Impact Forces during Heel-Toe Running

1995 ◽  
Vol 11 (4) ◽  
pp. 407-432 ◽  
Author(s):  
Benno M. Nigg ◽  
Gerald K. Cole ◽  
Gert-Peter Brüggemann

Impact forces have been speculated to be associated with the development of musculoskeletal injuries. However, several findings indicate that the concepts of “impact forces” and the paradigms of their “cushioning” may not be well understood in relation to the etiology of running injuries and that complex mechanisms may be responsible for injury development during running. The purposes of this paper are (a) to review impact mechanics during locomotion, (b) to review injuries and changes of biological tissue due to impact loading, and (c) to synthesize the mechanical and biological findings. In addition, directions for future research are discussed. Future research should address the development of noninvasive techniques to assess changes in the morphology and biochemistry of bone, cartilage, tendon, and ligaments; researchers should also try to simulate impact loading during activities such as running, focusing on the interaction of the various loading parameters that determine the acceptable windows of loading for biological tissues.

Author(s):  
Yuan Jing ◽  
Z. John Ma ◽  
Richard M. Bennett ◽  
David B. Clarke

Grade separations have been used along High-Speed Rail (HSR) to decrease traffic congestion and the danger that occurs at grade crossings. However, the concern with grade separations is the potential damage due to lateral impact of bridge superstructures by over-height vehicles. This is a concern with existing bridges, and lateral impact is not included in standard bridge code provisions. A new bridge technology, Hybrid Composite Beam (HCB), was proposed to meet the requirements of another HSR objective, that of a sustainable solution for the construction of new and replacement bridges in rail infrastructure. The hybrid composite beam combines advanced composite materials with conventional concrete and steel to create a bridge that is stronger and more resistance to corrosion than conventional materials. The HCB is composed of three main parts; the first is a FRP (fiber reinforced polymer) shell, which encapsulates the other two parts. The second part is the compression reinforcement which consists of concrete or cement grout that is pumped into a continuous conduit fabricated into the FRP shell. The third part of the HCB is the tension reinforcement that could consist of carbon or glass fibers, prestressed strands, or other materials that are strong in tension, which is used to equilibrate the internal forces in the compression reinforcement. The combination of conventional materials with FRP exploits the inherent benefits of each material and optimizes the overall performance of the structure. The behavior of this novel system has been studied during the last few years and some vertical static tests have been performed, but no dynamic or lateral impact tests have been conducted yet. Therefore, the main objective of this study is to evaluate the performance of HCB when subjected to lateral impact loading caused by over-height vehicles. This paper explains the advantages of HCB when used in bridge infrastructures. The commercial software ABAQUS was used to perform the finite element (FE) modeling of a 30ft long HCB. Test data was used to validate the results generated by FE analysis. A constant impact loading with a time duration of 0.1 second was applied to an area at the mid-span of the HCB. Lateral deflection and stress distribution were obtained from FE analysis, and local stress concentration can be observed from the stress contour. Full-scale beam dynamic testing will be conducted in the future research to better study the behavior of HCB when subjected to over-height vehicles.


2019 ◽  
Vol 15 (3) ◽  
pp. 157-165
Author(s):  
M.H. Foreman ◽  
J.R. Engsberg ◽  
J.H. Foreman

Rotational falls are a serious cause of injury and death to horse and rider, particularly in the cross-country phase of eventing. The forces involved when horses galloping cross-country strike an immovable fence are unknown. The objective of this study was to mathematically model those forces using existing kinematic data measured from jumping horses. Data were obtained from published research using motion capture to measure mechanics about the center of gravity of the jumping horse at take-off. A convenience method from video evidence of rotational falls was used to estimate time of collision (Δt). A point mass model using equations of impulse-momentum and incorporating key variables was systematically implemented in Matlab (r2016a). The mean collision time (Δt=0.79s) produced horizontal, vertical, and resultant impact forces of 8,580, 8,245, and 12,158 N, respectively. Reference curves of impact forces were created for ranges of relevant input variables including collision time. Proportional relationships showed that shorter impact duration led to higher magnitude of force transfer between horse and obstacle. This study presents a preliminary range of collision forces based on a simplified model and numerous assumptions related to input variables. Future research should work to build upon these estimates through more complex modelling and data collection to enhance applicability for the design of cross-country safety devices.


2015 ◽  
Vol 77 (28) ◽  
Author(s):  
Azmi Abou Basaif ◽  
Nashrul Fazli Mohd Nasir ◽  
Zulkarnay Zakaria ◽  
Ibrahim Balkhis ◽  
Shazwani Sarkawi ◽  
...  

