scholarly journals A comparison of acceleration and maximum speed sprint training on eccentric hamstring strength and hamstring muscle architecture

2021 ◽  
Vol 24 ◽  
pp. S6-S7
Author(s):  
B. Freeman ◽  
L. James ◽  
D. Opar ◽  
S. Tapley ◽  
W. Young
Keyword(s):  
Muscle Architecture ◽  
Maximum Speed ◽  
Hamstring Muscle ◽  
Sprint Training

scholarly journals The effects of eccentric training on hamstring muscle architecture

Kinesiology ◽  
2021 ◽  
Vol 53 (1) ◽  
pp. 141-153
Author(s):  
Murat Emirzeoğlu ◽  
Tüzün Fırat ◽  
Özlem Ülger
Keyword(s):  
Training Session ◽  
Muscle Thickness ◽  
Muscle Architecture ◽  
Eccentric Training ◽  
Hamstring Muscle ◽  
Cross Sectional ◽  
Functional Changes ◽  
Hamstring Injuries ◽  
Architectural Features ◽  
Hand Muscle

The architectural features of the hamstring muscle group are important to prevent injury or to reduce the risk of re-injury. Besides, eccentric training is often used in the rehabilitation of hamstring injuries. The aim of this systematic review was to examine the changes created by eccentric training on hamstring muscle architecture and to determine the minimal values of training duration and intensity for requiring functional changes. The research was conducted on the PubMed, Scopus, Web of Science, COCHRANE, CINAHL, and Pedro databases. Full-text studies examining the effect of eccentric training on at least one parameter of the hamstring muscle architecture were included in the review. Studies on cadavers and animals and studies involving different types of training combined with eccentric training were excluded. Twelve of the 7954 studies met the set criteria. According to the results, eccentric training undoubtedly increases fiber length. However, the pennation angle tends to decrease. On the other hand, muscle thickness and cross-sectional area tends to increase depending on the eccentric training. Although the frequency, number of sets and number of repetitions in sets were similar in the examined studies, muscle architecture changes were different. We think that eccentric training duration and the number of repetitions in total or per training session seem to have an impact on muscle architecture. In order to determine the minimal eccentric training program that can create these changes, quality research is needed to examine the duration, intensity and methods of eccentric training.

scholarly journals Effects of Plyometric and Repeated Sprint Training on Physical Performance

Sports ◽  
2020 ◽  
Vol 8 (7) ◽  
pp. 91
Author(s):  
Ivan Krakan ◽  
Luka Milanovic ◽  
Ivan Belcic
Keyword(s):  
Training Program ◽  
Physical Performance ◽  
Diagnostic Procedures ◽  
Maximum Speed ◽  
Plyometric Training ◽  
Sprint Training ◽  
Repeated Sprint Ability ◽  
Repeated Sprint ◽  
Significant Difference ◽  
Sprint Ability

The purpose of study was to resolve the effect of plyometric training and repeated sprint training on physical performance. The study was conducted on 41 subjects in two experimental groups (plyometric/repeated sprints training). Before and after the training program, subjects were subjected to diagnostic procedures that included standard test protocols. Results proved a statistically significant difference only after the plyometric training program compared to the repeated sprint group in countermovement jump (8.65% vs. 2.21%). In variable repeated jumps, an increased value was recorded (2.9% vs. 4.29%), like in sprint variables after the training program where certain trends of progress happened after the repeated sprint ability training and the specificity of the program (5 m = 0.89%, 10 m = 1.07% and 25 m = 1.35%), while plyometric training recorded unchanged values at 5 and 10 m, and a 0.27% improvement at 25 m. Stagnation of the 20-yard test was recorded in both groups. There was no difference between training programs in any variables of functional capacities, with similar measures recorded in repeated sprint ability. After six weeks of both training types, positive changes can be expected in explosive strength of lower extremities, increases in acceleration area, and maximum speed.

Hamstring muscle architecture and myotonometer measurements in elite professional football players with a prior strained hamstring

2023 ◽  
Author(s):  
F. Javier Núñez ◽  
Juan Carlos Martínez ◽  
Jan-Arie Overberg ◽  
Nacho Torreno ◽  
Luis Suarez-Arrones
Keyword(s):  
Muscle Architecture ◽  
Football Players ◽  
Professional Football ◽  
Hamstring Muscle

Impact of Askling L-PROTOCOL on muscle architecture, flexibility and sprint performance.

