scholarly journals Comparison of two measurement devices for obtaining horizontal force-velocity profile variables during sprint running

2022 ◽  
pp. 174795412110672
Author(s):  
Erin Feser ◽  
Kyle Lindley ◽  
Kenneth Clark ◽  
Neil Bezodis ◽  
Christian Korfist ◽  
...  
Keyword(s):  
Random Error ◽  
Maximum Velocity ◽  
American Football ◽  
Systematic Bias ◽  
Maximal Velocity ◽  
Horizontal Force ◽  
Time Data ◽  
Measured Velocity ◽  
Theoretical Maximum ◽  
Force Velocity

This study established the magnitude of systematic bias and random error of horizontal force-velocity (F-v) profile variables obtained from a 1080 Sprint compared to that obtained from a Stalker ATS II radar device. Twenty high-school athletes from an American football training group completed a 30 m sprint while the two devices simultaneously measured velocity-time data. The velocity-time data were modelled by an exponential equation fitting process and then used to calculate individual F-v profiles and related variables (theoretical maximum velocity, theoretical maximum horizontal force, slope of the linear F-v profile, peak power, time constant tau, and horizontal maximal velocity). The devices were compared by determining the systematic bias and the 95% limits of agreement (random error) for all variables, both of which were expressed as percentages of the mean radar value. All bias values were within 6.32%, with the 1080 Sprint reporting higher values for tau, horizontal maximal velocity, and theoretical maximum velocity. Random error was lowest for velocity-based variables but exceeded 7% for all others, with slope of the F-v profile being greatest at ±12.3%. These results provide practitioners with the information necessary to determine if the agreement between the devices and the magnitude of random error is acceptable within the context of their specific application.

Comparative force-velocity relation and analyses of myosin of dog atria and ventricles

1982 ◽  
Vol 243 (3) ◽  
pp. H391-H397 ◽  
Author(s):  
J. Wikman-Coffelt ◽  
H. Refsum ◽  
G. Hollosi ◽  
L. Rouleau ◽  
L. Chuck ◽  
...  
Keyword(s):  
Atpase Activity ◽  
Calcium Concentration ◽  
Maximum Velocity ◽  
Calcium Sensitivity ◽  
Myofibrillar Proteins ◽  
Maximal Velocity ◽  
Velocity Of Shortening ◽  
Force Velocity ◽  
Normal Calcium ◽  
Actin Concentration

The isolated muscle and purified myofibrillar proteins of canine atria and ventricles were compared relative to force-velocity relations and rate of adenosine 5'-triphosphatase (ATPase) activity as a function of calcium concentrations. The maximal stress development of isolated trabeculae of canine atria was similar to that of canine right ventricular papillary muscles when analyzed at saturating calcium concentrations (7.5 mM); however, stress was less in the atria when studied at normal calcium concentrations (2.5 mM). The maximal velocity of shortening of atrial trabeculae was about 2.3 times higher than that of ventricular muscle. Regulated actomyosin characterized from the myofibrillar proteins of the two tissues gave directionally similar calcium sensitivity. The maximum velocity of shortening for actin-activated atrial myosin of the dog was approximately 1.8 times higher when the latter was analyzed as a function of actin concentration. Both maximal tension of isolated muscle and regulated actomyosin ATPase activity were dependent on calcium concentration.

scholarly journals Gender-Related Differences in Mechanics of the Sprint Start and Sprint Acceleration of Top National-Level Sprinters

2020 ◽  
Vol 17 (18) ◽  
pp. 6447
Author(s):  
Dragan M. Mirkov ◽  
Olivera M. Knezevic ◽  
Amador Garcia-Ramos ◽  
Milan Čoh ◽  
Nejc Šarabon
Keyword(s):  
National Level ◽  
Accurate Information ◽  
Maximal Velocity ◽  
Time Data ◽  
Maximal Force ◽  
Acceleration Force ◽  
Laser Distance Sensor ◽  
Force Velocity ◽  
The Relationship ◽  
Kinematics And Kinetics

