scholarly journals Postactivation Potentiation Biases Maximal Isometric Strength Assessment

2014 ◽  
Vol 2014 ◽  
pp. 1-7 ◽  
Author(s):  
Leonardo Coelho Rabello Lima ◽  
Felipe Bruno Dias Oliveira ◽  
Thiago Pires Oliveira ◽  
Claudio de Oliveira Assumpção ◽  
Camila Coelho Greco ◽  
...  
Keyword(s):  
Force Production ◽  
Peak Torque ◽  
Isometric Strength ◽  
Isometric Contractions ◽  
Postactivation Potentiation ◽  
Healthy Male ◽  
Strength Assessment ◽  
Rate Of Torque Development ◽  
Electromyographic Signal ◽  
Torque Development

Postactivation potentiation (PAP) is known to enhance force production. Maximal isometric strength assessment protocols usually consist of two or more maximal voluntary isometric contractions (MVCs). The objective of this study was to determine if PAP would influence isometric strength assessment. Healthy male volunteers (n=23) performed two five-second MVCs separated by a 180-seconds interval. Changes in isometric peak torque (IPT), time to achieve it (tPTI), contractile impulse (CI), root mean square of the electromyographic signal during PTI (RMS), and rate of torque development (RTD), in different intervals, were measured. Significant increases in IPT (240.6 ± 55.7 N·mversus248.9 ± 55.1 N·m), RTD (746 ± 152 N·m·s−1versus727 ± 158 N·m·s−1), and RMS (59.1 ± 12.2%RMSMAX  versus54.8 ± 9.4%RMSMAX) were found on the second MVC. tPTI decreased significantly on the second MVC (2373 ± 1200 msversus2784 ± 1226 ms). We conclude that a first MVC leads to PAP that elicits significant enhancements in strength-related variables of a second MVC performed 180 seconds later. If disconsidered, this phenomenon might bias maximal isometric strength assessment, overestimating some of these variables.

The number of sessions required to stabilize peak torque and rate of torque development in isometric contractions in young, middle-age and older individuals

2016 ◽  
Vol 24 (2) ◽  
pp. 165-170
Author(s):  
Cleiton Augusto Libardi ◽  
Thiago Mattos Frota Souza ◽  
Miguel Soares Conceição ◽  
Mara Patricia Traina Chacon-Mikahil ◽  
Carlos Ugrinowitsch ◽  
...  
Keyword(s):  
Middle Age ◽  
Peak Torque ◽  
Isometric Contractions ◽  
Older Individuals ◽  
Rate Of Torque Development ◽  
Torque Development

scholarly journals Peak torque, rate of torque development and average torque of isometric ankle and elbow contractions show excellent test–retest reliability

2019 ◽  
Vol 39 (01) ◽  
pp. 67-76
Author(s):  
Daniel Simpson ◽  
Monika Ehrensberger ◽  
Christopher Nulty ◽  
Joanne Regan ◽  
Patrick Broderick ◽  
...  
Keyword(s):  
Muscle Function ◽  
Intraclass Correlation ◽  
Peak Torque ◽  
Testing Procedure ◽  
Ankle Dorsiflexion ◽  
Isometric Contractions ◽  
Elbow Extension ◽  
Rate Of Torque Development ◽  
Test Retest Reliability ◽  
Torque Development

Background: Peak Torque (PT), Rate of Torque Development (RTD) and Average Torque (AT) over a single contraction assess the three components of muscle function during isometric contractions. Surprisingly, AT has never been reported or its reliability confirmed.Objectives: This study aims to establish protocol reliability for ankle dorsiflexion and elbow extension isometric muscle function (PT, RTD, AT) in healthy participants using the Biodex System 3 Dynamometer.Methods: Twelve participants (6 male, 6 female, mean age [Formula: see text] years) performed four maximal isometric contractions on two occasions. Intraclass Correlation Coefficient (ICC), Typical Error (TE) and Coefficient of Variation (CV) for PT, RTD and AT were reported.Results: The ICC for all strength parameters varied from 0.98–0.92. TE for ankle dorsiflexion PT was 1.38[Formula: see text]Nm, RTD 7.43[Formula: see text]Nm/s and AT 1.33[Formula: see text]Nm, CV varied from [Formula: see text] to [Formula: see text]. For elbow extension, TE was 3.36[Formula: see text]Nm for PT, 14.87[Formula: see text]Nm/s for RTD and 3.03[Formula: see text]Nm for AT, CV varied from [Formula: see text] to [Formula: see text].Conclusion: Maximal isometric ankle dorsiflexion and elbow extension PT, RTD and AT can be evaluated with excellent reliability when following the described protocol. This testing procedure, including the application of AT, can be confidently applied in research, exercise or clinical settings.

