Sled Towing: The Optimal Overload for Peak Power Production

2017 ◽  
Vol 12 (8) ◽  
pp. 1052-1058 ◽  
Author(s):  
Andrea Monte ◽  
Francesca Nardello ◽  
Paola Zamparo
Keyword(s):  
Contact Time ◽  
Peak Power ◽  
Stride Length ◽  
Power Production ◽  
Step Length ◽  
Flight Time ◽  
Sprint Training ◽  
Joint Angles ◽  
Step Number ◽  
Increasing Load

Purpose:The effects of different loads on kinematic and kinetic variables during sled towing were investigated with the aim to identify the optimal overload for this specific sprint training.Methods:Thirteen male sprinters (100-m personal best: 10.91 ± 0.14 s) performed 5 maximal trials over a 20-m distance in the following conditions: unloaded and with loads from 15% to 40% of the athlete’s body mass (BM). In these calculations the sled mass and friction were taken into account. Contact and flight times, stride length, horizontal hip velocity (vh), and relative angles of hip, knee, and ankle (at touchdown and takeoff) were measured step by step. In addition, the horizontal force (Fh) and power (Ph) and maximal force (Fh0) and power (Ph0) were calculated.Results:vh, flight time, and step length decreased while contact time increased with increasing load (P < .001). These variables changed significantly also as a function of the step number (P < .01), except between the 2 last steps. No differences were observed in Fh among loads, but Fh was larger in sled towing than in unloaded. Ph was unaffected by load up to +20%BM but decreased with larger loads. Fh0 and Ph0 were achieved at 20%BM. Up to 20%BM, no significant effects on joint angles were observed at touchdown and takeoff, while at loads >30%BM joint angles tended to decrease.Conclusion:The 20%BM condition represents the optimal overload for peak power production—at this load sprinters reach their highest power without significant changes in their running technique (eg, joint angles).

scholarly journals Agreement Between Spatiotemporal Gait Parameters Measured by a Markerless Motion Capture System and Two Reference Systems—a Treadmill-Based Photoelectric Cell and High-Speed Video Analyses: Comparative Study (Preprint)

2020 ◽  
Author(s):  
Felipe García-Pinillos ◽  
Diego Jaén-Carrillo ◽  
Victor Soto Hermoso ◽  
Pedro Latorre Román ◽  
Pedro Delgado ◽  
...  
Keyword(s):  
Video Analysis ◽  
Contact Time ◽  
High Speed ◽  
Step Length ◽  
Flight Time ◽  
Reference Systems ◽  
Random Errors ◽  
Step Frequency ◽  
Temporal Parameters ◽  
High Speed Video

BACKGROUND Markerless systems to capture body motion require no markers to be attached to the body, thereby improving clinical feasibility and testing time. However, the lack of markers might affect the accuracy of measurements. OBJECTIVE This study aimed to determine the absolute reliability and concurrent validity of the Kinect system with MotionMetrix software for spatiotemporal variables during running at a comfortable velocity, by comparing data between the combination system and two widely used systems—OptoGait and high-speed video analysis at 1000 Hz. METHODS In total, 25 runners followed a running protocol on a treadmill at a speed of 12 km/h. The Kinect+MotionMetrix combination measured spatiotemporal parameters during running (ie, contact time, flight time, step frequency, and step length), which were compared to those obtained from two reference systems. RESULTS Regardless of the system, flight time had the highest coefficients of variation (OptoGait: 16.4%; video analysis: 17.3%; Kinect+MotionMetrix: 23.2%). The rest of the coefficients of variation reported were lower than 8.1%. Correlation analysis showed very high correlations (<i>r</i>&gt;0.8; <i>P</i>&lt;.001) and almost perfect associations (intraclass correlation coefficient&gt;0.81) between systems for all the spatiotemporal parameters except contact time, which had lower values. Bland-Altman plots revealed smaller systematic biases and random errors for step frequency and step length and larger systematic biases and random errors for temporal parameters with the Kinect+MotionMetrix system as compared to OptoGait (difference: contact time +3.0%, flight time −7.9%) and high-speed video analysis at 1000 Hz (difference: contact time +4.2%, flight time −11.3%). Accordingly, heteroscedasticity was found between systems for temporal parameters (<i>r</i><sup>2</sup>&gt;0.1). CONCLUSIONS The results indicate that the Kinect+MotionMetrix combination slightly overestimates contact time and strongly underestimates flight time as compared to the OptoGait system and high-speed video analysis at 1000 Hz. However, it is a valid tool for measuring step frequency and step length when compared to reference systems. Future studies should determine the reliability of this system for determining temporal parameters.

