Comparison Of Ground Reaction Forces Research Articles

Comparison of ground reaction forces as running speed increases between male and female runners

Comparison of ground reaction forces as running speed increases between male and female runners

Comparison of ground reaction force among stride types in baseball pitching.

This study aims to investigate the different ground reaction force (GRF) characteristics from different stride types. This study included 30 Taiwanese elite college and professional baseball pitchers. Each pitcher was classified into one of the following stride types: tall and fall (TF), dip and drive (DD), or mixed (MX). Our findings indicated that DD pitchers pressed their bodies forward earlier than TF pitchers. In contrast, the GRF of the pivot leg of TF pitchers increased slowly in the first half of the stride phase and continued to increase even after the stride leg touched the ground. This type of continuous pressing in TF was different from that in DD and MX pitchers, which decreased rapidly into the arm-cocking & acceleration phases. We conclude that the lower extremities were used differently by TF, DD and MX pitchers. This information could serve as a training guideline for coaches and pitchers to enhance training effectiveness, while simultaneously lowering injury risks.

Comparison of ground reaction force and contact time during various-direction lunges between badminton shoes without and with a lateral forefoot wedge sole

This study compared the ground reaction force (GRF), GRF ratio, and contact time between badminton shoes without and with a lateral forefoot wedge sole during lunges in three directions. Fifteen collegiate athletes wore forefoot wedge shoes (5° incline) and control shoes without a lateral forefoot wedge sole (in random order) and performed three typical badminton lunge movements (forward, lateral, and backward directions). A total of nine GRF, GRF ratio, and contact time parameters were analyzed. A paired t test was performed to assess the differences between two shoes. The significance level was set at p < 0.0056 (0.05/9) based on Bonferroni correction to avoid chances of type 1 errors. In the forward lunge, the forefoot wedge shoes resulted in a significantly higher average vertical ground reaction force (GRFv, 3.9%), average horizontal GRF (GRFh, 7.8%) in the braking phase and higher average GRFh (3.9%) in the propulsion phase than the control shoes. In the lateral lunge, the forefoot wedge shoes resulted in a significantly shorter total contact time (−4.6%) than the control shoes in the backward lunge, the forefoot wedge shoes resulted in a significantly higher GRFh to GRFv ratio (6.4%) in the braking phase compared with the control shoes. Thus, shoes with a lateral forefoot wedge sole can effectively enhance mechanical performance in direction changes during forward and backward badminton lunges, and shorter the contact time during lateral badminton lunges. Shoes with a lateral forefoot wedge sole can be considered when designing athletic footwear.

Comparison of ground reaction force and marker-based methods to estimate mediolateral center of mass displacement and margins of stability during walking

Dynamic balance control during human walking can be described by the distance between the mediolateral (ML) extrapolated center of mass (XCoM) position and the base of support, the margin of stability (MoS). The ML center of mass (CoM) position during treadmill walking can be estimated based on kinematic data (marker-based method) and a combination of ground reaction forces and center of pressure positions (GRF-based method). Here, we compare a GRF-based method with a full-body marker-based method for estimating the ML CoM, ML XCoM and ML MoS. Fifteen healthy adults walked on a dual-belt treadmill at comfortable walking speed for three minutes. Kinetic and kinematic data were collected and analyzed using a GRF-based and marker-based method to compare the ML CoM, ML XCoM and ML MoS. High correlation coefficients (r > 0.98) and small differences (Root Mean Square Difference < 0.0072 m) in ML CoM and ML XCoM were found between the GRF-based and marker-based methods. The GRF-based method resulted in larger ML XCoM excursion (0.0118 ± 0.0074 m) and smaller ML MoS values (0.0062 ± 0.0028 m) than the marker-based method, but these differences were consistent across participants. In conclusion, the GRF-based method is a valid method to determine the ML CoM, XCoM and MoS. One should be aware of higher ML XCoM and smaller ML MoS values in the GRF-based method when comparing absolute values between studies. The GRF-based method strongly reduces measurement times and can be used to provide real-time CoM-CoP feedback during treadmill gait training.

