Residual force enhancement and force depression in human single muscle fibres

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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The influence of training-induced sarcomerogenesis on the history dependence of force

Journal of Experimental Biology ◽

10.1242/jeb.218776 ◽

2020 ◽

Vol 223 (15) ◽

pp. jeb218776 ◽

Cited By ~ 3

Author(s):

Jackey Chen ◽

Parastoo Mashouri ◽

Stephanie Fontyn ◽

Mikella Valvano ◽

Shakeap Elliott-Mohamed ◽

...

Keyword(s):

Extensor Digitorum Longus ◽

Isometric Force ◽

Muscle Length ◽

Force Enhancement ◽

Active Muscle ◽

Training Groups ◽

Force Depression ◽

Residual Force ◽

Residual Force Enhancement ◽

Whole Muscle

ABSTRACTThe increase or decrease in isometric force following active muscle lengthening or shortening, relative to a reference isometric contraction at the same muscle length and level of activation, are referred to as residual force enhancement (rFE) and residual force depression (rFD), respectively. The purpose of these experiments was to investigate the trainability of rFE and rFD on the basis of serial sarcomere number (SSN) alterations to history-dependent force properties. Maximal rFE/rFD measures from the soleus and extensor digitorum longus (EDL) of rats were compared after 4 weeks of uphill or downhill running with a no-running control. SSN adapted to the training: soleus SSN was greater with downhill compared with uphill running, while EDL demonstrated a trend towards more SSN for downhill compared with no running. In contrast, rFE and rFD did not differ across training groups for either muscle. As such, it appears that training-induced SSN adaptations do not modify rFE or rFD at the whole-muscle level.

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Force depression following a stretch‐shortening cycle depends on the amount of residual force enhancement established in the initial stretch phase

Physiological Reports ◽

10.14814/phy2.14188 ◽

2019 ◽

Vol 7 (16) ◽

Author(s):

Rafael Fortuna ◽

Tobias Goecking ◽

Wolfgang Seiberl ◽

Walter Herzog

Keyword(s):

Force Enhancement ◽

Force Depression ◽

Residual Force ◽

Stretch Shortening Cycle ◽

Residual Force Enhancement

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Increased force following muscle stretching and simultaneous fibre shortening: Residual force enhancement or force depression – that is the question?

Journal of Biomechanics ◽

10.1016/j.jbiomech.2020.110216 ◽

2021 ◽

pp. 110216

Author(s):

Sheharzad Mahmood ◽

Andrew Sawatsky ◽

Walter Herzog

Keyword(s):

Force Enhancement ◽

Force Depression ◽

Muscle Stretching ◽

Residual Force ◽

Residual Force Enhancement

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Changes in Fascicle Lengths and Pennation Angles Do Not Contribute to Residual Force Enhancement/Depression in Voluntary Contractions

Journal of Applied Biomechanics ◽

10.1123/jab.27.1.64 ◽

2011 ◽

Vol 27 (1) ◽

pp. 64-73 ◽

Cited By ~ 21

Author(s):

Markus Tilp ◽

Simon Steib ◽

Gudrun Schappacher-Tilp ◽

Walter Herzog

Keyword(s):

Tibialis Anterior ◽

Fiber Length ◽

Force Enhancement ◽

Force Depression ◽

Muscle Stretching ◽

Skeletal Muscle Contraction ◽

Muscle Shortening ◽

Residual Force ◽

Residual Force Enhancement ◽

Voluntary Contractions

Force enhancement following muscle stretching and force depression following muscle shortening are well-accepted properties of skeletal muscle contraction. However, the factors contributing to force enhancement/depression remain a matter of debate. In addition to factors on the fiber or sarcomere level, fiber length and angle of pennation affect the force during voluntary isometric contractions in whole muscles. Therefore, we hypothesized that differences in fiber lengths and angles of pennation between force-enhanced/depressed and reference states may contribute to force enhancement/depression during voluntary contractions. The purpose of this study was to test this hypothesis. Twelve subjects participated in this study, and force enhancement/depression was measured in human tibialis anterior. Fiber lengths and angles of pennation were quantified using ultrasound imaging. Neither fiber lengths nor angles of pennation were found to differ between the isometric reference contractions and any of the force-enhanced or force-depressed conditions. Therefore, we rejected our hypothesis and concluded that differences in fiber lengths or angles of pennation do not contribute to the observed force enhancement/depression in human tibialis anterior, and speculate that this result is likely true for other muscles too.