(1) Background: Within the current study we aimed at exploring gender-related differences and the relationship between sprint start block kinematics and kinetics and sprint acceleration force–velocity (F-v) relationship parameters (maximal force [F0], maximal velocity [v0], maximal power [Pmax] and slope) in top national-level sprinters. (2) Methods: Twenty-eight sprinters (6 females) performed 10 maximal 30-m sprints. Start block and acceleration kinematics and kinetics were collected with an instrumented sprint start block and a laser distance sensor (KiSprint system). Displacement-time data were used to determine the F-v relationship through Samozino’s method. (3) Results: Start block rear foot maximal force (effect size [ES] = 1.08), rate of force development (ES = 0.90–1.33), F0 (ES = 1.38), v0 (ES = 1.83) and Pmax (ES = 1.95) were higher in males than in females (p ≤ 0.05). There were no differences in the slope, and ratio of horizontal-to-resultant force. F0, v0, and Pmax generally presented higher correlations with the start block kinetics (median r [range] = 0.49 [0.28, 0.78]) than with the kinematics (median r [range] = −0.27 [−0.52, 0.28]). (4) Conclusions: We confirmed that sprint block phase and sprint acceleration mechanics should be mutually assessed when analyzing sprinting performance. KiSprint system could provide more accurate information regarding mechanical pattern and technique during sprint initiation and acceleration, and potentially help create a more personalized and effective training program.

Impairment of Sprint Mechanical Properties in an Actual Soccer Match: A Pilot Study

2016 ◽  
Vol 11 (7) ◽  
pp. 893-898 ◽  
Author(s):  
Ryu Nagahara ◽  
Jean-Benoit Morin ◽  
Masaaki Koido
Keyword(s):  
Mechanical Properties ◽  
High Speed ◽  
Force Production ◽  
Maximal Velocity ◽  
Horizontal Force ◽  
Time Data ◽  
Long Distance ◽  
Soccer Match ◽  
Long Distance Running ◽  
Before And After

Purpose:To assess soccer-specific impairment of mechanical properties in accelerated sprinting and its relation with activity profiles during an actual match.Methods:Thirteen male field players completed 4 sprint measurements, wherein running speed was obtained using a laser distance-measurement system, before and after the 2 halves of 2 soccer matches. Macroscopic mechanical properties (theoretical maximal horizontal force [F0], maximal horizontal sprinting power [Pmax], and theoretical maximal sprinting velocity [V0]) during the 35-m sprint acceleration were calculated from speed–time data. Players’ activity profiles during the matches were collected using global positioning system units.Results:After the match, although F0 and Pmax did not significantly change, V0 was reduced (P = .038), and the magnitude of this reduction correlated with distance (positive) and number (negative) of high-speed running, number of running (negative), and other low-intensity activity distance (negative) during the match. Moreover, Pmax decreased immediately before the second half (P = .014).Conclusions:The results suggest that soccer-specific fatigue probably impairs players’ maximal velocity capabilities more than their maximal horizontal force-production abilities at initial acceleration. Furthermore, long-distance running, especially at high speed, during the match may induce relatively large impairment of maximal velocity capabilities. In addition, the capability of producing maximal horizontal power during sprinting is presumably impaired during halftime of a soccer match with passive recovery. These findings could be useful for players and coaches aiming to train effectively to maintain sprinting performance throughout a soccer match when planning a training program.

scholarly journals Sprint and Jump Mechanical Profiles in Academy Rugby League Players: Positional Differences and the Associations between Profiles and Sprint Performance

Sports ◽  
2021 ◽  
Vol 9 (7) ◽  
pp. 93
Author(s):  
Ben Nicholson ◽  
Alex Dinsdale ◽  
Ben Jones ◽  
Kevin Till
Keyword(s):  
Maximum Velocity ◽  
Mechanical Efficiency ◽  
Rugby League ◽  
Sprint Performance ◽  
Vertical Force ◽  
Horizontal Force ◽  
Cross Sectional ◽  
Performance Variables ◽  
Force Velocity ◽  
And Performance

