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 Sled-Pull Load–Velocity Profiling and Implications for Sprint Training Prescription in Young Male Athletes

Sports ◽  
2019 ◽  
Vol 7 (5) ◽  
pp. 119 ◽  
Author(s):  
Micheál J. Cahill ◽  
Jon L. Oliver ◽  
John B. Cronin ◽  
Kenneth P. Clark ◽  
Matt R. Cross ◽  
...  
Keyword(s):  
High School ◽  
Confidence Intervals ◽  
Young Male ◽  
Team Sport ◽  
Maximal Velocity ◽  
Sprint Training ◽  
Young Athletes ◽  
Male Athletes ◽  
Velocity Relationship ◽  
School Team

The purpose of this study was to examine the usefulness of individual load–velocity profiles and the between-athlete variation using the decrement in maximal velocity (Vdec) approach to prescribe training loads in resisted sled pulling in young athletes. Seventy high school, team sport, male athletes (age 16.7 ± 0.8 years) were recruited for the study. All participants performed one un-resisted and four resisted sled-pull sprints with incremental resistance of 20% BM. Maximal velocity was measured with a radar gun during each sprint and the load–velocity relationship established for each participant. A subset of 15 participants was used to examine the reliability of sled pulling on three separate occasions. For all individual participants, the load–velocity relationship was highly linear (r > 0.95). The slope of the load–velocity relationship was found to be reliable (coefficient of variation (CV) = 3.1%), with the loads that caused a decrement in velocity of 10, 25, 50, and 75% also found to be reliable (CVs = <5%). However, there was a large between-participant variation (95% confidence intervals (CIs)) in the load that caused a given Vdec, with loads of 14–21% body mass (% BM) causing a Vdec of 10%, 36–53% BM causing a Vdec of 25%, 71–107% BM causing a Vdec of 50%, and 107–160% BM causing a Vdec of 75%. The Vdec method can be reliably used to prescribe sled-pulling loads in young athletes, but practitioners should be aware that the load required to cause a given Vdec is highly individualized.

Peak power output is maintained in rabbit psoas and rat soleus single muscle fibers when CTP replaces ATP

1998 ◽  
Vol 85 (1) ◽  
pp. 76-83 ◽  
Author(s):  
Philip A. Wahr ◽  
Joseph M. Metzger
Keyword(s):  
Muscle Contraction ◽  
Peak Power ◽  
Muscle Length ◽  
Peak Power Output ◽  
Fiber Types ◽  
Rabbit Psoas ◽  
Cross Bridge ◽  
Chemomechanical Coupling ◽  
Velocity Relationship ◽  
Force Velocity

The chemomechanical coupling mechanism in striated muscle contraction was examined by changing the nucleotide substrate from ATP to CTP. Maximum shortening velocity [extrapolation to zero force from force-velocity relation ( V max) and slope of slack test plots ( V 0)], maximum isometric force (Po), power, and the curvature of the force-velocity curve [ a/Po(dimensionless parameter inversely related to the curvature)] were determined during maximum Ca2+-activated isotonic contractions of fibers from fast rabbit psoas and slow rat soleus muscles by using 0.2 mM MgATP, 4 mM MgATP, 4 mM MgCTP, or 10 mM MgCTP as the nucleotide substrate. In addition to a decrease in the maximum Ca2+-activated force in both fiber types, a change from 4 mM ATP to 10 mM CTP resulted in a decrease in V max in psoas fibers from 3.26 to 1.87 muscle length/s. In soleus fibers, V max was reduced from 1.94 to 0.90 muscle length/s by this change in nucleotide. Surprisingly, peak power was unaffected in either fiber type by the change in nucleotide as the result of a three- to fourfold decrease in the curvature of the force-velocity relationship. The results are interpreted in terms of the Huxley model of muscle contraction as an increase in f 1and g 1 coupled to a decrease in g 2(where f 1 is the rate of cross-bridge attachment and g 1 and g 2 are rates of detachment) when CTP replaces ATP. This adequately accounts for the observed changes in Po, a/Po, and V max. However, the two-state Huxley model does not explicitly reveal the cross-bridge transitions that determine curvature of the force-velocity relationship. We hypothesize that a nucleotide-sensitive transition among strong-binding cross-bridge states following Pi release, but before the release of the nucleotide diphosphate, underlies the alterations in a/Poreported here.

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.