2021 ◽  
Author(s):  
Diego Alonso-Fernandez ◽  
Juan Martinez-Fernandez ◽  
Pedro Docampo-Blanco ◽  
Rosana Fernandez-Rodriguez
Keyword(s):  
Muscle Architecture ◽  
Sprint Performance ◽  
Moderate Intensity ◽  
Control Group ◽  
Maximum Speed ◽  
Eccentric Training ◽  
Fascicle Length ◽  
Hamstring Flexibility ◽  
The Impact ◽  
Experimental Group

Eccentric training has been shown to be important for hamstring strain injuries rehabilitation and prevention. The Askling L-PROTOCOL (L-P), comprising three exercises aimed at eccentric training and hamstring lengthening, was shown to improve this injuries recovery and relapse times in comparison with other traditional exercise-based protocols. However, the causes of these results remain unclear. This study looks at the impact of an 8-week L-P followed by 4 weeks of detraining on the architecture of the biceps femoris long head, hamstring flexibility and sprint performance. Twenty-eight healthy individuals were divided into two groups: an experimental group, which carried out the L-P, and a control group with no training. Muscle architecture was measured using 2Dultrasound, hamstring flexibility using goniometry and sprint performance using sports radar equipment before(M1) and after(M2) the training period and after detraining(M3). No significant changes were observed between M1 and M2 in the experimental group with regard to fascicle length(t=-0.79,P>.05), theoretical maximum speed (t=-1.43,P>.05), horizontal force (t=0.09,P>.05), force application during sprint running(t=-0.09,P>.05) and horizontal power (t =-0.97,P>.05), but, however, changes were observed in hamstring flexibility (t=-4.42,d=0.98,P<.001) returning to pre-training values after detraining period(t=-1.11,P>.05). L-P has been shown to be an eccentric protocol of moderate intensity and easy implementation that could be interesting to include throughout a sport season.

scholarly journals Biceps Femoris Long Head Muscle Fascicles Actively Lengthen During the Nordic Hamstring Exercise

2021 ◽  
Vol 3 ◽  
Author(s):  
Brent J. Raiteri ◽  
Ronja Beller ◽  
Daniel Hahn
Keyword(s):  
Knee Flexion ◽  
Injury Risk ◽  
Biceps Femoris ◽  
Muscle Architecture ◽  
Muscle Action ◽  
Hamstring Muscle ◽  
Tracking Algorithms ◽  
Muscle Fascicle ◽  
Long Head ◽  
Biceps Femoris Long Head

Current debate exists around whether a presumed eccentric exercise, the Nordic hamstring exercise (NHE), actually causes active hamstring muscle lengthening. This is because of the decoupling that can occur between the muscle fascicle and muscle-tendon unit (MTU) length changes in relatively compliant human lower-limb MTUs, which results in MTU lengthening not necessarily causing muscle fascicle lengthening. This missing knowledge complicates the interpretation of why the NHE is effective at reducing running-related hamstring muscle injury risk in athletes previously unfamiliar with performing this exercise. The purpose of the study was therefore to investigate if the most-commonly injured hamstring muscle, the biceps femoris long head (BF), exhibits active muscle lengthening (i.e. an eccentric muscle action) during the NHE up until peak force in Nordic novices. External reaction force at the ankle, knee flexion angle, and BF and semitendinosus muscle activities were recorded from the left leg of 14 participants during the NHE. Simultaneously, BF muscle architecture was imaged using B-mode ultrasound imaging, and muscle architecture changes were tracked using two different tracking algorithms. From ~85 to 100% of peak NHE force, both tracking algorithms detected that BF muscle fascicles (n = 10) significantly lengthened (p &lt; 0.01) and had a mean positive lengthening velocity (p ≤ 0.02), while knee extension velocity remained positive (17°·s−1) over knee flexion angles from 53 to 37° and a duration of 1.6 s. Despite some individual cases of brief isometric fascicle behavior and brief fascicle shortening during BF MTU lengthening, the predominant muscle action was eccentric under a relatively high muscle activity level (59% of maximum). Eccentric hamstring muscle action therefore does occur during the NHE in relatively strong (429 N) Nordic novices, which might contribute to the increase in resting BF muscle fascicle length and reduction in running-related injury risk, which have previously been reported following NHE training. Whether an eccentric BF muscle action occurs in individuals accustomed to the NHE remains to be tested.