This cross-sectional study evaluated the sprint and jump mechanical profiles of male academy rugby league players, the differences between positions, and the associations between mechanical profiles and sprint performance. Twenty academy rugby league players performed 40-m sprints and squat jumps at increasing loads (0–80 kg) to determine individual mechanical (force-velocity-power) and performance variables. The mechanical variables (absolute and relative theoretical maximal force-velocity-power, force-velocity linear relationship, and mechanical efficiency) were determined from the mechanical profiles. Forwards had significantly (p < 0.05) greater vertical and horizontal force, momentum but jumped lower (unloaded) and were slower than backs. No athlete presented an optimal jump profile. No associations were found between jump and sprint mechanical variables. Absolute theoretical maximal vertical force significantly (p < 0.05) correlated (r = 0.71–0.77) with sprint momentum. Moderate (r = −0.47) to near-perfect (r = 1.00) significant associations (p < 0.05) were found between sprint mechanical and performance variables. The largest associations shifted from maximum relative horizontal force-power generation and application to maximum velocity capabilities and force application at high velocities as distance increased. The jump and sprint mechanical profiles appear to provide distinctive and highly variable information about academy rugby league players’ sprint and jump capacities. Associations between mechanical variables and sprint performance suggest horizontal and vertical profiles differ and should be trained accordingly.

scholarly journals Force-Velocity Profile of Competitive Kayakers: Evaluation of a Novel Single Kayak Stroke Test

2021 ◽  
Vol 80 (1) ◽  
pp. 49-59
Author(s):  
Milos Petrovic ◽  
Amador Garcia-Ramos ◽  
Danica Janicijevic ◽  
Alejandro Perez-Castilla ◽  
Olivera M. Knezevic ◽  
...  
Keyword(s):  
Bench Press ◽  
Maximum Velocity ◽  
Maximum Power ◽  
Maximum Force ◽  
Upper Body ◽  
Maximal Velocity ◽  
Female Age ◽  
Fatigue Monitoring ◽  
Force Velocity ◽  
The Individual

Abstract The assessment of the force-velocity (F-V) profile in athletes may have important applications for training prescription, injury management, and fatigue monitoring. This study aimed to assess whether a novel single kayak stroke test (SKST) is able to provide the F-V relationship variables (maximum force, maximum velocity and maximum power) of competitive kayakers with acceptable reliability and external validity. Six female (age: 20.3 ± 3.7 years) and eight male (age: 20.8 ± 2.4 years) elite kayakers performed the SKST, bench press, bench pull, and short Wingate kayak test. The individual F-V relationships were highly linear [median r (range): left stroke = 0.986 (0.897 - 0.998); right stroke = 0.987 (0.971 - 0.999)]. The reliability of the F-V relationship parameters obtained during the SKST was high (within-session: CV ≤ 4.48% and ICC ≥ 0.93; between-session: CV ≤ 8.06% and ICC ≥ 0.65). The validity of the F-V relationship parameters obtained during the SKST was generally very high for maximum power (r range = 0.825 - 0.975), high for maximum force during both the bench press and the bench pull (r range = 0.751 - 0.831), and high or moderate for maximal velocity during the bench pull (r = 0.770 - 0.829) and the bench press (r = 0.355 - 0.471), respectively. The SKST can be considered a feasible procedure for testing the maximal upper-body muscle mechanical capacities of kayakers.

