Postactivation potentiation in a human muscle: effect on the rate of torque development of tetanic and voluntary isometric contractions

2007 ◽  
Vol 102 (4) ◽  
pp. 1394-1401 ◽  
Author(s):  
Stéphane Baudry ◽  
Jacques Duchateau
Keyword(s):  
Muscle Activation ◽  
Muscle Performance ◽  
Similar Degree ◽  
Postactivation Potentiation ◽  
Muscle Twitch ◽  
Rate Of Torque Development ◽  
Adductor Muscles ◽  
Isometric Torque ◽  
Voluntary Contractions ◽  
Torque Development

Postactivation potentiation (PAP), a mechanism by which the torque of a muscle twitch is increased following a conditioning contraction, is well documented in muscular physiology, but little is known about its effect on the maximal rate of torque development and functional significance during voluntary movements. The objective of this study was to investigate the PAP effect on the rate of isometric torque development of electrically induced and voluntary contractions. To that purpose, the electromechanical responses of the thumb adductor muscles to a single electrical stimulus (twitch), a train of 15 pulses at 250 Hz (HFT250), and during ballistic (i.e., rapid torque development) voluntary contractions at torque levels ranging from 10 to 75% of maximal voluntary contraction (MVC) were recorded before and after a conditioning 6-s MVC. The results showed that the rate of torque development was significantly ( P < 0.001) increased after the conditioning MVC, but the effect was greater for the twitch (∼200%) compared with the HFT250 (∼17%) or ballistic contractions (range: 9–24%). Although twitch potentiation was maximal immediately after the conditioning MVC, maximal potentiation for HFT250 and ballistic contractions was delayed to 1 min after the 6-s MVC. Furthermore, the similar degree of potentiation for the rate of isometric torque development between tetanic and voluntary ballistic contractions indicates that PAP is not related to the modality of muscle activation. These observations suggest that PAP may be considered as a mechanism that can influence our contractions during daily tasks and can be utilized to improve muscle performance in explosive sports.

Postactivation potentiation in a human muscle: effect on the load-velocity relation of tetanic and voluntary shortening contractions

2007 ◽  
Vol 103 (4) ◽  
pp. 1318-1325 ◽  
Author(s):  
Stéphane Baudry ◽  
Jacques Duchateau
Keyword(s):  
Angular Velocity ◽  
Muscle Activation ◽  
Electrical Stimulus ◽  
Voluntary Contraction ◽  
Muscle Performance ◽  
Postactivation Potentiation ◽  
Muscle Twitch ◽  
Velocity Relation ◽  
Voluntary Contractions ◽  
Shortening Contractions

Recently it was demonstrated that postactivation potentiation (PAP), which refers to the enhancement of the muscle twitch torque as a result of a prior conditioning contraction, increased the maximal rate of torque development of tetanic and voluntary isometric contractions ( 3 ). In this study, we investigated the effects of PAP and its decay over time on the load-velocity relation. To that purpose, angular velocity of thumb adduction in response to a single electrical stimulus (twitch), a high-frequency train of 15 pulses at 250 Hz (HFT250), and during ballistic voluntary shortening contractions, performed against loads ranging from 10 to 50% of the maximum torque, were recorded before and after a conditioning 6-s maximal voluntary contraction (MVC). The results showed an increase of the peak angular velocity for the different loads tested after the conditioning MVC ( P < 0.001), but the effect was greatest for the twitch (∼182%) compared with the HFT250 or voluntary contractions (∼14% for both contraction types). The maximal potentiation occurred immediately following the conditioning MVC for the twitch, whereas it was reached 1 min later for the tetanic and ballistic voluntary contractions. At that time, the load-velocity relation was significantly shifted upward, and the maximal power of the muscle was increased (∼13%; P < 0.001). Furthermore, the results also indicated that the effect of PAP on shortening contractions was not related to the modality of muscle activation. In conclusion, the findings suggest a functional significance of PAP in human movements by improving muscle performance of voluntary dynamic contractions.

Hip Abductor Rate of Torque Development as Opposed to Isometric Strength Predicts Peak Knee Valgus During Landing: Implications for Anterior Cruciate Ligament Injury

2021 ◽  
pp. 1-6
Author(s):  
Kristen M. Stearns-Reider ◽  
Rachel K. Straub ◽  
Christopher M. Powers
Keyword(s):  
Cruciate Ligament ◽  
Muscle Performance ◽  
Ligament Injury ◽  
Knee Valgus ◽  
Rate Of Torque Development ◽  
Peak Knee ◽  
Hip Abductor ◽  
Isometric Torque ◽  
Anterior Cruciate ◽  
Torque Development