The enhanced ability to detect accurate location and measure the depth of a   metal inside a biological tissue is very useful in the assessment of medical condition and treatment. This manuscript proposed a solution via the measurement of the tissue properties using magnetic induction spectroscopy (MIS) method to describe the characterization of biological soft tissue. The objective of this study is to explore the viability of locating embedded metal inside a biological tissue by measuring the differences the biological tissue electrical properties using principle of Magnetic Induction Spectroscopy (MIS). Simulation is done using COMSOL Multiphysics software for accurate information on the involved parameters for both metal and biological tissues. Simulation has confirmed that MIS capable of detecting and locate embedded metal inside a biological tissue.


2018 ◽  
Vol 3 (3) ◽  
pp. 2473011418S0005
Author(s):  
Erin Futrell ◽  
Irene Davis

Category: Sports Introduction/Purpose: Vertical impact forces are highly influenced by the way the foot contacts the ground. These impact forces are associated with high loading rates which have been related to running injuries. As a result, clinicians have begun to use gait retraining interventions to reduce loadrates and prevent future impact-related injuries. Two types of gait retraining techniques have been promoted to reduce excessive running impacts. The first involves increasing cadence (CAD), or number of steps per minute, by 5-10%, thereby reducing stride length. The second type of gait retraining involves landing on the ball of the foot at ground contact, or using a forefoot strike (FFS). Both of these gait-retraining styles have been reported to reduce impacts, but they have not been compared with each other. Methods: 33 healthy runners (9M, 24F), running 5-15 mpw, with a rearfoot strike pattern with cadence < 170 steps/min were recruited. Subjects were randomly allocated to either FFS or CAD retraining. All subjects underwent an 8-session gait retraining program (over 2-3 wks) with auditory feedback on a treadmill. The CAD group ran to a digital metronome to increase cadence by 7.5%. The FFS group wore a wireless accelerometer that provided an auditory signal on footstrike pattern. A gait analysis was conducted at baseline, 1 wk, 1 month, and 6 months. Variables included vertical average and instantaneous load rates (VALR, VILR). A 2 x 4 repeated measures ANOVA was used to compare differences within and between the CAD and FFS groups at baseline, 1 week, 1 month and 6 months post retraining. For variables with significant interactions, simple main effects of group, as well as time were further explored using one-way ANOVA Results: There were significant interaction effects of time*group for VALR (p= 0.001), VILR (p=0.001) and foot angle (p< 0.001), but not cadence. For the simple main effects for the CAD group, VALR reduced by 14%, 7% and 16% at 1 week, 1 month, and 6 months post gait retraining respectively, compared with baseline (Figure 1). However, these reductions were not significant. For the FFS group, VALR was significantly reduced by 50%, 51% and 51% at 1 week, 1 month, and 6 months post gait retraining respectively. Interestingly, both the CAD and FFS groups increased cadence by similar amounts. Conclusion: Transitioning to a FFS pattern is significantly more effective than increasing CAD when reducing vertical loadrate (both VALR and VILR) is the goal. These changes persisted out to 6 months post gait retraining, suggesting permanence of the new pattern.


2020 ◽  
Vol 32 (1) ◽  
pp. 1-6
Author(s):  
Blessing Mkhwanazi ◽  
Julian David Pillay

Background: Ringball, a sport historically derived from conventional basketball and netball, demonstrates the evolution of traditional sport. The variations between these sports may predispose players to different risk factors and consequent injuries and their impact, yet they are usually considered comparably. Objective: To determine the prevalence of musculoskeletal injuries and to profile injuries based on location, severity, and mechanisms of occurrence. A further objective was to compare the injuries sustained in ringball with that of basketball and netball. Methods: A questionnaire-based study, administered to 110 ringball players in KwaZulu-Natal, South Africa, was applied. Data were described and compared using frequencies/ percentages for categorical variables. Results: Seventy-six ringball players completed the questionnaire (69% response rate). The prevalence of at least one injury during/after the last or current season was 80% (n=61). The most commonly reported injury was to the foot/ankle (36%; n=33) followed by the knee (29%; n=27) and wrist (9%; n=8). The most common mechanisms of injury reported were landing (15%; n=9), jumping (9%; n=5), goal shooting (7%; n=4), defending (7%; n=4) and collision (7%; n=4). Discussion: Ringball shares similar injuries to that of basketball/netball, with foot/ankle injuries being the most prevalent. The prevalence of other injuries in ringball differed from basketball/netball, suggesting variations between these sports as a contributor to the injuries described. Conclusion: The evolution of sport and the modifications in rules/techniques may create a nuanced injury profile to those commonly identified. The combination of a sport’s uniqueness/modification and its similarities to other sports warrants the need for more tailored approaches to injury prevention and a platform for future research.


