The Role of Water-Based Exercise on Vertical Ground Reaction Forces in Overweight Children: A Pilot Study

The aquatic environment represents an adequate and safe alternative for children with overweight to exercise. However, the magnitude of the vertical ground reaction force (Fz) during these exercises is unknown in this population. Therefore, our study aimed to compare the Fz during the stationary running exercise between the aquatic and land environments in children with overweight or obesity. The study is characterized as a cross-over study. Seven children, two with overweight and five with obesity (4 boys and 3 girls; 9.7 ± 0.8 years), performed two experimental sessions, one on land and another in the aquatic environment. In both conditions, each participant performed 15 repetitions of the stationary running exercise at three different cadences (60, 80, and 100 b min−1) in a randomized order. Their apparent weight was reduced by 72.1 ± 10.4% on average at the xiphoid process depth. The peak Fz, impulse, and loading rate were lower in the aquatic environment than on land (p < 0.001). Peak Fz was also lower at 80 b min−1 compared to 100 b min−1 (p = 0.005) and loading rate was higher at 100 b min−1 compared to 80 b min−1 (p = 0.003) and 60 b min−1 (p < 0.001) in the aquatic environment, whereas impulse was significantly reduced (p < 0.001) with the increasing cadence in both environments. It can be concluded that the aquatic environment reduces all the Fz outcomes investigated during stationary running and that exercise intensity seems to influence all these outcomes in the aquatic environment.

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In search of the pitching momentum that enables some lizards to sustain bipedal running at constant speeds

Journal of The Royal Society Interface ◽

10.1098/rsif.2013.0241 ◽

2013 ◽

Vol 10 (84) ◽

pp. 20130241 ◽

Cited By ~ 5

Author(s):

Sam Van Wassenbergh ◽

Peter Aerts

Keyword(s):

Reaction Force ◽

Vertical Ground Reaction Force ◽

Mass Model ◽

Temporal Asymmetry ◽

Long Time ◽

Reaction Forces ◽

Vertical Ground ◽

Vertical Ground Reaction Forces ◽

Angular Impulse ◽

Force Profiles

The forelimbs of lizards are often lifted from the ground when they start sprinting. Previous research pointed out that this is a consequence of the propulsive forces from the hindlimbs. However, despite forward acceleration being hypothesized as necessary to lift the head, trunk and forelimbs, some species of agamids, teiids and basilisks sustain running in a bipedal posture at a constant speed for a relatively long time. Biomechanical modelling of steady bipedal running in the agamid Ctenophorus cristatus now shows that a combination of three mechanisms must be present to generate the angular impulse needed to cancel or oppose the effect of gravity. First, the trunk must be lifted significantly to displace the centre of mass more towards the hip joint. Second, the nose-up pitching moment resulting from aerodynamic forces exerted at the lizard's surface must be taken into account. Third, the vertical ground-reaction forces at the hindlimb must show a certain degree of temporal asymmetry with higher forces closer to the instant of initial foot contact. Such asymmetrical vertical ground-reaction force profiles, which differ from the classical spring-mass model of bipedal running, seem inherent to the windmilling, splayed-legged running style of lizards.

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Lower-Extremity-Joint Cryotherapy Does Not Affect Vertical Ground-Reaction Forces during Landing

Journal of Sport Rehabilitation ◽

10.1123/jsr.10.2.132 ◽

2001 ◽

Vol 10 (2) ◽

pp. 132-142 ◽

Cited By ~ 12

Author(s):

Andrew G Jameson ◽

Stephen J Kinzey ◽

Jeffrey S Hallam

Keyword(s):