Peak knee valgus has been shown to predict anterior cruciate ligament injury. The purpose of the current study was to compare peak rate of torque development (RTD) to peak isometric torque as a predictor of peak knee valgus during landing. Twenty-three healthy females participated. Hip abductor muscle performance was quantified using 2 types of isometric contractions: sustained and rapid. Peak isometric torque was calculated from the sustained isometric contraction. Peak RTD was calculated from the rapid isometric contraction (0–50 and 0–200 ms after force initiation). Kinematic data were collected during the deceleration phase of a double-leg drop jump task. Linear regression was used to assess the ability of hip abductor muscle performance variables to predict peak knee valgus. Increased peak RTD during the 0 to 50 milliseconds window after force initiation was found to significantly predict lower peak knee valgus (P = .011, R2 = .32). In contrast, neither peak RTD from 0 to 200 milliseconds after force initiation window (P = .45, R2 = .03) nor peak isometric torque (P = .49, R2 = .03) predicted peak knee valgus. The inability of the hip abductors to rapidly generate muscular force may be more indicative of “at-risk” movement behavior in females than measures of maximum strength.

Initial phase of maximal voluntary and electrically stimulated knee extension torque development at different knee angles

2004 ◽  
Vol 97 (5) ◽  
pp. 1693-1701 ◽  
Author(s):  
C. J. de Ruiter ◽  
R. D. Kooistra ◽  
M. I. Paalman ◽  
A. de Haan
Keyword(s):  
Muscle Activation ◽  
Knee Extensor ◽  
Surface Emg ◽  
Knee Extension ◽  
Voluntary Contraction ◽  
Voluntary Activation ◽  
Knee Angle ◽  
Time Integral ◽  
Voluntary Contractions ◽  
Torque Development

We investigated the capacity for torque development and muscle activation at the onset of fast voluntary isometric knee extensions at 30, 60, and 90° knee angle. Experiments were performed in subjects ( n = 7) who had high levels (>90%) of activation at the plateau of maximal voluntary contractions. During maximal electrical nerve stimulation (8 pulses at 300 Hz), the maximal rate of torque development (MRTD) and torque time integral over the first 40 ms (TTI40) changed in proportion with torque at the different knee angles (highest values at 60°). At each knee angle, voluntary MRTD and stimulated MRTD were similar ( P < 0.05), but time to voluntary MRTD was significantly longer. Voluntary TTI40 was independent ( P > 0.05) of knee angle and on average (all subjects and angles) only 40% of stimulated TTI40. However, among subjects, the averaged (across knee angles) values ranged from 10.3 ± 3.1 to 83.3 ± 3.2% and were positively related ( r2 = 0.75, P < 0.05) to the knee-extensor surface EMG at the start of torque development. It was concluded that, although all subjects had high levels of voluntary activation at the plateau of maximal voluntary contraction, among subjects and independent of knee angle, the capacity for fast muscle activation varied substantially. Moreover, in all subjects, torque developed considerably faster during maximal electrical stimulation than during maximal voluntary effort. At different knee angles, stimulated MRTD and TTI40 changed in proportion with stimulated torque, but voluntary MRTD and TTI40 changed less than maximal voluntary torque.

scholarly journals Elbow Extensors and Volar Flexors Strength Capacity and Its Relation to Shooting Performance in Basketball Players—A Pilot Study

2020 ◽  
Vol 10 (22) ◽  
pp. 8206
Author(s):  
Darjan Smajla ◽  
Žiga Kozinc ◽  
Nejc Šarabon
Keyword(s):  
Scaling Factor ◽  
Long Distance ◽  
Basketball Players ◽  
Rate Of Torque Development ◽  
Strength Capacity ◽  
Isometric Torque ◽  
Muscle Groups ◽  
Sufficient Strength ◽  
Torque Development ◽  
Basketball Shooting

Rate of force/torque development scaling factor (RFD-SF/RTD-SF) has been used as a tool for assessing neuromuscular quickness. The aim was to investigate strength capacities of two major shooting muscle groups and their relationship to basketball shooting performance, and to compare the RFD-SF as well as shooting performance between junior and senior basketball players, and finally to examine the differences in RTD-SF between elbow extensors and volar flexors. In 23 male basketball players (13 juniors and 10 seniors) we assessed maximal isometric torque (TMVC), maximal rate of torque development and RTD-SF slope (kRTD-SF) for elbow extensors and volar flexors. The subjects performed 10 throws at 2.3 m (short) and 8.9 m (long) from the basket. Our results showed similar kRTD-SF and TMVC in both groups. Better shooting performance from short distance was observed in senior players. Significant associations between kRTD-SF, TMVC and shooting performance were found only in juniors. Elbow extensors TMVC was found to have a significant positive large association with shooting performance from long distance. It seems that muscle capacity has an important role in shooting performance in junior compared to players. Sufficient strength capacity of major shooting muscles is important for juniors’ shooting performance from a long distance.

