Identification of the most effective muscles in landing impact forces

2021 ◽  
pp. 175433712110324
Author(s):  
Marzieh Mojaddarasil ◽  
Mohammad Jafar Sadigh ◽  
Sayed Jalal Zahabi
Keyword(s):  
Lower Limb ◽  
Muscle Activation ◽  
Impact Force ◽  
Experimental Tests ◽  
The Body ◽  
Promising Tool ◽  
Impact Forces ◽  
Drop Landing ◽  
The Impact

The aim of this study was to evaluate the role of the main lower limb muscles in increasing or decreasing each lower limb joint impact force during drop landing. To do so, the body was modeled by a four-link musculoskeletal model consisting of eight main Hill-type muscles. Different drop landing scenarios were modeled by changing the activation levels of the considered muscles. In each landing simulation, the impact GRF and impact joint forces were obtained. In order to compare and rank the muscles with respect to their effect on each impact force, a computationally feasible zero-one (off-on) muscle activation analysis was proposed. The proposed approach revealed important features regarding the relation between different impact forces and muscle activations. Specifically, the results can be interpreted in terms of the role that each muscle potentially plays in causing or preventing certain injuries. Moreover, the results obtained from the analysis were further used to classify the muscles into four categories, depending on the effect they have on each impact force. The proposed theoretical analysis is seen to be a promising tool in predicting the role of muscles and their order of importance in the generation of lower limb impact forces in landing, without the need for experimental tests.

Vertical Impact Forces during Bench-Step Aerobics: Exercise Rate and Experience

1997 ◽  
Vol 84 (1) ◽  
pp. 267-274 ◽  
Author(s):  
M. Scharff-Olson ◽  
H. N. Williford ◽  
D. L. Blessing ◽  
R. Moses ◽  
T. Wang
Keyword(s):  
Body Weight ◽  
Impact Force ◽  
The Body ◽  
Distinctive Pattern ◽  
Novice Group ◽  
Impact Forces ◽  
Force Curves ◽  
The Mean ◽  
The Impact ◽  
Vertical Impact

The purpose of this study was to determine the effects of two bench-step exercise speeds on vertical impact forces and to explore this variable between novices and instructors. 12 women (mean age 24 yr.) randomly performed 8-min. protocols of the “basic” bench-stepping technique and a more advanced “travel” technique at 30 and 33 cycles · min.−1. Analysis showed that the faster exercise rate yielded significantly higher vertical impact forces on a reference (B-8) step height (20.3 cm). At 33 cycles · min.−1, the instructors' and novices' responses were both higher than those at 30 cycles · min.−1. The mean peak vertical impact force ranged from 1.54 times the body weight for the novice group at 30 cycles · min.−1 to 1.87 times the body weight for instructors at 33 cycles · min.−1. A comparison of the groups' force curves showed a distinctive pattern in the loading of the impact forces. Specifically, the instructors consistently produced a transitory decrement in force prior to attaining peak force. In addition, the novices exhibited nonuniform increases in the production of vertical impact force across other step heights at the faster (33 cycles · min.−1) speed. Thus, experience with bench-step exercise may afford an ability to make uniform and force-absorbing adjustments in the resultant vertical impact forces at increased speeds.

Effect of Upper and Lower Extremity Control Strategies on Predicted Injury Risk During Simulated Forward Falls: A Study in Healthy Young Adults

2008 ◽  
Vol 130 (4) ◽  
Author(s):  
JiaHsuan Lo ◽  
James A. Ashton-Miller
Keyword(s):  
Kinetic Energy ◽  
Injury Risk ◽  
Impact Force ◽  
The Body ◽  
Whole Body ◽  
Joint Control ◽  
Negative Work ◽  
Impact Forces ◽  
Hip Flexion ◽  
The Impact

