Search results

1

Relationships Between Vertical Jump Strength Metrics and 5 Meters Sprint Time

100%

Marques M., Gil H., Ramos R., Costa A., Marinho D.

Journal of Human Kinetics

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2011

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vol. 29

115-122

EN

The aim of this study was to examine the relationship between short sprint time (5 m) and strength metrics of the countermovement jump (CMJ) using a linear transducer in a group of trained athletes. Twenty-five male, trained subjects volunteered to participate in the study. Each volunteer performed 3 maximal CMJ trials on a Smith machine. Peak instantaneous power was calculated by the product of velocity taken with the linear transducer. For sprint testing, each subject performed three maximum 5 m sprints. Only the best attempt was considered in both tests. Pearson product-moment correlation coefficients between 5 m sprint performance and strength metrics of the CMJ were generally positive and of clear moderate to strong magnitude (r = -0.664 to -0.801). More noticeable was the significant predictive value of bar displacement time (r= ~0.70) to sprint performance. Nevertheless, a non-significant predictive value of peak bar velocity and rate of force development measurements was found. These results underline the important relationship between 5 m sprint and maximal lower body strength, as assessed by the force, power and bar velocity displacement. It is suggested that sprinting time performance would benefit from training regimens aimed to improve these performance qualities.

2

Lower-Limb Power cannot be Estimated Accurately from Vertical Jump Tests

100%

Tessier J.-F., Basset F.-A., Simoneau M., Teasdale N.

Journal of Human Kinetics

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2013

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vol. 38

5-13

EN

The countermovement jump test is often adopted to monitor lower-limb power of an individual. Despite several studies on the validity of this test, there is still a need to determine the minimal difference needed to be confident that a difference in power between two individuals is present or that a true change in the performance of an individual has occurred. In this study, power was measured from ground reaction forces and compared to that obtained from predictive equations for two groups of subjects (67 trained and 20 highly trained individuals). The height of each jump was determined with kinematic techniques. The main outcome is a large discrepancy between power calculated from ground reaction forces and that calculated from predictive equations. For the trained group, the R-square value between power and predicted power was 0.53 and the minimal difference to consider that two individuals were different was 821.7 W. For the highly trained individuals, a much larger R-square value was obtained (0.94). Despite this, the minimal difference to consider that two individuals were different was still large (689.3 W). The large minimal differences obtained raise serious concerns about using countermovement jumps for appraisal and monitoring of lower-limb power of an individual.

3

EVIDENCE FOR THE INVALIDITY OF THE WINGATE TEST FOR THE ASSESSMENT OF PEAK POWER, POWER DECREMENT AND MUSCULAR FATIGUE

88%

Robergs R. A., Kennedy D., Gibson A. L., Zuhl M., Hsu H.-S., Beam J., Salgado R. M., White A. C., Majumdar A., Lawson S., Estrada E., Sierra G.

Central European Journal of Sport Sciences and Medicine

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2015

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vol. 10

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issue 2

63-78

EN

We hypothesized that the protocol-induced initial cadence of the WAnT is too high to allow high muscle force production and peak power generation. Twenty endurance, strength or power trained subjects (9 male, 11 female) completed two 30 s maximal exertion stationary cycle ergometer tests involving the traditional peak cadence start (TRAD) vs. a stationary start (STAT). Inertia corrected mechanical power, cadence, EMG from the vastus lateralis, and applied force to the pedals were measured continuously throughout both tests. Peak power was higher during TRAD; 11.32 ±1.41 vs. 10.40 ±1.35 Watts/kg (p < 0.0001), as was peak cadence; 171.4 ±16.3 vs. 120.9 ±15.1 rev/min (p < 0.0001). However, during TRAD EMG root mean squared (rms) increased continuously throughout the test, force applied to the pedals increased from 1 to 3 s (0.73 ±0.27 vs. 0.90 ±0.39 N/kg; p = 0.02) and thereafter remained relatively stable. EMG mean frequency also increased from 1 to 3 s, but then decreased throughout the remainder of the test. During TRAD, mechanical power decreased near immediately despite increasing EMG rms, EMGmean frequency and force application to the pedals. The initial 10 s of data from the WAnT is invalid. We recommend that intense cycle ergometer testing should commence with a stationary start.

