scholarly journals Reliability of Sprint Force-Velocity-Power Profiles Obtained with KiSprint System

2021 ◽  
pp. 357-364
Author(s):  
Nejc Šarabon ◽  
Žiga Kozinc ◽  
Amador Garcia Ramos ◽  
Olivera M. Knežević ◽  
Milan Čoh ◽  
...  
Keyword(s):  
Sagittal Plane ◽  
Ground Reaction Forces ◽  
Relative Reliability ◽  
Future Studies ◽  
Reaction Forces ◽  
Force Velocity ◽  
Individualized Training ◽  
High Level ◽  
Maximal Effort ◽  
Absolute Reliability

This study aimed to assess the within- and between-session reliability of the KiSprint system for determining force-velocity-power (FVP) profiling during sprint running. Thirty (23 males, 7 females; 18.7 ± 2.6 years;) young high-level sprinters performed maximal effort sprints in two sessions separated by one week. Split times (5, 10, 20 and 30 m), which were recorded with a laser distance meter (a component of the KiSprint system), were used to determine the horizontal FVP profile using the Samozino’s field-based method. This method assesses the FVP relationships through estimates of the step-averaged ground reaction forces in sagittal plane during sprint acceleration using only anthropometric and spatiotemporal (split times) data. We also calculated the maximal theoretical power, force and velocity capabilities and the slope of the FV relationship, the maximal ratio of horizontal-to-resultant force (RF), and the decrease in the RF (DRF). Overall, the results showed moderate or good to excellent within- and between-session reliability for all variables (ICC > 0.75; CV < 10 %), with the exception of FV slope and DRF that showed low relative reliability (ICC = 0.47-0.48 within session, 0.31-0.33 between-session) and unacceptable between-session absolute reliability values (CV = 10.9-11.1 %). Future studies are needed to optimize the protocol in order to maximize the reliability of the FVP variables, especially when practitioners are interested in the FV slope and DRF. In summary, our results question the utility of the sprint-based FVP profiling for individualized training prescription, since the reliability of the FV slope and D RF variables is highly questionable.

scholarly journals The effect of walking speed on the foot inter-segment kinematics, ground reaction forces and lower limb joint moments

PeerJ ◽  
2018 ◽  
Vol 6 ◽  
pp. e5517 ◽  
Author(s):  
Dong Sun ◽  
Gusztáv Fekete ◽  
Qichang Mei ◽  
Yaodong Gu
Keyword(s):  
Lower Limb ◽  
Walking Speed ◽  
Sagittal Plane ◽  
External Rotation ◽  
Center Of Mass ◽  
Ground Reaction Forces ◽  
Joint Moments ◽  
Angle Variation ◽  
Foot Kinematics ◽  
Reaction Forces

Background Normative foot kinematic and kinetic data with different walking speeds will benefit rehabilitation programs and improving gait performance. The purpose of this study was to analyze foot kinematics and kinetics differences between slow walking (SW), normal walking (NW) and fast walking (FW) of healthy subjects. Methods A total of 10 healthy male subjects participated in this study; they were asked to carry out walks at a self-selected speed. After measuring and averaging the results of NW, the subjects were asked to perform a 25% slower and 25% faster walk, respectively. Temporal-spatial parameters, kinematics of the tibia (TB), hindfoot (HF), forefoot (FF) and hallux (HX), and ground reaction forces (GRFs) were recorded while the subjects walked at averaged speeds of 1.01 m/s (SW), 1.34 m/s (NW), and 1.68 m/s (FW). Results Hindfoot relative to tibia (HF/TB) and forefoot relative to hindfoot (FF/HF) dorsiflexion (DF) increased in FW, while hallux relative to forefoot (HX/FF) DF decreased. Increased peak eversion (EV) and peak external rotation (ER) in HF/TB were observed in FW with decreased peak supination (SP) in FF/HF. GRFs were increased significantly with walking speed. The peak values of the knee and ankle moments in the sagittal and frontal planes significantly increased during FW compared with SW and NW. Discussion Limited HF/TB and FF/HF motion of SW was likely compensated for increased HX/FF DF. Although small angle variation in HF/TB EV and FF/HF SP during FW may have profound effects for foot kinetics. Higher HF/TB ER contributed to the FF push-off the ground while the center of mass (COM) progresses forward in FW, therefore accompanied by higher FF/HF abduction in FW. Increased peak vertical GRF in FW may affected by decreased stance duration time, the biomechanical mechanism maybe the change in vertical COM height and increase leg stiffness. Walking speed changes accompanied with modulated sagittal plane ankle moments to alter the braking GRF during loading response. The findings of foot kinematics, GRFs, and lower limb joint moments among healthy males may set a reference to distinguish abnormal and pathological gait patterns.

