Maximum rate of force development is increased by antagonist conditioning contraction

1994 ◽  
Vol 77 (2) ◽  
pp. 807-811 ◽  
Author(s):  
M. D. Grabiner
Keyword(s):  
Maximum Rate ◽  
Isometric Force ◽  
Knee Extensor ◽  
Knee Extension ◽  
Quadriceps Femoris ◽  
Rate Of Force Development ◽  
Force Development ◽  
Knee Flexor ◽  
Flexor Muscles ◽  
Conditioning Contraction

Nine subjects performed maximum contractions with the knee extensor muscles on an isokinetic device set at 4.36 rad/s. The knee extensions were preceded by isometric conditioning contractions of the antagonist knee flexor muscles. The conditioning contraction forces were 0, 25, 50, 75, and 100% of the maximum isometric force. The purpose of the study was to determine 1) the effects of graded conditioning contractions with the knee flexor muscles on the maximum performance of the quadriceps femoris and 2) whether the effects of the conditioning contractions are similarly distributed to components of the quadriceps femoris. The increased initial quadriceps femoris activation levels associated with the conditioning contractions were similarly distributed to quadriceps femoris components. In contrast with previously published research on exercise performed at substantially lower knee extension velocities, the maximum knee extension force and the work performed were not affected by the conditioning contractions. However, the maximum rate of force development increased significantly (P < 0.05). The intensity of the knee flexor conditioning contractions likely influences agonist motor unit activation variables, but this influence may be related to the speed of the agonist contraction.

Isokinetic Strength After ACL Reconstruction: Influence of Concomitant Anterolateral Ligament Reconstruction

2021 ◽  
pp. 194173812110054
Author(s):  
Benoit Gillet ◽  
Yoann Blache ◽  
Isabelle Rogowski ◽  
Grégory Vigne ◽  
Bertrand Sonnery-Cottet ◽  
...  
Keyword(s):  
Muscle Strength ◽  
Ligament Reconstruction ◽  
Knee Extensor ◽  
Anterolateral Ligament ◽  
Flexor Muscle ◽  
Knee Flexor ◽  
Strength Recovery ◽  
Flexor Muscles ◽  
Knee Muscle ◽  
Knee Muscle Strength

Background: To reduce the rate of anterior cruciate ligament (ACL) graft rupture, recent surgeries have involved anterolateral ligament reconstruction (ALLR). This reconstruction procedure harvests more knee flexor muscle tendons than isolated ACL reconstruction (ACLR), but its influence on knee muscle strength recovery remains unknown. This study aimed to assess the influence of ALLR with a gracilis graft on the strength of the knee extensor and flexor muscles at 6 months postoperatively. Hypothesis: The additional amount of knee flexor harvest for ALLR would result in impairment in knee flexor muscle strength at 6 months postoperatively. Study Design: Retrospective cohort study. Level of Evidence: Level 2. Methods: A total of 186 patients were assigned to 2 groups according to the type of surgery: ACL + ALLR (graft: semitendinosus + gracilis, n = 119) or isolated ACLR (graft: semitendinosus, n = 67). The strength of the knee extensor and flexor muscles was assessed using an isokinetic dynamometer at 90, 180, and 240 deg/s for concentric and 30 deg/s for eccentric contractions and compared between groups using analysis of variance statistical parametric mapping. Results: Regardless of the surgery and the muscle, the injured leg produced significantly less strength than the uninjured leg throughout knee flexion and extension from 30° to 90° for each angular velocity (30, 90, 180, and 240 deg/s). However, the knee muscle strength was similar between the ACL + ALLR and ACLR groups. Conclusion: The addition of ALLR using the gracilis tendon during ACLR does not alter the muscle recovery observed at 6 months postoperatively. Clinical Relevance: Although more knee flexor muscle tendons were harvested in ACL + ALLR, the postoperative strength recovery was similar to that of isolated ACLR.

Acute Physiological Response to Light- and Heavy-load Power-oriented Exercise in Older Adults

2021 ◽  
Author(s):  
Carlos Rodriguez-Lopez ◽  
Julian Alcazar ◽  
Jose Losa-Reyna ◽  
JuanManuel Carmona-Torres ◽  
Aurora Maria Cruz-Santaella ◽  
...  
Keyword(s):  
Older Adults ◽  
Creatine Kinase ◽  
Resistance Training ◽  
Isometric Force ◽  
Rate Of Force Development ◽  
Heavy Load ◽  
Force Development ◽  
Sit To Stand ◽  
Light Load ◽  
Maximal Isometric Force

