Neural and contractile determinants of burst‐like explosive isometric contractions of the knee extensors

D’Emanuele, Samuel; Tarperi, Cantor; Rainoldi, Alberto; Schena, Federico; Boccia, Gennaro

doi:10.1111/sms.14244

Cited by 8 publications

(6 citation statements)

References 41 publications

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“…It is unsurprising that repetitive explosive contractions impair the neural drive as neural drive is the main determinant of rapid contractions. 20,21,44 Indirect evidence of decreased muscle excitation and motor unit recruitment occurrence could also be found in the significant drop of normalized RMS (d ~ 1.0) and normalized MFCV (d ~ 0.6) over the first 50-100 ms of contractions. To remove the effect of sarcolemma property changes, we normalized each RMS estimate to the corresponding M-wave peak-topeak amplitude and the MFCV estimate by the M-wave CV.…”

Section: Discussionmentioning

confidence: 97%

“…In turn, spinal and supraspinal mechanisms have likely lowered the motor unit recruitment and discharge rate in the first phase of voluntary contractions. It is unsurprising that repetitive explosive contractions impair the neural drive as neural drive is the main determinant of rapid contractions 20,21,44 . Indirect evidence of decreased muscle excitation and motor unit recruitment occurrence could also be found in the significant drop of normalized RMS ( d ~ 1.0) and normalized MFCV ( d ~ 0.6) over the first 50–100 ms of contractions.…”

Section: Discussionmentioning

confidence: 99%

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Decreased neural drive affects the early rate of force development after repeated burst‐like isometric contractions

Boccia,

D'Emanuele,

Brustio

et al. 2023

Scandinavian Med Sci Sports

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The neural drive to the muscle is the primary determinant of the rate of force development (RFD) in the first 50 ms of a rapid contraction. It is still unproven if repetitive rapid contractions specifically impair the net neural drive to the muscles. To isolate the fatiguing effect of contraction rapidity, 17 male adult volunteers performed 100 burst‐like (i.e., brief force pulses) isometric contractions of the knee extensors. The response to electrically‐evoked single and octet femoral nerve stimulation was measured with high‐density surface electromyography (HD‐sEMG) from the vastus lateralis and medialis muscles. Root mean square (RMS) of each channel of HD‐sEMG was normalized to the corresponding M‐wave peak‐to‐peak amplitude, while muscle fiber conduction velocity (MFCV) was normalized to M‐wave conduction velocity to compensate for changes in sarcolemma properties. Voluntary RFD 0–50 ms decreased (d = −0.56, p < 0.001) while time to peak force (d = 0.90, p < 0.001) and time to RFDpeak increased (d = 0.56, p = 0.034). Relative RMS (d = −1.10, p = 0.006) and MFCV (d = −0.53, p = 0.007) also decreased in the first 50 ms of voluntary contractions. Evoked octet RFD 0–50 ms (d = 0.60, p = 0.020), M‐wave amplitude (d = 0.77, p = 0.009) and conduction velocity (d = 1.75, p < 0.001) all increased. Neural efficacy, i.e., voluntary/octet force ratio, largely decreased (d = −1.50, p < 0.001). We isolated the fatiguing impact of contraction rapidity and found that the decrement in RFD, particularly when calculated in the first 50 ms of muscle contraction, can mainly be explained by a decrease in the net neural drive.

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Section: Discussionmentioning

confidence: 97%

Section: Discussionmentioning

confidence: 99%

Decreased neural drive affects the early rate of force development after repeated burst‐like isometric contractions

Boccia,

D'Emanuele,

Brustio

et al. 2023

Scandinavian Med Sci Sports

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“…Altogether and in contrast to that observed for maximal muscle strength (peak torque), the present RTD data clearly indicate that a separate familiarization session is necessary to improve the motor coordination required for reaching true maximal explosive muscle force production and to achieve acceptable reliability for KE RTD in adults with obesity. Both early and late phase RTD, which mainly represents neural and muscular determinants, respectively (Cossich & Maffiuletti, 2020; D'Emanuele et al, 2023; Tillin et al, 2010), benefit from familiarization. It has previously been demonstrated that co‐contraction of the antagonist occurs in people who are not habituated to a specific task that requires rapid force production (Duchateau & Enoka, 2002).…”

Section: Discussionmentioning

confidence: 99%

“…To our best knowledge, only a single previous study has assessed the test−retest reliability of isometric KF RTD, which was examined in healthy young males and females using isokinetic dynamometry (Mentiplay et al, 2015). (Cossich & Maffiuletti, 2020;D'Emanuele et al, 2023;Tillin et al, 2010), benefit from familiarization. It has previously been demonstrated that co-contraction of the antagonist occurs in people who are not habituated to a specific task that requires rapid force production (Duchateau & Enoka, 2002).…”