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The influence of training-induced sarcomerogenesis on the history dependence of force

10.1101/2020.03.31.018895 ◽

2020 ◽

Author(s):

Jackey Chen ◽

Parastoo Mashouri ◽

Stephanie Fontyn ◽

Mikella Valvano ◽

Shakeap Elliott-Mohamed ◽

...

Keyword(s):

Isometric Force ◽

Muscle Length ◽

Force Enhancement ◽

Force Depression ◽

Summary Statement ◽

Residual Force ◽

Residual Force Enhancement ◽

Whole Muscle ◽

Insight Into ◽

Sarcomere Number

AbstractThe increase or decrease in isometric force following active muscle lengthening or shortening, relative to a reference isometric contraction at the same muscle length and level of activation, are referred to as residual force enhancement (rFE) and residual force depression (rFD), respectively. The purpose of these experiments was to gain further mechanistic insight into the trainability of rFE and rFD, on the basis of serial sarcomere number (SSN) alterations to length-dependent properties. Maximal rFE/rFD measures from the soleus and extensor digitorum longus (EDL) of rats were compared after 4 weeks of uphill/downhill running and a no running control. Serial sarcomere numbers adapted to the training: soleus serial sarcomere number was greater with downhill compared to uphill running, while EDL demonstrated a trend towards more serial sarcomeres for downhill compared to no running. In contrast, absolute and normalized rFE/rFD did not differ across training groups for either muscle. As such, it appears that training-induced SSN adaptations do not modify rFE/rFD at the whole-muscle level.Summary StatementThe addition and subtraction of serial sarcomeres induced by downhill and uphill running, respectively, did not influence the magnitude of stretch-induced force enhancement and shortening-induced force depression.

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The mechanisms of the residual force enhancement after stretch of skeletal muscle: non-uniformity in half-sarcomeres and stiffness of titin

Proceedings of The Royal Society B Biological Sciences ◽

10.1098/rspb.2012.0467 ◽

2012 ◽

Vol 279 (1739) ◽

pp. 2705-2713 ◽

Cited By ~ 38

Author(s):

Dilson E. Rassier

Keyword(s):

Skeletal Muscles ◽

Sarcomere Length ◽

State Level ◽

Muscle Fibres ◽

Force Enhancement ◽

Considerable Debate ◽

Residual Force ◽

Residual Force Enhancement ◽

Near Future ◽

New Evidence

When activated skeletal muscles are stretched, the force increases significantly. After the stretch, the force decreases and reaches a steady-state level that is higher than the force produced at the corresponding length during purely isometric contractions. This phenomenon, referred to as residual force enhancement , has been observed for more than 50 years, but the mechanism remains elusive, generating considerable debate in the literature. This paper reviews studies performed with single muscle fibres, myofibrils and sarcomeres to investigate the mechanisms of the stretch-induced force enhancement. First, the paper summarizes the characteristics of force enhancement and early hypotheses associated with non-uniformity of sarcomere length. Then, it reviews new evidence suggesting that force enhancement can also be associated with sarcomeric structures. Finally, this paper proposes that force enhancement is caused by: (i) half-sarcomere non-uniformities that will affect the levels of passive forces and overlap between myosin and actin filaments, and (ii) a Ca 2+ -induced stiffness of titin molecules. These mechanisms are compatible with most observations in the literature, and can be tested directly with emerging technologies in the near future.

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