Comparison between photoplethysmographic heart rate monitor from Polar Vantage M and Polar V800 with H10 chest strap while running on a treadmill: Validation of the Polar Precision PrimeTM photoplestimographic system

2020 ◽  
pp. 175433712097665
Author(s):  
Emilio J Ruiz-Malagón ◽  
Santiago A Ruiz-Alias ◽  
Felipe García-Pinillos ◽  
Gabriel Delgado-García ◽  
Victor M Soto-Hermoso
Keyword(s):  
Heart Rate ◽  
Random Error ◽  
Maximum Speed ◽  
Systematic Bias ◽  
Long Distance ◽  
Time Intervals ◽  
Heart Rate Monitor ◽  
Calibration Time

Chest bands have been the most used device to monitor heart rate during running. However, some runners feel uncomfortable with the use of bands due to the friction and pressure exerted on the chest. Thus, the aim of this study was to determine if the photoplethysmography (PPG) system Polar Precision Prime used in the Polar Vantage M watch could replace chest bands (Polar V800-H10) to monitor heart rate with the same precision. A group of 37 people, middle-distance and long-distance professional runners, participated in this study. The submaximal speed was determined using 50% of the participants’ maximum speed in the height of their season. The Polar Vantage M reported high correlation ( r > 0.84) and high ICC (ICC > 0.86) when comparing its heart rate monitor with the Polar V800 synchronised with H10 chest strap during recording intervals of more than 2 min. The systematic bias and random error were very small (<1 bpm), especially for the 600 s recording interval (0.26 ± 5.10 bpm). Nevertheless, the error increased for 10 s (−5.13 ± 9.20 bpm), 20 s (−8.65 ± 12.60 bpm) and 30 s (−10.71 ± 14.99 bpm) time intervals. In conclusion, the PPG Polar Precision Prime included in the Polar Vantage M demonstrates that it could be a valid alternative to chest bands for monitoring heart rate while running, taking into account some usage considerations, good strap adjustment and an initial calibration time during the first 2–3 min.

scholarly journals The effects of lower-limb wearable resistance on sprint performance in high school American football athletes: A nine-week training study

2021 ◽  
pp. 174795412110034
Author(s):  
Erin H Feser ◽  
Christian Korfist ◽  
Kyle Lindley ◽  
Neil E Bezodis ◽  
Kenneth Clark ◽  
...  
Keyword(s):  
Lower Limb ◽  
American Football ◽  
Control Group ◽  
Maximal Velocity ◽  
Sprint Training ◽  
Post Intervention ◽  
Training Time ◽  
Sprint Running ◽  
Mass Load ◽  
Low Volume

Time constraints often result in the challenge to fit desired programming into training time allotments. Wearable resistance (WR) may be an option to optimise the training content in function of constrained training time. The purpose of this study was to determine the effects of a lower-limb WR sprint running training intervention on athlete speed capabilities following a nine-week off-season, low volume training period within a sample of American football high school athletes. Nineteen athletes completed pre- and post-intervention testing of two maximal effort 30 m sprints. Horizontal force-velocity mechanical profiling variables, sprint times, and maximal velocity were calculated from sprint running velocity data collected by a radar device. The athletes completed seventeen dedicated sprint training sessions during the off-season. The intervention (WR) group completed the sessions with 1% body mass load attached to the shanks (i.e. 0.50% body mass load on each limb). The control group completed the same training sessions unloaded. Post-intervention, no statistically significant between group differences were observed ( p > 0.05). However, athletes in both groups experienced increases in velocity measures following the sprint training. The greater adjusted mean theoretical maximal velocity scores ( p > 0.05; ES = 0.30) found for the WR group compared to the control group at post-intervention may suggest that WR amplifies the nuances of the training protocol itself. Coaches can consider using lower-limb WR training to increase in-session workloads during periods of low volume training but more research is needed to better understand to what extent WR training might provide an added value to optimise both the training content and planning, as well as the athlete’s training response in order to improve sprint running performance.

scholarly journals Association between vertical and horizontal force-velocity-power profiles in netball players

2020 ◽  
Vol 17 (1) ◽  
Author(s):  
Juan Antonio Escobar-Álvarez ◽  
Juan Pedro Fuentes-García ◽  
Filipe Almeida Viana-da-Conceição ◽  
Pedro Jiménez-Reyes
Keyword(s):  
Horizontal Force ◽  
Force Velocity