scholarly journals Gradual vs. Maximal Acceleration: Their Influence on the Prescription of Maximal Speed Sprinting in Team Sport Athletes

Sports ◽  
2018 ◽  
Vol 6 (3) ◽  
pp. 66
Author(s):  
Warren Young ◽  
Grant Duthie ◽  
Lachlan James ◽  
Scott Talpey ◽  
Dean Benton ◽  
...  
Keyword(s):  
Interval Training ◽  
Team Sport ◽  
Maximum Speed ◽  
Sprint Training ◽  
Experimental Conditions ◽  
Maximum Acceleration ◽  
Maximal Acceleration ◽  
Maximal Speed ◽  
Speed Effect ◽  
Peak Speed

The primary purpose of this study was to determine if a difference existed between peak speed attained when performing a sprint with maximal acceleration versus from a gradual build-up. Additionally, this investigation sought to compare the actual peak speed achieved when instructed to reach 75% and 90% of maximum speed. Field sport athletes (n = 21) performed sprints over 60 m under the experimental conditions, and the peak speed was assessed with a radar gun. The gradual build-up to maximum speed (8.30 ± 0.40 m∙s−1) produced the greater peak speed (effect size = 0.3, small) than the maximum acceleration run (8.18 ± 0.40 m∙s−1), and the majority of participants (62%) followed this pattern. For the sub-maximum runs, the actual mean percentage of maximum speed reached was 78 ± 6% for the 75% prescribed run and 89 ± 5% for the 90% prescription. The errors in attaining the prescribed peak speeds were large (~15%) for certain individuals, especially for the 75% trial. Sprint training for maximum speed should be performed with a gradual build-up of speed rather than a maximum acceleration. For sub-maximum interval training, the ability to attain the prescribed target peak speed can be challenging for field sport athletes, and therefore where possible, feedback on peak speeds reached should be provided after each repetition.

scholarly journals Effect of Traditional and Resisted Sprint Training in Highly Trained Female Team Handball Players

2015 ◽  
Vol 10 (5) ◽  
pp. 642-647 ◽  
Author(s):  
Live S. Luteberget ◽  
Truls Raastad ◽  
Olivier Seynnes ◽  
Matt Spencer
Keyword(s):  
Pennation Angle ◽  
Muscle Architecture ◽  
Sprint Performance ◽  
Sprint Training ◽  
Fascicle Length ◽  
Sprint Time ◽  
Beneficial Effects ◽  
Team Handball ◽  
Perfect Correlation ◽  
Underlying Mechanisms

Fast acceleration is an important performance factor in handball. In addition to traditional sprint training (TST), resisted-sprint training (RST) is a method often used to improve acceleration. However, studies on RST show conflicting results, and underlying mechanisms have not been studied.Purpose:To compare the effects of RST, by sled towing, against TST on sprint performance and muscle architecture.Methods:Participants (n = 18) were assigned to either RST or TST and completed 2 training sessions of RST or TST per week (10 wk), in addition to their normal team training. Sprint tests (10 and 30 m) and measurements of muscle architecture were performed pre- and posttraining.Results:Beneficial effects were found in the 30-m-sprint test for both groups (mean; ±90% CL: TST = −0.31; ±0.19 s, RST = −0.16; ±0.13 s), with unclear differences between the groups. Only TST had a beneficial effect on 10-m time (−0.04; ±0.04 s), with a likely difference between the 2 groups (85%, ES = 0.60). Both groups had a decrease in pennation angle (−6.0; ±3.3% for TST and −2.8; ±2.0% for RST), which had a nearly perfect correlation with percentage change in 10-m-sprint performance (r = .92). A small increase in fascicle length (5.3; ±3.9% and 4.0; ±2.1% for TST and RST, respectively) was found, with unclear differences between groups.Discussion:TST appears to be more effective than RST in enhancing 10-m-sprint time. Both groups showed similar effects in 30-m-sprint time. A similar, yet small, effect of sprint training on muscle architecture was observed in both groups.