Comparison of ground reaction forces and joint kinematics between three different tempos during push-up exercise

Abstract Study aim This study was aimed to analysis in detail how different tempos [2:0:2 (30 bpm), 1:0:1 (60 bpm), Explosive (EXP)] effect to ground reaction forces (vGRF) and joint kinematics of push-up exercise (PUP). Material and methods Twenty-four recreationally male athletes (age: 24.9 ± 3.6 years) participated in this study. Kinetic and kinematic data were obtained by load-cells and a motion analysis software. Data was analysed from a single repetition which is showed peak vGRF of dominant side during PUP. Joint velocities were calculated by taking the difference between the descent and ascent phases. Results There was significant difference between 2:0:2 (30 bpm) – EXP in terms of dominant side of shoulder (p ≤ 0.02) and between 1:0:1 (60 bpm) – EXP in the dominant elbow joint displacements (p ≤ 0.05). The velocity differences between the descent and ascent phases of shoulder and elbow joints were found statistically significant between tempos (p ≤ 0.05). In terms of range of motion (ROM) of right and left side, there was significant differences between tempos (p ≤ 0.001). No significant differences were found between all tempos in the ascent phase of right-left and left descent phase in terms of average vGRF (p &gt; 0.05) except right descent average vGRF (p ≤ 0.02). Conclusions In conclusion, right-left sides of ROM was used most effectively in 2:0:2 (30 bpm) and 1:0:1 (60 bpm) tempos. Less displacement was also observed in EXP and when tempo increased percentage of peak vGRF (at elbow flexion phase for right-left sides) to total repetition decreased. Highest ascent and descent phase velocity differences (for right-left sides) and highest peak vGRF (elbow flexion phase) observed in EXP. This study shows that increasing tempo will result in more unsteady joint kinematics and more vGRF, so if the goal is controlled and safe PUP, tempo should be slow.

Comparison of Ground Reaction Forces between Combat Boots and Sports Shoes

It is unclear whether military shoes (combat boots and sports shoes) attenuate loading rate or affect force transfer during walking. Therefore, this study compared ground reaction forces (GRF) related to impact and force transfer between combat boots, military sports shoes, and running shoes. Ten army recruits walked over a walkway with two force plates embedded. GRF were measured when walking barefoot (for data normalisation) and with combat boots, military sports shoes, and running shoes. Loading rate, first and second peak forces, and push-off rate of force were computed along with temporal analysis of waveforms. Reduced loading rate was observed for the running shoe compared to the combat boot (p = 0.02; d = 0.98) and to the military sports shoe (p = 0.04; d = 0.92). The running shoe elicited a smaller second peak force than the combat boot (p &lt; 0.01; d = 0.83). Walking with military shoes and combat boots led to larger force transfer than running shoes, potentially due to harder material used in midsole composition (i.e., styrene-butadiene rubber). Combat boots did not optimise load transmission and may lead, in a long-term perspective, to greater injury risk.

Outcome after Modified Maquet Procedure in dogs with unilateral cranial cruciate ligament rupture: Evaluation of recovery limb function by use of force plate gait analysis.

IntroductionCranial cruciate ligament failure is one of the principal causes of canine lameness. Several surgical procedures were proposed to achieve joint stabilisation; among these, the Modified Maquet Procedure involves using a titanium foam wedge to achieve and maintain the tibial tuberosity advancement. The force-plate analysis provides to objectively assess normal and abnormal gait and the outcome of different surgical techniques. The study evaluates the outcome of limbs that underwent Modified Maquet Procedure using land-force plate analysis comparing the operated limb with its healthy contralateral one as a control.Materials and methodsThirty-five dogs with unilateral cranial cruciate ligament rupture were evaluated. Outcome after surgery was assessed by orthopaedic and radiographic evaluations and force plate gait analysis performed before surgery, at 15, 30 and 90 days after surgery. For objective comparison of ground reaction forces, data of operated limb were compared to contralateral limb on each time control and Symmetry Index at 90 days was determined. Healing radiographic signs, minor and major complication were reported.ResultsA significant improvement in ground reaction forces was reached in all the treated limbs between set time intervals. The median percentage increase in ground reaction forces was constant from 15 to 90 days, with a Symmetry Index >9 in 54.2% of patients suggesting a normal gait symmetry. A complete bone healing was noticed at 90 days follow-up radiographic assessment. We experienced three major (8.5%) and one minor (2.8%) complications.ConclusionsTo the Authors’ knowledge, this is the first study in the veterinary literature that assessed outcomes of dogs undergoing Modified Maquet Procedure for the treatment of cranial cruciate ligament rupture using force plate gait analysis and healthy contralateral limb as a control group. Our results confirm that Modified Maquet Procedure is an effective method to stabilise the stifle joint.