scholarly journals Lower extremity stiffness in habitual forefoot strikers during running on different overground surfaces

2021 ◽  
Vol 23 (2) ◽  
Author(s):  
Ziwei Zeng ◽  
Lulu Yin ◽  
Wenxing Zhou ◽  
Yu Zhang ◽  
Jiayi Jiang ◽  
...  
Keyword(s):  
Lower Extremity ◽  
Sagittal Plane ◽  
Joint Stiffness ◽  
Ground Reaction Forces ◽  
Factors Affecting ◽  
Vertical Stiffness ◽  
Synthetic Rubber ◽  
Peak Knee ◽  
Reaction Forces ◽  
Artificial Grass

Purpose: Sports surface is one of the known external factors affecting running performance and injury. To date, we have found no study that examined the lower extremity stiffness in habitual forefoot strikers running on different overground surfaces. Therefore, the objective of this study was to investigate lower extremity stiffness and relevant kinematic adjustments in habitual forefoot strikers while running on different surfaces. Methods: Thirty-one male habitual forefoot strikers were recruited in this study. Runners were instructed to run at a speed of 3.3 m/s (±5%) on three surfaces, named synthetic rubber, concrete, and artificial grass. Results: No significant differences were found in leg stiffness, vertical stiffness, and joint stiffness in the sagittal plane during running on the three surfaces (p > 0.05). Running on artificial grass exerted a greater displacement in knee joint angle than running on synthetic rubber (p = 0.002, 95% CI = 1.52–7.35 degrees) and concrete (p = 0.006, 95% CI = 1.04–7.25 degrees). In the sagittal plane, peak knee moment was lower on concrete than on artificial grass (p = 0.003, 95% CI = 0.11–0.58 Nm/kg), whereas peak ankle moment was lower on synthetic rubber than on concrete (p < 0.001, 95% CI = 0.03–0.07 Nm/kg) and on artificial grass (p < 0.001, 95% CI = 0.02–0.06 Nm/kg). Among the three surfaces, the maximal ground reaction forces on concrete were the lowest (p < 0.05). Conclusions: This study indicated that running surfaces cannot influence lower extremity stiffness in habitual forefoot strikers at current running speed. Kinematic adjustments of knee and ankle, as well as ground reaction forces, may contribute to maintaining similar lower extremity stiffness.

The effects of strength training upon front foot contact ground reaction forces and ball release speed among high-level cricket pace bowlers

2021 ◽  
pp. 1-17
Author(s):  
Samuel J. Callaghan ◽  
Robert G. Lockie ◽  
Jamie Tallent ◽  
Robert F. Chipchase ◽  
Warren A. Andrews ◽  
...  
Keyword(s):  
Strength Training ◽  
Ground Reaction Forces ◽  
Ball Release ◽  
Reaction Forces ◽  
High Level ◽  
Release Speed

scholarly journals Characterization of Multiple Movement Strategies in Participants With Chronic Ankle Instability

2019 ◽  
Vol 54 (6) ◽  
pp. 698-707 ◽  
Author(s):  
J. Ty Hopkins ◽  
S. Jun Son ◽  
Hyunsoo Kim ◽  
Garritt Page ◽  
Matthew K. Seeley
Keyword(s):  
Sagittal Plane ◽  
Ankle Instability ◽  
Vertical Jump ◽  
Frontal Plane ◽  
Chronic Ankle Instability ◽  
Control Group ◽  
Ground Reaction Forces ◽  
Sensorimotor Deficits ◽  
Movement Strategies ◽  
Reaction Forces