4

Influence of Static Stretching Duration on Quadriceps Force Development and Eletromyographic Activity

88%

Rossi L., Pereira R., Simão R., Brandalize M., Gomes A.

Human Movement

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2010

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vol. 11

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issue 2

137-143

EN

Purpose. The purpose of the present study was to analyze the influence of static stretching duration on quadriceps muscle isometric force and electromyographic (EMG) activity of the rectus femoris and vastus lateralis. Basic procedures. Twenty recreationally-active healthy men were selected for the study. On two separate days, participants took part in two stretching protocols of different durations. Following a specific warmup, participants performed isometric strength assessments of the dominant leg before and after a bout of quadriceps stretching. The stretching protocol consisted of two stretches for the quadriceps muscle for three repetitions of 30 seconds on one visit, and 60 seconds on the other. Main findings. The results revealed a significant reduction in quadriceps muscle mean and peak forces and EMG activity for the rectus femoris with both 30- and 60-second stretching protocols (p ≤ 05). However, EMG activity of the vastus lateralis decreased significantly only in the 60-second protocol (p ≤ 05). Conclusions. Both stretching protocols induced significant decreases in strength and EMG activity, although the stretching duration (60 × 30) did not appear to be a major influencing factor for the current strength reductions. In this perspective, coaches and athletes should avoid flexibility training which consists in stretching repetitions of 30 seconds or longer prior to competitions.

5

THE APPLICABILITY OF USING PARAMETERS OF THE AUTOCORRELATION FUNCTION IN THE ASSESSMENT OF HUMAN BALANCE DURING QUIET BIPENDAL STANCE

75%

Stodółka J., Korzewa L., Stodółka W., Gambal J.

Central European Journal of Sport Sciences and Medicine

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2017

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vol. 17

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issue 1

79-87

EN

The purpose of the study was to analyze the parameters of the autocorrelation function when assessing time series ground reaction force (GRF) signals during quiet standing. GRF in the three directions were recorded on two Kistler force plates during three 15-s trials in a sample of 82 (31 females and 51 males) participants. Autocorrelation was performed on the GRF data and four parameters characterizing the function were computed. Comparisons of the right- and left-foot parameter means showed significant differences in mediolateral GRF for the time of the function's decay to 0, magnitude of the derivative output, and mean decay velocity to the extremum. Significant correlations were observed among all parameters – weak correlations between the time of the function's decay to 0 and the time to the first extremum and strong correlations between the derivative output and mean decay velocity to the extremum. The analyzed autocorrelation function parameters can serve as a precise measure of the motor control process during quiet standing. The strong correlations observed between the four parameters indicate that they evaluate similar properties of the central nervous system as a regulator of balance maintenance.

6

Evaluation of Consecutive Maximum Contractions as a Test of Neuromuscular Function

75%

Suzovic D., Nedeljkovic A., Pazin N., Planic N., Jaric S.

Journal of Human Kinetics

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2008

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vol. 20

51-61

EN

The aim of the study was to conduct a preliminary evaluation of consecutive maximum contractions (CMC) as a test of neuromuscular function. Eleven participants performed externally paced isometric CMC (i.e., a series of consecutive maximum force exertions and relaxations) of the quadriceps muscle. The derived variables included the peak forces, and the maximum rates of force development and relaxation. The results revealed high within-day reliability of CMC variables, while their correlations with the jumping performance were consistently higher than those of the variables of the standard strength test (SST). CMC variables also showed fairly stable values across a wide range of frequencies, while their peak force revealed a strong relationship with maximum force of SST despite being about considerably lower. Therefore, we conclude that CMC could be developed into a standard test of neuromuscular function. In addition to capturing the muscle actions based on different neural activation pattern than SST, CMC could also be based on simpler testing procedure, lower force exertion, and self-selected frequencies.

7

Specific Measurement of Tethered Running Kinetics and its Relationship to Repeated Sprint Ability

75%

Sousa F., Reis I. d., Ribeiro L., Martins L., Gobatto C.