scholarly journals Potentiation Increases Peak Twitch Torque by Enhancing Rates of Torque Development and Relaxation

2013 ◽  
Vol 38 ◽  
pp. 83-94 ◽  
Author(s):  
Christian Froyd ◽  
Fernando Gabe Beltrami ◽  
Jørgen Jensen ◽  
Timothy David Noakes
Keyword(s):  
Electrical Stimulation ◽  
Maximal Voluntary Contraction ◽  
Femoral Nerve ◽  
Voluntary Contraction ◽  
Physically Active ◽  
Isometric Maximal Voluntary Contraction ◽  
Rate Of Torque Development ◽  
Voluntary Contractions ◽  
Torque Development ◽  
Similar Peak

Abstract The aim of this study was to measure the extent to which potentiation changes in response to an isometric maximal voluntary contraction. Eleven physically active subjects participated in two separate studies. Single stimulus of electrical stimulation of the femoral nerve was used to measure torque at rest in unpotentiated quadriceps muscles (study 1 and 2), and potentiated quadriceps muscles torque in a 10 min period after a 5 s isometric maximal voluntary contraction of the quadriceps muscles (study 1). Additionally, potentiated quadriceps muscles torque was measured every min after a further 10 maximal voluntary contractions repeated every min (study 2). Electrical stimulation repeated several times without previous maximal voluntary contraction showed similar peak twitch torque. Peak twitch torque 4 s after a 5 s maximal voluntary contraction increased by 45±13% (study 1) and by 56±10% (study 2), the rate of torque development by 53±13% and 82±29%, and the rate of relaxation by 50±17% and 59±22%, respectively, but potentiation was lost already two min after a 5 s maximal voluntary contraction. There was a tendency for peak twitch torque to increase for the first five repeated maximal voluntary contractions, suggesting increased potentiation with additional maximal voluntary contractions. Correlations for peak twitch torque vs the rate of torque development and for the rate of relaxation were r2= 0.94 and r2=0.97. The correlation between peak twitch torque, the rate of torque development and the rate of relaxation suggests that potentiation is due to instantaneous changes in skeletal muscle contractility and relaxation.

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.

Age-related decline in rate of torque development is accompanied by lower maximal motor unit discharge frequency during fast contractions

2008 ◽  
Vol 104 (3) ◽  
pp. 739-746 ◽  
Author(s):  
Malgorzata Klass ◽  
Stéphane Baudry ◽  
Jacques Duchateau
Keyword(s):  
Motor Unit ◽  
Discharge Frequency ◽  
Maximal Rate ◽  
Unit Discharge ◽  
Rate Of Torque Development ◽  
Age Related ◽  
Motor Unit Discharge ◽  
Integrated Emg ◽  
Voluntary Contractions ◽  
Torque Development

The aim of this study was to investigate the association between the rate of torque development and maximal motor unit discharge frequency in young and elderly adults as they performed rapid submaximal contractions with the ankle dorsiflexors. Recordings were obtained of the torque exerted by the dorsiflexors during the isometric contractions and the surface and intramuscular electromyograms (EMGs) from the tibialis anterior. The maximal rate of torque development and integrated EMG (percentage of total EMG burst) at peak rate of torque development during fast contractions were lower in elderly than young adults by 48% ( P < 0.05) and 16.5% ( P < 0.05), respectively. The young adults, but not the elderly adults, exhibited a positive association ( r2 = 0.33; P < 0.01) between the integrated EMG computed up to the peak rate of torque development and the maximal rate of torque development achieved during the fast contractions. These age-related changes during fast voluntary contractions were accompanied by a decline ( P < 0.001) in motor unit discharge frequency (19, 28, and 34% for first 3 interspike intervals, respectively) and in the percentage of units (45%; P < 0.05) that exhibited double discharges (doublets) at brief intervals (<5 ms). Because aging decreased the maximal rate of torque development of fast voluntary contractions to a greater extent (∼10%) than that of an electrically evoked twitch, collectively the results indicate that the age-related decline in maximal motor unit discharge frequency likely limit, in addition to the slowing of muscle contractile properties, the performance of fast voluntary contractions.

Muscle activation in unilateral and bilateral efforts assessed by motor nerve and cortical stimulation

1996 ◽  
Vol 80 (4) ◽  
pp. 1351-1356 ◽  
Author(s):  
R. D. Herbert ◽  
S. C. Gandevia
Keyword(s):  
Muscle Activation ◽  
Motor Nerve ◽  
Voluntary Activation ◽  
Left Elbow ◽  
Twitch Interpolation ◽  
Adductor Muscles ◽  
Muscle Groups ◽  
The Right ◽  
Voluntary Contractions ◽  
Contralateral Muscle