AbstractThis study investigated the acute responses to volume-load-matched heavy-load (80% 1RM) versus light-load (40% 1RM) power-oriented resistance training sessions in well-functioning older adults. Using a randomized cross-over design, 15 volunteers completed each condition on a leg press. Neuromuscular (maximal isometric force and rate of force development) and functional performance (power during sit-to-stand test), lactate, and muscle damage biochemistry (creatine kinase, lactate dehydrogenase and C-reactive protein serum concentration) were assessed pre- and post-exercise. Performance declines were found after heavy-load (Cohen’s d effect size (d); maximal isometric force=0.95 d; rate of force development=1.17 d; sit-to-stand power =0.38 d, all p<0.05) and light-load (maximal isometric force=0.45 d; rate of force development=0.9 d; sit-to-stand power=1.17 d, all p<0.05), while lactate concentration increased only after light-load (1.7 d, p=0.001). However, no differences were found between conditions (all p>0.05). Both conditions increased creatine kinase the day after exercise (marginal effect=0.75 d, p<0.001), but no other blood markers increased (all, p>0.05). Irrespective of the load used, power training induced non-clinically significant decreases in sit-to-stand performance, moderate declines in maximal isometric force, but pronounced decreases in the rate of force development. Furthermore, the metabolic stress and muscle damage were minor; both sessions were generally well tolerated by well-functioning older adults without previous experience in resistance training.

The Frank-Starling mechanism is not mediated by changes in rate of cross-bridge detachment

1997 ◽  
Vol 273 (5) ◽  
pp. H2428-H2435 ◽  
Author(s):  
Thomas Wannenburg ◽  
Paul M. L. Janssen ◽  
Dongsheng Fan ◽  
Pieter P. De Tombe
Keyword(s):  
Cardiac Muscle ◽  
Maximum Rate ◽  
Sarcomere Length ◽  
Myosin Head ◽  
Isometric Force ◽  
Force Development ◽  
Cross Bridge ◽  
Average Slope ◽  
The Cross ◽  
Kinetics Of

We tested the hypothesis that the Frank-Starling relationship is mediated by changes in the rate of cross-bridge detachment in cardiac muscle. We simultaneously measured isometric force development and the rate of ATP consumption at various levels of Ca2+ activation in skinned rat cardiac trabecular muscles at three sarcomere lengths (2.0, 2.1, and 2.2 μm). The maximum rate of ATP consumption was 1.5 nmol ⋅ s−1 ⋅ μl fiber vol−1, which represents an estimated adenosinetriphosphatase (ATPase) rate of ∼10 s−1 per myosin head at 24°C. The rate of ATP consumption was tightly and linearly coupled to the level of isometric force development, and changes in sarcomere length had no effect on the slope of the force-ATPase relationships. The average slope of the force-ATPase relationships was 15.5 pmol ⋅ mN−1 ⋅ mm−1. These results suggest that the mechanisms that underlie the Frank-Starling relationship in cardiac muscle do not involve changes in the kinetics of the apparent detachment step in the cross-bridge cycle.

Relationship Between Isometric Force–Time Characteristics and Sprint Kayaking Performance

2020 ◽  
pp. 1-6
Author(s):  
Danny Lum ◽  
Abdul Rashid Aziz
Keyword(s):  
Bench Press ◽  
Isometric Force ◽  
Rate Of Force Development ◽  
Isometric Strength ◽  
Mean Power ◽  
Force Development ◽  
Peak Rate ◽  
Time To Completion ◽  
Strength Tests ◽  
Force Time

Force–time characteristics obtained during isometric strength tests are significantly correlated to various sporting movements. However, data on the relationship between isometric force–time characteristics and sprint kayaking performance are lacking in the literature. Purpose: The purpose of the study was, therefore, to investigate the relationship between sprint kayaking performance with ergometer performance and measures from 3 isometric strength tests: isometric squat, isometric bench press, and isometric prone bench pull. Methods: A total of 23 sprint kayaking athletes performed all 3 tests, at 90° and 120° knee angles for isometric squat and at elbow angles for isometric bench press and isometric prone bench pull, and a 200-m sprint on-water to attain the fastest time-to-completion (OWTT) possible and on a kayak ergometer to attain the highest mean power (LABTT) possible. Results: There was a significant inverse correlation between OWTT and LABTT (r = −.90, P < .001). The peak forces achieved from all isometric strength tests were significantly correlated with time-to-completion for OWTT and mean power for LABTT (r = −.44 to −.88, P < .05 and .47 to .80, P < .05, respectively). OWTT was significantly correlated with the peak rate of force development during all isometric tests except for the isometric squat at a 120° knee angle (r = −.47 to −.62, P < .05). LABTT was significantly correlated with peak rate of force development from the isometric bench press and isometric prone bench pull (r = .64–.86, P < .01). Conclusion: Based on the observed strong correlations, the mean power attained during LABTT is a good predictor of OWTT time-to-completion. Furthermore, upper- and lower-body maximum strength and peak rate of force development are equally important for on-water and ergometer sprint kayaking performance.

