Mitigating the bilateral deficit: reducing neural deficits through residual force enhancement and activation reduction

MacDonald, Graham Z.; Mazara, Nicole; Herzog, Walter; Power, Geoffrey A.

doi:10.1007/s00421-018-3924-x

Cited by 7 publications

(2 citation statements)

References 27 publications

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“…Furthermore, the magnitudes of rFE we observed in single fibres (6-46%) are within previously reported ranges in single fibres from the human vastus lateralis 8 . Our observation of ∼30% of participants being rFE non-responders for in-vivo voluntary contractions is also consistent with previous studies 36–38 .…”

Section: Discussionsupporting

confidence: 93%

Residual force enhancement decreases when scaling from the single muscle fibre to joint level in humans

Hinks,

Jacob,

Patterson

et al. 2024

Preprint

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Residual force enhancement (rFE), defined as increased isometric force following active lengthening compared to a fixed-end isometric contraction at the same muscle length and level of activation, is present across all scales of muscle. While rFE is always present at the cellular level, often rFE ‘non-responders’ are observed during joint-level voluntary contractions. We compared rFE between the joint level and single fibre level (vastus lateralis biopsies) in 16 young males.In-vivovoluntary knee-extensor rFE was measured by comparing steady-state isometric torque between a stretch-hold (maximal activation at 150°, stretch to 70°, hold) and a fixed-end isometric contraction, with ultrasonographic recording of vastus lateralis fascicle length (FL). Fixed-end contractions were performed at 67.5°, 70°, 72.5°, and 75°; the joint angle that most closely matched FL of the stretch-hold contraction’s isometric steady-state was used to calculate rFE. The starting and ending FLs of the stretch-hold contraction were expressed as % optimal FL, determined via torque-angle relationship. In single fibre experiments, the starting and ending fibre lengths were matched relative to optimal length determined fromin-vivotesting, yielding an average sarcomere excursion of ∼2.2-3.4µm. There was a greater magnitude of rFE at the single fibre (∼20%) than joint level (∼5%) (P=0.004), with ‘non-responders’ only observed at the joint level. By comparing rFE across scales within the same participants, we show the development of the rFE non-responder phenomenon is upstream of rFE’s cellular mechanisms, with rFE only lost rather than gained when scaling from single fibres to the joint level.

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Section: Discussionsupporting

confidence: 93%

Residual force enhancement decreases when scaling from the single muscle fibre to joint level in humans

Hinks,

Jacob,

Patterson

et al. 2024

Preprint

Self Cite

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“…This phenomenon has been observed in isometric and dynamic contractions in a variety of sports (3,18,21). The BD may represent a control limitation of the neuromuscular system (12) and could have important implications for sports requiring the development of absolute strength (17). This may be especially important to athletes considering that bilateral resistance training can reduce BD or cause a bilateral facilitation (21), where maximal bilateral force production is greater than the sum of unilateral forces (11).…”

Section: Introductionmentioning

confidence: 99%

Is Bilateral Deficit in Handgrip Strength Associated With Performance in Specific Judo Tasks?

Turnes

Silva

Kons

et al. 2019

Journal of Strength and Conditioning Research

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Turnes, T, Silva, BA, Kons, RL, and Detanico, D. Is bilateral deficit in handgrip strength associated with performance in specific judo tasks? J Strength Cond Res 36(2): 455-460, 2022-The aim of this study was to identify the existence of bilateral deficit (BD) on maximal handgrip strength during standing and seated positions in judo athletes and to correlate this with judo-specific tasks. Nineteen male judo athletes (age 22.1 6 4.6 years) performed unilateral and bilateral handgrip strength tests in seated and standing postures to calculate bilateral index (BI). Athletes then performed the Judogi Grip Strength Test (dynamic and isometric modes) and Special Judo Fitness Test. The comparisons between bilateral and unilateral handgrip strength for each position, weight categories, or training experience (novice ,10 years and advanced .10 years) were made by paired and unpaired t-tests. The sum of bilateral forces was significantly lower than unilateral forces at standing (unilateral: 105 6 20 vs. bilateral: 102 6 21 kgf, BI: 23.0 6 5.9%, p 5 0.043), but not at seated position (unilateral: 100 6 19 vs. bilateral: 98 6 19 kgf, BI: 22.1 6 7.3%, p 5 0.230), indicating BD only at standing position. Pearson coefficient correlations were not significant between judo tests and BI, with similar performance in judo tests between athletes with BD and bilateral facilitation (p . 0.05). Significant BD was observed at standing position in advanced (2 4.5 6 7.1%, p 5 0.049) but not in novice athletes (20.9 6 3.8%, p 5 0.592). We concluded that BI in maximal handgrip strength test was not related with judo-specific tests. However, the BD occurred only at standing position, suggesting that postural stability may contribute for this phenomenon.

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The history-dependent features of muscle force production: A challenge to the cross-bridge theory and their functional implications

Hahn

Han

Joumaa

2023

Journal of Biomechanics

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Mitigating the bilateral deficit: reducing neural deficits through residual force enhancement and activation reduction

Abstract: Residual force enhancement appears to mitigate the BLD, alleviating the effects of a decrease in neural drive by allowing more force for a given level of muscle activation when compared to a purely isometric contraction.

Cited by 7 publications

References 27 publications

Residual force enhancement decreases when scaling from the single muscle fibre to joint level in humans

Residual force enhancement decreases when scaling from the single muscle fibre to joint level in humans

Is Bilateral Deficit in Handgrip Strength Associated With Performance in Specific Judo Tasks?

The history-dependent features of muscle force production: A challenge to the cross-bridge theory and their functional implications

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