A waveform test for variance inequality, with a comparison of ground reaction force during walking in younger vs. older adults

Various methods have been suggested for estimating the variability in biomechanical variables during gait. However, all current measures of variability are performed on discrete measurements extracted from the kinematic or kinetic waveforms, which provide no temporal information on where differences in variability occur. This study used a variance equality test to compare temporal differences in group variance along the entire ground reaction force waveform. The variance equality test used an F-statistic whose critical value was determined using the random field theory function within the one-dimensional statistical parametric mapping package. Twenty healthy younger and twenty older adults were included in the study and completed gait analysis as they walked along a level walkway at a self-selected pace. Variance for each group was calculated and compared at each interval along the waveform to produce the F-value. The F-value was compared against a calculated F-critical value to determine where in the waveform significant differences in ground reaction force variance occurred. Results suggest that younger individuals may exhibit greater ground reaction force variance during heel contact in the vertical and posterior directions, and that older individuals may exhibit greater variability in the mediolateral direction at toe-off. This study was able to identify differences in ground reaction force variance within the gait cycle between younger and older adults. The findings of this study warrant the use of the function as a suitable method to compare variance along the entire waveform between two groups.

Comparison of ground reaction force during gait between the nonparetic side in hemiparetic patients and the dominant side in healthy subjects.

Considering the occurrence of gait impairment following stroke, walk-ing recovery is an important goal of rehabilitation. Ground reaction force (GRF) is used for gait assessment of rehabilitation progress during exercise in stroke patients. The aim of this study was to compare the GRF during gait of the nonparetic side in hemiparetic patients and the dominant side in healthy subjects. Twenty hemiparetic patients and 20 healthy subjects were enrolled in the study. Force plate was used to evaluate GRF during gait. Additionally, with the patients and subjects in supine position, we measured their range of motion (ROM) in ankle dor-siflexion using a digital goniometer. The force values of stance phase on the nonparetic side of hemiparetic patients were significantly less than on the dominant side of healthy subjects (P<0.05). The impulse values of stance phase on the paretic side and the nonparetic side of hemiparetic patients were significantly greater than on the dominant side of healthy subjects (P<0.05). The ankle ROM result was signifi-cantly correlated with the GRF values (P<0.05). It is important to assess and understand the nonparetic side as well as paretic side. These re-sults suggest that the analysis of GRF for exercise rehabilitation will be a valuable clinical evaluation in hemiparetic patients after a stroke.

Comparison Of Ground Reaction Forces Derived From Force Plate And Motion Capture Systems During Vertical Jumps

PURPOSES: This investigation compared the ground reaction forces (GRFs) between a force plate and GRF derived from a markerless motion capture system (MCS) during a counter-movement vertical jump (CMVJ). METHODS: Healthy, recreationally active men (n=10; ±SD; age=22.5±2.1 yrs, height=180.8±4.6 cm, weight=80.8±7.5 kg) and women (n=8; age=20.5±0.8 yrs, height=171.7±5.7 cm, weight=68.1±7.2 kg) volunteered to preform 3 CMVJs separated by 30 seconds of rest. A 3-D markerless motion capture system (MCS; DARI Motion, Scientific Analytics, Lincoln, NE) was sampled at 50 Hz, while a uni-axial force plate (Rice Lake Weighing Systems, Rice Lake, WI) and a data acquisition system (Biopac, Goleta, CA) sampling at 1000 Hz was used and resampled to 50 Hz for analysis. Participants begin the CMVJ standing on the force plate while in the MCS capture area. Ground reaction peak force (PF) was determined as the max force before takeoff, and ground reaction mean force (MF) was determined across the entire CMVJ from start of the motion to takeoff. Linear regressions were performed to compare MF and PF between the two devices (i.e. MCS vs. force plate) with the Pearson correlation (r), coefficient of determination (r2), and standard error of the measurement (SEM) calculated. Paired samples t-tests (MCS vs. force plate; p≤0.05) were performed on the MF and PF. RESULTS: Mean ± SD and results are shown in table 1. Paired samples t-tests indicated significant differences (<0.01) for MF and PF. Linear regression analysis indicated excellent agreement between MCS and force plate for MF (r=0.97, r2=0.93, SEM=13.99N) and PF (r=0.92. r2=0.84, SEM=35.72 N), respectively. CONCLUSION: Although significant differences were indicated, the linear regression analysis indicated that GRF can be accurately derived from a MCS without the use of a force plate. Furthermore, the intricate kinetic characteristics of human motion can be validly determined without being restricted to performing on a force plate.