scholarly journals Agreement Between Spatiotemporal Gait Parameters Measured by a Markerless Motion Capture System and Two Reference Systems—a Treadmill-Based Photoelectric Cell and High-Speed Video Analyses: Comparative Study

10.2196/19498 ◽  
2020 ◽  
Vol 8 (10) ◽  
pp. e19498
Author(s):  
Felipe García-Pinillos ◽  
Diego Jaén-Carrillo ◽  
Victor Soto Hermoso ◽  
Pedro Latorre Román ◽  
Pedro Delgado ◽  
...  
Keyword(s):  
Video Analysis ◽  
Contact Time ◽  
High Speed ◽  
Step Length ◽  
Flight Time ◽  
Reference Systems ◽  
Random Errors ◽  
Step Frequency ◽  
Temporal Parameters ◽  
High Speed Video

Background Markerless systems to capture body motion require no markers to be attached to the body, thereby improving clinical feasibility and testing time. However, the lack of markers might affect the accuracy of measurements. Objective This study aimed to determine the absolute reliability and concurrent validity of the Kinect system with MotionMetrix software for spatiotemporal variables during running at a comfortable velocity, by comparing data between the combination system and two widely used systems—OptoGait and high-speed video analysis at 1000 Hz. Methods In total, 25 runners followed a running protocol on a treadmill at a speed of 12 km/h. The Kinect+MotionMetrix combination measured spatiotemporal parameters during running (ie, contact time, flight time, step frequency, and step length), which were compared to those obtained from two reference systems. Results Regardless of the system, flight time had the highest coefficients of variation (OptoGait: 16.4%; video analysis: 17.3%; Kinect+MotionMetrix: 23.2%). The rest of the coefficients of variation reported were lower than 8.1%. Correlation analysis showed very high correlations (r>0.8; P<.001) and almost perfect associations (intraclass correlation coefficient>0.81) between systems for all the spatiotemporal parameters except contact time, which had lower values. Bland-Altman plots revealed smaller systematic biases and random errors for step frequency and step length and larger systematic biases and random errors for temporal parameters with the Kinect+MotionMetrix system as compared to OptoGait (difference: contact time +3.0%, flight time −7.9%) and high-speed video analysis at 1000 Hz (difference: contact time +4.2%, flight time −11.3%). Accordingly, heteroscedasticity was found between systems for temporal parameters (r2>0.1). Conclusions The results indicate that the Kinect+MotionMetrix combination slightly overestimates contact time and strongly underestimates flight time as compared to the OptoGait system and high-speed video analysis at 1000 Hz. However, it is a valid tool for measuring step frequency and step length when compared to reference systems. Future studies should determine the reliability of this system for determining temporal parameters.

scholarly journals Kinematics and Kinetics of Bulgarian-Bag-Overloaded Sprints in Young Athletes

Life ◽  
2020 ◽  
Vol 10 (11) ◽  
pp. 282
Author(s):  
Marco Duca ◽  
Athos Trecroci ◽  
Enrico Perri ◽  
Damiano Formenti ◽  
Giampietro Alberti
Keyword(s):  
Peak Power ◽  
Power Production ◽  
Maximal Velocity ◽  
Sprint Training ◽  
Young Athletes ◽  
Production Methods ◽  
Velocity Relationship ◽  
Force Velocity ◽  
Kinetics Of ◽  
Kinematics And Kinetics

Background: Effective sprinting requires large acceleration capabilities. To accelerate, large amount of force must be produced and applied effectively. The use of different implements such as sleds and vests can increase the amount of force produced and alter sprinting effectiveness. We propose the use of increasing overload via the Bulgarian Bag (BB) as a means to modify athletes’ sprint and acutely increase force and power production. Methods: 24 young athletes performed three sprints over 20 m in three different conditions: unloaded (BW) and loaded with BB weighing 2.5% (BB2.5) and 5% (BB5) of the athlete’s body mass. Sprint times at 2.5, 5, 10, 15, and 20 m were acquired and used to compute the force–velocity relationship for the sprints. Maximal velocity (V0), peak force (F0), peak power (PP), and decrease in ratio of force (DRF) were computed. Results: the additional load caused a decrease in sprint times (p < 0.05) and V0 (p = 0.028), conversely no differences were found for F0 (p = 0.21), PP (p = 0.50), and DRF (p = 0.83). Conclusions: Based on those findings, BB can be an alternative method to effectively overload sprint training toward improving sprinting performance.

