The influence of running velocity and midsole hardness on external impact forces in heel-toe running (original) (raw)
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Increased vertical impact forces and altered running mechanics with softer midsole shoes
PloS one, 2015
To date it has been thought that shoe midsole hardness does not affect vertical impact peak forces during running. This conclusion is based partially on results from experimental data using homogeneous samples of participants that found no difference in vertical impact peaks when running in shoes with different midsole properties. However, it is currently unknown how apparent joint stiffness is affected by shoe midsole hardness. An increase in apparent joint stiffness could result in a harder landing, which should result in increased vertical impact peaks during running. The purpose of this study was to quantify the effect of shoe midsole hardness on apparent ankle and knee joint stiffness and the associated vertical ground reaction force for age and sex subgroups during heel-toe running. 93 runners (male and female) aged 16-75 years ran at 3.33 ± 0.15 m/s on a 30 m-long runway with soft, medium and hard midsole shoes. The vertical impact peak increased as the shoe midsole hardness ...
Mechanical analysis of the landing phase in heel-toe running
Journal of Biomechanics, 1992
Results of mechanical analyses of running may be helpful in the search for the etiology of running injuries. In this study a mechanical analysis was made of the landing phase of three trained heel-toe runners, running at their preferred speed and style. The body was modeled as a system of seven linked rigid segments, and the positions of markers defining these segments were monitored using 200 Hz video analysis.
The effect of muscle stiffness and damping on simulated impact force peaks during running
Journal of Biomechanics, 1999
It has been frequently reported that vertical impact force peaks during running change only minimally when changing the midsole hardness of running shoes. However, the underlying mechanism for these experimental observations is not well understood. An athlete has various possibilities to in#uence external and internal forces during ground contact (e.g. landing velocity, geometrical alignment, muscle tuning, etc.). The purpose of this study was to discuss one possible strategy to in#uence external impact forces acting on the athlete's body during running, the strategy to change muscle activity (muscle tuning). The human body was modeled as a simpli"ed mass}spring}damper system. The model included masses of the upper and the lower bodies with each part of the body represented by a rigid and a non-rigid wobbling mass. The in#uence of mechanical properties of the human body on the vertical impact force peak was examined by varying the spring constants and damping coe$cients of the spring}damper units that connected the various masses. Two types of shoe soles were modeled using a non-linear force deformation model with two sets of parameters based on the force}deformation curves of pendulum impact experiments. The simulated results showed that the regulation of the mechanical coupling of rigid and wobbling masses of the human body had an in#uence on the magnitude of the vertical impact force, but not on its loading rate. It was possible to produce the same impact force peaks altering speci"c mechanical properties of the system for a soft and a hard shoe sole. This regulation can be achieved through changes of joint angles, changes in joint angular velocities and/or changes in muscle activation levels in the lower extremity. Therefore, it has been concluded that changes in muscle activity (muscle tuning) can be used as a possible strategy to a!ect vertical impact force peaks during running.
Barefoot and Shod Running with Different Strike Patterns: A Kinetic Analysis
2014
The purpose of this study was to determine, if running barefoot versus shod conditions over ground has any impact on kinetic variables of forefoot/mid-foot (FF/MF) versus rearfoot (RF) strike patterns. Ten men between the ages of 18 and 22 were recruited. All subjects performed five 20m runs, in each condition, over force platforms. Peak horizontal force and impulse were obtained from both braking and propulsive periods as well as peak vertical force. Results include: peak vertical force for the RF pattern in barefoot running was higher than all other conditions (p < 0.01), higher braking impulses in the RF pattern in both conditions, particularly barefoot (p < 0.01), and higher propulsive impulses in FF pattern in both conditions (p < 0.01). It is concluded that the most differences are found between strike patterns rather than between barefoot and shod running.
The effects of footwear on impact force during running: a model-based study
A lumped-parameter model of the human body during running was previously developed. The model was used to study the effects of footwear on the impact force during running. However, the parameters of the model were considered constant regardless of the shoe type. Experimental studies have shown that the stiffness and damping of the human body are adjusted in accordance with the stiffness and damping of the shoe-ground system. In this paper, we study how the parameters of the model are adjusted, when the shoe parameters change. The original model is improved by adding a controller which resembles the function of the CNS. The effects of footwear on the impact force are studied by using the improved model. Three different bound limits are used for the model parameters to study the effects of the upper and lower parameter limits on the results. It has been shown that the model can explain the contradictory observations about the effects of footwear on the impact force.