Section: Rapid Force Capacity (Rtd)mentioning

confidence: 99%

Intersession reliability of lower limb muscle strength assessments in adults with obesity eligible for bariatric surgery

Gam,

Petz,

Bjerre

et al. 2024

Clin Physio Funct Imaging

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BackgroundThe aim of this study was to examine the test−retest reliability in lower limb muscle strength and rate of torque development (RTD) using isokinetic dynamometry in adults with obesity, with a body mass index (BMI) ≥ 35 kg/m2.MethodThirty‐two adults with a BMI of 43.8 ± 6.6 kg/m2 eligible for bariatric surgery were enroled in the study. Isokinetic and isometric knee extensor (KE) and flexor (KF) strength were assessed in an isokinetic dynamometer (Biodex 4) during three test sessions separated by 3−7 days.ResultsThere were no statistical differences in peak KE and KF torque for any test modalities between sessions. Intraclass correlation (ICC) was 0.91−0.94 between sessions 1 and 2 and 0.94−0.97 between sessions 2 and 3. Standard error of measurement (SEM%) and coefficient of variation (CV) ranged across test sessions from 4.3% to 7.3%. KE RTD showed high test−retest reliability following familiarization, with ICC, CV and SEM% values ranging from 0.84 to 0.90, 13.3%−20.3% and 14.6%−24.9%, respectively.ConclusionMaximal lower limb muscle strength measured by isokinetic dynamometry showed excellent test−retest reliability manifested by small measurement errors and low CV. Reliability was slightly improved by including a familiarization session. KE RTD but not KF RTD demonstrated high test−retest reliability following familiarization. The present data indicate that isokinetic dynamometry can be used to detect even small changes in lower limb muscle strength in adults with obesity.

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“…This physiological feature of RFD may explain why this variable is often more sensitive to changes than MVF [ 16 ], especially when the fatiguing task comprises rapid force production [ 17 ]. The analysis of muscle excitation in the first 50 ms of contraction employing high-density electromyography (HD-EMG) might provide even more insights into the causes of possible decrement of early RFD [ 17 , 18 , 19 ].…”

Section: Introductionmentioning

confidence: 99%

Upper-Limb Muscle Fatigability in Para-Athletes Quantified as the Rate of Force Development in Rapid Contractions of Submaximal Amplitude

Boccia,

Brustio,

Beratto

et al. 2024

JFMK

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This study aimed to compare neuromuscular fatigability of the elbow flexors and extensors between athletes with amputation (AMP) and athletes with spinal cord injury (SCI) for maximum voluntary force (MVF) and rate of force development (RFD). We recruited 20 para-athletes among those participating at two training camps (2022) for Italian Paralympic veterans. Ten athletes with SCI (two with tetraplegia and eight with paraplegia) were compared to 10 athletes with amputation (above the knee, N = 3; below the knee, N = 6; forearm, N = 1). We quantified MVF, RFD at 50, 100, and 150 ms, and maximal RFD (RFDpeak) of elbow flexors and extensors before and after an incremental arm cranking to voluntary fatigue. We also measured the RFD scaling factor (RFD-SF), which is the linear relationship between peak force and peak RFD quantified in a series of ballistic contractions of submaximal amplitude. SCI showed lower levels of MVF and RFD in both muscle groups (all p values ≤ 0.045). Despite this, the decrease in MVF (Cohen’s d = 0.425, p < 0.001) and RFDpeak (d = 0.424, p = 0.003) after the incremental test did not show any difference between pathological conditions. Overall, RFD at 50 ms showed the greatest decrease (d = 0.741, p < 0.001), RFD at 100 ms showed a small decrease (d = 0.382, p = 0.020), and RFD at 150 ms did not decrease (p = 0.272). The RFD-SF decreased more in SCI than AMP (p < 0.0001). Muscle fatigability impacted not only maximal force expressions but also the quickness of ballistic contractions of submaximal amplitude, particularly in SCI. This may affect various sports and daily living activities of wheelchair users. Early RFD (i.e., ≤50 ms) was notably affected by muscle fatigability.

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Neural and contractile determinants of burst‐like explosive isometric contractions of the knee extensors

Cited by 8 publications

References 41 publications

Decreased neural drive affects the early rate of force development after repeated burst‐like isometric contractions

Decreased neural drive affects the early rate of force development after repeated burst‐like isometric contractions

Intersession reliability of lower limb muscle strength assessments in adults with obesity eligible for bariatric surgery

Upper-Limb Muscle Fatigability in Para-Athletes Quantified as the Rate of Force Development in Rapid Contractions of Submaximal Amplitude

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