Context Chronic ankle instability (CAI) is characterized by multiple sensorimotor deficits, affecting strength, postural control, motion, and movement. Identifying specific deficits is the key to developing appropriate interventions for this patient population; however, multiple movement strategies within this population may limit the ability to identify specific movement deficits. Objective To identify specific movement strategies in a large sample of participants with CAI and to characterize each strategy relative to a sample of uninjured control participants. Design Descriptive laboratory study. Setting Biomechanics laboratory. Patients or Other Participants A total of 200 individuals with CAI (104 men, 96 women; age = 22.3 ± 2.2 years, height = 174.2 ± 9.5 cm, mass = 72.0 ± 14.0 kg) were selected according to the inclusion criteria established by the International Ankle Consortium and were fit into clusters based on movement strategy. A total of 100 healthy individuals serving as controls (54 men, 46 women; age = 22.2 ± 3.0 years, height = 173.2 ± 9.2 cm, mass = 70.7 ± 13.4 kg) were compared with each cluster. Main Outcome Measure(s) Lower extremity joint biomechanics and ground reaction forces were collected during a maximal vertical jump landing, followed immediately by a side cut. Data were reduced to functional output or curves, kinematic data from the frontal and sagittal planes were reduced to a single representative curve for each plane, and representative curves were clustered using a Bayesian clustering technique. Estimated functions for each dependent variable were compared with estimated functions from the control group to describe each cluster. Results Six distinct clusters were identified from the frontal-plane and sagittal-plane data. Differences in joint angles, joint moments, and ground reaction forces between clusters and the control group were also identified. Conclusions The participants with CAI demonstrated 6 distinct movement strategies, indicating that CAI could be characterized by multiple distinct movement alterations. Clinicians should carefully evaluate patients with CAI for sensorimotor deficits and quality of movement to determine the appropriate interventions for treatment.

scholarly journals Individuality decoded by running patterns: Movement characteristics that determine the uniqueness of human running

PLoS ONE ◽  
2021 ◽  
Vol 16 (4) ◽  
pp. e0249657
Author(s):  
Fabian Hoitz ◽  
Vinzenz von Tscharner ◽  
Jennifer Baltich ◽  
Benno M. Nigg
Keyword(s):  
Neural Network ◽  
Sagittal Plane ◽  
Gait Recognition ◽  
Transverse Plane ◽  
Human Gait ◽  
Ground Reaction Forces ◽  
Movement Trajectories ◽  
Gait Characteristics ◽  
The Neural Network ◽  
Reaction Forces

Human gait is as unique to an individual as is their fingerprint. It remains unknown, however, what gait characteristics differentiate well between individuals that could define the uniqueness of human gait. The purpose of this work was to determine the gait characteristics that were most relevant for a neural network to identify individuals based on their running patterns. An artificial neural network was trained to recognize kinetic and kinematic movement trajectories of overground running from 50 healthy novice runners (males and females). Using layer-wise relevance propagation, the contribution of each variable to the classification result of the neural network was determined. It was found that gait characteristics of the coronal and transverse plane as well as medio-lateral ground reaction forces provided more information for subject identification than gait characteristics of the sagittal plane and ground reaction forces in vertical or anterior-posterior direction. Additionally, gait characteristics during the early stance were more relevant for gait recognition than those of the mid and late stance phase. It was concluded that the uniqueness of human gait is predominantly encoded in movements of the coronal and transverse plane during early stance.

A Technique to Evaluate Foot Function During the Stance Phase of Gait

1995 ◽  
Vol 16 (12) ◽  
pp. 764-770 ◽  
Author(s):  
Karen Lohmann Siegel ◽  
Thomas M. Kepple ◽  
Paul G. O'Connell ◽  
Lynn H. Gerber ◽  
Steven J. Stanhope
Keyword(s):  
Stance Phase ◽  
Center Of Pressure ◽  
Three Dimensional ◽  
Ground Reaction Forces ◽  
Coordinate Systems ◽  
Future Studies ◽  
Case Examples ◽  
Reaction Forces ◽  
Foot Function ◽  
The Impact

A technique to measure foot function during the stance phase of gait is described. Advantages of the method include its three-dimensional approach with anatomically based segment coordinate systems. This allows variables such as ground reaction forces and center of pressure location to be expressed in a local foot coordinate system, which gives more anatomical meaning to the interpretation of results. Application of the measurement technique to case examples of patients with rheumatoid arthritis demonstrated its ability to discriminate normal from various levels of pathological function. Future studies will utilize this technique to study the impact of pathology and treatment on foot function.