Adaptation of the human calcaneus to variations of impact forces during running
Clinical Biomechanics, 1999
Objective. The in¯uence of varied forces under the heel induced by changes in midsole hardness on adaptations of the human calcaneus during running training was investigated. Design. A longitudinal study was conducted over a period of 20 weeks with subjects training for 50 km per week on average. Background. The skeletal systems' metabolism acts highly dynamic, governed by mechanical factors. The amount of running training has been shown to increase the bone mineral density in the calcaneus. Mechanical factors have not been controlled in former investigations. Methods. Bone quality parameters were determined before and after the training by use of an ultrasound system and quantitative MRI while the mechanics of foot-ground contact were controlled. The total group of 26 subjects was divided into three subgroups based upon dierent magnitude of forces under the heel inside the shoe. Results. The biomechanical testing demonstrate no relationship between midsole hardness and external or in-shoe impacts. Bone parameters showed speci®c dierences for all groups which are pronounced in runners with intermediate impacts. Conclusions. The observed variations re¯ect metabolic changes in bone marrow which appear to be eected by the impact magnitude and cannot be characterised as negative. Relevance The current data imply that no negative changes of impacts on calcaneal bone were produced by high amounts of training in distance running. The mechanical testing indicates that the potential of modifying calcaneal adaptation directly by varying midsole hardness is limited.
Shoe midsole hardness, sex and age effects on lower extremity kinematics during running
Journal of biomechanics, 2012
Previous studies investigating the effects of shoe midsole hardness on running kinematics have often used male subjects from within a narrow age range. It is unknown whether shoe midsole hardness has the same kinematic effect on male and female runners as well as runners from different age categories. As sex and age have an effect on running kinematics, it is important to understand if shoe midsole hardness affects the kinematics of these groups in a similar fashion. However, current literature on the effects of sex and age on running kinematics are also limited to a narrow age range distribution in their study population. Therefore, this study tested the influence of three different midsole hardness conditions, sex and age on the lower extremity kinematics during heel-toe running. A comprehensive analysis approach was used to analyze the lower-extremity kinematic gait variables for 93 runners (male and female) aged 16-75 years. Participants ran at 3.33 7 0.15 m/s on a 30 m-long runway with soft, medium and hard midsoles. A principal component analysis combined with a support vector machine showed that running kinematics based on shoe midsole hardness, sex, and age were separable and classifiable. Shoe midsole hardness demonstrated a subject-independent effect on the kinematics of running. Additionally, it was found that age differences affected the more dominant movement components of running compared to differences due to the sex of a runner.
Clinical Biomechanics, 1997
Objective. Perceptual ratings of mechanical variables were compared with biomechanical variables that are related to running injuries. Design. Eight identical running shoes with a relatively close range of midsole hardness were used. Ground reaction force (GRF), in-shoe pressure distribution and rearfoot motion were measured during running. Perceptual ratings were obtained after the running trials. Background. Previous studies reported high correlations between cushioning perception and biomechanical variables for shoes that featured large differences in midsole hardness. Mef~ods. A 15point categorical rating scale was used to judge impact severity, pressure magnitude and rearfoot motion in running. Rating scores were compared with biomechanical variables (GRF, pressure distribution and pronation values) using regression analyses. Resuk. Re$ression analyses revealed high relations between different biomechanical variables and the perception scores. The best relation to perception was analysed for the median power frequency of the vertical GRF (r2 = 0.97). A negative correlation (r2 = 0.54) between the first impect of GRF and the perception of impact severity could be revealed. Conclusion. The present study suggests that the body's sensory system seems to differentiate well between impacts of different frequency content. Based on perceptual abilities, subjects ad&p? their running style to avoid high heel impacts, Relevance Perception of injury-related variables is an important issue in the discussion of the etiology of sports injuries. The protection and prevention abilii of the human body is restricted, if runners are not able to perceive the intensity of factors that are related to running injuries.
Lower extremity joint loading during impact in running
Clinical Biomechanics, 1996
Objective. The main purpose of this study was to estimate lower extremity joint impact loading in running and the influences of muscles on this loading. Design. A 2D simulation model that included skeletal motion, muscles, and soft-tissue movement was developed in this study. Background.