Journal of Human Kinetics

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2015

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vol. 49

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issue 1

245-256

EN

Repeated sprint ability has been widely studied by researchers, however, analysis of the relationship between most kinetic variables and the effect of fatigue is still an ongoing process. To search for the best biomechanical parameter to evaluate repeated sprint ability, several kinetic variables were measured in a tethered field running test and compared regarding their sensitivity to fatigue and correlation with time trials in a free running condition. Nine male sprint runners (best average times: 100 m = 10.45 ± 0.07 s; 200 m = 21.36 ± 0.17 s; 400 m = 47.35 ± 1.09 s) completed two test sessions on a synthetic track. Each session consisted of six 35 m sprints interspersed by 10 s rest under tethered field running or free running conditions. Force, power, work, an impulse and a rate of force development were all directly measured using the sensors of a new tethered running apparatus, and a one-way ANOVA with Scheffé post-hoc test used to verify differences between sprints (p < 0.05). Pearson product-moment correlation measured the relationship between mechanical variables and free running performance. A total impulse, the rate of force development and maximum force did not show significant differences for most sprints. These three variables presented low to moderate correlations with free running performance (r between 0.01 and -0.35). Maximum and mean power presented the strongest correlations with free running performance (r = -0.71 and -0.76, respectively; p < 0.001), followed by mean force (r = -0.61; p < 0.001) and total work (r = -0.50; p < 0.001). It was concluded that under a severe work-to-rest ratio condition, power variables were better suited to evaluating repeated sprint ability than the other studied variables.

8

Effect of vibrational therapy on muscle tissue

63%

Pogwizd P., Pasterczyk-Szczurek A., Bigosińska M.

Medical Rehabilitation

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2018

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vol. 22(3)

11-19

PL

Wstęp: U dorosłego człowieka mięśnie stanowią średnio około 40% jego masy ciała. Są podstawowym elementem strukturalnym i funkcjonalnym układu mięśniowo-szkieletowego opartego w głównej mierze na kurczliwości ich włókien. Taki stan rzeczy między innymi zapewnia i wywołuje określone w danej sytuacji reakcje motoryczne, wpływa na zachowanie równowagi i balans mięśniowy, sprawność połączeń nerwowo-mięśniowych, a także decyduje o wydolności układu ruchu. Cel pracy: Celem pracy było dokonanie przeglądu piśmiennictwa, dotyczącego oddziaływania zabiegów z wykorzystaniem bodźca wibracyjnego na tkankę mięśniową człowieka. Szczególną uwagę zwrócono na zaobserwowaną poprawę jego właściwości motorycznych po zakończeniu terapii wibracyjnej. Podjęto także próbę przedstawienia możliwie, jak najszerszego zastosowania zabiegów wibracyjnych w różnych stanach chorobowych związanych z funkcjonalnością tkanki mięśniowej, dlatego uwzględniono w prezentowanym przeglądzie badania zróżnicowane pod względem grup docelowych oraz badanych mięśni. Materiał i metody: Analizie poddano piśmiennictwo krajowe i zagraniczne, w którym zostało omówione pozytywne działanie zabiegów wibracyjnych na zdolności motoryczne dorosłego człowieka. Wybrano badania, których autorzy podawali najważniejsze parametry zastosowanego bodźca wibracyjnego takie jak: częstotliwość, amplituda i czas ekspozycji. Analizowano prace z przestrzeni ostatnich 15 lat (nie wliczając części historycznej). Jednak, aż 70% przywołanych badań była opublikowana w ciągu ostatnich 5 lat. Dokonano analizy przedmiotowych danych w następujących bazach: Medline, Embase, Cochrane CENTRAL trials register, ScienceDirect, PubMed, IEEE Xplore, Wiley Online Library. Słowa kluczowe, jakie użyto to: mięśnie, siła, wibracja, WBV. Podsumowanie-Wnioski: Liczne doniesienia wskazują na pozytywny wpływ terapii wibracyjnej na tkankę mięśniową człowieka. Zabiegi te między innymi zapobiegają zanikowi mięśni, a na tej drodze poprawiają lub odtwarzają utracone zdolności motoryczne badanych osób. Zabiegi z wykorzystaniem wibracji mogą być wykonywane przez samych chorych bez szczególnego nadzoru specjalistycznego, urządzenia je wywołujące są proste w obsłudze i nie wymagają znacznego wysiłku fizycznego, co jest niewątpliwą zaletą dla osób starszych i schorowanych oraz sportowców w okresie restytucji. Wydaje się celowym, aby ewentualne przyszłe badania dotyczące możliwości wykorzystania wibracji w różnych stanach chorobowych, w tym obejmujących szeroko rozumianą patologię układu mięśniowo-szkieletowego, skoncentrować na opracowaniu optymalnych parametrów i warunków stosowania zabiegów wibracyjnych, skojarzenia ich z wybranymi jednostkami chorobowymi, opracowania wskazań i przeciwwskazań do ich wykorzystania, a także ustalenia hipotez efektywności podejmowanych działań oraz naukowej ich weryfikacji.