The comparison of ground reaction forces and lower limb muscles correlation and activation time delay between forward and backward walking

This study aimed to compare the ground reaction forces (GRF) and lower limb muscles correlation and activation time delay between Forward (FW) and Backward (BW) walking. Twenty-four male students participated in this research. Electromyogram activities of gluteus medius, biceps femoris, medial gastrocnemius, soleus and anterior tibialis muscles along with GRFs were measured. Each participant performed two FW and two BW trials bare foot. Statistical parametric mapping (SPM) analysis was performed over anterior-posterior and vertical GRFs time series. The paired t-test was used in SPM analysis. Cross-correlation analysis compared similarity in shape and time delay of EMG pattern. SPM analysis of GRFs showed that these two walking modes have asymmetrical kinetic behavior during most parts of stance phase. Based on cross-correlation analysis, the shape of EMG activation profiles differed, where a phase shift in the muscle activation pattern of approximately 60% occurred. This shift may indicate different control mechanisms, at the spinal level, underpin FW and BW walking modalities.

A comparison of ground reaction forces during level and cross-slope walking in Labrador Retrievers.

BackgroundInclined or slippery surfaces and various other types of obstacles are common demands in our environment. Dogs with impaired locomotion might have difficulties to manage rough terrain. Gait analyses using force plates or pressure plates, which are well established to characterize limb loads in human medicine as well as in animals, are mostly limited to level surfaces. Therefore, the aim of this study was to investigate the effect of cross-slope walking in ten healthy Labrador Retrievers using a pressure plate walkway system. The dogs walked over the pressure plate on a level surface, with a lateral elevation angle of 10° (CS1) or 15° (CS2) until five valid trials were achieved. Three measurements were obtained at weekly intervals. Peak vertical force (PFz), vertical impulse (IFz), step length, and velocity were determined.ResultsCompared to level walking (LW), cross-slope walking was associated with a significant decrease in GRF of the up-slope (US) hindlimb, which was compensated for by the down-slope (DS) forelimb. The other diagonal limb pair showed less pronounced effects during CS1, but in CS2 more weight was shifted onto the DS hindlimb during the first two measurements, thus reducing weight on the US forelimb (for IFz). The effect diminished from trial to trial, with GRF values approaching LW standards finally. The IFz was a more sensitive measure than the PFz. The step length of the DS forelimb was significantly decreased in both cross-slope conditions, while the step length of the US forelimb only decreased during CS2.ConclusionsThe dogs adapted their gait pattern and step length to compensate for the discrepancy in apparent leg length caused by the cross-slope. The results suggest that cross-slope walking requires functional musculoskeletal adaptations that may be difficult for animals with impaired locomotion. Further, this knowledge might be of clinical impact for early diagnosis of neurological disorders, mild lameness and proprioceptive deficits.

Comparison of ground reaction force during different angle of squatting

Dali, S., Justine, M., Ahmad, H. & Othman, Z. (2013). Comparison of ground reaction force during different angle of squatting. J. Hum. Sport Exerc., 8(3), pp.778-787. Squatting is a form of closed kinetic chain movement which commonly being employed in exercise training. However, little is known regarding the amount of force being imposed on the knee at different angles of squat. Thus, the purpose of this study was to compare the vertical ground reaction force (VGRF) at different angles of squatting among the military personnel. Thirty-seven subjects (age=27.1±2.77 years old) participated in this cross-sectional comparative study. The peak of VGRF was identified during squatting at 40o, 70o, and 110 o of knee flexion, which was measured using a force platform. The data were analysed using the one way repeated measure ANOVA and Pairwise Comparisons via Bonferroni adjustment. The VGRF were shown significantly different between the three angles of squatting (p 0 .05), the result was corrected using Greenhouse-Geiser Epsilon and continued to show a significant different [F (1.36, 49.08)=43.56] (p<0.05). The effect size was large (ηρ²=0.55). This study suggests that the angle of knee flexion during squatting exercise may influence VGRF. Deep squatting was found to generate the highest VGRF compared to semi and half squatting. Thus, it is suggested that squatting may be best performed at smaller angle in order to avoid excessive force that may be detrimental