Repeated Measures ◽

Vertical Jump ◽

Reaction Force ◽

Vertical Ground Reaction Force ◽

Physically Active ◽

Before And After ◽

Reaction Forces ◽

Vertical Ground ◽

Chronic Injuries ◽

Vertical Ground Reaction Forces

Context:Cryotherapy is commonly used in the care of acute and chronic injuries. It decreases pain, reduces swelling, and causes vasoconstriction of blood vessels. Its detrimental effects on motor activity might predispose physically active individuals to further injury.Objective:To examine the effects of cryotherapy on vertical-ground-reaction-force (VGRF) during a 2-legged landing from a 2-legged targeted vertical jump.Design:2 × 4 MANOVA with repeated measures.Setting:Biomechanics laboratory.Participants:10 men, means: 22.40 ± 1.26 years, 76.01 ± 26.95 kg, 182.88 ± 6.88 cm.Intervention:VGRF during landing from a targeted vertical jump (90% of maximum) was measured before and after four 20-minute cryotherapy treatments.Results:There were no significant differences in VGRF as a result of cryotherapy.Conclusion:Under the constraints of this study there is no evidence that returning to activity immediately after cryotherapy predisposes an athlete to injury because of a change in VGRF.

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Comparison of Simultaneously Collected Kinetic Data with Force Plates and a Pressure Walkway

Veterinary and Comparative Orthopaedics and Traumatology ◽

10.1055/s-0038-1666875 ◽

2018 ◽

Vol 31 (05) ◽

pp. 327-331 ◽

Cited By ~ 2

Author(s):

Gabriella Sandberg ◽

Bryan Torres ◽

Amanda Berjeski ◽

Steven Budsberg

Keyword(s):

Kinetic Data ◽

Reaction Force ◽

Vertical Force ◽

Pressure Data ◽

Vertical Ground Reaction Force ◽

Reaction Forces ◽

Pelvic Limb ◽

Vertical Ground ◽

Vertical Ground Reaction Forces ◽

Collection Methods

Objective This article compares simultaneously collected kinetic data (percent limb distribution and limb symmetry) with force plates (FP) and a pressure walkway. Animals This study included 18 healthy client-owned adult dogs. Methods Vertical ground reaction force and pressure data were collected during two sessions 1 week apart (days 1 and 7) using both FP and pressure mat systems. Vertical ground reaction forces and vertical pressure data were each collected alone as well as simultaneously. A mixed effects model was used to test for differences in force, force percent data and symmetry indices (SI) that were calculated for the thoracic and pelvic limb pairs, between collection systems. A Pearson's correlation was used to test for correlations between force, force percentage and SI. Results There was no difference in peak vertical force (PVF) or total pressure index (TPI) data collected alone or when collected with pressure mat overlay the FP. Small but significant differences were found in percent limb distribution between PVF% and TPI%. Significant differences were found in the calculated SI for forelimbs and hindlimbs. Correlations between the PVF% and TPI% distribution were significant in both the fore- and hindlimbs. While there was a significant correlation between the forelimb SI, there was no significant correlation between the SI in the hindlimbs. Clinical Significance The method of calculating PVF and TPI percentages allowed for comparison between the collection methods. Significant differences were noted in the calculated SI between the collection methods and direct comparisons is not advisable.

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The Effect of External Ankle Support on Vertical Ground-Reaction Force and Lower Body Kinematics

Journal of Sport Rehabilitation ◽

10.1123/jsr.14.4.301 ◽

2005 ◽

Vol 14 (4) ◽

pp. 301-312 ◽

Cited By ~ 6

Author(s):

Brad Hodgson ◽

Laurie Tis ◽

Steven Cobb ◽

Elizabeth Higbie

Keyword(s):