scholarly journals Maximal Sprint Speed in Boys of Increasing Maturity

2015 ◽  
Vol 27 (1) ◽  
pp. 85-94 ◽  
Author(s):  
Robert W. Meyers ◽  
Jonathan L. Oliver ◽  
Michael G. Hughes ◽  
John B. Cronin ◽  
Rhodri S. Lloyd
Keyword(s):  
Contact Time ◽  
Stride Length ◽  
Peak Height ◽  
Flight Time ◽  
Sprint Performance ◽  
Height Velocity ◽  
Stride Frequency ◽  
Peak Height Velocity ◽  
Sprint Speed ◽  
Maximal Speed

The purpose of this study was to examine the natural development of the mechanical features of sprint performance in relation to maturation within a large cohort of boys. Three hundred and thirty-six boys (11-15 years) were analyzed for sprint performance and maturation. Maximal speed, stride length (SL), stride frequency (SF), flight time (FT) and contact time (CT) were assessed during a 30m sprint. Five maturation groups (G1-5) were established based on age from peak height velocity (PHV) where G1=>2.5years pre-PHV, G2 = 2.49-1.5years pre-PHV, G3 = 1.49-0.5years pre-PHV, G4 = 0.49years pre- to 0.5years post-PHV and G5 = 0.51-1.5years post-PHV. There was no difference in maximal speed between G1, G2 and G3 but those in G4 and G5 were significantly faster (p < .05) than G1-3. Significant increases (p < .05) in SL were observed between groups with advancing maturation, except G4 and G5 (p > .05). SF decreased while CT increased (both p < .05) between G1, G2 and G3, but no further significant changes (p > .05) were observed for either variable between G3, G4 and G5. While G1-3 increased their SL, concomitant decreases in SF and increases in CT prevented them from improving maximal speed. Maximal sprint speed appears to develop around and post-PHV as SF and CT begin to stabilize, with increases in maximal sprint speed in maturing boys being underpinned by increasing SL.

Influence of RunScribe™ placement on the accuracy of spatiotemporal gait characteristics during running

2019 ◽  
Vol 234 (1) ◽  
pp. 11-18 ◽  
Author(s):  
Felipe García-Pinillos ◽  
José M Chicano-Gutiérrez ◽  
Emilio J Ruiz-Malagón ◽  
Luis E Roche-Seruendo
Keyword(s):  
Video Analysis ◽  
Contact Time ◽  
High Speed ◽  
Intraclass Correlation ◽  
Step Length ◽  
Flight Time ◽  
Systematic Bias ◽  
Step Frequency ◽  
High Speed Video ◽  
Spatiotemporal Parameters

This study aimed to examine the influence of RunScribe location (i.e. lace shoe vs heel shoe) on the accuracy of spatiotemporal gait characteristics during running by comparing data with a high-speed video analysis system at 1000 Hz. A total of 49 endurance runners performed a running protocol on a treadmill at comfortable velocity. Two systems were used to determine spatiotemporal parameters (i.e. contact time, flight time, step frequency, and step length) during running: high-speed video analysis at 1000 Hz and two different RunScribe placements (i.e. lace shoe vs heel shoe). The pairwise comparisons showed some between-system differences in both lace shoe (contact time: p = 0.009; step frequency: p = 0.001) and heel shoe (flight time: p = 0.006; step frequency: p = 0.010), although the effect sizes were small (effect size < 0.3 in all cases). The intraclass correlation coefficients revealed an almost perfect association between systems for contact time and flight time (intraclass correlation coefficient: 0.85–0.90), and step length and step frequency (intraclass correlation coefficient: 0.96–0.97), regardless of the RunScribe placement. Bland–Altman plots revealed that the lace shoe location yielded smaller systematic bias, random errors, and narrower limits of agreement for spatiotemporal parameters during running, except for SF, which had a higher accuracy in a heel shoe location. The results suggest that RunScribe is a valid system to measure spatiotemporal parameters during running on a treadmill according to a high-speed video analysis at 1000 Hz. In addition, the data indicate that the location of the RunScribe system (lace shoe vs heel shoe) plays an important role on the accuracy of spatiotemporal parameters. The lace shoe placement showed smaller systematic bias, random errors, and narrower limits of agreement for contact time, flight time, and step length, whereas the heel shoe placement was slightly more accurate for the step frequency.

