Corticospinal and transcallosal modulation of unilateral and bilateral contractions of lower limbs

Škarabot, Jakob; Perellón‐Alfonso, Ruben; Cronin, Neil J.; Bon, Jurij; Strojnik, Vojko; Avela, Janne

doi:10.1007/s00421-016-3475-y

Cited by 10 publications

(6 citation statements)

References 91 publications

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“…The strength of the correlation may have been impacted by the slightly different testing positions and procedures between the two testing methods. The bilateral nature of the GroinBar may evoke a bilateral deficit phenomenon: the inability to generate maximal force when both limbs are operating simultaneously (22)(23)(24)(25), which could have impacted on the strength values. During HHD testing, athletes were also able to hold the side of the plinths however this was not reproduced with GroinBar testing, which is performed on the floor.…”

Section: Accepted Manuscriptmentioning

confidence: 99%

A novel device to assess hip strength: Concurrent validity and normative values in male athletes

O'Brien

Bourne

Heerey

et al. 2019

Physical Therapy in Sport

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Section: Accepted Manuscriptmentioning

confidence: 99%

A novel device to assess hip strength: Concurrent validity and normative values in male athletes

O'Brien

Bourne

Heerey

et al. 2019

Physical Therapy in Sport

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“…The MT was defined as the minimal intensity needed to evoke an MEP of >200 μV in three out of five trials in the tonically active SOL (Škarabot et al., 2016), and MT showed a very high level of day‐to‐day reliability (day‐to‐day coefficient of variation of 4.40%) in our study.…”

Section: Methodsmentioning

confidence: 49%

Effects of caffeine on neuromuscular function in a non‐fatigued state and during fatiguing exercise

Mesquita

Cronin

Kyröläinen

et al. 2020

Experimental Physiology

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Caffeine enhances exercise performance, but its mechanisms of action remain unclear. In this study, we investigated its effects on neuromuscular function in a non-fatigued state and during fatiguing exercise. Eighteen men participated in this randomized, double-blind, placebo-controlled crossover trial. Baseline measures included plantarflexion force, drop jump, squat jump, voluntary activation of triceps surae muscle, soleus muscle contractile properties, M-wave, -motoneuron excitability (H-reflex), corticospinal excitability, short-interval intracortical inhibition, intracortical facilitation, silent period evoked by transcranial magnetic stimulation (SP) and plasma potassium and caffeine concentrations. Immediately after baseline testing, participants ingested caffeine (6 mg⋅kg −1 ) or placebo. After a 1-h rest, baseline measures were repeated, followed by a fatiguing stretch-shortening cycle exercise (sets of 40 bilateral rebound jumps on a sledge apparatus) until task failure. Neuromuscular testing was carried out throughout the fatigue protocol and afterwards. Caffeine enhanced drop jump height (by 4.2%) and decreased the SP (by 12.6%) in a non-fatigued state. A caffeine-related decrease in SP and short-interval intracortical inhibition before the fatiguing activity was associated with an increased time to task failure. The participants who benefitted from an improved performance on the caffeine day reported a significantly lower sense of effort during exercise and had an accelerated postexercise recovery of M-wave amplitude. Caffeine modulates inhibitory mechanisms of the CNS, recovery of M-wave amplitude and perception of effort. This study lays the groundwork for future examinations of differences in caffeine-induced neuromuscular changes between those who are deemed to benefit from caffeine ingestion and those who are not.

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“…Reportedly, knee extension BLD was present in the first test session, but there was no BI in a second session, suggesting a further lack of repeatability in the measure (Secher et al, 1988). Since the Secher et al’s (1988) study, no other work has reported lower extremity values in more than one test session, but studies have proposed that training may influence the BLD estimate (Howard & Enoka, 1991; Škarabot, Alfonso, et al, 2016). Using absolute peak values, this work reported the presence of knee extension facilitation (greater bilateral force than unilateral) in a bilaterally trained weightlifting group (BI = 6.6 ± 4.7), no BI in unilaterally trained group (BI = −6.6 ± 7.1) and BLD in an untrained group (−9.5 ± 6.8) (Howard & Enoka, 1991).…”

Section: Discussionmentioning

confidence: 99%

“…When calculated by the average peak value, facilitation was no longer evident in the bilaterally trained group (Howard & Enoka, 1991). To further our argument, the aforementioned populations were later mimicked, reporting no BI across all groups (bilateral BI: −11.6 ± 16.0%; unilateral: −11.5 ± 10.5%; untrained: −4.5 ± 13.1%) using measures of averaged peak forces (Škarabot, Alfonso, et al, 2016). Such nuanced changes in calculation suggest there may be methodological flaws throughout prior BLD literature, influencing our present understanding of the underlying mechanism.…”

Section: Discussionmentioning

confidence: 99%

“…In the evaluation of BLD, differences in performance characteristics between each maximal force measure produces altered outcomes, and therefore the enactment of a single decisive maximal force definition is necessary. The BLD phenomenon is considered the ability to produce the greatest force in unilateral and bilateral contractions, and therefore many studies have observed the phenomenon using absolute peak force (Aune et al, 2013; Behm et al, 2003; Botton et al, 2016; Buckthorpe et al, 2013; Howard & Enoka, 1991; Škarabot, Alfonso, et al, 2016). Characteristically, this measure is easy to interpret, but a single maximal measure may be prone to error from ancillary muscle activity, sudden postural adjustments, or instrument noise.…”

Section: Introductionmentioning

confidence: 99%

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The Bilateral Deficit Phenomenon in Elbow Flexion: Explanations for Its Inconsistent Occurrence and Detection

et al. 2021

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The underlying mechanism(s) of the Bilateral Deficit (BLD) phenomenon is without consensus. Methodological inconsistencies across prior works may be an important source of equivocal results and interpretations. Based on repeatability problems with the BLD measure and maximal force definition, the presence or absence of the BLD phenomenon is altered, shifting conclusions of its mechanistic cause. Our purpose in this study was to examine methodological inconsistencies in applying the BLD measure to establish optimal methods for evaluating the underlying mechanism. Eleven healthy participants engaged in one familiarity and five test sessions, completing bilateral and unilateral elbow maximal voluntary isometric contractions. We defined maximal force by averaged and absolute peak and plateau values. BLD was evident if the bilateral index (BI), the ratio of the bilateral over summed unilateral forces, was statistically different from zero. We addressed interclass correlations (ICC), Chronbach’s α, standard error of the mean, and minimal detectable change between and within sessions for all force measures and BI. We evaluated all combinations of sessions (i.e., 1–2, 3–5, 5–6) and maximal forces to establish the optimal number of sessions to achieve reliability. BLD was present for test sessions, but not for familiarization. All measures of maximal force were highly reliable between and within sessions (ICC(2,1) ≥ .895). BI was only considered significantly reliable in sessions 3–5 ( p < .027), defined by absolute and average plateau forces, but reliability was still quantifiably poor (absolute: ICC(2,1) = .392; average: ICC(2,1) = .375). These results demonstrate that high force reliability within and between sessions does not translate to stable and reliable BI, potentially exposing the lack of any defined BLD mechanism.

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Corticospinal and transcallosal modulation of unilateral and bilateral contractions of lower limbs

Cited by 10 publications

References 91 publications

A novel device to assess hip strength: Concurrent validity and normative values in male athletes

A novel device to assess hip strength: Concurrent validity and normative values in male athletes

Effects of caffeine on neuromuscular function in a non‐fatigued state and during fatiguing exercise

The Bilateral Deficit Phenomenon in Elbow Flexion: Explanations for Its Inconsistent Occurrence and Detection

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