scholarly journals Optimizing the load for peak power and peak velocity development during resisted sprinting

2021 ◽  
Vol 9 (1) ◽  
pp. 128-134
Author(s):  
Aleksander Matusiński ◽  
Artur Gołaś ◽  
Adam Zając ◽  
Magdalena Nitychoruk ◽  
Adam Maszczyk
Keyword(s):  
Body Mass ◽  
Body Height ◽  
Ground Surface ◽  
Random Order ◽  
Maximum Speed ◽  
Sprint Training ◽  
Technology System ◽  
Additional Resistance ◽  
Sprinting Speed ◽  
Resisted Sprinting

Introduction: Resistance towing is perhaps the most specific form of developing strength and power in muscles involved directly during the start, acceleration and at maximum speed. Resisted sprint training may involve towing a sled which provides an overload through the friction between the sled and ground surface or a modern advanced training device which uses drag technology to provide fully controlled resistance during the movement, such as the 1080 Sprint. The main objective of the study was to evaluate the optimal loading for the development of power in the engine assisted drag technology system SPRINT 1080. Material and methods: We evaluated the changes in running velocity and the generated force and power during resisted sprints over 30m with a load of 1, 3, 6, 9, 12 and 15 kg. Seven male sprinters with national and international experience participated in the study. Their average age, body mass and body height were 22.2 ± 2.4 years, 77.43 ± 4.63 kg, and 178.6 ± 3.2 cm, respectively. All athletes performed six 30 m sprints with 5 min rest intervals in between. The first sprint was performed without additional resistance, while the remaining 5 were performed in an random order with additional resistance of 3, 6, 9, 12 and 15 kg. After receiving a verbal signal, the participant started at will from a semi crouched position. During the resisted sprint trials, the time [s] and the following variables were recorded in peak values: power output [W], generated force [N], and sprinting velocity [m/s]. Results: Our results show that loading with 6 kg decreased sprinting velocity by 9.37% while the generated horizontal power increased by 31,32%. The 6 kg loading on the Sprint 1080device corresponded to 8% body mass, yet as mentioned before the baseline results were not fully free sprinting as the tested athletes reached velocities 0.5-0.6 m/s greater without the harness. Conclusion: Taking into account this fact, our results seem to confirm previous findings, that external loads between 8 and 13% may be optimal for improving power and sprinting speed at the same time.

The correlation of hamstring muscle functionality with hamstring muscle strength and ultrasound based hamstring muscle architecture parameters

2020 ◽  
Vol 81 ◽  
pp. 178
Author(s):  
G. Karaca ◽  
N.E. Akalan ◽  
O.B. Gozubuyuk ◽  
S. Devran ◽  
H. Evrendilek ◽  
...  
Keyword(s):  
Muscle Strength ◽  
Muscle Architecture ◽  
Hamstring Muscle

Detection of viruses by electron microscopy: Increased sensitivity by direct micro-ultracentrifugation of samples

1987 ◽  
Vol 45 ◽  
pp. 908-909
Author(s):  
Alain R. Trudel ◽  
M. Trudel
Keyword(s):  
Electron Microscopy ◽  
Fold Increase ◽  
Observation Time ◽  
Clinical Samples ◽  
Maximum Speed ◽  
Viral Particles ◽  
Structural Details ◽  
Latex Spheres ◽  
Increased Sensitivity ◽  
Size Of Particles

AirfugeR (Beckman) direct ultracentrifugation of viral samples on electron microscopy grids offers a rapid way to concentrate viral particles or subunits and facilitate their detection and study. Using the A-100 fixed angle rotor (30°) with a K factor of 19 at maximum speed (95 000 rpm), samples up to 240 μl can be prepared for electron microscopy observation in a few minutes: observation time is decreased and structural details are highlighted. Using latex spheres to calculate the increase in sensitivity compared to the inverted drop procedure, we obtained a 10 to 40 fold increase in sensitivity depending on the size of particles. This technique also permits quantification of viral particles in samples if an aliquot is mixed with latex spheres of known concentration.Direct ultracentrifugation for electron microscopy can be performed on laboratory samples such as gradient or column fractions, infected cell supernatant, or on clinical samples such as urine, tears, cephalo-rachidian liquid, etc..

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