scholarly journals Comparison of the biomechanical parameters during drop jump on compliant and noncompliant surfaces: A new methodological approach

2021 ◽  
Author(s):  
Fırat Özdalyan ◽  
Hikmet Gümüş ◽  
Celal Gençoğlu ◽  
Mert Tunar ◽  
Caner Çetinkaya ◽  
...  
Keyword(s):  
Knee Joint ◽  
Injury Risk ◽  
Force Sensing ◽  
Vertical Force ◽  
Drop Jump ◽  
Plyometric Training ◽  
Joint Angles ◽  
Loading Rates ◽  
Reaction Forces ◽  
Biomechanical Parameters

Objective: Bilateral plyometric training of the lower extremities has been shown to provide improvement in vertical force production. However, designing a proper plyometric training program and choosing the appropriate surface is critical, otherwise the risk of injury and lower extremity joint pathologies increases. The aim of this study was to compare biomechanical parameters between mini-trampoline and noncompliant surface during drop jumping. Materials and Methods: Thirty-four male adults participated in the study. Active markers were placed on the left knee, ankle and hip joints of the participants. Also, a force sensing resistor was placed under the participants’ left shoes. During drop jumping, the knee joint angles were recorded by the camera while a data set of reaction forces and loading rates were collected using a force sensing resistor. Data were compared with paired samples T-test. The level of significance was set at p ≤ 0.05. Results: The mean values of maximum reaction forces and loading rates were greater on the noncompliant surface (p < 0.001). Mean knee joint angles for frame at which the knee angle is minimum and the frames one before and one after the frame at which the minimum value is obtained were similar between surfaces, however, were found to be smaller on noncompliant surface for the remaining eight frames (p < 0.05). Conclusion: This study indicates that the range of bending values in the knee joint is greater on noncompliant surface compared to mini-trampoline during drop jump. Since the mini-trampoline resulted in lower reaction forces and loading rates, it can be used as an exercise equipment to minimize the injury risk of plyometric training.

scholarly journals Machine Learning-Based Estimation of Ground Reaction Forces and Knee Joint Kinetics from Inertial Sensors While Performing a Vertical Drop Jump

Sensors ◽  
2021 ◽  
Vol 21 (22) ◽  
pp. 7709
Author(s):  
Serena Cerfoglio ◽  
Manuela Galli ◽  
Marco Tarabini ◽  
Filippo Bertozzi ◽  
Chiarella Sforza ◽  
...  
Keyword(s):  
Neural Network ◽  
Machine Learning ◽  
Knee Joint ◽  
Field Analysis ◽  
Ground Reaction Forces ◽  
Drop Jump ◽  
Joint Moments ◽  
Data Set ◽  
Joint Kinetics ◽  
Reaction Forces

Nowadays, the use of wearable inertial-based systems together with machine learning methods opens new pathways to assess athletes’ performance. In this paper, we developed a neural network-based approach for the estimation of the Ground Reaction Forces (GRFs) and the three-dimensional knee joint moments during the first landing phase of the Vertical Drop Jump. Data were simultaneously recorded from three commercial inertial units and an optoelectronic system during the execution of 112 jumps performed by 11 healthy participants. Data were processed and sorted to obtain a time-matched dataset, and a non-linear autoregressive with external input neural network was implemented in Matlab. The network was trained through a train-test split technique, and performance was evaluated in terms of Root Mean Square Error (RMSE). The network was able to estimate the time course of GRFs and joint moments with a mean RMSE of 0.02 N/kg and 0.04 N·m/kg, respectively. Despite the comparatively restricted data set and slight boundary errors, the results supported the use of the developed method to estimate joint kinetics, opening a new perspective for the development of an in-field analysis method.

scholarly journals Effects of Plyometric Training on Soft and Hard Surfaces for Improving Running Economy

2021 ◽  
Vol 79 (1) ◽  
pp. 187-196
Author(s):  
Johan Lännerström ◽  
Lina C Nilsson ◽  
Daniele A Cardinale ◽  
Glenn Björklund ◽  
Filip J Larsen
Keyword(s):  
Time Trial ◽  
Running Economy ◽  
Drop Jump ◽  
Plyometric Training ◽  
Running Performance ◽  
Force Development ◽  
Jump Training ◽  
Jump Test ◽  
Soft Surface ◽  
Reaction Forces