Fall-related wrist fractures are common at any age. We used a seven-link, sagittally symmetric, biomechanical model to test the hypothesis that systematically alterations in the configuration of the body during a forward fall from standing height can significantly influence the impact force on the wrists. Movement of each joint was accomplished by a pair of agonist and antagonist joint muscle torque actuators with assigned torque-angle, torque-velocity, and neuromuscular latency properties. Proportional-derivative joint controllers were used to achieve desired target body segment configurations in the pre- and∕or postground contact phases of the fall. Outcome measures included wrist impact forces and whole-body kinetic energy at impact in the best, and worst, case impact injury risk scenarios. The results showed that peak wrist impact force ranged from less than 1kN to more than 2.5kN, reflecting a fourfold difference in whole-body kinetic energy at impact (from less than 40J to more than 160J) over the range of precontact hip and knee joint angles used at impact. A reduction in the whole-body kinetic energy at impact was primarily associated with increasing negative work associated with hip flexion. Altering upper extremity configuration prior to impact significantly reduced the peak wrist impact force by up to 58% (from 919Nto2212N). Increased peak wrist impact forces associated greater shoulder flexion and less elbow flexion. Increasing postcontact arm retraction can reduce the peak wrist impact force by 28% (from 1491Nto1078N), but postcontact hip and knee rotations had a relatively small effect on the peak wrist impact force (8% reduction; from 1411Nto1303N). In summary, the choice of the joint control strategy during a forward fall can significantly affect the risk of wrist injury. The most effective strategy was to increase the negative work during hip flexion in order to dissipate kinetic energy thereby reducing the loss in potential energy prior to first impact. Extended hip or elbow configurations should be avoided in order to reduce forearm impact forces.

scholarly journals Effects of Two Fatigue Protocols on Impact Forces and Lower Extremity Kinematics during Drop Landings: Implications for Noncontact Anterior Cruciate Ligament Injury

2017 ◽  
Vol 2017 ◽  
pp. 1-8 ◽  
Author(s):  
Rui Xia ◽  
Xini Zhang ◽  
Xi Wang ◽  
Xiaole Sun ◽  
Weijie Fu
Keyword(s):  
Loading Rate ◽  
Impact Force ◽  
Collegiate Athletes ◽  
Maximal Heart Rate ◽  
Fatigue Protocol ◽  
Impact Forces ◽  
Duration Time ◽  
Drop Landing ◽  
The Impact ◽  
Peak Impact Force

The purpose of the study was to determine the effects of fatigue on the impact forces and sagittal plane kinematics of the lower extremities in a drop landing task. 15 male collegiate athletes were recruited. Five successful trials of a drop landing task were obtained during prefatigue and postfatigue in two fatigue protocols (constant speed running fatigue protocol [R-FP] and shuttle running + vertical jumping fatigue protocol [SV-FP]). Duration time, maximal heart rate, and RPE of each protocol were measured separately. Kinematic measures of the hip, knee, and ankle joints at different times coupled with peak impact force and loading rate were acquired. Our results showed a more flexed landing posture due to an increase in hip and knee flexion angles in the postfatigue condition. However, no differences in peak impact force and loading rate were found between pre- and postfatigue conditions. The changes were similar between protocols, but the SV-FP showed a significantly shorter exercise duration time than the R-FP. Fatigued athletes in this study demonstrated altered motor control strategies during a drop landing task, which may be an intentional or unintentional protective strategy for preventing themselves from potential ACL injury.

scholarly journals Erythrocytes: Central Actors in Multiple Scenes of Atherosclerosis

2021 ◽  
Vol 22 (11) ◽  
pp. 5843
Author(s):  
Chloé Turpin ◽  
Aurélie Catan ◽  
Olivier Meilhac ◽  
Emmanuel Bourdon ◽  
François Canonne-Hergaux ◽  
...  
Keyword(s):  
Iron Homeostasis ◽  
The Body ◽  
Diabetic Patients ◽  
Special Focus ◽  
Plaque Progression ◽  
Cell Dysfunction ◽  
Circulating Cells ◽  
The Impact ◽  
Progression Of Atherosclerosis

The development and progression of atherosclerosis (ATH) involves lipid accumulation, oxidative stress and both vascular and blood cell dysfunction. Erythrocytes, the main circulating cells in the body, exert determinant roles in the gas transport between tissues. Erythrocytes have long been considered as simple bystanders in cardiovascular diseases, including ATH. This review highlights recent knowledge concerning the role of erythrocytes being more than just passive gas carriers, as potent contributors to atherosclerotic plaque progression. Erythrocyte physiology and ATH pathology is first described. Then, a specific chapter delineates the numerous links between erythrocytes and atherogenesis. In particular, we discuss the impact of extravasated erythrocytes in plaque iron homeostasis with potential pathological consequences. Hyperglycaemia is recognised as a significant aggravating contributor to the development of ATH. Then, a special focus is made on glycoxidative modifications of erythrocytes and their role in ATH. This chapter includes recent data proposing glycoxidised erythrocytes as putative contributors to enhanced atherothrombosis in diabetic patients.

