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.

Interrelationships among Jumping Power, Sprinting Power and Pubertal Status after Controlling for Size in Young Male Soccer Players

2017 ◽  
Vol 124 (2) ◽  
pp. 329-350 ◽  
Author(s):  
Giovani S. Cunha ◽  
Sean P. Cumming ◽  
João Valente-dos-Santos ◽  
João P. Duarte ◽  
Gustavo Silva ◽  
...  
Keyword(s):  
Body Size ◽  
Effect Size ◽  
Power Output ◽  
Allometric Scaling ◽  
Young Male ◽  
Soccer Players ◽  
Large Effect Size ◽  
Maximal Power Output ◽  
Pubertal Status ◽  
Small Effect Size

This study examined power output on jumping and sprinting tests in young soccer players of differing pubertal status, while controlling for body size with allometric scaling exponents. A total of 46 males aged 12–18 years (14.17 years) were divided into three groups: pre-pubescent ( n = 12), pubescent ( n = 22), and post-pubescent ( n = 12). Participants performed a series of tests, including the squat jump (SJ), countermovement jump (CMJ), and 10-meter and 30-meter sprint test protocols. The Post-PUB group was older ( F = 112.411, p < 0.001), more experienced in competitive soccer ( F = 8.055, p = 0.001), taller ( F = 28.940, p < 0.001), and heavier ( F = 20.618, p < 0.001), when compared to peers in the other groups. Mean differences in jumping and sprinting performances suggested a significant effect for pubertal status on performance in the 10-meter sprint (large effect size, F = 8.191, p < 0.001) and 30-meter sprint (large effect size, F = 8.093, p < 0.001) after allometric scaling. Power output derived from SJ (small effect size, F = 0.536, p = 0.001) and CMJ (small effect size, F = 1.058, p = 0.356) showed no significant differences across players of varying pubertal status. Biological maturation showed a large effect on maximal power output for sprints, but not for jumps, when the effect of body size was adjusted by statistically derived allometric exponents in young male soccer players.

Lower Limb Force, Velocity, Power Capabilities during Leg Press and Squat Movements

2017 ◽  
Vol 38 (14) ◽  
pp. 1083-1089 ◽  
Author(s):  
Johnny Padulo ◽  
Gian Migliaccio ◽  
Luca Ardigò ◽  
Bruno Leban ◽  
Marco Cosso ◽  
...  
Keyword(s):  
Velocity Profile ◽  
Effect Size ◽  
Power Output ◽  
Lower Limb ◽  
Maximal Power ◽  
Maximal Power Output ◽  
Optimal Velocity ◽  
Leg Press ◽  
Maximal Force ◽  
Force Velocity

AbstractThe aim was to compare lower-limb power, force, and velocity capabilities between squat and leg press movements. Ten healthy sportsmen performed ballistic lower-limb push-offs against 5-to-12 different loads during both the squat and leg press. Individual linear force-velocity and polynomial power-velocity relationships were determined for both movements from push-off mean force and velocity measured continuously with a pressure sensor and linear encoder. Maximal power output, theoretical maximal force and velocity, force-velocity profile and optimal velocity were computed. During the squat, maximal power output (17.7±3.59 vs. 10.9±1.39 W·kg−1), theoretical maximal velocity (1.66±0.29 vs. 0.88±0.18 m·s−1), optimal velocity (0.839±0.144 vs. 0.465±0.107 m·s−1), and force-velocity profile (−27.2±8.5 vs. −64.3±29.5 N·s·m−1·kg−1) values were significantly higher than during the leg press (p=0.000, effect size=1.72–3.23), whereas theoretical maximal force values (43.1±8.6 vs. 51.9±14.0 N·kg−1, p=0.034, effect size=0.75) were significantly lower. The mechanical capabilities of the lower-limb extensors were different in the squat compared with the leg press with higher maximal power due to much higher velocity capabilities (e.g. ability to produce force at high velocities) even if moderately lower maximal force qualities.