scholarly journals Effectiveness of an ankle–foot orthosis on walking in patients with stroke: a systematic review and meta-analysis

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Yoo Jin Choo ◽  
Min Cheol Chang
Keyword(s):  
Stride Length ◽  
Walking Speed ◽  
Sagittal Plane ◽  
Meta Analysis ◽  
Step Length ◽  
Stride Time ◽  
Plane Angle ◽  
Ankle Foot Orthosis ◽  
Biomechanical Parameters ◽  
Foot Orthosis

AbstractWe conducted a meta-analysis to investigate the effectiveness of ankle–foot orthosis (AFO) use in improving gait biomechanical parameters such as walking speed, mobility, and kinematics in patients with stroke with gait disturbance. We searched the MEDLINE (Medical Literature Analysis and Retrieval System Online), CINAHL (Cumulative Index to Nursing and Allied Health Literature), Cochrane, Embase, and Scopus databases and retrieved studies published until June 2021. Experimental and prospective studies were included that evaluated biomechanics or kinematic parameters with or without AFO in patients with stroke. We analyzed gait biomechanical parameters, including walking speed, mobility, balance, and kinematic variables, in studies involving patients with and without AFO use. The criteria of the Cochrane Handbook for Systematic Reviews of Interventions were used to evaluate the methodological quality of the studies, and the level of evidence was evaluated using the Research Pyramid model. Funnel plot analysis and Egger’s test were performed to confirm publication bias. A total of 19 studies including 434 participants that reported on the immediate or short-term effectiveness of AFO use were included in the analysis. Significant improvements in walking speed (standardized mean difference [SMD], 0.50; 95% CI 0.34–0.66; P < 0.00001; I2, 0%), cadence (SMD, 0.42; 95% CI 0.22–0.62; P < 0.0001; I2, 0%), step length (SMD, 0.41; 95% CI 0.18–0.63; P = 0.0003; I2, 2%), stride length (SMD, 0.43; 95% CI 0.15–0.71; P = 0.003; I2, 7%), Timed up-and-go test (SMD, − 0.30; 95% CI − 0.54 to − 0.07; P = 0.01; I2, 0%), functional ambulation category (FAC) score (SMD, 1.61; 95% CI 1.19–2.02; P < 0.00001; I2, 0%), ankle sagittal plane angle at initial contact (SMD, 0.66; 95% CI 0.34–0.98; P < 0.0001; I2, 0%), and knee sagittal plane angle at toe-off (SMD, 0.39; 95% CI 0.04–0.73; P = 0.03; I2, 46%) were observed when the patients wore AFOs. Stride time, body sway, and hip sagittal plane angle at toe-off were not significantly improved (p = 0.74, p = 0.07, p = 0.07, respectively). Among these results, the FAC score showed the most significant improvement, and stride time showed the lowest improvement. AFO improves walking speed, cadence, step length, and stride length, particularly in patients with stroke. AFO is considered beneficial in enhancing gait stability and ambulatory ability.

EFFECT OF ACCUPRESSURE PEN ON DISTANCE VARIABLE IN SCIATICA PATIENTS -A RANDOMIZED CONTROL TRIAL

2021 ◽  
pp. 28-31
Author(s):  
Urja S. Vaidya ◽  
Roshani S. Patel
Keyword(s):  
Randomized Control Trial ◽  
Stride Length ◽  
Step Length ◽  
Control Group ◽  
Exclusion Criteria ◽  
Parametric Test ◽  
Group A ◽  
Randomized Control ◽  
Experimental Group ◽  
Distance Variable

Background: Sciatica is a radiating pain which is treated with manual accupressure and after a time electro accupressure came into introduction. Aim And Objective: Aim: To nd out the effectiveness of accupressure pen to improve the distance variable To nd out the effect of Objective: accupressure pen on pain and distance variable in sciatica patient To compare the experimental group to the control group On the basis of Method: inclusion and exclusion criteria 30 participants were selected. They were treated with electro accupressure pen for 3 alternative days / week for 3 weeks, after that re-assessment was taken with NPRS, Slump and Distance variables. The data was analyzed using SPSS Version Results: 21.Parametric test was used .In Group A improvement was seen Accupressure Conclusions: pen is effective to reduce pain and improve step length and stride length in Sciatica Patients

scholarly journals A commercially available energy drink does not improve peak power production on multiple 20-second Wingate tests