scholarly journals Neural and muscular determinants of maximal rate of force development

2020 ◽  
Vol 123 (1) ◽  
pp. 149-157 ◽  
Author(s):  
Jakob L. Dideriksen ◽  
Alessandro Del Vecchio ◽  
Dario Farina
Keyword(s):  
Motor Unit ◽  
Maximum Rate ◽  
Rapid Development ◽  
Motor Units ◽  
Rate Of Force Development ◽  
Time Range ◽  
Limiting Factor ◽  
Force Development ◽  
Twitch Contraction ◽  
Discharge Rates

The ability to produce rapid forces requires quick motor unit recruitment, high motor unit discharge rates, and fast motor unit force twitches. The relative importance of these parameters for maximum rate of force development (RFD), however, is poorly understood. In this study, we systematically investigated these relationships using a computational model of motor unit pool activity and force. Across simulations, neural and muscular properties were systematically varied in experimentally observed ranges. Motor units were recruited over an interval starting from contraction onset (range: 22–233 ms). Upon recruitment, discharge rates declined from an initial rate (range: 89–212 pulses per second), with varying likelihood of doublet (interspike interval of 3 ms; range: 0–50%). Finally, muscular adaptations were modeled by changing average twitch contraction time (range: 42–78 ms). Spectral analysis showed that the effective neural drive to the simulated muscle had smaller bandwidths than the average motor unit twitch, indicating that the bandwidth of the motor output, and thus the capacity for explosive force, was limited mainly by neural properties. The simulated RFD increased by 1,050 ± 281% maximal voluntary contraction force per second from the longest to the shortest recruitment interval. This effect was more than fourfold higher than the effect of increasing the initial discharge rate, more than fivefold higher than the effect of increasing the chance of doublets, and more than sixfold higher than the effect of decreasing twitch contraction times. The simulated results suggest that the physiological variation of the rate by which motor units are recruited during ballistic contractions is the main determinant for the variability in RFD across individuals. NEW & NOTEWORTHY An important limitation of human performance is the ability to generate explosive movements by means of rapid development of muscle force. The physiological determinants of this ability, however, are poorly understood. In this study, we show using extensive simulations that the rate by which motor units are recruited is the main limiting factor for maximum rate of force development.

Muscle fiber composition, jumping performance, and rate of force development adaptations induced by different power training volumes in females

2020 ◽  
Vol 45 (9) ◽  
pp. 996-1006 ◽  
Author(s):  
Spyridon Methenitis ◽  
Thomas Mpampoulis ◽  
Polyxeni Spiliopoulou ◽  
George Papadimas ◽  
Constantinos Papadopoulos ◽  
...  
Keyword(s):  
Muscle Fiber ◽  
Isometric Force ◽  
Fiber Type ◽  
High Volume ◽  
Rate Of Force Development ◽  
Training Volume ◽  
Power Training ◽  
Power Performance ◽  
Force Development ◽  
Low Volume

This study aimed to investigate the effect of 3 different eccentric-only power training volumes on muscle fiber type composition and power performance. Twenty-nine females were assigned into 3 groups and performed 10 weeks of either 3 (low volume), 6 (moderate volume), or 9 (high volume) sets/session of 4 fast-velocity eccentric-only half-squats against 70% of concentric 1-repetition maximum (1RM), followed by 3 maximum countermovement jumps (CMJs) after each set. Half-squat 1RM, CMJ height/power, maximum isometric force, rate of force development (RFD) and muscle fiber cross-sectional area (CSA) were increased in all groups (p = 0.001). Low-volume training induced higher increases in CMJ height/power and early RFD, compared with the moderate- and high-volume training programs (p < 0.001). Significant reductions in type IIx muscle fiber percentages and %CSAs were found after moderate- and high-volume training, with concomitant increases in type IIa fibers (p = 0.001). Significant correlations were found between the changes in type IIa and type IIx percentages, fiber CSA, %CSA, and the changes in performance (r: –0.787 to 0.792; p < 0.05). These results suggest that relatively large eccentric power training volumes may result in detrimental neuromuscular adaptations, minimal changes in early RFD, and a reduction of type IIx muscle fiber percentage. Novelty Low but not high volume of power training maintains type IIx muscle fibers. Early rate of force development increases after a low- or moderate-power training volume, but not after a high-power training volume. Training-induced changes in type IIx muscle fiber percentage is related with changes in early rate of force development.

scholarly journals Intramuscular fiber conduction velocity, isometric force and explosive performance