Abstract The present study investigated the effects of plyometric jump training on hard and soft surfaces on running economy (RE), maximal oxygen uptake (VO2max), running performance and the rate of force development in orienteers. Nineteen orienteers (11 women and 8 men, body mass 61.1 ± 7.3 kg, age 21 ± 5.8 yrs) were randomly stratified based on sex, age, VO2max and RE to plyometric jumping training (8 sessions over 4 weeks) on either a hard or a soft surface. RE, VO2max and running performance were assessed on a treadmill and outdoor on- and off-trail loops. Moreover, ground reaction forces and force development were assessed during a one leg drop-jump test. The training intervention led to an overall 2-7% improvement in treadmill and off-trail RE, independent of the jumping surface and running velocity assessed. These improvements were not explained by force development during drop jump tests, which remained unchanged following the intervention. The changes in time-trial performance were associated with changes in RE. Plyometric training improved RE with no difference between the hard or the soft training surface and improved RE was also independent of the running speed assessed. Furthermore, improved running performance was associated with changes in RE after the intervention.

scholarly journals Utility of Kinetic and Kinematic Jumping and Landing Variables as Predictors of Injury Risk: A Systematic Review

2020 ◽  
Vol 2 (4) ◽  
pp. 287-304 ◽  
Author(s):  
Jason S. Pedley ◽  
Rhodri S. Lloyd ◽  
Paul J. Read ◽  
Isabel S. Moore ◽  
Mark De Ste Croix ◽  
...  
Keyword(s):  
Performance Measures ◽  
Injury Risk ◽  
Reaction Force ◽  
Separation Distance ◽  
Lower Extremity Injury ◽  
Ground Reaction Forces ◽  
Drop Jump ◽  
Jump Landing ◽  
Risk Of Injury ◽  
Reaction Forces

Abstract Purpose Jump-landing assessments provide a means to quantify an individual’s ability to attenuate ground reaction forces, generate lower limb explosive power and maintain joint alignment. In order to identify risk factors that can be targeted through appropriate training interventions, it is necessary to establish which (scalar) objective kinetic, kinematic, and performance measures are most associated with lower-extremity injury. Methods Online searches of MEDLINE, SCOPUS, EBSCOHost, SPORTDiscus and PubMed databases were completed for all articles published before March 2020 in accordance with PRISMA guidelines. Results 40 articles investigating nine jump-landing assessments were included in this review. The 79% of studies using drop jump (n = 14) observed an association with future injury, while only 8% of countermovement jump studies (n = 13) observed an association with injury risk. The 57% of studies using unilateral assessments found associations with risk of injury (n = 14). Studies using performance measures (jump height/distance) as outcome measure were only associated with injury risk in 30% of cases. However, those using kinetic and/or kinematic analyses (knee abduction moment, knee valgus angle, knee separation distance, peak ground reaction force) found associations with injury in 89% of studies. Conclusion The landing element of jump-landing assessments appears to be superior for identifying individuals at greater risk of injury; likely due to a closer representation of the injury mechanism. Consequently, jump-landing assessments that involve attenuation of impact forces such as the drop jump appear most suited for this purpose but should involve assessment of frontal plane knee motion and ground reaction forces.

scholarly journals Effect of drop jump technique on the reactive strength index

2016 ◽  
Vol 52 (1) ◽  
pp. 157-164 ◽  
Author(s):  
Artur Struzik ◽  
Grzegorz Juras ◽  
Bogdan Pietraszewski ◽  
Andrzej Rokita
Keyword(s):  
Force Plate ◽  
Jump Height ◽  
Drop Jump ◽  
Plyometric Training ◽  
Strength Index ◽  
Basketball Players ◽  
Male Youth ◽  
Kinematic Data ◽  
Drop Jumps ◽  
Reaction Forces