Comparison of Ground Reaction Forces and Contact Times Between 2 Lateral Plyometric Exercises in Professional Soccer Players

There are no studies which have examined the differences in kinetics between lateral plyometric exercises and the selection of these exercises is largely based on the experience and observation of coaches. This study aimed to compare ground reaction forces (GRF) and contact times (GCT) between 2 lateral plyometric exercises: lateral alternative leg hopping (HOP), and speed lateral footwork (SPEED). 16 professional male soccer players (age: 24.6±5.5 years; and BMI: 21.7±2.2 kg.m - 2) participated in this within-participant repeated measures study. 3-dimensional GRF data were measured by force platform. Our study revealed significant differences between the 2 lateral plyometric exercises in all kinetics parameters (F=573.7, P<0.01). HOP produced significantly longer GCT (0.45 s vs. 0.23 s, P<0.01, large effect), significantly higher values (P<0.05, large effect) in peak force (3.31 vs. 2.47 Body Weight [BW]), peak rate of force development (0.94 vs. 0.29 BW/s), and impulse (0.76 vs. 0.31 BW.s) except for peak force in the medial-lateral (P<0.05, medium effect) and impulse in the anterio-posterior direction (not significant, small effect). Therefore, SPEED is an exercise that aims to increase step frequency because of its short GCT (< 0.25 s) while HOP increases leg strength and power.

Comparison of Ground Reaction Forces Between Four Plyometric Pushup Variations

Plyometric exercises utilize the stretch-shortening muscle cycle to produce large amounts of force in short durations. Unlike the lower extremity plyometrics, data concerning the loads and intensity associated with upper extremity plyometrics is limited. PURPOSE: To compare ground reaction forces (GRF) between the clap pushup (CPU) and drop box pushups (DPU) from 3.8cm (1.5 in), 7.6cm (3 in), and 10.2cm (4.5 in) heights. METHODS: Fifteen healthy active male subjects (18-35 years) performed four repetitions of each plyometric pushup variation in a counterbalanced order. Pushups were completed with each upper extremity positioned over a separate forceplate. Four dependent variables, peak force (PF), time to peak force (TPF), loading rate (LR) and propulsion rate (PR), were calculated for each extremity from the computed vertical GRF. Statistical analysis consisted of separate limb by variation repeated measures analysis of variance. In addition, repetition time (RT), defined as the length of time the dominant limb was in contact with the forceplate, was statistically compared between variations. RESULTS: No significant differences were revealed for RT (P=.080, h2p=.193) or PF (P=.752, h2p=.030). The dominant limb demonstrated a significantly earlier TPF (P=.003, h2p=.502). Post hoc analysis of a significant limb by variation interaction (P=.003, h2p=.300) revealed the dominant CPU and 10.2cm DPU LR to be significantly greater than the nondominant. Further, for both limbs, the CPU LR was significantly greater than the DPU at the two lowest heights. The CPU PR was significantly greater than the three DPU (P<.001, h2p=.422). CONCLUSION: These data provide documentation and add rationale for determining upper extremity plyometric progression. The PF associated with CPU and DPU are similar and altering DPU height did not affect PF. In contrast, the CPU demonstrated the highest LR and PR suggesting that it may be a more powerful exercise than DPU. The longer TPF and higher LR (CPU and 10.2cm DPU) for the dominant extremity illustrate bilateral disparity in rate of eccentric loading. Further research on these exercises is needed to better clarify the demands imposed on the upper extremity during the eccentric and concentric phases when performing plyometric exercise.