EN

In an adult human, on average, muscles constitute about 40% of their body mass. They are the basic structural and functional elements of the musculoskeletal system based mainly on shrinkage of their fibres. This state, among others, ensures and induces motor reactions defined in a given situation, affects balance and muscle balance, the efficiency of neuromuscular connections, and also decides the efficiency of the motor system. The aim of the work was to review literature regarding the impact of treatments using vibrational stimulus on human muscle tissue. Particular attention was paid to the observed improvement of its motor properties after the completion of t vibrational therapy application. An attempt was also made to present the widest possible use of vibrational procedures in various disease states related to the functionality of muscle tissue, which is why in the present overview, the included research was differentiated in terms of target groups and investigated muscles. The analysis included domestic and foreign literature, in which the positive effect of vibrational treatments on the motor properties of adults was discussed. Studies were selected, the authors of which described the most important parameters of the vibrational stimulus used, such as: frequency, amplitude and duration of exposure. Research work from the last 15 years has been analysed (not including the historical part). However, as many as 70% of the studies referred to have been published in the last 5 years. Data from the following databases was analysed: Medline, Embase, Cochrane CENTRAL trials register, ScienceDirect, PubMed, IEEE Xplore, Wiley Online Library. Key words used: muscles, force, vibration, WBV. Numerous reports indicate the positive effect of vibrational therapy on human muscle tissue. These treatments, among others, prevent muscle atrophy, and in this way, improve or reproduce the lost motor skills of the investigated people. Treatments with the use of vibrations can be performed by the patients themselves without special supervision, the devices that trigger them are easy to use and do not require significant physical effort, which is an undoubted advantage for the elderly and ill patients as well as athletes during the restitution period. It seems wise that any future research regarding the possibility of use of using vibrations in various disease states, including covering the broadly understood pathology of the musculoskeletal system, should focus on the development of optimal parameters and conditions for the use of vibration treatments, associating them with selected disease entities, developing indications and contraindications for their use, as well as determine hypotheses of the effectiveness of undertaken activities and their scientific verification. This article is licensed under a Creative Commons Attribution-ShareAlike 4.0 International License. null

9

Influence of anxiety on the muscles strength in the leg after ACL reconstruction

51%

Dubaj W., Jarosz A., Hładki W.

Medical Rehabilitation

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2012

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vol. 16(4)

