Shock absorption when fatigued

NewsBot · Sep 4, 2006

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The effect of lower extremity fatigue on shock attenuation during single-leg landing
Evan Coventry, Kristian M. O’Connor, Barbara A. Hart, Jennifer E. Earl, Kyle T. Ebersole
Clinical Biomechanics (in press)

Background
The forces that are imposed on the body due to landings must be attenuated primarily in the lower extremity. Muscles assist in the absorption of these forces, and it has been shown that a fatigued muscle decreases the body’s ability to attenuate shock from running. The purpose of the study was to determine the effect of lower extremity fatigue on shock attenuation and joint mechanics during a single-leg drop landing.

Methods
Ten active male participants were recruited (eight used for analysis). Each participant took part in a fatigue landing protocol. This protocol included cycles of a drop landing, a maximal countermovement jump, and five squats, repeated until exhaustion. Accelerometers attached to the skin measured tibia and head accelerations. Lower extremity kinematics were collected using an electromagnetic tracking system and kinetics were collected using a forceplate. A repeated-measures ANOVA (P<0.05) was performed on each of the dependent variables across the cycles of the fatigue protocol.

Findings
Fatigue was induced, however there was no significant change in shock attenuation throughout the body. Hip and knee flexion increased and ankle plantarflexion decreased at touchdown with fatigue. Hip joint work increased and ankle work decreased.

Interpretation
This change in work distribution is thought to be a compensatory response to utilize the larger hip extensors that are better suited to absorb the mechanical energy of the impact. The results suggested that the lower extremity is able to adapt to fatigue though altering kinematics at impact and redistributing work to larger proximal muscles.
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Admin2 · Sep 4, 2006

Shock absorbtion / cushioning

Related threads:
Rearfoot motion and shock attenuation
Shock absorbing insoles do not reduce injury rate
Barefoot walking decreased loads

Simon Spooner · Sep 5, 2006

NewsBot said:

The effect of lower extremity fatigue on shock attenuation during single-leg landing
Evan Coventry, Kristian M. O’Connor, Barbara A. Hart, Jennifer E. Earl, Kyle T. Ebersole
Clinical Biomechanics (in press)
Click to expand...

So the questions then become:

How is this system regulated?

How can we manipulate it to our advantage?

NewsBot · Nov 10, 2012

The effects of lower extremity muscle fatigue on the vertical ground reaction force: a meta-analysis.
Zadpoor AA, Nikooyan AA.
Proc Inst Mech Eng H. 2012 Aug;226(8):579-88.

There is currently no consensus in the literature on whether the magnitude of the ground reaction force or loading rate decreases or increases with muscle fatigue. In this article, the effects of lower extremity muscle fatigue on the magnitude of the ground reaction force and loading rate during running and drop landing are examined. Through a systematic search of the literature, 24 articles are identified that satisfy the inclusion criteria and study the relationship between fatigue and the ground reaction force variables during running, single-leg drop landing, and bilateral drop landing. The articles are categorized based on the type of locomotion they study. To determine whether or not the ground reaction force peaks/loading rate are markedly affected by fatigue, meta-analyses are conducted both separately for each type of locomotion and for an aggregate of all studies. The results of the meta-analyses show that the ground reaction force active peak significantly decreases for the following study groups: aggregate of all included studies, studies of drop landing (both single-leg and bilateral), and studies of bilateral landing only. The ground reaction force active peak did not significantly change in running and single-leg drop landing. The effects of muscle fatigue on the magnitude of the ground reaction force impact peak and loading rate was always insignificant.
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NewsBot · Jan 14, 2013

Decreased foot inversion force and increased plantar surface after maximal incremental running exercise
Bruno Vie, Christelle Brerro-Saby, Jean Paul Weber, Yves Jammes
Gait & Posture; Article in Press

Formulating the hypothesis that a maximal running exercise could induce fatigue of some foot muscles, we searched for electromyographic (EMG) signs of fatigue in the tibialis anterior (TA), peroneus longus (PL), and gastrocnemius medialis (GM) muscles. We also searched for post-exercise alterations of the stationary upright standing in normal-arched feet subjects.

Healthy subjects performed a maximal running exercise. Surface EMGs of the TA, PL, and GM muscles were analysed during maximal dynamic efforts. Before and after the running bout, we measured the evoked compound muscle potential (M-wave) in TA, the maximal force into inversion (MIF), and the repartition of the plantar and barycentre surfaces with a computerised stationary platform.

During maximal running exercise, the median frequency of the EMG spectra declined in TA while it remained stable in the PL and GM muscles. After the exercise, MIF decreased, and both the rearfoot plantar surface and the barycentre surface increased.