2016 ◽  
Vol 51 (1) ◽  
pp. 93-101 ◽  
Author(s):  
Spyridon Methenitis ◽  
Gerasimos Terzis ◽  
Nikolaos Zaras ◽  
Angeliki-Nikoletta Stasinaki ◽  
Nikolaos Karandreas
Keyword(s):  
Conduction Velocity ◽  
Muscle Fiber ◽  
Isometric Force ◽  
Vastus Lateralis ◽  
Rate Of Force Development ◽  
Muscle Fiber Conduction Velocity ◽  
Force Development ◽  
Leg Press ◽  
Explosive Performance ◽  
Maximum Isometric Force

Abstract Conduction of electrical signals along the surface of muscle fibers is acknowledged as an essential neuromuscular component which is linked with muscle force production. However, it remains unclear whether muscle fiber conduction velocity (MFCV) is also linked with explosive performance. The aim of the present study was to investigate the relationship between vastus lateralis MFCV and countermovement jumping performance, the rate of force development and maximum isometric force. Fifteen moderately-trained young females performed countermovement jumps as well as an isometric leg press test in order to determine the rate of force development and maximum isometric force. Vastus lateralis MFCV was measured with intramuscular microelectrodes at rest on a different occasion. Maximum MFCV was significantly correlated with maximum isometric force (r = 0.66, p < 0.01), nevertheless even closer with the leg press rate of force development at 100 ms, 150 ms, 200 ms, and 250 ms (r = 0.85, r = 0.89, r = 0.91, r = 0.92, respectively, p < 0.01). Similarly, mean MFCV and type II MFCV were better correlated with the rate of force development than with maximum isometric leg press force. Lower, but significant correlations were found between mean MFCV and countermovement jump power (r = 0.65, p < 0.01). These data suggest that muscle fiber conduction velocity is better linked with the rate of force development than with isometric force, perhaps because conduction velocity is higher in the larger and fastest muscle fibers which are recognized to contribute to explosive actions.

scholarly journals Rate of Force Development Is Related to Maximal Force and Sit-to-Stand Performance in Men With Stages 3b and 4 Chronic Kidney Disease

2021 ◽  
Vol 2 ◽  
Author(s):  
Jared M. Gollie ◽  
Michael O. Harris-Love ◽  
Samir S. Patel ◽  
Nawar M. Shara ◽  
Marc R. Blackman
Keyword(s):  
Chronic Kidney Disease ◽  
Kidney Disease ◽  
Knee Extensor ◽  
Muscle Thickness ◽  
Rectus Femoris ◽  
Rate Of Force Development ◽  
Knee Extensors ◽  
Clinical Trial Registration ◽  
Force Development ◽  
Sit To Stand

Introduction: The primary aims of the present study were to assess the relationships of early (0–50 ms) and late (100–200 ms) knee extensor rate of force development (RFD) with maximal voluntary force (MVF) and sit-to-stand (STS) performance in participants with chronic kidney disease (CKD) not requiring dialysis.Methods: Thirteen men with CKD (eGFR = 35.17 ±.5 ml/min per 1.73 m2, age = 70.56 ±.4 years) and 12 non-CKD men (REF) (eGFR = 80.31 ± 4.8 ml/min per 1.73 m2, age = 70.22 ±.9 years) performed maximal voluntary isometric contractions to determine MVF and RFD of the knee extensors. RFD was measured at time intervals 0–50 ms (RFD0−50) and 100–200 ms (RFD100−200). STS was measured as the time to complete five repetitions. Measures of rectus femoris grayscale (RF GSL) and muscle thickness (RF MT) were obtained via ultrasonography in the CKD group only. Standardized mean differences (SMD) were used to examine differences between groups. Bivariate relationships were assessed by Pearson's product moment correlation.Results: Knee extensor MVF adjusted for body weight (CKD=17.14 ±.1 N·kg0.67, REF=21.55 ±.3 N·kg0.67, SMD = 0.79) and STS time (CKD = 15.93 ±.4 s, REF = 12.23 ±.7 s, SMD = 1.03) were lower in the CKD group than the REF group. Absolute RFD100−200 was significantly directly related to adjusted MVF in CKD (r = 0.56, p = 0.049) and REF (r = 0.70, p = 0.012), respectively. STS time was significantly inversely related to absolute (r = −0.75, p = 0.008) and relative RFD0−50 (r = −0.65, p = 0.030) in CKD but not REF (r = 0.08, p = 0.797; r = 0.004, p = 0.991). Significant inverse relationships between RF GSL adjusted for adipose tissue thickness and absolute RFD100−200 (r =−0.59, p = 0.042) in CKD were observed.Conclusion: The results of the current study highlight the declines in strength and physical function that occur in older men with CKD stages 3b and 4 not requiring dialysis. Moreover, early RFD was associated with STS time in CKD while late RFD was associated MVF in both CKD and REF.Clinical Trial Registration: ClinicalTrials.gov, identifier: NCT03160326 and NCT02277236.

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