Force-Velocity-Power Profiling During Weighted-Vest Sprinting in Soccer

2019 ◽  
Vol 14 (6) ◽  
pp. 747-756 ◽  
Author(s):  
Jorge Carlos-Vivas ◽  
Elena Marín-Cascales ◽  
Tomás T. Freitas ◽  
Jorge Perez-Gomez ◽  
Pedro E. Alcaraz
Keyword(s):  
Effect Size ◽  
Power Output ◽  
Field Method ◽  
Maximum Power ◽  
Soccer Players ◽  
Total Force ◽  
Ground Reaction Forces ◽  
Time Data ◽  
Reaction Forces ◽  
Force Velocity

Purpose: To describe the load–velocity relationship and the effects of increasing loads on spatiotemporal and derived kinetic variables of sprinting using weighted vests (WV) in soccer players and determining the load that maximizes power output. Methods: A total of 23 soccer players (age 20.8 [1.5] y) performed 10 maximal 30-m sprints wearing a WV with 5 different loads (0%, 10%, 20%, 30%, and 40% body mass [BM]). Sprint velocity and time were collected using a radar device and wireless photocells. Mechanical outputs were computed using a recently developed valid and reliable field method that estimates the step-averaged ground-reaction forces during overground sprint acceleration from anthropometric and spatiotemporal data. Raw velocity–time data were fitted by an exponential function and used to calculate the net horizontal ground-reaction forces and horizontal power output. Individual linear force–velocity relationships were then extrapolated to calculate the theoretical maximum horizontal force (F0) and velocity and the ratio of force application (proportion of the total force production that is directed forward at sprint start). Results: Magnitude-based inferences showed an almost certain decrease in F0 (effect size = 0.78–3.35), maximum power output (effect size = 0.78–3.81), and maximum ratio of force (effect size = 0.82–3.87) as the load increased. The greatest changes occurred with loads heavier than 20% BM, especially in ratio of force. In addition, the maximum power was achieved under unloaded conditions. Conclusions: Increasing load in WV sprinting affects spatiotemporal and kinetic variables. The greatest change in ratio of force happened with loads heavier than 20% BM. Thus, the authors recommend the use of loads ≤20% BM for WV sprinting.

Quadriceps Inhibition Induced by an Experimental Knee Joint Effusion Affects Knee Joint Mechanics during a Single-Legged Drop Landing

2007 ◽  
Vol 35 (8) ◽  
pp. 1269-1275 ◽  
Author(s):  
Riann M. Palmieri-Smith ◽  
Jennifer Kreinbrink ◽  
James A. Ashton-Miller ◽  
Edward M. Wojtys
Keyword(s):  
Knee Joint ◽  
Sagittal Plane ◽  
Quadriceps Muscle ◽  
Knee Extension ◽  
Joint Effusion ◽  
Ground Reaction Forces ◽  
Joint Mechanics ◽  
Drop Landing ◽  
Muscle Inhibition ◽  
Reaction Forces

Background Arthrogenic quadriceps muscle inhibition accompanies knee joint effusion and impedes rehabilitation after knee joint injury. Hypothesis We hypothesized that an experimentally induced knee joint effusion would cause arthrogenic quadriceps muscle inhibition and lead to increased ground reaction forces, as well as sagittal plane knee angles and moments, during a single-legged drop landing. Study Design Controlled laboratory study. Methods Nine subjects (4 women and 5 men) underwent 4 conditions (no effusion, lidocaine injection, “low” effusion [30 mL], and “high” effusion [60 mL]) and then performed a single-legged drop landing. Lower extremity muscle activity, peak sagittal plane knee flexion angles, net sagittal plane knee moments, and peak ground reaction forces were measured. Results Vastus medialis and lateralis activity were decreased during the low and high effusion conditions (P < .05). However, increases in peak ground reaction forces and decreases in peak knee flexion angle and net knee extension moments occurred only during the high effusion condition (P < .05). Conclusions Knee joint effusion induced quadriceps inhibition and altered knee joint mechanics during a landing task. Subjects landed with larger ground reaction forces and in greater knee extension, thereby suggesting that more force will be transferred to the knee joint and its passive restraints when quadriceps inhibition is present. Clinical Relevance Knee joint effusion results in arthrogenic quadriceps muscle inhibition, increasing loading about the knee that may potentially increase the risk of future knee joint trauma or degeneration.

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