Stiffness Adaptations in Shod Running

When mechanical parameters of running are measured, runners have to be accustomed to testing conditions. Nevertheless, habituated runners could still show slight evolutions of their patterns at the beginning of each new running bout. This study investigated runners' stiffness adjustments during shoe and barefoot running and stiffness evolutions of shoes. Twenty-two runners performed two 4-minute bouts at 3.61 m·s–1shod and barefoot after a 4-min warm-up period. Vertical and leg stiffness decreased during the shoe condition but remained stable in the barefoot condition,p< 0.001. Moreover, an impactor test showed that shoe stiffness increased significantly during the first 4 minutes,p< 0.001. Beyond the 4th minute, shoe properties remained stable. Even if runners were accustomed to the testing condition, as running pattern remained stable during barefoot running, they adjusted their leg and vertical stiffness during shoe running. Moreover, as measurements were taken after a 4-min warm-up period, it could be assumed that shoe properties were stable. Then the stiffness adjustment observed during shoe running might be due to further habituations of the runners to the shod condition. To conclude, it makes sense to run at least 4 minutes before taking measurements in order to avoid runners' stiffness alteration due to shoe property modifications. However, runners could still adapt to the shoe.

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Increase in Leg Stiffness Reduces Joint Work During Backpack Carriage Running at Slow Velocities

Journal of Applied Biomechanics ◽

10.1123/jab.2016-0226 ◽

2017 ◽

Vol 33 (5) ◽

pp. 347-353 ◽

Cited By ~ 6

Author(s):

Bernard Liew ◽

Kevin Netto ◽

Susan Morris

Keyword(s):

Linear Models ◽

Running Economy ◽

Joint Work ◽

Economy Running ◽

Leg Stiffness ◽

Kinematic Method ◽

Running Pattern ◽

The Impact ◽

The Relationship ◽

Healthy Participants

Optimal tuning of leg stiffness has been associated with better running economy. Running with a load is energetically expensive, which could have a significant impact on athletic performance where backpack carriage is involved. The purpose of this study was to investigate the impact of load magnitude and velocity on leg stiffness. We also explored the relationship between leg stiffness and running joint work. Thirty-one healthy participants ran overground at 3 velocities (3.0, 4.0, 5.0 m·s−1), whilst carrying 3 load magnitudes (0%, 10%, 20% weight). Leg stiffness was derived using the direct kinetic-kinematic method. Joint work data was previously reported in a separate study. Linear models were used to establish relationships between leg stiffness and load magnitude, velocity, and joint work. Our results found that leg stiffness did not increase with load magnitude. Increased leg stiffness was associated with reduced total joint work at 3.0 m·s−1, but not at faster velocities. The association between leg stiffness and joint work at slower velocities could be due to an optimal covariation between skeletal and muscular components of leg stiffness, and limb attack angle. When running at a relatively comfortable velocity, greater leg stiffness may reflect a more energy efficient running pattern.

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Is passive metatarsophalangeal joint stiffness related to leg stiffness, vertical stiffness and running economy during sub-maximal running?

Gait & Posture ◽

10.1016/j.gaitpost.2016.07.004 ◽

2016 ◽

Vol 49 ◽

pp. 303-308 ◽

Cited By ~ 7

Author(s):

Hok Sum Man ◽

Wing Kai Lam ◽

Justin Lee ◽

Catherine M. Capio ◽

Aaron Kam Lun Leung

Keyword(s):

Joint Stiffness ◽

Metatarsophalangeal Joint ◽

Running Economy ◽

Vertical Stiffness ◽

Leg Stiffness

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Mechanical Property Determination of Bone Through Nanoindentation Testing and Finite Element Simulation

ASME 2007 Summer Bioengineering Conference ◽

10.1115/sbc2007-176801 ◽

2007 ◽

Author(s):

Jingzhou Zhang ◽

Timothy C. Ovaert

Keyword(s):

Young’S Modulus ◽

Mechanical Response ◽

Bone Cells ◽

Young's Modulus ◽

Maximum Load ◽

Indentation Creep ◽

Testing Conditions ◽

Element Simulation ◽

Unloading Rate ◽

Testing Condition

Measurement of the mechanical properties of bone is important for estimation of the local mechanical response of bone cells to loading experienced on a larger scale. An increasing number of measurements of the hardness and Young’s modulus of bone tissue have been undertaken using nanoindentation [1,2]. However, testing conditions have not been uniform. The interactions that can occur between testing condition parameters were considered in this study, and average hardness and Young’s modulus were obtained as a function of indentation creep testing conditions (maximum load, loading/unloading rate (both equal in magnitude), load-holding time, and indenter shape).