Vertical Impulse as a Determinant of Combination of Step Length and Frequency During Sprinting

2018 ◽  
Vol 39 (04) ◽  
pp. 282-290 ◽  
Author(s):  
Ryu Nagahara ◽  
Yohei Takai ◽  
Hiroaki Kanehisa ◽  
Tetsuo Fukunaga
Keyword(s):  
Step Length ◽  
Soccer Players ◽  
Ground Reaction Forces ◽  
Acceleration Phase ◽  
Mean Values ◽  
Reaction Forces ◽  
The Mean ◽  
Initial Acceleration ◽  
Braking Phase ◽  
Step Section

AbstractThis study aimed to clarify the influence of vertical impulse on the magnitude of step length (SL) and frequency (SF) and their ratio during the entire acceleration phase of maximal sprinting. Thirty-nine male soccer players performed 60-m sprints, during which step-to-step ground reaction forces were recorded over a 50-m distance. The mean values of spatiotemporal variables and vertical and anteroposterior impulses for each set of four steps during the acceleration phase until the 28th step were computed to examine relationships among variables in seven sections. When controlling for the influence of running speed, stature and corresponding duration of braking or propulsion, vertical impulses during the propulsive phase at the 1st–4th step section and those during the braking phases in the sections from the 5th–8th to the 25th–28th step were positively correlated with SL and SL/SF ratio and negatively correlated with SF, whereas the anteroposterior impulses were not correlated with SL or SF. In conclusion, the current results demonstrate that vertical impulse during the propulsive phase in the initial acceleration stage and that during the braking phase in the middle and later acceleration stages are the most likely determinants of the combination of SL and SF during sprinting.

scholarly journals Effects of carbohydrate intake on time to exhaustion and anaerobic contribution during supramaximal exercise

2016 ◽  
Vol 29 (5) ◽  
pp. 691-697 ◽  
Author(s):  
Victor José BASTOS-SILVA ◽  
Sara Kely LEARSI ◽  
Alan de Albuquerque MELO ◽  
Adriano Eduardo LIMA-SILVA ◽  
Gustavo Gomes de ARAUJO
Keyword(s):  
Effect Size ◽  
Power Output ◽  
Constant Load ◽  
Cycle Ergometer ◽  
Maximum Power ◽  
Carbohydrate Intake ◽  
Time To Exhaustion ◽  
Supramaximal Exercise ◽  
Physically Active ◽  
Maximum Power Output

ABSTRACT Objective: This study evaluated the effect of carbohydrate intake on time to exhaustion and anaerobic contribution during supramaximal exercise on a cycle ergometer. Methods: The sample comprised ten participants with a mean age of 23.9±2.5 years, mean body mass of 75.1±12.3 kg, mean height of 170.0±1.0 cm, and mean body fat of 11.3±5.2%. The participants underwent an incremental test to determine maximal oxygen uptake and maximum power output, and two supramaximal tests with a constant load of 110% of the maximum power output to exhaustion. Thirty minutes before the supramaximal tests the participants consumed carbohydrates (2 g.kg-1) or placebo. Results: The times to exhaustion of carbohydrate and placebo did not differ (carbohydrate: 170.7±44.6s; placebo: 156.1±26.7s, p=0.17; effect size=0.39). Similarly, the anaerobic contributions of the two treatments did not differ (carbohydrate: 3.0±0.9 L; placebo: 2.7±1.1 L, p=0.23; effect size=0.29). Conclusion: Carbohydrate intake was not capable of increasing time to exhaustion and anaerobic contribution in physically active men cycling at 110% of maximum power output.