AbstractThe basic drill of plyometric training aimed at improving lower limb power and jump height is a drop jump. This exercise can be performed using different techniques, which substantially affects jump variables. Therefore, the aim of this study was to compare the values of the reactive strength index (RSI) for countermovement drop jumps (CDJs) and bounce drop jumps (BDJs). The study was carried out in a group of 8 male youth basketball players. The tests were conducted using the AMTI BP600900 force plate to measure ground reaction forces and the Noraxon MyoMotion system to record kinematic data. Each player performed two CDJs and two BDJs from the height of 15, 30, 45 and 60 cm. The RSI was calculated as a ratio of jump height and contact time. Moreover, the RSI was determined for the amortization and take-off phases separately. Significant differences (p < 0.05) between RSI values for CDJs and BDJs were recorded for jumps from 30, 45 and 60 cm. Differences in RSI values for jumps from 15 cm were not significant. Furthermore, CDJ height values were significantly higher (p < 0.05) than the values recorded for BDJs. Times of contact, amortization and take-off during BDJs were significantly shorter (p < 0.05) than the respective values obtained for CDJs. Therefore, the use of the RSI to monitor plyometric training should be based on the drop jump technique that is commonly performed by basketball players.

Examination of the Feasibility of a 2-Dimensional Portable Assessment of Knee Joint Stability: A Pilot Study

2020 ◽  
Vol 36 (6) ◽  
pp. 381-389
Author(s):  
Ryan Zerega ◽  
Carolyn Killelea ◽  
Justin Losciale ◽  
Mallory Faherty ◽  
Timothy Sell
Keyword(s):  
Knee Joint ◽  
Knee Flexion ◽  
Injury Risk ◽  
Cruciate Ligament ◽  
Acl Injury ◽  
Initial Contact ◽  
Ground Reaction Forces ◽  
Joint Stability ◽  
Reaction Forces ◽  
Acl Injury Risk

Rupture of the anterior cruciate ligament (ACL) remains extremely common, with over 250,000 injuries annually. Currently, clinical tests have poor utility to accurately screen for ACL injury risk in athletes. In this study, the position of a knee marker was tracked in 2-dimensional planes to predict biomechanical variables associated with ACL injury risk. Three-dimensional kinematics and ground reaction forces were collected during bilateral, single-leg stop-jump tasks for 44 healthy male military personnel. Knee marker position data were extracted to construct 2-dimensional 95% prediction ellipses in each anatomical plane. Knee marker variables included: ellipse areas, major/minor axes lengths, orientation of ellipse axes, absolute ranges of knee position, and medial knee collapse. These variables were then used as predictor variables in stepwise multiple linear regression analyses for 7 biomechanical variables associated with ACL injury risk. Knee flexion excursion, normalized peak vertical ground reaction forces, and knee flexion angle at initial contact were the response variables that generated the highest adjusted R2 values: .71, .37, and .31, respectively. The results of this study provide initial support for the hypothesis that tracking a single marker during 2-dimensional analysis can accurately reflect the information gathered from 3-dimensional motion analysis during a task assessing knee joint stability.

scholarly journals Different Drop Heights in Bilateral Asymmetry and Interjoint Coordination during Repetitive Drop-Jumps

Symmetry ◽  
2021 ◽  
Vol 13 (9) ◽  
pp. 1590
Author(s):  
Ke-Ke Zhang ◽  
Yi-Ming Chen ◽  
Yu-Ge Li ◽  
Shun Yao ◽  
Yu Su ◽  
...  
Keyword(s):  
Injury Risk ◽  
Lower Extremities ◽  
Repeated Measure ◽  
Drop Jump ◽  
Interjoint Coordination ◽  
Significant Difference ◽  
Drop Jumps ◽  
Reaction Forces ◽  
The Difference ◽  
Side Asymmetry