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Similar Running Economy With Different Running Patterns Along the Aerial-Terrestrial Continuum

International Journal of Sports Physiology and Performance ◽

10.1123/ijspp.2016-0107 ◽

2017 ◽

Vol 12 (4) ◽

pp. 481-489 ◽

Cited By ~ 10

Author(s):

Thibault Lussiana ◽

Cyrille Gindre ◽

Kim Hébert-Losier ◽

Yoshimasa Sagawa ◽

Philippe Gimenez ◽

...

Keyword(s):

The Body ◽

Running Economy ◽

Energy Utilization ◽

Leg Stiffness ◽

Spatiotemporal Parameters ◽

Foot Strike ◽

Coupling Time ◽

Running Pattern ◽

The Relationship ◽

Gastrocnemius Lateralis

Purpose:No unique or ideal running pattern is the most economical for all runners. Classifying the global running patterns of individuals into 2 categories (aerial and terrestrial) using the Volodalen method could permit a better understanding of the relationship between running economy (RE) and biomechanics. The main purpose was to compare the RE of aerial and terrestrial runners.Methods:Two coaches classified 58 runners into aerial (n = 29) or terrestrial (n = 29) running patterns on the basis of visual observations. RE, muscle activity, kinematics, and spatiotemporal parameters of both groups were measured during a 5-min run at 12 km/h on a treadmill. Maximal oxygen uptake (V̇O2max) and peak treadmill speed (PTS) were assessed during an incremental running test.Results:No differences were observed between aerial and terrestrial patterns for RE, V̇O2max, and PTS. However, at 12 km/h, aerial runners exhibited earlier gastrocnemius lateralis activation in preparation for contact, less dorsiflexion at ground contact, higher coactivation indexes, and greater leg stiffness during stance phase than terrestrial runners. Terrestrial runners had more pronounced semitendinosus activation at the start and end of the running cycle, shorter flight time, greater leg compression, and a more rear-foot strike.Conclusions:Different running patterns were associated with similar RE. Aerial runners appear to rely more on elastic energy utilization with a rapid eccentric-concentric coupling time, whereas terrestrial runners appear to propel the body more forward rather than upward to limit work against gravity. Excluding runners with a mixed running pattern from analyses did not affect study interpretation.

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Comparison of whole-body vertical stiffness and leg stiffness during single-leg hopping in place in children and adults

Journal of Biomechanics ◽

10.1016/j.jbiomech.2017.03.001 ◽

2017 ◽

Vol 56 ◽

pp. 71-75 ◽

Cited By ~ 4

Author(s):

Matthew Beerse ◽

Jianhua Wu

Keyword(s):

Whole Body ◽

Vertical Stiffness ◽

Leg Stiffness

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Warm-up with a Weighted Vest Improves Running Performance via Leg Stiffness and Running Economy

Medicine & Science in Sports & Exercise ◽

10.1249/01.mss.0000496349.77814.fb ◽

2014 ◽

Vol 46 ◽

pp. 948 ◽

Cited By ~ 1

Author(s):

Kyle Barnes ◽

Will Hopkins ◽

Mike McGuigan ◽

Andrew Kilding

Keyword(s):

Running Economy ◽

Running Performance ◽

Warm Up ◽

Leg Stiffness ◽

Weighted Vest

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Estimates of Running Ground Reaction Force Parameters from Motion Analysis

Journal of Applied Biomechanics ◽

10.1123/jab.2015-0329 ◽

2017 ◽

Vol 33 (1) ◽

pp. 69-75 ◽

Cited By ~ 9

Author(s):

Gaspare Pavei ◽

Elena Seminati ◽

Jorge L.L. Storniolo ◽

Leonardo A. Peyré-Tartaruga

Keyword(s):