Power output of sound-producing muscles in the tree frogs Hyla versicolor and Hyla chrysoscelis

1999 ◽  
Vol 202 (22) ◽  
pp. 3225-3237 ◽  
Author(s):  
M. Girgenrath ◽  
R.L. Marsh
Keyword(s):  
Power Output ◽  
Maximum Power ◽  
Trunk Muscles ◽  
Total Power ◽  
Hyla Versicolor ◽  
Tree Frog ◽  
Hyla Chrysoscelis ◽  
Force Velocity ◽  
External Oblique

Sound-producing muscles provide the opportunity of studying the limits of power production at high contractile frequencies. We used the work loop technique to determine the power available from the external oblique muscles in two related species of North American gray tree frog, Hyla chrysoscelis and Hyla versicolor. These trunk muscles contract cyclically, powering high-intensity sound production in anuran amphibians. The external oblique muscles in H. chrysoscelis have an in vivo operating frequency of 40–55 Hz at 20–25 degrees C, whereas in H. versicolor these muscles contract with a frequency of 20–25 Hz at these temperatures. In vivo investigations have shown that these muscles use an asymmetrical sawtooth length trajectory (with a longer shortening phase compared with the lengthening phase) during natural cycles. To study the influence of this particular length trajectory on power output, we subjected the muscles to both sinusoidal and sawtooth length trajectories. In both species, the sawtooth trajectory yielded a significantly higher power output than the sinusoidal length pattern. The maximum power output during sawtooth cycles was similar in both species (54 W kg(−)(1) in H. chrysoscelis and 58 W kg(−)(1) in H. versicolor). These values are impressive, particularly at the operating frequencies and temperatures of the muscle. The sinusoidal length trajectory yielded only 60 % of the total power output compared with the sawtooth trajectory (34 W kg(−)(1) for H. chrysoscelis and 36 W kg(−)(1) for H. versicolor). The optimum cycle frequencies maximizing the power output using a sawtooth length pattern were approximately 44 Hz for H. chrysoscelis and 21 Hz for H. versicolor. These frequencies are close to those used by the two species during calling. Operating at higher frequencies, H. chrysoscelis maximized power at a strain amplitude of only 8 % compared with a value of 12 % in H. versicolor. These strains match those used in vivo during calling. The stimulus timing observed in vivo during calling was also similar to that yielding maximum power at optimal frequency in both species (6 ms and 8 ms before the start of shortening in H. chrysoscelis and H. versicolor, respectively). As expected, twitch duration in H. chrysoscelis is much shorter than that in H. versicolor (23 ms and 37 ms, respectively). There was a less remarkable difference between their maximum shortening velocities (V(max)) of 13.6 L(0)s(−)(1) in H. chrysoscelis and 11.1 L(0)s(−)(1) in H. versicolor, where L(0) is muscle length. The force-velocity curves are very flat, which increases power output. At the myofibrillar level, the flat force-velocity curves more than compensate for the lower peak isometric force found in these muscles. The data presented here emphasize the importance of incorporating in vivo variables in designing in vitro studies.

scholarly journals Time series of ground reaction forces following a single leg drop jump landing in elite youth soccer players consist of four distinct phases

2016 ◽  
Vol 50 ◽  
pp. 137-144 ◽  
Author(s):  
Duncan P. Fransz ◽  
Arnold Huurnink ◽  
Vosse A. de Boode ◽  
Idsart Kingma ◽  
Jaap H. van Dieën
Keyword(s):  
Time Series ◽  
Soccer Players ◽  
Ground Reaction Forces ◽  
Drop Jump ◽  
Youth Soccer ◽  
Jump Landing ◽  
Reaction Forces

Differences in Sprint Mechanical Force–Velocity Profile Between Trained Soccer and Futsal Players

2019 ◽  
Vol 14 (4) ◽  
pp. 478-485 ◽  
Author(s):  
Pedro Jiménez-Reyes ◽  
Amador García-Ramos ◽  
Victor Cuadrado-Peñafiel ◽  
Juan A. Párraga-Montilla ◽  
José A. Morcillo-Losa ◽  
...  
Keyword(s):  
Velocity Profile ◽  
Testing Procedure ◽  
Mechanical Force ◽  
Resultant Force ◽  
Soccer Players ◽  
Maximal Power ◽  
Time Data ◽  
Force Velocity ◽  
High Level ◽  
Different Levels