We concluded that a maximal running bout elicits EMG signs of fatigue, though only in the TA muscle. It also elicits post-exercise changes in the foot position during stationary upright standing which indicates a foot eversion. These data solely concern a maximal running test and they can not be extrapolated to walking or running at a low speed.
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Highlights
► We hypothesised that maximal running could induce fatigue of some foot muscles.
► Surface electromyograms (EMG) of three foot muscles were recorded during running.
► We measured maximal foot inversion force and repartition of the plantar surfaces.
► EMG signs of fatigue were measured in a foot invertor muscle (tibialis anterior)
► Running elicited post-exercise foot eversion during stationary upright standing.
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NewsBot · Mar 12, 2013

Effect of Functional Fatigue on Vertical Ground Reaction Force Among Individuals with Flat Feet.
Boozari S, Jamshidi AA, Sanjari MA, Jafari H.
J Sport Rehabil. 2013 Mar 8.

CONTEXT:
Flat foot as one of the lower extremity deformities might change kinetic variables of gait. Fatigue is one of the factors which can alter the vertical ground reaction force (GRF). Effect of fatiguing condition on vertical GRF was not documented in individuals with flat feet.

OBJECTIVE:
To examine the fatigue effect on vertical GRF in individuals with flat feet compared with a normal group during barefoot walking.

DESIGN:
Repeated measure ANOVA for the effects of fatigue on individuals with flat feet and normal feet.

SETTING:
Biomechanics laboratory.

PARTICIPANTS:
Seventeen subjects with flat feet and 17 normal subjects (recruited according to their arch height ratio) completed the test.

MAIN OUTCOME MEASURES:
Three vertical GRF measures (F1; the first peak force, F2; minimum force; and F3; the second peak force) were extracted before and after a functional fatigue protocol.

RESULTS:
No significant interaction between fatigue and group was observed for the three vertical GRF measures. For F2, fatigue and group effects were significant (p = 0.001 and p = 0.02, respectively). Furthermore, F2 was higher in the flat feet group compared with the normal group; F2 also increased after fatigue. For F3, only a significant fatigue effect was observed (p = 0.004). F3 decreased after fatigue in both groups.

CONCLUSIONS:
In the flat feet group, a decrease in the variation of vertical GRF might be due to more flexible foot joints. After fatigue, muscles might lose their ability to control the foot joints and cause higher F2 in the flat feet group.
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NewsBot · Mar 19, 2013

Gait Characteristics Over the Course of a Race in Recreational Marathon Competitors
John E. A. Bertram, Leif Prebeau-Menezes & Matthew J. Szarko
Research Quarterly for Exercise and Sport Volume 84, Issue 1, 2013

We analyzed gait and function of the supporting limb in participants of a marathon race at three stages: prerace, midrace (18 km), and near the end of the race (36 km). We confirmed that the most successful runners were able to maintain running speed for the duration of the race with little change in speed or gait. Speed slowed progressively during the race for those with slower race times, but stride frequency–stride length relationships remained normal for the speed they ran. These findings differ from most lab-based studies of fatigue, in which runners are forced to match a constant preset treadmill speed. Small changes in maximum ground force were seen in both slow- and fast-running participants as race end approached.
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NewsBot · Aug 15, 2013

Effect of functional fatigue on vertical ground-reaction force in individuals with flat feet.
Boozari S, Jamshidi AA, Sanjari MA, Jafari H.
J Sport Rehabil. 2013 Aug;22(3):177-83.

Context: Flat foot is one of the lower extremity deformities that might change kinetic variables of gait. Fatigue is one of the factors that can alter the vertical ground-reaction force (GRF). The effect of a fatiguing condition on vertical GRF has not been documented in individuals with flat feet.

Objective: To examine the fatigue effect on vertical GRF in individuals with flat feet compared with a normal group during barefoot walking.

Design: Repeated-measure ANOVA for the effects of fatigue on individuals with flat feet and normal feet.

Setting: Biomechanics laboratory. Participants: 17 subjects with flat feet and 17 normal subjects (recruited according to their arch-height ratio).

Main Outcome Measures: Three vertical GRF measures (F1, the first peak force; F2, minimum force; and F3, the second peak force) were extracted before and after a functional fatigue protocol.

Results: No significant interaction between fatigue and group was observed for the 3 vertical GRF measures. For F2, fatigue and group effects were significant (P = .001 and P = .02, respectively). Furthermore, F2 was higher in the flat-feet group than in the normal group; F2 also increased after fatigue. For F3, only a significant fatigue effect was observed (P = .004). F3 decreased after fatigue in both groups.

Conclusions: In the flat-feet group, a decrease in the variation of vertical GRF might be due to more flexible foot joints. After fatigue, muscles might lose their ability to control the foot joints and cause higher F2 in the flat-feet group.
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NewsBot · Oct 29, 2013

THE EFFECT OF FATIGUE ON PLANTAR PRESSURE IN A
COMPETITIVE COLLEGIATE SOCCER PLAYER
B.A. Gladish, J.A. Davis, PhD, Elon University Elon, M. E. Russell, MS,
M. W. Krzyzewski
Presnted at 2013 ACSM Southeast meeting