Influence of Attached Masses on Impact Forces and Running Style in Heel-Toe Running

1987 ◽  
Vol 3 (3) ◽  
pp. 264-275 ◽  
Author(s):  
Alexander Bahlsen ◽  
Benno M. Nigg
Keyword(s):  
Body Mass ◽  
High Speed ◽  
Impact Force ◽  
Force Plate ◽  
The Body ◽  
Additional Mass ◽  
Impact Forces ◽  
Running Shoes ◽  
High Speed Film ◽  
Vertical Impact

Impact forces analysis in heel-toe running is often used to examine the reduction of impact forces for different running shoes and/or running techniques. Body mass is reported to be a dominant predictor of vertical impact force peaks. However, it is not evident whether this finding is only true for the real body mass or whether it is also true for additional masses attached to the body (e.g., running with additional weight or heavy shoes). The purpose of this study was to determine the effect of additional mass on vertical impact force peaks and running style. Nineteen subjects (9 males, 10 females) with a mean mass of 74.2 kg/56.2 kg (SD = 10.0 kg and 6.0 kg) volunteered to participate in this study. Additional masses were attached to the shoe (.05 and .1 kg), the tibia (.2, .4, .6 kg), and the hip (5.9 and 10.7 kg). Force plate measurements and high-speed film data were analyzed. In this study the vertical impact force peaks, Fzi, were not affected by additional masses, the vertical active force peaks, Fza, were only affected by additional masses greater than 6 kg, and the movement was only different in the knee angle at touchdown, ϵ0, for additional masses greater than .6 kg. The results of this study did not support findings reported earlier in the literature that body mass is a dominant predictor of external vertical impact force peaks.

The Effects of Upstream Flexible Barrier on the Debris Flow Entrainment and Impact Dynamics on a Terminal Barrier

2021 ◽  
Author(s):  
Hervé Vicari ◽  
C.W.W. Ng ◽  
Steinar Nordal ◽  
Vikas Thakur ◽  
W.A. Roanga K. De Silva ◽  
...  
Keyword(s):  
Debris Flow ◽  
Debris Flows ◽  
Impact Force ◽  
Dynamic Pressure ◽  
Pressure Coefficient ◽  
Flexible Barrier ◽  
Impact Forces ◽  
Flexible Barriers ◽  
The Impact ◽  
Bed Entrainment

The destructive nature of debris flows is mainly caused by flow bulking from entrainment of an erodible channel bed. To arrest these flows, multiple flexible barriers are commonly installed along the predicted flow path. Despite the importance of an erodible bed, its effects are generally ignored when designing barriers. In this study, three unique experiments were carried out in a 28 m-long flume to investigate the impact of a debris flow on both single and dual flexible barriers installed in a channel with a 6 m-long erodible soil bed. Initial debris volumes of 2.5 m<sup>3</sup> and 6 m<sup>3</sup> were modelled. For the test setting adopted, a small upstream flexible barrier before the erodible bed separates the flow into several surges via overflow. The smaller surges reduce bed entrainment by 70% and impact force on the terminal barrier by 94% compared to the case without an upstream flexible barrier. However, debris overflowing the deformed flexible upstream barrier induces a centrifugal force that results in a dynamic pressure coefficient that is up to 2.2 times higher than those recommended in guidelines. This suggests that although compact upstream flexible barriers can be effective for controlling bed entrainment, they should be carefully designed to withstand higher impact forces.

scholarly journals The confidence delusion: A sociological exploration of participants’ confidence in sport-for-development