The difference of drop heights will affect the biomechanics of lower extremities during drop-jump (DJ) landing. Therefore, this study explored the effects of drop heights and training volumes on interjoint coordination and the side-to-side asymmetry of the lower extremities during landing. Twenty males were randomly assigned to perform 200 DJs (DJs200) from 30, 40 and 50 cm (drop-jump height (DJH) 30, DJH40 and DJH50) platform. One-way ANOVA repeated measure, using MATLAB software, was used to compare the differences of interjoint coordination, side-to-side asymmetry of ground contact time (GCT) and the maximum impact in vertical ground-reaction forces peak (I-vGRFpeak) in the 1st, 50th, 100th, 150th and 200th jumps (DJ1, DJs50, DJs100, DJs150 and DJs200). To examine whether significant differences exist, the least significant difference’s (LSD) method was used for post-hoc comparison. The mean absolute relative phase (MARP) and deviation phase (DP) of hip–knee were lower than DJH50 at DJH30 and DJH40, while side-to-side asymmetry of GCT and I-vGRFpeak were greater than DJH30 and DJH40 at DJH50 within DJs200 (all p <0.05). However, there was no significant difference in MARP and DP of hip–ankle and knee–ankle. Therefore, training at DJH30 may effectively improve jumping performance and reduce musculoskeletal injury risk.

Ground reaction force and hoof deceleration patterns on two different surfaces at the trot

2006 ◽  
Vol 3 (4) ◽  
pp. 209-216 ◽  
Author(s):  
Pia Gustås ◽  
Christopher Johnston ◽  
Stig Drevemo
Keyword(s):  
Ground Reaction Force ◽  
Reaction Force ◽  
Force Plate ◽  
Ground Surface ◽  
Ground Reaction Forces ◽  
Triaxial Accelerometer ◽  
Loading Rates ◽  
Sand Surface ◽  
Reaction Forces ◽  
Force Data

AbstractThe objective of the present study was to compare the hoof deceleration and ground reaction forces following impact on two different surfaces. Seven unshod Standardbreds were trotted by hand at 3.0–5.7 m s− 1 over a force plate covered by either of the two surfaces, sandpaper or a 1 cm layer of sand. Impact deceleration data were recorded from one triaxial accelerometer mounted on the fore- and hind hooves, respectively. Ground reaction force data were obtained synchronously from a force plate, sampled at 4.8 kHz. The differences between the two surfaces were studied by analysing representative deceleration and force variables for individual horses. The maximum horizontal peak deceleration and the loading rates of the vertical and the horizontal forces were significantly higher on sandpaper compared with the sand surface (P < 0.001). In addition, the initial vertical deceleration was significantly higher on sandpaper in the forelimb (P < 0.001). In conclusion, it was shown that the different qualities of the ground surface result in differences in the hoof-braking pattern, which may be of great importance for the strength of the distal horse limb also at slow speeds.

scholarly journals Metabolic cost of generating horizontal forces during human running

1999 ◽  
Vol 86 (5) ◽  
pp. 1657-1662 ◽  
Author(s):  
Young-Hui Chang ◽  
Rodger Kram
Keyword(s):  
Body Weight ◽  
Oxygen Consumption ◽  
Metabolic Cost ◽  
Ground Reaction Forces ◽  
Vertical Force ◽  
Order Of Magnitude ◽  
Reaction Forces ◽  
The Cost ◽  
Support Body Weight ◽  
Human Running

Previous studies have suggested that generating vertical force on the ground to support body weight (BWt) is the major determinant of the metabolic cost of running. Because horizontal forces exerted on the ground are often an order of magnitude smaller than vertical forces, some have reasoned that they have negligible cost. Using applied horizontal forces (AHF; negative is impeding, positive is aiding) equal to −6, −3, 0, +3, +6, +9, +12, and +15% of BWt, we estimated the cost of generating horizontal forces while subjects were running at 3.3 m/s. We measured rates of oxygen consumption (V˙o 2) for eight subjects. We then used a force-measuring treadmill to measure ground reaction forces from another eight subjects. With an AHF of −6% BWt,V˙o 2 increased 30% compared with normal running, presumably because of the extra work involved. With an AHF of +15% BWt, the subjects exerted ∼70% less propulsive impulse and exhibited a 33% reduction inV˙o 2. Our data suggest that generating horizontal propulsive forces constitutes more than one-third of the total metabolic cost of normal running.

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