2010 ◽  
Vol 7 (S1) ◽  
Author(s):  
Bill I Campbell ◽  
Marcus Kilpatrick ◽  
Colin Wilborn ◽  
Paul La Bounty ◽  
Brittany Parker ◽  
...  
Keyword(s):  
Peak Power ◽  
Power Production ◽  
Energy Drink ◽  
Available Energy

scholarly journals Análisis biomecánico de la competición de 3000 m obstáculos (Biomechanical analysis of the 3000 m steeplechase competition)

Retos ◽  
2015 ◽  
pp. 157-162
Author(s):  
Ana Ogueta-Alday ◽  
Fernando Muñoz Molleda ◽  
Juan García-López
Keyword(s):  
Velocity Ratio ◽  
El Paso ◽  
Step Length ◽  
Flight Time ◽  
Biomechanical Analysis ◽  
World Record ◽  
Male And Female ◽  
London 2012 ◽  
The World ◽  
And Gender

El objetivo es analizar el comportamiento de las variables cinemáticas del paso del obstáculo y la ría, su relación con el rendimiento y la influencia del género y la fatiga en la prueba de 3000 m obstáculos. Durante el XVII Mitin Ciudad de Mataró (clasificatorio para los JJOO de Londres-2012) se analizaron dos pruebas donde participaron 35 atletas (19 hombres y 16 mujeres) que fueron divididos en 3 grupos de nivel en función de su rendimiento comparado con el Récord del Mundo. Las grabaciones fueron digitalizadas mediante un análisis cinemático en 2D (Kinescan-IBV). Algunas variables en el paso del obstáculo (velocidad, distancia de batida y porcentaje tiempo de vuelo) y de la ría (velocidad y pérdida de velocidad en las últimas vueltas) fueron sensibles al nivel, y otras al género (obstáculo: velocidad y distancia de batida relativas a la velocidad de la prueba; ría: velocidad relativa a la velocidad de la prueba). Las variables que no fueron sensibles al nivel, género y fatiga permiten establecer valores de referencia para el entrenamiento (ej. distancia de ataque ~53-55% en el obstáculo y ~35-39% en la ría). En conclusión, este es el primer estudio que analiza conjuntamente la biomecánica del paso del obstáculo y la ría en una prueba de 3000 m obstáculos, relacionando variables biomecánicas con el rendimiento y el género. Se observó que existe una falta de amplitud en el paso del obstáculo en mujeres, y que tanto hombres como mujeres deberían mejorar su técnica de paso de la ría.Palabras clave: Biomecánica, carrera, obstáculos, rendimiento.Abstract: The purpose of this study was to analyze the kinematic variables of both steeplechase and steeplechase water jumps, their relationship with performance, and the influence of some factors such as gender and fatigue during a 3000 m steeplechase competition. Two races of the XVII Athletics Meeting Ciudad de Mataró (National Trials for London-2012 Olympic Games) were recorded. Thirty-five athletes were analyzed (19 male and 16 female) and classified into 3 groups according to their competition performance level compared to the World Record. Images were digitalized by a 2D kinematic analysis (Kinescan-IBV). The results showed that some biomechanical variables of the steeplechase jump (steeplechase velocity, step length and percentage of flight time) and steeplechase water jump (steeplechase velocity and its decrease over the laps) were related to performance. Other variables were sensitive to the gender (steeplechase jump: steeplechase/competition velocity ratio and step length/steeplechase velocity ratio; steeplechase water jump: steeplechase/competition velocity ratio). The variables which were not related to performance, gender or fatigue allowed establishing reference values for training (e.g. takeoff distance of ~53-55% in the steeplechase jump and ~35-39% in the steeplechase water jump). In conclusion, this is the first study that simultaneously analyzed the biomechanics of both steeplechase and steeplechase water jumps during a 3000 m steeplechase competition, relating biomechanical variables to performance and gender. The comparisons with respect to previous studies indicated that the females had a short step length in the steeplechase, and that both male and female should improve their steeplechase water jump technique.Keywords: biomechanics, running, steeplechase, performance.

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