Soccer is a popular recreational activity that has been linked to higher rates of 5th metatarsal
stress fractures in male soccer players as compared to females. More soccer injuries occur at
the ends of halves, which may be explained by fatigue. Metatarsal loading patterns can be
studied through plantar pressure measurements, though there is little research investigating the
influence of fatigue on plantar pressure in cleated sports. PURPOSE: The purpose of this
study was to investigate the effect of fatigue on plantar loading patterns in a male soccer player.
METHODS: This case study utilized a pretest/posttest design to compare plantar pressure data
collected while the subject performed soccer cutting maneuvers before and after a fatiguing
intervention. Levels of fatigue were measured using the Borg scale and validated using blood
lactate measures. Initial fatigue levels were recorded and plantar pressure data were recorded
during an agility course consisting of side and cross-cuts. A modified Loughborough
Intermittent Shuttle Test was utilized as the fatiguing intervention. Fatigue levels and plantar
pressure data were again collected during the agility course. RESULTS: A fatigued condition
resulted in a 38% increase in peak pressure, a 34% increase in maximum force, a 10%
reduction in foot contact time, and no substantial change was found in contact area in the lateral
aspect of the foot, where the 5th metatarsal is located. CONCLUSIONS: Several aspects of
plantar pressure appear to substantially change with fatigue and further research should be
conducted to see if these trends are replicated in larger populations of male soccer players to
determine significance.
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NewsBot · Nov 2, 2013

The influence of physical activity in foot posture and plantar pressures
Gijón Noguerón, Gabriel; Bravo Aguilar, María; Abian Vicen, Javier; Luque Suárez, Alejandro; Paéz Moguer, Joaquín
Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

Background and aims The regular practice of physical activity to improve people´s physical condition such as running or jogging,can damage the lower limb in 79% of the people who practice it.The aim of this study was to determine if foot posture and gait can be modified after 45 minutes of running.

Method The sample consisted in 116 healthy adults (92 men and 24 women) with non-pathological feet. The mean age of the participants was 28,31 ± 6,01 years, BMI of 23.45 ± 1.96 kg/m2 and training hours per week of 11.02 ± 4.22. Outcome measures were collected at baseline and after 45 minutes of running at an average speed of 12 km/h, and included the Foot Posture Index (FPI) and a pedobarography analysis with the system Biofoot(IBV, Valencia(Spain).

Results The results show foot posture can be modified after 45 minutes of running. The FPI changed from 6,14 ± 2,61 to 4,86 ± 2,65. Furthermore, maximum pressure peak was reduced in the forefoot and increased in the midfoot..The pedobarometric measurement in the heel contact was reduced in the internal area of the foot.The average of maximum pressure was reduced in the internal area and in the forefoot.

Conclusion The findings suggest that,after running, pronated foot tends to change its posture into a neutral position, and a decrease in maximum pressure forces in the forefoot and in the area internal the foot is presented.
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http://www.riuma.uma.es/xmlui/handle/10630/6171#sthash.I7daBEGg.dpuf

NewsBot · Dec 2, 2013

Blog post from Runners Connect:
The Effects of Fatigue on Your Running Form: How Your Form Breaks Down (and what injuries occur) During Short Races and Speed Workouts

NewsBot · Mar 28, 2022

Shock Response Spectrum Analysis of Fatigued Runners
Daniel Benjamin et al
Sensors (Basel). 2022 Mar 18;22(6):2350

The purpose of this study was to determine the effect of fatigue on impact shock wave attenuation and assess how human biomechanics relate to shock attenuation during running. In this paper, we propose a new methodology for the analysis of shock events occurring during the proposed experimental procedure. Our approach is based on the Shock Response Spectrum (SRS), which is a frequency-based function that is used to indicate the magnitude of vibration due to a shock or a transient event. Five high level CrossFit athletes who ran at least three times per week and who were free from musculoskeletal injury volunteered to take part in this study. Two Micromachined Microelectromechanical Systems (MEMS) accelerometers (RunScribe®, San Francisco, CA, USA) were used for this experiment. The two RunScribe pods were mounted on top of the foot in the shoelaces. All five athletes performed three maximum intensity runs: the 1st run was performed after a brief warmup with no prior exercise, then the 2nd and the 3rd run were performed in a fatigued state. Prior to the 2nd and the 3rd run, the athletes were asked to perform at maximum intensity for two minutes on an Assault AirBike to tire them. For all five athletes, there was a direct correlation between fatigue and an increase in the aggressiveness of the SRS. We noticed that for all five athletes for the 3rd run the average SRS peaks were significantly higher than for the 1st run and 2nd run (p < 0.01) at the same natural frequency of the athlete. This confirms our hypothesis that fatigue causes a decrease in the shock attenuation capacity of the musculoskeletal system thus potentially involving a higher risk of overuse injury.
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Shock absorption when fatigued

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Shock absorption when fatigued

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Concerned and shocked newbie

Use of extracorporeal shock wave therapy for children’s foot, ankle and leg concerns

Chattanooga RPW Mobile shockwave machine AS NEW

Shockwave for plantar fasciitis in cancer patients

Menisci Did Not Evolve to be Shock Absorbers

HealthWave/shockwave therapy Program FDA Cleared

Selling shockwave machine. Melbourne Australia $3000

Share This Page

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