2009 ◽  
Vol 19 (1) ◽  
pp. 3 ◽  
Author(s):  
L Meyer ◽  
L Van Niekerk ◽  
E Prinsloo ◽  
M Steenkamp ◽  
Q Louw

Objective. To determine the prevalence of musculoskeletal injuries among adolescent squash players in the Western Cape. Design. A retrospective descriptive survey was conducted during the first week of May 2006. Three schools were randomly selected from a list of the top 10 schools in the Western Cape high school squash league of 2005, with 106 squash players aged 13 - 18 years participating in the study. Setting. Injury data were collected for 106 players at three schools randomly selected from a list of the top 10 schools in the Western Cape high school squash league of 2005. Interventions. An adapted structured self-administered questionnaire based on a previously validated musculoskeletal injury questionnaire was used to collect the data. Main outcome measures. The main variables investigated were prevalence, mechanism and injury site of musculoskeletal squash injuries. Results. Twenty-nine per cent of the players (N = 31) reported that they had sustained a squash injury in the 4 weeks prior to data collection. A total of 48 injuries were reported by the injured players. The most common injuries included those of the thigh (19%), shoulder (13%) and lower back (13%). Forty-two per cent of players reported no specific mechanism of injury, but experienced pain not associated with a traumatic injury only while playing squash. Conclusion. A relatively high prevalence of squash injuries was found. This preliminary study serves as a baseline for future research. Areas for further investigation were identified and this could lead to the implementation of preventive programmes and education to prevent injuries among adolescent squash players. South African Journal of Sports Medicine Vol. 19 (1) 2007: pp. 3-8


2020 ◽  
Author(s):  
Pauline Barbeau ◽  
Alan Michaud ◽  
Candyce Hamel ◽  
Danielle Rice ◽  
Becky Skidmore ◽  
...  

ABSTRACT Introduction Musculoskeletal injuries (MSKi) are a common challenge for those in military careers. Compared to their male peers, reports indicate that female military members and recruits are at greater risk of suffering MSKi during training and deployment. The objectives of this study were to identify the types and causes of MSKi among female military personnel and to explore the various risk factors associated with MSKi. Materials and Methods A scoping review was conducted over a 4-month time frame of English language, peer-reviewed studies published from 1946 to 2019. Search strategies for major biomedical databases (e.g., MEDLINE; Embase Classic + Embase; and the following EBM Reviews—Cochrane Central Register of Controlled Trials, Cochrane Database of Systematic Reviews, Database of Abstracts of Reviews of Effects, Health Technology Assessment, and the NHS Economic Evaluation Database) were developed by a senior medical information specialist and included 2,891 titles/abstracts. Study selection and data collection were designed according to the Population, Concept, and Context framework. Studies were included if the study population provided stratified data for females in a military context. Results From a total of 2,287 citations captured from the literature searches, 168 peer-reviewed publications (144 unique studies) were eligible for inclusion. Studies were identified from across 10 countries and published between 1977 and 2019. Study designs were primarily prospective and retrospective cohorts. Most studies assessed both prevalence/incidence and risk factors for MSKi (62.50%), with few studies assessing cause (13.69%). For MSKi of female recruits compared to active female members, the prevalence was higher (19.7%-58.3% vs. 5.5%-56.6%), but the incidence (0.02%-57.7% vs. 13.5%-71.9%) was lower. The incidence of stress fractures was found to be much higher in female recruits than in active members (1.6%-23.9% vs. 2.7%). For anthropometric risk factors, increased body fat was a predictor of MSKi, but not stress fractures. For physiological risk factors for both female military groups, being less physically fit, later menarche, and having no/irregular menses were predictors of MSKi and stress fractures. For biomechanical risk factors, among female recruits, longer tibial length and femoral neck diameter increased the risk of stress fractures, and low foot arch increased risk of an ankle sprain. For female active military members, differences in shoulder rotation and bone strength were associated with risk of MSKi. For biological sex, being female compared to male was associated with an increased risk of MSKi, stress fractures, and general injuries. The consequences of experiencing MSKi for active military included limited duties, time off, and discharge. For recruits, these included missed training days, limited duty days, and release. Conclusions This scoping review provides insight into the current state of the evidence regarding the types and causes of MSKi, as well as the factors that influence MSKi among females in the military. Future research endeavors should focus on randomized controlled trials examining training paradigms to see if women are more susceptible. The data presented in the scoping review could potentially be used to develop training strategies to mitigate some of the identified barriers that negatively impact women from pursuing careers in the military.