13-20

PL

Założenia: Izolowane zerwanie więzadła krzyżowego przedniego kolana ACL jest trzecim co do częstości urazem więzadłowym stawu kolanowego. Postępowanie obejmuje rekonstrukcję i rehabilitację pooperacyjną. Wyniki leczenia ocenia się m.in. na podstawie testów ortopedycznych, badań siły mięśniowej i pomiarów obwodów, porównywanych do nogi przeciwnej. Stan kliniczny operowanego więzadła nie zawsze jest zbieżny z odczuciami pacjenta co do własnego zdrowia. Wpływ na samoocenę zdrowia przez pacjenta i przebieg rehabilitacji ma między innymi nasilenie lęku. Cel: Ocena wpływu predyspozycji do reagowania lękiem na skuteczność rehabilitacji, ocenianej w oparciu o pomiary siły mięśni, po operacyjnym leczeniu przerwanego więzadła krzyżowego przedniego kolana. Materiał i metoda: Badano 201 pacjentów z rozpoznanym zerwaniem więzadła krzyżowego przedniego kolana (113 kobiet i 88 mężczyzn). Wszyscy pacjenci zostali poddani rekonstrukcji więzadła krzyżowego przedniego oraz sześciomiesięcznemu leczeniu rehabilitacyjnemu. Do oceny nasilenia lęku jako cechy badanego przed zabiegiem operacyjnym zastosowano Kwestionariusz STAI, a do dwukrotnego badania siły mięśni (tydzień przed i po 6 miesiącach od operacji) zastosowano dynamometr.Wyniki: Badani wykazujący małe nasilenie lęku-cechy (poniżej 3,5 stena) istotnie częściej niż badani wykazujący duże nasilenie lęku-cechy (powyżej 7,5 stena) uzyskiwali po rehabilitacji zwiększenie siły mięśni przywodzicieli stawu biodrowego i prostowników stawu kolanowego, oraz poprawę w teście leg press operowanej kończyny dolnej.Wnioski: Zwiększona predyspozycja do reagowania lękiem może być przyczyną gorszych wyników rehabilitacji pacjentów po operacyjnej rekonstrukcji więzadła krzyżowego przedniego. W przypadku pacjentów o nasilonym lęku, rehabilitowanych po operacyjnej rekonstrukcji więzadła krzyżowego przedniego, należy rozważyć zastosowanie indywidualnego programu rehabilitacji, uwzględniającego psychoterapię.

EN

Background: The rupture of the anterior cruciate ligament (ACL) constitutes the third most frequent ligament injury of the knee joint. The approach involves its reconstruction and post-operational rehabilitation. The results of treatment are evaluated on the basis of, among other things, orthopaedic tests, tests of muscle strength and circumference measurements when compared to the other leg. The clinical state of the ligament is not always in accordance with the patient’s perceptions as to their state of health. An influence on the self evaluation of health on the part of the patient is brought about by, among other things, an intensification in fear and anxiety.Objective: An evaluation of the influence of a predisposition for an anxiety reaction on the effectiveness of rehabilitation, evaluated in relation to the measurement of muscle strength, following operational treatment of the injured ACL.Materials and Methods: 201 patients (113 women and 88 men) were tested who had a diagnosed of the ACL injury. All the patients were subjected to a reconstruction of the ACL as well as a period of six months of rehabilitation treatment. The STAI questionnaire was used in the evaluation of the trait-anxiety prior to the operational procedure, while twice a dynamometer was used in the testing of muscle strength (a week before and six months after the operation).Results: Those patients displaying a small intensification in trait-anxiety (lower than 3.5) significantly more often than those patients displaying a large intensification in trait-anxiety (over 7.5) gained increased muscle strength following rehabilitation of the hip joint adductor and the extensors of the knee joint, as well as an improvement in the leg press test of the lower limb operated on. Conclusions: An increased predisposition for an anxiety reaction may be the reason for poorer rehabilitation results in patients following an operational reconstruction of the ACL. It may be necessary in the case of patients undergoing rehabilitation after an operational reconstruction of the ACL and who display an intensive anxiety of the said to consider the application of an individual programme of rehabilitation, one incorporating elements of psychotherapy.

Refine search results

Relationships Between Vertical Jump Strength Metrics and 5 Meters Sprint Time

Lower-Limb Power cannot be Estimated Accurately from Vertical Jump Tests

EVIDENCE FOR THE INVALIDITY OF THE WINGATE TEST FOR THE ASSESSMENT OF PEAK POWER, POWER DECREMENT AND MUSCULAR FATIGUE

Influence of Static Stretching Duration on Quadriceps Force Development and Eletromyographic Activity

THE APPLICABILITY OF USING PARAMETERS OF THE AUTOCORRELATION FUNCTION IN THE ASSESSMENT OF HUMAN BALANCE DURING QUIET BIPENDAL STANCE

Evaluation of Consecutive Maximum Contractions as a Test of Neuromuscular Function

Specific Measurement of Tethered Running Kinetics and its Relationship to Repeated Sprint Ability

Effect of vibrational therapy on muscle tissue

Influence of anxiety on the muscles strength in the leg after ACL reconstruction