Search results for "FORCE"

Modeling muscle mechanics of arm and leg movement : a new approach to Hill's equation

2015

EFFECTS OF STRIKING STRATEGY ON LOWER EXTREMITY LOADING DURING RUNNING

2013

Backround It is expected that every second runner has a running-related overuse injury each year. The knee joint and Achilles tendon are the most commonly injured sites covering both about one fifth of all running related injuries. 1 Runners can be categorized into rearfoot strikers, mid-foot strikers or forefoot strikers based on the landing strategy at the instant of initial ground contact. Forefoot or mid-foot striking has been shown to reduce impact peak and loading rate of the ground reaction force during early stance phase. 2 Furthermore, the finding of the recent study suggest that forefoot striking may potentially decrease the risk of running-related injuries. 3 However, the effect …

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…

The Tongue, Mandible, Hyoid System.

2017

The craniocervical-mandibular system works in harmony and allows different functional tasks as the postural control of the cervical region. This system is formed by the temporomandibular joint, the masticatory muscles and ligaments connecting the temporomandibular joint and the cervical region. It has been seen to affect human posture, and many disorders of the temporomandibular joints may affect this functional arrangement. Notwithstanding this system considered as a functional arrangement, may offer various clinical explanations, it does not hold anatomical connections with the posterior region of the cranium, thus it should not be refered to as a craniocervical arrangement. For this reas…

Analysis and optimization of hybrid double lap aluminum-GFRP joints

2014

In this paper a systematic investigation of the mechanical performance of hybrid double-lap Al-GFRP bonded-bolted joints, has been carried out by using experimental analyses and numerical simulations. In order to detect the optimal geometric configuration, as well as to highlight the contribution of adhesive and bolts, the results relative to hybrid joints have been compared with those of simply adhesively bonded and simply bolted joints. The experimental and numerical results have shown that by using the minimum overlap length provided from theory, the bolt leads to a significant decreasing of both the maximum shear and the maximum peel stresses in the adhesive layer and, consequently, the…

Redesign of a Reverse Shoulder Prosthesis: Kinematic and Mechanical Study

2014

In this work a commercial reverse shoulder prosthesis has been redesigned to improve performances in terms of range of movements of the implant and stability to dislocation. A kinematic and mechanic study has been performed using a realistic solid model of the prothesised shoulder: in particular, all the components of the prosthesis have been acquired via a 3D laser scanner and inserted in a virtual humerus-glenoid system by reproducing the common surgical procedure. The final model has been used to measure the maximum angles of abduction and rotation of the arm and the shear forces that cause dislocation. Modifications proposed to the commercial prosthesis are: a different orientation of t…

Effects of muscle activation on shear between human soleus and gastrocnemius muscles

2015

Lateral connections between muscles provide pathways for myofascial force transmission. To elucidate whether these pathways have functional roles in vivo, we examined whether activation could alter the shear between the soleus (SOL) and lateral gastrocnemius (LG) muscles. We hypothesized that selective activation of LG would decrease the stretch-induced shear between LG and SOL. Eleven volunteers underwent a series of knee joint manipulations where plantar flexion force, LG, and SOL muscle fascicle lengths and relative displacement of aponeuroses between the muscles were obtained. Data during a passive full range of motion were recorded, followed by 20° knee extension stretches in both pass…

Comparison between the directly measured achilles tendon force and the tendon force calculated from the ankle joint moment during vertical jumps.

1988

Summary The purpose of this study was to compare the relationship between the achilles tendon force and the tendon force estimated from the ankle joint moment (EATF) during vertical jump. A healthy male subject performed the following jumps on the force platform: (a) maximal vertical jump from a squat position without counter-movement; (b) maximal vertical jump from an erect standing position with a preliminary counter-movement; (c) repetitive submaximal hopping on the spot with preferred frequency. The achilles tendon force was measured directly with an implanted tendon transducer in all jumping conditions. In addition the joint moment obtained from the film and ground reaction force was u…

On the control of a muscular force model including muscular fatigue

2015

Electromyostimulation has been used for several decades by athletes or physiotherapists in order to create a muscular reinforcement. However, the efficiency of electromyostimulation is limited by muscular fatigue and by induced pain. Currently, the systems of electromyostimulation do not adapt the stimulation parameters automatically by taking into account physiological parameters such as muscular fatigue. To adapt the stimulation parameters to muscular responses and in order to optimize the rehabilitation sessions, a control of force using an indicator of muscular fatigue could be used. In this paper, we propose two ways to control the force by using a physiological model which includes th…

Numerical experimental analysis of hybrid double lap aluminum-CFRP joints

2015

Abstract Due to their reliability and ease of assembly, both the adhesively bonded and the mechanical joints are commonly used in different fields of modern industrial design and manufacturing, to joint composite materials or composites with metals. As it is well known, adhesively bonded joints are characterized by high stiffness and good fatigue life, although delamination phenomena localized near the free edges may limit their use, especially for applications where corrosive environments and/or moisture can lead to premature failure of the bonding. In these cases, a possible alternative is given by the well-known mechanical joints. On the contrary, these last joints (bolted, riveted) requ…