Purpose: To compare the sprint mechanical force–velocity (F–V) profile between soccer and futsal players. A secondary aim was, within each sport, to study the differences in sprint mechanical F–V profile between sexes and players of different levels. Methods: A total of 102 soccer players (63 men) and 77 futsal players (49 men) who were competing from the elite to amateur levels in the Spanish league participated in this investigation. The testing procedure consisted of 3 unloaded maximal 40-m sprints. The velocity–time data recorded by a radar device were used to calculate the variables of the sprint acceleration F–V profile (maximal theoretical force [F0], maximal theoretical velocity [V0], maximal power [Pmax], decrease in the ratio of horizontal to resultant force [DRF], and maximal ratio of horizontal to resultant force [RFpeak]). Results: Futsal players showed a higher F0 than soccer players (effect size [ES] range: 0.11–0.74), while V0 (ES range: −0.48 to −1.15) and DRF (ES range: −0.75 to −1.45) was higher for soccer players. No significant differences were observed between soccer and futsal players for Pmax (ES range: −0.43 to 0.19) and RFpeak (ES range: −0.49 to 0.30). Men and high-level players presented an overall enhanced F–V profile compared with women and their lower-level counterparts, respectively. Conclusions: The higher F0 and lower V0 of futsal players could be caused by the game’s specific demands (larger number of accelerations but over shorter distances than in soccer). These results show that the sprint mechanical F–V profile is able to distinguish between soccer and futsal players.

Plasma and synovial concentrations of carprofen in dogs with chronic osteoarthritis

2001 ◽  
Vol 14 (01) ◽  
pp. 19-24 ◽  
Author(s):  
T. A. Schneider ◽  
S. C. Budsberg
Keyword(s):  
Synovial Fluid ◽  
Cruciate Ligament ◽  
Plasma Concentrations ◽  
Force Plate ◽  
Total Force ◽  
Ground Reaction Forces ◽  
Test Protocol ◽  
Time Period ◽  
Significant Difference ◽  
Reaction Forces

SummaryThe objective of this study was to measure the synovial and plasma concentration of carprofen in normal and osteoarthritic stifle joints throughout a 12-hour period. Eight healthy male mixed breed hound dogs with chronic right stifle osteoarthritis (OA) secondary to right cruciate ligament transection, were used. Each dog was treated with carprofen (2mg/kg every 12 hours) for 14 days at four different time periods. Prior to treatment, each dog had baseline data collected that included two force plate evaluations (seven days apart), synovial fluid, and plasma collections. Plasma samples were collected at three hours post drug administration on days two, four, six, eight, 10, and 12. On days #7 and 14 plasma, serum, bilateral stifle synovial fluid and ground reaction forces (GRFs) were collected at three, six, nine, or 12 hours post-medication, depending upon the test protocol. Vertical and cranio-caudal ground reaction forces were recorded at each time period. Plasma concentrations measured at three hours remained constant over each testing protocol. There were not any differences between the plasma carprofen concentrations at three, nine, or 12 hours between days #7 or 14. A significant difference was not found in the carprofen synovial concentrations between left and right stifles at any time. Significant increases in vertical impulse data were found at six hours post-treatment, for all of the collection periods on days three, seven and 14. During the study, there was not any indication that carprofen had a ‘preference’ for the OA stifle as opposed to the normal stifle. Carprofen administration increased the total force transmitted through the abnormal limb.Carprofen concentrations in the plasma and synovial fluid and ground reaction forces were measured in dogs with single stifle osteoarthritis at three, six, nine and 12 hours following dosing at 2 mg/kg every 12 hours. Carprofen did not have a ‘preference’ for the OA stifle as opposed to the normal stifle. Carprofen administration increased the total force transmitted through the abnormal limb.

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