Residual Force Enhancement in Humans: A Systematic Review

A systematic literature search was conducted to review the evidence of residual force enhancement (RFE) in vivo human muscle. The search, adhered to the PRISMA statement, of CINAHL, EBSCO, Embase, MEDLINE, and Scopus (inception—July 2017) was conducted. Full-text English articles that assessed at least 1 measure of RFE in vivo voluntarily contracted human skeletal muscle were selected. The methodologies of included articles were assessed against the Downs and Black checklist. Twenty-four studies were included (N = 424). Pooled Downs and Black scores ranked “fair” ( [2.26]). RFE was observed in all muscles tested. Joint range of motion varied from 15° to 60°. Contraction intensities ranged from 10% to >95% maximum. Although transient force enhancement during the stretch phase may change with angular velocity, RFE in the subsequent isometric phase is independent of velocity. The magnitude of RFE was influenced by smaller stretch amplitudes and greatest at joint angles indicative of longer muscle lengths. Contraction and activation intensity influenced RFE, particularly during the initial isometric contraction phase of a poststretch isometric contraction. RFE resulted in increased torque production, reduced muscular activation, and enhanced torque production when the neuromuscular system is weakened seen in an aged population.

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Effect of Active Lengthening and Shortening on Small-Angle X-ray Reflections in Skinned Skeletal Muscle Fibres

International Journal of Molecular Sciences ◽

10.3390/ijms22168526 ◽

2021 ◽

Vol 22 (16) ◽

pp. 8526

Author(s):

Venus Joumaa ◽

Ian C. Smith ◽

Atsuki Fukutani ◽

Timothy R. Leonard ◽

Weikang Ma ◽

...

Keyword(s):

Steady State ◽

Small Angle ◽

Isometric Contraction ◽

Sarcomere Length ◽

Force Enhancement ◽

X Ray ◽

Cross Bridge ◽

Residual Force ◽

Residual Force Enhancement ◽

Cross Bridges

Our purpose was to use small-angle X-ray diffraction to investigate the structural changes within sarcomeres at steady-state isometric contraction following active lengthening and shortening, compared to purely isometric contractions performed at the same final lengths. We examined force, stiffness, and the 1,0 and 1,1 equatorial and M3 and M6 meridional reflections in skinned rabbit psoas bundles, at steady-state isometric contraction following active lengthening to a sarcomere length of 3.0 µm (15.4% initial bundle length at 7.7% bundle length/s), and active shortening to a sarcomere length of 2.6 µm (15.4% bundle length at 7.7% bundle length/s), and during purely isometric reference contractions at the corresponding sarcomere lengths. Compared to the reference contraction, the isometric contraction after active lengthening was associated with an increase in force (i.e., residual force enhancement) and M3 spacing, no change in stiffness and the intensity ratio I1,1/I1,0, and decreased lattice spacing and M3 intensity. Compared to the reference contraction, the isometric contraction after active shortening resulted in decreased force, stiffness, I1,1/I1,0, M3 and M6 spacings, and M3 intensity. This suggests that residual force enhancement is achieved without an increase in the proportion of attached cross-bridges, and that force depression is accompanied by a decrease in the proportion of attached cross-bridges. Furthermore, the steady-state isometric contraction following active lengthening and shortening is accompanied by an increase in cross-bridge dispersion and/or a change in the cross-bridge conformation compared to the reference contractions.

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The influence of residual force enhancement on spinal and supraspinal excitability

PeerJ ◽

10.7717/peerj.5421 ◽

2018 ◽

Vol 6 ◽

pp. e5421 ◽

Cited By ~ 8

Author(s):

Caleb T. Sypkes ◽

Benjamin J. Kozlowski ◽

Jordan Grant ◽

Leah R. Bent ◽

Chris J. McNeil ◽

...

Keyword(s):

Skeletal Muscle ◽

Steady State ◽

Evoked Potentials ◽

Isometric Contraction ◽

Motor Evoked Potentials ◽

Isometric Force ◽

Force Enhancement ◽

Active Muscle ◽

Residual Force ◽

Residual Force Enhancement

Background Following active muscle lengthening, there is an increase in steady-state isometric force as compared with a purely isometric contraction at the same muscle length and level of activation. This fundamental property of skeletal muscle is known as residual force enhancement (RFE). While the basic mechanisms contributing to this increase in steady-state isometric force have been well documented, changes in central nervous system (CNS) excitability for submaximal contractions during RFE are unclear. The purpose of this study was to investigate spinal and supraspinal excitability in the RFE isometric steady-state following active lengthening of the ankle dorsiflexor muscles. Methods A total of 11 male participants (20–28 years) performed dorsiflexions at a constant level of electromyographic activity (40% of maximum). Half of the contractions were purely isometric (8 s at an ankle angle of 130°), and the other half were during the RFE isometric steady-state following active lengthening (2 s isometric at 90°, a 1 s lengthening phase at 40°/s, and 5 s at 130°). Motor evoked potentials (MEPs), cervicomedullary motor evoked potentials (CMEPs), and compound muscle action potentials (M-waves) were recorded from the tibialis anterior during the purely isometric contraction and RFE isometric steady-state. Results Compared to the purely isometric condition, following active lengthening, there was 10% RFE (p < 0.05), with a 17% decrease in normalized CMEP amplitude (CMEP/Mmax) (p < 0.05) and no change in normalized MEP amplitude (MEP/CMEP) (p > 0.05). Discussion These results indicate that spinal excitability is reduced during submaximal voluntary contractions in the RFE state with no change in supraspinal excitability. These findings may have further implications to everyday life offering insight into how the CNS optimizes control of skeletal muscle following submaximal active muscle lengthening.