Dissecting muscle power output

1999 ◽  
Vol 202 (23) ◽  
pp. 3369-3375 ◽  
Author(s):  
R.K. Josephson
Keyword(s):  
Time Course ◽  
Muscle Activation ◽  
Muscle Force ◽  
Muscle Power ◽  
Muscle Length ◽  
Velocity Relationship ◽  
Shortening Deactivation ◽  
Force Velocity ◽  
Work Done ◽  
Kinetics Of

The primary determinants of muscle force throughout a shortening-lengthening cycle, and therefore of the net work done during the cycle, are (1) the shortening or lengthening velocity of the muscle and the force-velocity relationship for the muscle, (2) muscle length and the length-tension relationship for the muscle, and (3) the pattern of stimulation and the time course of muscle activation following stimulation. In addition to these primary factors, there are what are termed secondary determinants of force and work output, which arise from interactions between the primary determinants. The secondary determinants are length-dependent changes in the kinetics of muscle activation, and shortening deactivation, the extent of which depends on the work that has been done during the preceding shortening. The primary and secondary determinants of muscle force and work are illustrated with examples drawn from studies of crustacean muscles.

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).

Comparison of Knee Kinematics and Kinetics during Stair Ascent in Single-Radius and Multiradius Total Knee Arthroplasty

2018 ◽  
Vol 32 (09) ◽  
pp. 872-878 ◽  
Author(s):  
Bonnie Sumner ◽  
John D. McCamley ◽  
David J. Jacofsky ◽  
Marc C. Jacofsky
Keyword(s):  
Total Knee Arthroplasty ◽  
Knee Arthroplasty ◽  
Knee Kinematics ◽  
Power Production ◽  
Healthy Controls ◽  
Stair Ascent ◽  
Total Knee ◽  
Kinetics Of ◽  
Kinematics And Kinetics ◽  
Single Radius

AbstractTraditionally total knee arthroplasty (TKA) design has been based on theories of the movement of the healthy knee joint. Currently, there are two competing theories on the flexion/extension axis of rotation of the knee with disparate radii of rotation, and thus differing movement patterns. The purpose of our study was to compare stair ascent kinematics and kinetics of single-radius (SR) and multiradius (MR) TKA subjects. We hypothesized that the knee kinematics and kinetics of SR TKA patients would more closely replicate healthy age matched controls during stair ascent than MR TKA patients, 1 year after TKA. Both patient groups had large improvements in biomechanical and clinical outcome measures following surgical intervention. However, the SR knee design performs closer to healthy controls than MR knees during stair ascent, supporting results that have been previously obtained for level walking. SR TKA subjects demonstrated reduced power production and sagittal moment compared with controls, albeit more than MR TKA subjects. This study demonstrates that patients who receive SR TKA have kinematics more closely aligned to normal patterns postoperatively than those who received an MR TKA. The power production and sagittal moment of the healthy controls most closely match previously published values of younger adults, SR TKA group most closely matches older adults, while the MR TKA group has lower power production and sagittal moments than either previously published age group. This strongly suggests that the biomechanical differences found in this study are evidence of functional deficiencies. Further research is needed to determine how these deficiencies progress with patient aging.

scholarly journals Development and Validation of Prediction Formula of Wingate Test Peak Power From Force–Velocity Test in Male Soccer Players

2021 ◽  
Vol 12 ◽  
Author(s):  
Pantelis T. Nikolaidis ◽  
Beat Knechtle
Keyword(s):  
Body Mass ◽  
Fat Mass ◽  
Peak Power ◽  
Prediction Equation ◽  
Mean Difference ◽  
Interindividual Variation ◽  
Soccer Players ◽  
Maximal Velocity ◽  
Force Velocity ◽  
Development And Validation

Peak power of the Wingate anaerobic test (WAnT), either in W (Ppeak) or in W.kg–1 (rPpeak), has been widely used to evaluate the performance of soccer players; however, its relationship with force–velocity (F-v) test (e.g., whether these tests can be used interchangeably) has received little scientific attention so far. The aim of this work was to develop and validate a prediction equation of Ppeak and rPpeak from F-v characteristics in male soccer players. Participants were 158 adult male soccer players (sport experience 11.4 ± 4.5 years, mean ± standard deviation, approximately five weekly training units, age 22.6 ± 3.9 years, body mass 74.8 ± 7.8 kg, and height 178.3 ± 7.8 cm) who performed both WAnT and F-v test. An experimental (EXP, n = 79) and a control group (CON, n = 79) were used for development and validation, respectively, of the prediction equation of Ppeak and rPpeak from F-v test. In EXP, Ppeak correlated very largely with body mass (r = 0.787), fat-free mass (r = 0.765), largely with maximal power of F-v test (Pmax; r = 0.639), body mass index (r = 0.603), height (r = 0.558), moderately with theoretical maximal force (F0; r = 0.481), percentage of body fat (r = 0.471), fat mass (r = 0.443, p &lt; 0.001); rPpeak correlated with rPmax (largely; r = 0.596, p &lt; 0.001), theoretical maximal velocity (v0; moderately; r = 0.341, p = 0.002), F0 (small magnitude; r = 0.280, p = 0.012), BF (r = −0.230, p = 0.042), and fat mass (r = −0.242, p = 0.032). Ppeak in EXP could be predicted using the formula “44.251 + 7.431 × body mass (kg) + 0.576 × Pmax (W) – 19.512 × F0” (R = 0.912, R2 = 0.833, standard error of estimate (SEE) = 42.616), and rPpeak from “3.148 + 0.218 × rPmax (W.kg–1) + v0 (rpm)” (R = 0.765, R2 = 0.585, SEE = 0.514). Applying these formulas in CON, no bias was observed between the actual and the predicted Ppeak (mean difference 2.5 ± 49.8 W; 95% CI, −8.7, 13.6; p = 0.661) and rPpeak (mean difference 0.05 ± 0.71 W.kg–1; 95% CI, −0.11, 0.21, p = 0.525). These findings provided indirect estimates of Ppeak of the WAnT, especially useful in periods when this test should not be applied considering the fatigue it causes; in this context, the F-v test can be considered as an alternative of exercise testing for estimating the average Ppeak of a group of soccer players rather than for predicting individual scores when the interindividual variation of performance is small.