Comparison of ground reaction forces and antagonist muscle coactivation during stair walking with ageing

Stair walking is a demanding task in old age. Ground reaction force (GRF) analysis, relative EMG activation, and muscular coactivation were performed during stair walking. The aim was to investigate the ageing effect on GRF distribution and muscle antagonist coactivation during stair walking, at varied speed. During ascending at maximal velocity old subjects demonstrated reduced GRF in all examined phases (range: 28–35%), whereas muscle coactivation only was elevated for the Entire stance phase (18.5%). GRF parameters during ascent and descent at freely chosen speed demonstrated differences between age groups (5–28%). Furthermore, muscle coactivation was elevated in old subjects (e.g. Entire stance phase (17–19%)) along with greater EMG activation in all muscles (16–65%). At standardized gait velocity only minor differences in GRF were observed between age groups. However, elderly subjects showed elevated muscular coactivation (e.g. loading phase and entire stance phase (18–22%)) along with greater EMG activation (35–66%). Conclusions: Differences between age groups in neuromotor and kinetic stair walking strategy do not depend upon the age-related decline in velocity alone, but rather reflect a uniform alteration. This needs to be considered during rehabilitation and/or clinical settings at old age.

Changes in ground reaction force during jump landing in subjects with functional instability of the ankle joint

Objective. To identify changes in ground reaction force during jump landing in subjects with functional instability of the ankle joint. Design. Comparison of ground reaction force during jump landing between subjects with functional instability and healthy controls. Background. We have recently demonstrated significantly altered patterns of ankle and knee movement immediately pre- and post-impact in subjects with functional instability compared to healthy controls. We now examine the changes in timing and magnitude of forces sustained by the unstable ankle during jump landing. Methods. Fourteen subjects with unstable ankles and 10 age, sex and activity matched controls performed five single leg jumps onto a force platform whilst ground reaction forces were sampled. Timing and magnitudes of forces during the first 150 ms following impact were analysed and compared between groups. Results. Lateral and anterior force peaks occurred significantly earlier in subjects with functional instability. Significant differences were seen between groups' time-averaged vertical, frontal and sagittal components of ground reaction force. These ranged from 5% (frontal force) to 100% (vertical force) of body mass. These changes occur immediately post-impact and too early for reflex correction/modification. Conclusions. The disordered force patterns observed in subjects with functional instability are likely to result in repeated injury due to significant increase in stress on ankle joint structures during jump landing. We suggest that they are most likely to result from deficits in feed-forward motor control. Relevance These results identify the potentially injurious nature of the changes in the forces applied to the unstable ankle joint during jump landing. The timing of these changes suggests that they are caused by a motor control deficit. Treatment approaches aimed at retraining feed-forward control of ankle joint movement could succeed in restoring more normal patterns of force absorption and reduce the occurrence of repeated micro-trauma to ankle structures.

Comparison of ground reaction forces between obese and control young adults during quiet standing on a baropodometric platform

Objective. To determine whether centre of pressure location, plantar surface areas, or plantar pressures differ between obese and control young adults during quiet standing. Design. Cross-sectional study in university setting. Background. Given the characteristic distribution of body fat in obesity, it is possible that obesity may systematically alter centre of pressure location, plantar ground contact areas and pressure distributions in males and females. Methods. Thirty-eight obese subjects (23 women and 15 men) and 34 healthy controls (18 women and 16 men) with a mean age of 23 years were studied. Subjects were asked to stand bipedally on a baropodometric platform while centre of pressure location, plantar ground contact surface areas and pressures were measured over a 5 s interval. Group differences were examined by analyses of variance and Fisher’s PLSD test. Results. No significant group differences were found in centre of pressure location by weight or gender. Obesity was associated in both sexes with significantly larger plantar contact areas (+12.2%, P<0.0001 for women and +9.9%, P<0.005 for men) and pressures (mean load: +52.6% for women and +44.7% for men, P<0.0001 in both of sexes; peak pressure: +45.5% for women and +40.5% for men, P<0.0001 in both of sexes). There were significant gender differences in plantar contact areas ( P<0.0001), while were no significant differences in mean and peak pressures. Conclusions. Although centre of pressure location was unaffected by obesity, these young obese individuals showed significantly increased plantar contact areas and pressures. Relevance The higher plantar pressures associated with obesity may have negative ramifications for foot function over the longer term.

Comparison of Ground Reaction Forces between Overground and Treadmill Walking

Comparison of Ground Reaction Forces between Overground and Treadmill Walking