Voluntary muscle activation was measured with twitch interpolation in 11 subjects during attempted maximal voluntary contractions of the right thumb adductor muscles either in isolation (“thumb alone”) or as the subjects simultaneously performed maximal voluntary contractions of the left thumb adductors or left elbow flexors (“both thumbs” or “thumb and elbow”, respectively). During thumb alone contractions, median voluntary activation of the right thumb adductors was 90.3%, and subjects fully activated the thumb adductors on 22% of all contractions. Transcranial magnetic stimulation of the cortex during maximal voluntary efforts produced small twitchlike force increases, suggesting that at least part of the voluntary activation failure was attributable to suboptimal corticospinal drive. Maximal voluntary force produced by the right thumb adductors in the three conditions differed by < 2% (P = 0.21), and the ability to activate the thumb adductors in the both thumbs condition was only marginally less than during thumb alone contractions (median 88.6%; P = 0.004).Thus subjects are usually unable to fully activate their thumb adductors with maximal voluntary efforts, and simultaneous maximal contractions of contralateral muscle groups have little effect on this ability.

Voluntary and Evoked Muscle Contractile Characteristics in Active Men and Women

1994 ◽  
Vol 19 (3) ◽  
pp. 253-265 ◽  
Author(s):  
David G. Behm ◽  
Digby G. Sale
Keyword(s):  
Gender Differences ◽  
Maximum Rate ◽  
Peak Torque ◽  
Contraction Rate ◽  
Rate Of Torque Development ◽  
Voluntary Contractions ◽  
Evoked Contractions ◽  
Muscle Contractile ◽  
Torque Development ◽  
Key Words Gender

Eight men and 8 women were tested for voluntary and isometric evoked contractions of the dorsiflexors. Maximal voluntary contractions were conducted isometrically (30° plantarflexion) and isokinetically. Men produced greater peak torques at all but the highest isokinetic velocity. They exceeded women in measures of absolute voluntary isometric (33.8%), tetanic (46.3%), and twitch (37.9%) peak torque. Men demonstrated a higher tetanus/MVC ratio (17.8%). This ratio disparity would indicate that gender differences in peak torque in this study were more dependent upon muscle mechanisms. Although men exceeded women in measures of absolute voluntary maximum rate of torque development (MRTD) (38.7%), tetanic MRTD (39.1%), twitch MRTD (27.9%), voluntary maximum rate of torque relaxation (MRTR) (46.9%), and tetanic MRTR (41.9%), there were no significant gender differences in percentage rates of torque development or relaxation with voluntary or evoked contractions. Therefore the central and peripheral mechanisms controlling MRTD and MRTR may be similar between the sexes. Key words: gender strength differences, muscle contraction, rate of torque, tetanus, twitch

Peak power is reduced following lengthening contractions despite a maintenance of shortening velocity

2013 ◽  
Vol 38 (12) ◽  
pp. 1196-1205 ◽  
Author(s):  
Geoffrey A. Power ◽  
Brian H. Dalton ◽  
Charles L. Rice ◽  
Anthony A. Vandervoort
Keyword(s):  
Peak Power ◽  
Recovery Period ◽  
Shortening Velocity ◽  
Lengthening Contractions ◽  
Maximum Voluntary Isometric Contraction ◽  
Relative Contribution ◽  
Rate Of Torque Development ◽  
Isometric Torque ◽  
Torque Development ◽  
Shortening Contractions

Following repetitive lengthening contractions, power (the product of torque and velocity) is impaired during shortening contractions. However, the relative contribution of each component to power loss and the underlying factors are unclear. We investigated neuromuscular properties of the dorsiflexors in 8 males (27 ± 3 years) and 8 females (26 ± 4 years) for a potential sex-related difference before, during, and after 150 unaccustomed maximal lengthening actions. Velocity-dependent power was determined from shortening contractions at 8 levels (1 N·m to 70% of maximum voluntary isometric contraction (MVC)) before, after, and throughout recovery assessed at 0–30 min, 24 h, and 48 h. Immediately following task termination, both sexes displayed similar impairments of 30%, 4%, and 10% in MVC torque, shortening velocity, and overall peak power, respectively (P < 0.05). Peak rate of isometric torque development (RTD) was reduced by 10% in males, but females exhibited a 35% reduction (P < 0.05). Rate of torque development for the MVC remained depressed in both sexes throughout the 30 min recovery period; however, the RTD returned to normal by 24 h in males but did not recover by 48 h in females. Power was reduced preferentially at higher loads (i.e., 60% MVC), with a greater loss in females (65%) than males (45%). For lower loads (<20% MVC), power was impaired minimally (4%–8%; P < 0.05) and recovered within 30 min in both groups. The reduction in maximal angular velocity persisted until 30 min of recovery, and peak power did not recover until 24 h for both sexes. Unaccustomed lengthening contractions decreased power preferentially at higher loads, whereas peak power was reduced minimally owing to maintenance of maximal shortening velocity.

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