2019 ◽  
Vol 5 (2) ◽  
pp. 109-116
Author(s):  
Ivan A. Konobeev ◽  
Yurij A. Kurachenko ◽  
Igor’ N. Sheino

It is experimentally proven that nanoparticles of high-Z materials can be used as radiosensitizers for photon beam therapy. In the authors’ opinion, data available as of today on the impact of secondary particles (electrons, photons and positrons generated in biological tissue by penetrating beam of primary photons) on the distribution of deposited dose during photon beam therapy in the presence of nanoparticles, are insufficient. Investigation of this impact constituted the main goal of this work. Two-stage simulation was performed using Geant4 platform. During the first stage a layer of biological tissue (water) was irradiated by monoenergetic photon sources with energies ranging from 10 keV to 6 MeV. As the result of this modeling spectra of electrons, photons and positrons were obtained at the depth of 5 cm. During the second stage the obtained photon spectra were used to irradiate gold, gadolinium and water nanoparticles. Radial distributions of energy deposited around nanoparticles were obtained as the result of this modeling. Radial DEF (Dose Enhancement Factor) values around nanoparticles of gold and gadolinium positioned in water at the depth of 5 cm were obtained after processing the collected data. Contributions from primary photons and secondary particles (electrons, photons and positrons generated in the layer of water with 5-cm thickness by the penetrating beam of primary photons) in the additional dose deposited around the nanoparticles were calculated as well. It was demonstrated that layer of biological tissue placed between the source of photons and nanoparticles considerably changes the initial spectrum of photons and this change is significant in the analysis of mechanism of radiosensitization of biological tissues by nanoparticles for all energies of photon sources (up to 6 MeV). It was established that interaction of electrons and positrons with nanoparticles does not lead to significant increase of additional dose in the vicinity of their surfaces and can be most likely excluded from consideration in the analysis of radiosensitization mechanism of nanoparticles.


2021 ◽  
Author(s):  
N.V. Kovalenko ◽  
K.V. Sovin ◽  
O.A. Ryabushkin

Problem formulating. The vital processes of biological tissues are closely related to their electrical properties. An important task is to create a physical and mathematical model that will link the electrical properties of tissues to their physiological state. Goal. Construction of a model of biological tissue electrical properties based on the equations of ion electrodiffusion. Result. The paper presents the model of biological tissue electrical properties based on the ion electrodiffusion equations, and compares the simulation results with the experimental results presented in the literature. Practical meaning. The presented model can be used to describe processes occurring in tissue at the level of concentration and conductivity of ions in individual cells and cell membranes. In particular, the process of tissue degradation during laser radiation heating can be described.


Author(s):  
Chia-Li Hsu ◽  
Chich-Haung Yang ◽  
Jen-Hung Wang ◽  
Chung-Chao Liang

Many studies exist on the incidence and related risk factors of running injuries, such as those obtained during marathons. However, in gorge-terrain marathons, an insufficient number of reports exist in the relevant literature. Therefore, this study aimed to explore the incidence of musculoskeletal injuries occurring in participants in the 2013 to 2018 Taroko Gorge Marathons in Taiwan and the distribution of running injuries and related influencing factors. A total of 718 runners who entered the physiotherapy station presented with records of treatment and injuries and filled out a running-related injury and self-training questionnaire for further statistical analysis. The association between risk factors and injury were evaluated by logistic regression. The injured areas on the lower extremities after the gorge marathon were as follows: 28% in the knees, 20% in the posterior calves, 13% in the thighs, 10% in the ankles, and 8% in the feet. The analysis of injury-related risk factors showed that male athletes demonstrated a higher risk of thigh injury than female athletes (OR = 2.42, p = 0.002). Underweight runners exhibited a higher risk of thigh injury (OR = 3.35, p = 0.006). We conclude that in the gorge marathon the rates of knee, calf, thigh, and foot injuries are significantly increased. Medical professionals, coaches, and runners may use the findings of this study to reduce the potential risk of running injuries in marathons.


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