Motion Analysis ◽

Ground Reaction Force ◽

Center Of Mass ◽

Reaction Force ◽

The Body ◽

Vertical Force ◽

Vertical Stiffness ◽

Leg Stiffness ◽

Force Peak ◽

Body Center

We compared running mechanics parameters determined from ground reaction force (GRF) measurements with estimated forces obtained from double differentiation of kinematic (K) data from motion analysis in a broad spectrum of running speeds (1.94–5.56 m⋅s–1). Data were collected through a force-instrumented treadmill and compared at different sampling frequencies (900 and 300 Hz for GRF, 300 and 100 Hz for K). Vertical force peak, shape, and impulse were similar between K methods and GRF. Contact time, flight time, and vertical stiffness (kvert) obtained from K showed the same trend as GRF with differences < 5%, whereas leg stiffness (kleg) was not correctly computed by kinematics. The results revealed that the main vertical GRF parameters can be computed by the double differentiation of the body center of mass properly calculated by motion analysis. The present model provides an alternative accessible method for determining temporal and kinetic parameters of running without an instrumented treadmill.

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A Simple Method for Measuring Stiffness during Running

Journal of Applied Biomechanics ◽

10.1123/jab.21.2.167 ◽

2005 ◽

Vol 21 (2) ◽

pp. 167-180 ◽

Cited By ~ 143

Author(s):

Jean-Benoît Morin ◽

Georges Dalleau ◽

Heikki Kyröläinen ◽

Thibault Jeannin ◽

Alain Belli

Keyword(s):

High Speed ◽

Sine Wave ◽

Force Platform ◽

Mechanical Parameters ◽

Wave Method ◽

Leg Length ◽

Mass Model ◽

Time Curve ◽

Simple Method ◽

Vertical Stiffness

The spring-mass model, representing a runner as a point mass supported by a single linear leg spring, has been a widely used concept in studies on running and bouncing mechanics. However, the measurement of leg and vertical stiffness has previously required force platforms and high-speed kinematic measurement systems that are costly and difficult to handle in field conditions. We propose a new “sine-wave” method for measuring stiffness during running. Based on the modeling of the force-time curve by a sine function, this method allows leg and vertical stiffness to be estimated from just a few simple mechanical parameters: body mass, forward velocity, leg length, flight time, and contact time. We compared this method to force-platform-derived stiffness measurements for treadmill dynamometer and overground running conditions, at velocities ranging from 3.33 m·s–1to maximal running velocity in both recreational and highly trained runners. Stiffness values calculated with the proposed method ranged from 0.67% to 6.93% less than the force platform method, and thus were judged to be acceptable. Furthermore, significant linear regressions (p< 0.01) close to the identity line were obtained between force platform and sine-wave model values of stiffness. Given the limits inherent in the use of the spring-mass model, it was concluded that this sine-wave method allows leg and stiffness estimates in running on the basis of a few mechanical parameters, and could be useful in further field measurements.

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Mechanism of leg stiffness adjustment for hopping on surfaces of different stiffnesses

Journal of Applied Physiology ◽

10.1152/jappl.1998.85.3.1044 ◽

1998 ◽

Vol 85 (3) ◽

pp. 1044-1055 ◽

Cited By ~ 235

Author(s):

Claire T. Farley ◽

Han H. P. Houdijk ◽

Ciska Van Strien ◽

Micky Louie

Keyword(s):

Computer Simulation ◽

Joint Stiffness ◽

Force Platform ◽

Torsional Stiffness ◽

Knee Angle ◽

Ankle Stiffness ◽

Surface Stiffness ◽

Leg Stiffness ◽

Stiffness Adjustment

When humans hop in place or run forward, leg stiffness is increased to offset reductions in surface stiffness, allowing the global kinematics and mechanics to remain the same on all surfaces. The purpose of the present study was to determine the mechanism for adjusting leg stiffness. Seven subjects hopped in place on surfaces of different stiffnesses (23–35,000 kN/m) while force platform, kinematic, and electromyographic data were collected. Leg stiffness approximately doubled between the most stiff surface and the least stiff surface. Over the same range of surfaces, ankle torsional stiffness increased 1.75-fold, and the knee became more extended at the time of touchdown (2.81 vs. 2.65 rad). We used a computer simulation to examine the sensitivity of leg stiffness to the observed changes in ankle stiffness and touchdown knee angle. Our model consisted of four segments (foot, shank, thigh, head-arms-trunk) interconnected by three torsional springs (ankle, knee, hip). In the model, an increase in ankle stiffness 1.75-fold caused leg stiffness to increase 1.7-fold. A change in touchdown knee angle as observed in the subjects caused leg stiffness to increase 1.3-fold. Thus both joint stiffness and limb geometry adjustments are important in adjusting leg stiffness to allow similar hopping on different surfaces.

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