scholarly journals Peak Torque and Rate of Torque Development Influence on Repeated Maximal Exercise Performance: Contractile and Neural Contributions

PLoS ONE ◽  
2015 ◽  
Vol 10 (4) ◽  
pp. e0119719 ◽  
Author(s):  
Baptiste Morel ◽  
David M. Rouffet ◽  
Damien Saboul ◽  
Samuel Rota ◽  
Michel Clémençon ◽  
...  
Keyword(s):  
Exercise Performance ◽  
Maximal Exercise ◽  
Peak Torque ◽  
Rate Of Torque Development ◽  
Torque Development

Peak torque and rate of torque development in elderly with and without fall history

2010 ◽  
Vol 25 (5) ◽  
pp. 450-454 ◽  
Author(s):  
Paulo Cesar Barauce Bento ◽  
Gleber Pereira ◽  
Carlos Ugrinowitsch ◽  
André Luiz Felix Rodacki
Keyword(s):  
Peak Torque ◽  
Rate Of Torque Development ◽  
Torque Development

scholarly journals Isometric and dynamic strength and neuromuscular attributes as predictors of vertical jump performance in 11- to 13-year-old male athletes

2017 ◽  
Vol 42 (9) ◽  
pp. 924-930 ◽  
Author(s):  
Brandon John McKinlay ◽  
Phillip J. Wallace ◽  
Raffy Dotan ◽  
Devon Long ◽  
Craig Tokuno ◽  
...  
Keyword(s):  
Vastus Lateralis ◽  
Peak Torque ◽  
Soccer Players ◽  
Neural Activation ◽  
Male Athletes ◽  
Neuromuscular Activation ◽  
Jump Performance ◽  
Rate Of Torque Development ◽  
Dynamic Contractions ◽  
Torque Development

In explosive contractions, neural activation is a major factor in determining the rate of torque development, while the latter is an important determinant of jump performance. However, the contribution of neuromuscular activation and rate of torque development to jump performance in children and youth is unclear. The purpose of this study was to examine the relationships between the rate of neuromuscular activation, peak torque, rate of torque development, and jump performance in young male athletes. Forty-one 12.5 ± 0.5-year-old male soccer players completed explosive, unilateral isometric and dynamic (240°/s) knee extensions (Biodex System III), as well as countermovement-, squat-, and drop-jumps. Peak torque (pT), peak rate of torque development (pRTD), and rate of vastus lateralis activation (Q30) during the isometric and dynamic contractions were examined in relation to attained jump heights. Isometric pT and pRTD were strongly correlated (r = 0.71) but not related to jump performance. Dynamic pT and pRTD, normalized to body mass, were significantly related to jump height in all 3 jumps (r = 0.38–0.66, p < 0.05). Dynamic normalized, but not absolute pRTD, was significantly related to Q30 (r = 0.35, p < 0.05). In young soccer players, neuromuscular activation and rate of torque development in dynamic contractions are related to jump performance, while isometric contractions are not. These findings have implications in the choice of training and assessment methods for young athletes.

scholarly journals Child–adult differences in muscle strength and activation pattern during isometric elbow flexion and extension

2009 ◽  
Vol 34 (4) ◽  
pp. 609-615 ◽  
Author(s):  
Bareket Falk ◽  
Charlotte Usselman ◽  
Raffy Dotan ◽  
Laura Brunton ◽  
Panagiota Klentrou ◽  
...  
Keyword(s):  
Muscle Strength ◽  
Muscle Activation ◽  
Motor Units ◽  
Elbow Flexion ◽  
Peak Torque ◽  
Electromechanical Delay ◽  
Cross Sectional ◽  
Rate Of Torque Development ◽  
Torque Development ◽  
Flexion And Extension