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Force produced by isolated sarcomeres and half-sarcomeres after an imposed stretch

AJP Cell Physiology ◽

10.1152/ajpcell.00208.2011 ◽

2012 ◽

Vol 302 (1) ◽

pp. C240-C248 ◽

Cited By ~ 37

Author(s):

Dilson E. Rassier ◽

Ivan Pavlov

Keyword(s):

Isometric Contraction ◽

Sarcomere Length ◽

Psoas Muscle ◽

Force Measurements ◽

Force Enhancement ◽

In Series ◽

Photodiode Array ◽

Residual Force ◽

Residual Force Enhancement ◽

Induced Changes

When a stretch is imposed to activated muscles, there is a residual force enhancement that persists after the stretch; the force is higher than that produced during an isometric contraction in the corresponding length. The mechanisms behind the force enhancement remain elusive, and there is disagreement if it represents a sarcomeric property, or if it is associated with length nonuniformities among sarcomeres and half-sarcomeres. The purpose of this study was to investigate the effects of stretch on single sarcomeres and myofibrils with predetermined numbers of sarcomeres ( n = 2, 3. . . , 8) isolated from the rabbit psoas muscle. Sarcomeres were attached between two precalibrated microneedles for force measurements, and images of the preparations were projected onto a linear photodiode array for measurements of half-sarcomere length (SL). Fully activated sarcomeres were subjected to a stretch (5–10% of initial SL, at a speed of 0.3 μm·s−1·SL−1) after which they were maintained isometric for at least 5 s before deactivation. Single sarcomeres showed two patterns: 31 sarcomeres showed a small level of force enhancement after stretch (10.46 ± 0.78%), and 28 sarcomeres did not show force enhancement (−0.54 ± 0.17%). In these preparations, there was not a strong correlation between the force enhancement and half-sarcomere length nonuniformities. When three or more sarcomeres arranged in series were stretched, force enhancement was always observed, and it increased linearly with the degree of half-sarcomere length nonuniformities. The results show that the residual force enhancement has two mechanisms: 1) stretch-induced changes in sarcomeric structure(s); we suggest that titin is responsible for this component, and 2) stretch-induced nonuniformities of half-sarcomere lengths, which significantly increases the level of force enhancement.

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Residual force enhancement contributes to increased performance during stretch-shortening cycles of human plantar flexor muscles in vivo

Journal of Biomechanics ◽

10.1016/j.jbiomech.2018.06.003 ◽

2018 ◽

Vol 77 ◽

pp. 190-193 ◽

Cited By ~ 12

Author(s):

Daniel Hahn ◽

Timotheus N. Riedel

Keyword(s):

Plantar Flexor ◽

Force Enhancement ◽

Flexor Muscles ◽

Residual Force ◽

Residual Force Enhancement ◽

Plantar Flexor Muscles

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Residual force enhancement in human skeletal muscles: A systematic review and meta-analysis

Journal of Sport and Health Science ◽

10.1016/j.jshs.2021.05.006 ◽

2021 ◽

Author(s):

Daiani de Campos ◽

Lucas B.R. Orssatto ◽

Gabriel S. Trajano ◽

Walter Herzog ◽

Heiliane de Brito Fontana

Keyword(s):

Systematic Review ◽

Skeletal Muscles ◽

Meta Analysis ◽

Force Enhancement ◽

Residual Force ◽

Residual Force Enhancement ◽

Human Skeletal Muscles

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Modifiability of the history dependence of force through chronic eccentric and concentric biased resistance training

Journal of Applied Physiology ◽

10.1152/japplphysiol.00928.2018 ◽

2019 ◽

Vol 126 (3) ◽

pp. 647-657 ◽

Cited By ~ 11

Author(s):

Jackey Chen ◽

Geoffrey A. Power

Keyword(s):

Steady State ◽

Resistance Training ◽

Isometric Force ◽

Eccentric Training ◽

Force Enhancement ◽

History Dependence ◽

Force Depression ◽

Residual Force ◽

Residual Force Enhancement ◽

Concentric Training

The increase and decrease in steady-state isometric force following active muscle lengthening and shortening are referred to as residual force enhancement (RFE) and force depression (FD), respectively. The RFE and FD states are associated with decreased (activation reduction; AR) and increased (activation increase; AI) neuromuscular activity, respectively. Although the mechanisms have been discussed over the last 60 years, no studies have systematically investigated the modifiability of RFE and FD with training. The purpose of the present study was to determine whether RFE and FD could be modulated through eccentric and concentric biased resistance training. Fifteen healthy young adult men (age: 24 ± 2 yr, weight: 77 ± 8 kg, height: 178 ± 5 cm) underwent 4 wk of isokinetic dorsiflexion training, in which one leg was trained eccentrically (−25°/s) and the other concentrically (+25°/s) over a 50° ankle excursion. Maximal and submaximal (40% maximum voluntary contraction) steady-state isometric torque and EMG values following active lengthening and shortening were compared to purely isometric values at the same joint angles and torque levels. Residual torque enhancement (rTE) decreased by ~36% after eccentric training ( P < 0.05) and increased by ~89% after concentric training ( P < 0.05), whereas residual torque depression (rTD), AR, AI, and optimal angles for torque production were not significantly altered by resistance training ( P ≥ 0.05). It appears that rTE, but not rTD, for the human ankle dorsiflexors is differentially modifiable through contraction type-dependent resistance training. NEW & NOTEWORTHY The history dependence of force production is a property of muscle unexplained by current cross bridge and sliding filament theories. Whether a muscle is actively lengthened (residual force enhancement; RFE) or shortened (force depression) to a given length, the isometric force should be equal to a purely isometric contraction—but it is not! In this study we show that eccentric training decreased RFE, whereas concentric training increased RFE and converted all nonresponders (i.e., not exhibiting RFE) into responders.

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