Contractile properties of the striated adductor muscle in the bay scallop Argopecten irradians at several temperatures

1993 ◽  
Vol 176 (1) ◽  
pp. 175-193 ◽  
Author(s):  
J. M. Olson ◽  
R. L. Marsh
Keyword(s):  
Adductor Muscle ◽  
Contractile Properties ◽  
Temperature Sensitive ◽  
Maximal Velocity ◽  
Argopecten Irradians ◽  
Passive Force ◽  
Twitch Force ◽  
Peak Tension ◽  
Bay Scallop ◽  
Force Velocity

The isometric and isotonic contractile properties of the cross-striated adductor muscle of the bay scallop (Argopecten irradians) were measured in vitro at 10, 15 and 20 degrees C. The length at which twitch force was maximal as a function of the closed length in situ (L0/Lcl) averaged 1.38 +/− 0.01 (mean +/− S.E.M.) at 10 degrees C. This length is very close to the typical length at maximum gape during natural swimming at this temperature. Passive force was very low over the range of lengths measured here; at L0, passive force averaged approximately 0.08 N cm-2, or only 0.5% of the corresponding peak twitch force. The mean peak isometric twitch force (Ptw,max) at 10 degrees C was 21.43 +/− 0.68 N cm-2 (S.E.M.), and the ratio of peak twitch force to tetanic force (Ptw,max/P0) averaged 0.89 +/− 0.01. Temperature did not affect either twitch force (Ptw), once fatigue was taken into account, or Ptw,max/P0. In contrast, the time-related properties of twitch contractions (latent period, tL; time to peak tension, tPtw; and time from peak tension to half-relaxation, t50%R) were positively modified by temperature at all temperatures measured (Q10 &gt; 1.8). All three properties were more temperature-sensitive over the range 10–15 degrees C than over the range 15–20 degrees C. The force-velocity relationships of the striated adductor muscle were fitted to the hyperbolic-linear (HYP-LIN) equation. The force-velocity curves of the striated adductor muscle of the scallop were strongly influenced by temperature. Maximal velocity at zero force (Vmax), and therefore maximal power output, increased significantly with temperature. The Q10 over the temperature range 10–15 degrees C (1.42) was significantly lower than that over the range 15–20 degrees C (2.41). The shape of the force-velocity relationship, assessed through comparisons of the power ratio (Wmax/VmaxP0), was not influenced by temperature.

Teleseismic slowness-azimuth station corrections for the International Monitoring System Seismic Network

1999 ◽  
Vol 89 (4) ◽  
pp. 989-1003 ◽  
Author(s):  
István Bondár ◽  
Robert G. North ◽  
Gregory Beall
Keyword(s):  
Monitoring System ◽  
Global Network ◽  
Systematic Bias ◽  
International Monitoring System ◽  
Time Data ◽  
International Monitoring ◽  
Event Location ◽  
Systematic Biases ◽  
Predicted Values ◽  
Test Ban

Abstract The prototype International Data Center (PIDC) in Arlington, Virginia, has been developing and testing software and procedures for use in the verification of the Comprehensive Test Ban Treaty. After three years of operation with a global network of array and three-component stations, it has been possible to characterize various systematic biases of those stations that are designated in the Treaty as part of the International Monitoring System (IMS). These biases include deviations of azimuth and slowness measurements from predicted values, caused largely by lateral heterogeneity. For events recorded by few stations, azimuth and slowness are used in addition to arrival-time data for location by the PIDC. Corrections to teleseismic azimuth and slowness observations have been empirically determined for most IMS stations providing data to the PIDC. Application of these corrections is shown to improve signal association and event location. At some stations an overall systematic bias can be ascribed to local crustal structure or to unreported instrumental problems. The corrections have been applied in routine operation of the PIDC since February 1998.

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