Statistical Analysis ◽

Repeated Measures ◽

Reaction Force ◽

Vertical Ground Reaction Force ◽

Kinematic Data ◽

Ankle Angle ◽

Reaction Forces ◽

Vertical Ground ◽

Ankle Support ◽

Vertical Ground Reaction Forces

Objective:To examine the effects of external ankle support on vertical ground-reaction forces (VGRF) and kinematic data.Methods:Subjects completed 2 braced and 2 nonbraced 0.61-m hanging drop landings onto a force platform. Kinematic data were collected with 8 digital-optical cameras sampling at 120 Hz.Subjects:12 Division I female volleyball players.Statistical Analysis:A repeated-measures ANOVA with Bonferroni correction (P < .05) was used to determine whether significant differences existed between test conditions for peak VGRF, loading rate, hip angle, knee angle, and ankle angle at right-foot contact for peak 1 and peak 2 of the VGRF curve over the first 100 milliseconds of the landing phase, as well as total hip range of motion (ROM), total knee ROM, and total ankle ROM for the entire landing phase.Results:There were significant increases in peak P1 and LR1 and a significant decrease in ankle-angle change at right-foot contact in braced trials compared with the nonbraced condition.

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Vertical Ground Reaction Force Redistribution During Experimentally Induced Shoulder Lameness in Dogs

Veterinary and Comparative Orthopaedics and Traumatology ◽

10.1055/s-0038-1633089 ◽

1994 ◽

Vol 07 (04) ◽

pp. 154-157 ◽

Cited By ~ 14

Author(s):

R. M. McLaughlin ◽

J. K. Roush ◽

Dominique Griffon

Keyword(s):

Ground Reaction Force ◽

Reaction Force ◽

Total Force ◽

Ground Reaction Forces ◽

Vertical Force ◽

Vertical Ground Reaction Force ◽

Reaction Forces ◽

Vertical Ground ◽

Vertical Ground Reaction Forces ◽

Surgically Induced

SummaryThe redistribution of vertical ground reaction forces after surgically induced forelimb lameness was evaluated in five Greyhounds at the walk. Vertical ground reaction forces were measured by force plate analysis before, three days, and seven days after a craniolateral approach to the shoulder was performed unilaterally in each dog.At day # 3, peak vertical force was significantly decreased in the operated forelimbs and in the ipsilateral hindlimbs. Peak vertical force was significantly increased in the contralateral fore- and hindlimbs. The total peak vertical force applied to both forelimbs did not change, nor did the total force applied to both hindlimbs. At day # 7, peak vertical force in each of the four limbs had returned to preoperative levels. Results of this study document the redistribution of ground reaction forces (at the walk) between the four limbs in the dog after an acute, surgically induced forelimb lameness.The redistribution of ground reaction force was evaluated in five Greyhounds before and during forelimb lameness. Lameness was induced by a craniolateral approach to one shoulder in each dog. At day # 3 after surgery, peak vertical force was decreased in the operated forelimbs and ipsilateral hindlimbs. Peak vertical force was increased in the contralateral fore- and hindlimbs. The distribution of ground reaction force in the four limbs returned to preoperative values seven days after surgery.

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Running ground reaction forces across footwear conditions are predicted from the motion of two body mass components

Journal of Applied Physiology ◽

10.1152/japplphysiol.00925.2018 ◽

2019 ◽

Vol 126 (5) ◽

pp. 1315-1325 ◽

Cited By ~ 3

Author(s):

Andrew B. Udofa ◽

Kenneth P. Clark ◽

Laurence J. Ryan ◽

Peter G. Weyand

Keyword(s):