2018 ◽  
Vol 55 (4) ◽  
pp. 383-398
Author(s):  
David S Scott
Keyword(s):  
Personal Development ◽  
The Body ◽  
Individual Interviews ◽  
Everyday Lives ◽  
Sport For Development ◽  
Development Capacity ◽  
The Social ◽  
Ethnographic Methodology ◽  
The Impact

Although sport is widely utilised as a tool for personal development, capacity building, and fostering peace, there are still numerous theoretical gaps in our knowledge about how sport influences individuals’ identities, and how this translates into their everyday lives. Within the academic literature there has been seemingly little focus placed upon participants’ emotional and embodied accounts of their sport-for-development (SfD) experiences. This paper uses phenomenologically-inspired theory to explore individuals’ lived experiences of a SfD course, and their descriptions of the social interactions and feelings of confidence they encountered, in order to address this lack of experiential data. An ethnographic methodology was used to collect data through four sports leadership course observations, and cyclical interviews over 4–10 months with eleven course attendees, plus individual interviews with five tutors. Participants’ understandings of their course experiences and the subsequent influence these understandings had on their lives were described through their use of the term confidence. A further phenomenological and sociological interrogation of this term enabled confidence to be seen as being experienced as a ‘frame’ and ‘through the body’ by participants. This study provides original conceptualisations of confidence in relation to participants’ SfD experiences, as well as important discussions regarding the role of emotions and embodiment in understanding the impact of SfD on participants’ everyday lives.

scholarly journals Comparison of branded rugby headguards on their effectiveness in reducing impact on the head

2018 ◽  
Vol 4 (1) ◽  
pp. e000361 ◽  
Author(s):  
Erin R A Frizzell ◽  
Graham P Arnold ◽  
Weijie Wang ◽  
Rami J Abboud ◽  
Tim S Drew
Keyword(s):  
Impact Force ◽  
Linear Acceleration ◽  
Baseline Measurement ◽  
Peak Acceleration ◽  
Impact Forces ◽  
Impact Attenuation ◽  
The Mean ◽  
Force Reduction ◽  
The Right ◽  
The Impact

AimTo compare the available brands of rugby headguards and evaluate their impact attenuation properties at various locations on the cranium, with regard to concussion prevention.MethodsSeven different branded headguards were fitted onto a rigid headform and drop-tested in three different positions. An accelerometer measured the linear acceleration the headform experienced on impact with the ground. Each test involved dropping the headform from a height that generated 103.8 g on average when bare, which is the closest acceleration to the upper limit of the concussion threshold of 100 g. A mean peak acceleration for each drop position was calculated and compared with the bare baseline measurement.ResultsEach headguard demonstrated a significant decrease in the mean peak acceleration from the baseline value (all p≤0.01). Overall the Canterbury Ventilator was the most effective headguard, decreasing the impact force on average by 47%. The least effective was the XBlades Elite headguard, averaging a force reduction of 27%. In five of the seven headguards, the right side of the headwear was the most effective at reducing impact force.ConclusionOverall, the results indicate that it would be beneficial to wear a headguard during rugby in order to reduce the impact forces involved in head collisions. There was also a clear difference in performance between the tested brands, establishing the Canterbury headguard as the most effective. However, only one model of headguard from each brand was tested, so further research evaluating all other models should be considered.

scholarly journals STUDY ON IMPACT FORCES OF THE UNDERWATER CAVITY PROJECTILE

2016 ◽  
Vol 54 (6) ◽  
pp. 797
Author(s):  
Nguyen Thai Dung ◽  
Nguyen Duc Thuyen
Keyword(s):  
Drag Force ◽  
Impact Force ◽  
Center Of Mass ◽  
Forward Direction ◽  
Cavity Wall ◽  
Impact Point ◽  
Impact Forces ◽  
Underwater Projectile ◽  
The Impact ◽  
Cavity Effect

The motion of the underwater projectile with cavity effect including two motions: the projectile moves in the forward direction, center of mass of the projectile rotation around its nose makes tail of the projectile impacts on the cavity wall. According to, the impact forces occur, they include the drag force at its none, the impact force at impact point. The paper studies the forces occur on during motion of the underwater cavity projectile. Added, this paper considers the effect of the length and distributive projectile to the magnitude of impact force and the drag force of the underwater cavity projectile.

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