scholarly journals Operating length and velocity of human M. vastus lateralis fascicles during vertical jumping

2017 ◽  
Vol 4 (5) ◽  
pp. 170185 ◽  
Author(s):  
Maria Elissavet Nikolaidou ◽  
Robert Marzilger ◽  
Sebastian Bohm ◽  
Falk Mersmann ◽  
Adamantios Arampatzis
Keyword(s):  
Velocity Potential ◽  
Vastus Lateralis ◽  
Power Production ◽  
Velocity Curve ◽  
Mechanical Power ◽  
Jump Height ◽  
Velocity Relationship ◽  
Force Velocity ◽  
The Mean ◽  
Force Potential

Humans achieve greater jump height during a counter-movement jump (CMJ) than in a squat jump (SJ). However, the crucial difference is the mean mechanical power output during the propulsion phase, which could be determined by intrinsic neuro-muscular mechanisms for power production. We measured M. vastus lateralis (VL) fascicle length changes and activation patterns and assessed the force–length, force–velocity and power–velocity potentials during the jumps. Compared with the SJ, the VL fascicles operated on a more favourable portion of the force–length curve (7% greater force potential, i.e. fraction of VL maximum force according to the force–length relationship) and more disadvantageous portion of the force–velocity curve (11% lower force potential, i.e. fraction of VL maximum force according to the force–velocity relationship) in the CMJ, indicating a reciprocal effect of force–length and force–velocity potentials for force generation. The higher muscle activation (15%) could therefore explain the moderately greater jump height (5%) in the CMJ. The mean fascicle-shortening velocity in the CMJ was closer to the plateau of the power–velocity curve, which resulted in a greater (15%) power–velocity potential (i.e. fraction of VL maximum power according to the power–velocity relationship). Our findings provide evidence for a cumulative effect of three different mechanisms—i.e. greater force–length potential, greater power–velocity potential and greater muscle activity—for an advantaged power production in the CMJ contributing to the marked difference in mean mechanical power (56%) compared with SJ.

Maintenance of Velocity and Power With Cluster Sets During High-Volume Back Squats

2016 ◽  
Vol 11 (7) ◽  
pp. 885-892 ◽  
Author(s):  
James J. Tufano ◽  
Jenny A. Conlon ◽  
Sophia Nimphius ◽  
Lee E. Brown ◽  
Laurent B. Seitz ◽  
...  
Keyword(s):  
Peak Power ◽  
Peak Velocity ◽  
High Volume ◽  
Effect Sizes ◽  
Maximal Velocity ◽  
Mean Power ◽  
Mean Velocity ◽  
Cluster Set ◽  
Cluster Sets ◽  
Force Velocity

Purpose:To compare the effects of a traditional set structure and 2 cluster set structures on force, velocity, and power during back squats in strength-trained men.Methods:Twelve men (25.8 ± 5.1 y, 1.74 ± 0.07 m, 79.3 ± 8.2 kg) performed 3 sets of 12 repetitions at 60% of 1-repetition maximum using 3 different set structures: traditional sets (TS), cluster sets of 4 (CS4), and cluster sets of 2 (CS2).Results:When averaged across all repetitions, peak velocity (PV), mean velocity (MV), peak power (PP), and mean power (MP) were greater in CS2 and CS4 than in TS (P < .01), with CS2 also resulting in greater values than CS4 (P < .02). When examining individual sets within each set structure, PV, MV, PP, and MP decreased during the course of TS (effect sizes 0.28–0.99), whereas no decreases were noted during CS2 (effect sizes 0.00–0.13) or CS4 (effect sizes 0.00–0.29).Conclusions:These results demonstrate that CS structures maintain velocity and power, whereas TS structures do not. Furthermore, increasing the frequency of intraset rest intervals in CS structures maximizes this effect and should be used if maximal velocity is to be maintained during training.

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