Ground Reaction Force ◽

Lower Limb ◽

Reaction Force ◽

Ground Reaction Forces ◽

Vertical Ground Reaction Force ◽

Time Patterns ◽

Foot Strike ◽

Reaction Forces ◽

Vertical Ground ◽

Force Time

Although running shoes alter foot-ground reaction forces, particularly during impact, how they do so is incompletely understood. Here, we hypothesized that footwear effects on running ground reaction force-time patterns can be accurately predicted from the motion of two components of the body’s mass (mb): the contacting lower-limb (m1 = 0.08mb) and the remainder (m2 = 0.92mb). Simultaneous motion and vertical ground reaction force-time data were acquired at 1,000 Hz from eight uninstructed subjects running on a force-instrumented treadmill at 4.0 and 7.0 m/s under four footwear conditions: barefoot, minimal sole, thin sole, and thick sole. Vertical ground reaction force-time patterns were generated from the two-mass model using body mass and footfall-specific measures of contact time, aerial time, and lower-limb impact deceleration. Model force-time patterns generated using the empirical inputs acquired for each footfall matched the measured patterns closely across the four footwear conditions at both protocol speeds ( r2 = 0.96 ± 0.004; root mean squared error = 0.17 ± 0.01 body-weight units; n = 275 total footfalls). Foot landing angles (θF) were inversely related to footwear thickness; more positive or plantar-flexed landing angles coincided with longer-impact durations and force-time patterns lacking distinct rising-edge force peaks. Our results support three conclusions: 1) running ground reaction force-time patterns across footwear conditions can be accurately predicted using our two-mass, two-impulse model, 2) impact forces, regardless of foot strike mechanics, can be accurately quantified from lower-limb motion and a fixed anatomical mass (0.08mb), and 3) runners maintain similar loading rates (ΔFvertical/Δtime) across footwear conditions by altering foot strike angle to regulate the duration of impact. NEW & NOTEWORTHY Here, we validate a two-mass, two-impulse model of running vertical ground reaction forces across four footwear thickness conditions (barefoot, minimal, thin, thick). Our model allows the impact portion of the impulse to be extracted from measured total ground reaction force-time patterns using motion data from the ankle. The gait adjustments observed across footwear conditions revealed that runners maintained similar loading rates across footwear conditions by altering foot strike angles to regulate the duration of impact.

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The Relationship Between Vertical Ground Reaction Force, Loading Rate, and Sound Characteristics During a Single-Leg Landing

Journal of Sport Rehabilitation ◽

10.1123/jsr.2018-0260 ◽

2020 ◽

Vol 29 (5) ◽

pp. 541-546

Author(s):

Caroline Lisee ◽

Tom Birchmeier ◽

Arthur Yan ◽

Brent Geers ◽

Kaitlin O’Hagan ◽

...

Keyword(s):

Ground Reaction Force ◽

Loading Rate ◽

Reaction Force ◽

Measurement Techniques ◽

Sound Frequency ◽

Clinical Population ◽

Vertical Ground Reaction Force ◽

Vertical Ground ◽

The Relationship ◽

Linear Loading

Context: Landing kinetic outcomes are associated with injury risk and may be persistently altered after anterior cruciate ligament injury or reconstruction. However, it is challenging to assess kinetics clinically. The relationship between sound characteristics and kinetics during a limited number of functional tasks has been supported as a potential clinical alternative. Objective: To assess the relationship between kinetics and sound characteristics during a single-leg landing task. Design: Observational Setting: Laboratory. Participants: There was total of 26 healthy participants (15 males/11 females, age = 24.8 [3.6] y, height = 176.0 [9.1] cm, mass = 74.9 [14.4] kg, Tegner Activity Scale = 6.1 [1.1]). Intervention: Participants completed single-leg landings onto a force plate while audio characteristics were recorded. Main Outcome Measures: Peak vertical ground reaction force, linear loading rate, instantaneous loading rate, peak sound magnitude, sound frequency were measured. Means and SDs were calculated for each participant’s individual limbs. Spearman rho correlations were used to assess the relationships between audio characteristics and kinetic outcomes. Results: Peak sound magnitude was positively correlated with normalized peak vertical ground reaction force (ρ = .486, P = .001); linear loading rate (ρ = .491, P = .001); and instantaneous loading rate (ρ = .298, P = .03). Sound frequency was negatively correlated with instantaneous loading rate (ρ = −.444, P = .001). Conclusions: Peak sound magnitude may be more helpful in providing feedback about an individual’s normalized vertical ground reaction force and linear loading rate, and sound frequency may be more helpful in providing feedback about instantaneous loading rate. Further refinement in sound measurement techniques may be required before these findings can be applied in a clinical population.

