed an isometric test for 5 seconds in each condition. After that, they performed a set of 5 repetitions with 70% of the maximum isometric force obtained in each one of the previously evaluated conditions. During the isometric tests, records of electromyographic activity and force production were obtained, whereas …
Analysis and control of the muscle force by electrostimulation
2019
Muscle reconditioning techniques have been developed extensively in these recent years as part of the reeducation of the atrophied muscle, but also to reinforce the healthy muscle of the sedentary or sportive subject. The monitoring of the stimulated muscle by recording the electrical activity and the muscle response is necessary to detect for example the muscle fatigue and/or avoid tissue damage in the case of deconditioned muscle. The aim of this thesis is initially to analyse the muscle response in terms of force produced as response to the electrostimulation (ES). This analysis has allowed us to develop a new force model that can predict the effect of the stimulation amplitude of the cu…