Muscle strength and activation were compared in boys and men during maximal voluntary elbow flexion and extension contractions. Peak torque, peak rate of torque development (dτ/dτmax), rate of muscle activation, and electromechanical delay (EMD) were measured in 15 boys (aged 9.7 ± 1.6 years) and 16 men (aged 22.1 ± 2.8 years). During flexion, peak torque was significantly lower in boys than in men (19.5 ± 5.8 vs. 68.5 ± 11.0 Nm, respectively; p < 0.05), even when controlling for upper-arm cross-sectional area (CSA), and peak electromyography activity. Boys also exhibited a lower normalized dτ/dτmax (7.2 ± 1.7 vs. 9.5 ± 1.6 (Nm·s–1)·(Nm–1), respectively; p < 0.05) and a significantly longer EMD (75.5 ± 28.4 vs. 47.6 ± 17.5 ms, respectively). The pattern was similar for extension, except that group differences in peak torque were no longer significant when normalized for CSA. These results suggest that children may be less able to recruit or fully utilize their higher-threshold motor units, resulting in lower dimensionally normalized maximal torque and rate of torque development.

Effect of Aging on Trunk Muscle Function and Its Influence on Falls Among Older Adults

2020 ◽  
Vol 28 (5) ◽  
pp. 699-706
Author(s):  
Jaqueline M. Porto ◽  
Sállua B. Spilla ◽  
Luciana M. Cangussu-Oliveira ◽  
Renato C. Freire Júnior ◽  
Ana Paula M. Nakaishi ◽  
...  
Keyword(s):  
Older Adults ◽  
Muscle Function ◽  
Peak Torque ◽  
Young Group ◽  
Trunk Muscle ◽  
Tukey Test ◽  
Rate Of Torque Development ◽  
Extensor Torque ◽  
Post Hoc ◽  
Torque Development

The objective was to determine whether trunk muscle function is influenced by the aging process and to identify if the trunk can be an important factor in older people’s falls over a period of 1 year. The peak torque, rate of torque development, and torque steadiness of the trunk extensors and flexors were compared between a young group, older group (older adults with no episodes of falls), and older faller group (older adults who had suffered at least one fall episode over a period of 1 year) by one-way analysis of variance, followed by the post hoc Tukey test. The adjusted multivariate linear regression was applied to verify the association between the number of falls and the trunk parameters in older adults. The young group showed higher extensors and flexors peak torque and rate of torque development, and lower extensor torque steadiness at 10% when compared with older groups. Only trunk flexor peak torque showed a negative association with the number of future falls (p = .042), but there was no difference in trunk muscle function between the older group and the older faller group.

scholarly journals Passive Stiffness and Maximal and Explosive Strength Responses After an Acute Bout of Constant-Tension Stretching

2019 ◽  
Vol 54 (5) ◽  
pp. 519-526 ◽  
Author(s):  
Ty B. Palmer ◽  
Ryan M. Thiele
Keyword(s):  
Time Course ◽  
Outcome Measurement ◽  
Peak Torque ◽  
Passive Stiffness ◽  
Explosive Strength ◽  
Rate Of Torque Development ◽  
Short Bout ◽  
Constant Tension ◽  
Before And After ◽  
Torque Development

Context Constant-tension (CT) stretching has been used to reduce hamstrings passive stiffness; however, the time course of hamstrings stiffness responses during a short bout of this type of stretching and the effects on maximal and explosive strength remain unclear. Objective To examine the time course of hamstrings passive-stiffness responses during a short, practical bout of manual straight-legged–raise (SLR) CT passive stretches and their effects on maximal and explosive strength in healthy young women. Design Descriptive laboratory study. Setting Research laboratory. Patients or Other Participants Eleven healthy women (age = 24 ± 4 years, height = 167 ± 4 cm, mass = 65 ± 8 kg) participated. Intervention(s) Participants underwent four 15-second SLR CT passive stretches of the hamstrings. Main Outcome Measurement(s) Hamstrings passive stiffness was calculated from the slopes of the initial (phase 1) and final (phase 2) portions of the angle-torque curves generated before and after the stretching intervention and at the beginning of each 15-second stretch. Hamstrings peak torque and rate of torque development were derived from maximal voluntary isometric contractions performed before and after the stretching intervention. Results The slope coefficients (collapsed across phase) for the third and fourth stretches and the poststretching assessment were lower than the prestretching assessment (P range = .004–.04), but they were not different from each other (P &gt; .99). In addition, no differences in peak torque (t10 = −0.375, P = .72) or rate of torque development (t10 = −0.423, P = .68) were observed between prestretching and poststretching. Conclusions A short bout of SLR CT passive stretching may effectively reduce hamstrings stiffness without negatively influencing maximal and explosive strength.

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