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A 6-Week Transition to Maximal Running Shoes Does Not Change Running Biomechanics

The American Journal of Sports Medicine ◽

10.1177/0363546519826086 ◽

2019 ◽

Vol 47 (4) ◽

pp. 968-973 ◽

Cited By ~ 4

Author(s):

J.J. Hannigan ◽

Christine D. Pollard

Keyword(s):

Ground Reaction Force ◽

Loading Rate ◽

Impact Force ◽

Reaction Force ◽

Vertical Ground Reaction Force ◽

Risk Of Injury ◽

Impact Peak ◽

Running Shoes ◽

Vertical Ground ◽

The Impact

Background: A recent study suggested that maximal running shoes may increase the impact force and loading rate of the vertical ground-reaction force during running. It is currently unknown whether runners will adapt to decrease the impact force and loading rate over time. Purpose: To compare the vertical ground-reaction force and ankle kinematics between maximal and traditional shoes before and after a 6-week acclimation period to the maximal shoe. Study Design: Controlled laboratory study. Methods: Participants ran in a traditional running shoe and a maximal running shoe during 2 testing sessions 6 weeks apart. During each session, 3-dimensional kinematics and kinetics were collected during overground running. Variables of interest included the loading rate, impact peak, and active peak of the vertical ground-reaction force, as well as eversion and dorsiflexion kinematics. Two-way repeated measures analyses of variance compared data within participants. Results: No significant differences were observed in any biomechanical variable between time points. The loading rate and impact peak were higher in the maximal shoe. Runners were still everted at toe-off and landed with less dorsiflexion, on average, in the maximal shoe. Conclusion: Greater loading rates and impact forces were previously found in maximal running shoes, which may indicate an increased risk of injury. The eversion mechanics observed in the maximal shoes may also increase the risk of injury. A 6-week transition to maximal shoes did not significantly change any of these measures. Clinical Relevance: Maximal running shoes are becoming very popular and may be considered a treatment option for some injuries. The biomechanical results of this study do not support the use of maximal running shoes. However, the effect of these shoes on pain and injury rates is unknown.

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Factors Affecting Peak Vertical Ground Reaction Forces in Running

International Journal of Sport Biomechanics ◽

10.1123/ijsb.2.1.41 ◽

1986 ◽

Vol 2 (1) ◽

pp. 41-49 ◽

Cited By ~ 49

Author(s):

Edward C. Frederick ◽

John L. Hagy

Keyword(s):

Body Mass ◽

Stride Length ◽

Reaction Force ◽

Step Length ◽

Leg Length ◽

Vertical Ground Reaction Force ◽

Anthropometric Parameters ◽

Factors Affecting ◽

Reaction Forces ◽

Vertical Ground

Nine subjects (6 males, 3 females) ranging in body mass from 90.9 to 45.5 kg ran repeated trials across a force platform while being filmed at 50 fps. The subjects ran five barefooted trials at each of three speeds: 3.35, 3.83, and 4.47 m · s−1. Force data were collected on-line and analyzed for the magnitude and temporal characteristics of the initial impact (Fz1) peak and the active (Fz2) peak of vertical ground reaction force (VGRF). Multiple regression and correlation analysis were used to study the relationship between the magnitudes of these kinetic data and kinematic and anthropometric data taken from the film and from measurements of the subjects. The results support the general conclusion that speed and, indirectly, body mass are significant effectors of the magnitudes of Fz1. In addition, other factors that correlate significantly with Fz1 are reciprocal ponderal index (RPI) and stature; half-stride length, step length, leg length, and vertical hip excursion during a half-stride cycle; and hip offset, contact angle, and dorsiflexion angle at contact. Body mass correlates highly with Fz2 (r = 0.95). Other significant factors correlating with Fz2 are RPI, stature, vertical hip excursion, dorsiflexion angle, hip offset, half-stride length, and step length. These data support earlier findings that speed and the effective mass of the leg at contact are important effectors of the magnitude of Fzl. In addition, the kinematic and anthropometric parameters that contribute significantly to the variability in Fzl and F are generally cross-correlated with body size and/or running speed.

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