Passive Muscle Length Changes Affect Twitch Potentiation in Power Athletes

Gago, Paulo; Marques, Mário C.; Marinho, Daniel A.; Ekblom, Maria

doi:10.1249/mss.0000000000000245

Cited by 9 publications

(13 citation statements)

References 41 publications

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“…Significant enhancements in PT, RTD and RTR lasted for a minimum of one minute to a maximum of five minutes (Figures 2A, B and C). Such behavior is in line with previous findings (Fukutani et al, 2014; Gago et al, 2014b; Vandervoort et al, 1983) and indicates PAP related effects on the muscle contractile properties.…”

Section: Discussionsupporting

confidence: 93%

“…extended versus flexed knee) on plantarflexor twitch PAP. While Fukutani et al (2014) investigated PAP of the plantarflexors in a flexed knee position to isolate the soleus muscle, others have used an extended knee position (Fukutani et al, 2013; Gago et al, 2014b; Vandervoort et al, 1983), but no one has compared PAP in a flexed and an extended position within the same subjects. Previous studies have indicated that flexing the knee changes the gastrocnemius muscle architecture resulting in impaired force transfer and neuromuscular inhibition of the gastrocnemius (Cresswell et al, 1995; Kawakami et al, 1998; Kennedy and Cresswell 2001; Tamaki et al, 1997).…”

Section: Introductionmentioning

confidence: 99%

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Post Activation Potentiation of the Plantarflexors: Implications of Knee Angle Variations

Gago

Arndt

Ekblom

2017

Journal of Human Kinetics

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Flexing the knee to isolate the single joint soleus from the biarticular gastrocnemius is a strategy for investigating individual plantarflexor’s post activation potentiation (PAP). We investigated the implications of testing plantarflexor PAP at different knee angles and provided indirect quantification of the contribution of gastrocnemius potentiation to the overall plantarflexor enhancements post conditioning. Plantarflexor supramaximal twitches were measured in ten male power athletes before and after a maximal isometric plantarflexion (MVIC) at both flexed and extended knee angles. Mean torque and soleus (SOLRMS) and medial gastrocnemius (MGRMS) activity were measured during the MVIC. The mean torque and MGRMS of the MVIC were lower (by 33.9 and 42.4%, respectively) in the flexed compared to the extended position, with no significant difference in SOLRMS. After the MVIC, twitch peak torque (PT) and the rate of torque development (RTR) potentiated significantly more (by 17.4 and 14.7% respectively) in the extended as compared to the flexed knee position, but only immediately (5 s) after the MVIC. No significant differences were found in the twitch rate of torque development (RTD) potentiation between positions. It was concluded that knee joint configuration should be taken into consideration when comparing studies of plantarflexor PAP. Furthermore, results reflect a rather brief contribution of the gastrocnemius potentiation to the overall plantarflexor twitch enhancements.

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Section: Discussionsupporting

confidence: 93%

Section: Introductionmentioning

confidence: 99%

Post Activation Potentiation of the Plantarflexors: Implications of Knee Angle Variations

Gago

Arndt

Ekblom

2017

Journal of Human Kinetics

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“…The enhanced PT and RTD together with reduced and RT 10-90 that recovered to baseline within 5 to 10 min after the end of the MVIC (Figs. 2 to 4) were expected and in support of previous studies (Baudry and Duchateau, 1394;Fukutani et al, 2013;Gago et al, 2014b;Jubeau et al, 2010). With the exception of the RT10-90 in the shortening mode (Fig.…”

Section: Post Activation Potentiation Of the Contractile Propertiessupporting

confidence: 91%

“…4), the conditioning affected twitch contractile properties in similar directions for all three modes. The magnitude and duration of potentiation did, however, vary between modes as it has previously been reported for the knee extensors and plantar flexors (Babault et al, 2008;Gago et al, 2014b).…”

Section: Post Activation Potentiation Of the Contractile Propertiesmentioning

confidence: 50%

“…After these 10 min, a further 2 min of rest were allowed before the next protocol was initiated. The isometric mode was investigated with the foot at 90°while passive rotations at 30°/s were used both for the lengthening and shortening modes as in Gravel et al (1987), Gago et al (2014b) and Babault et al (2008). Similarly, to Gravel et al (1987), the present study also included a pilot study to ensure that the timing of the supramaximal twitches was optimized to occur at an identical ankle joint angle across modes.…”

Section: Methodsmentioning

confidence: 99%

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Effects of post activation potentiation on electromechanical delay

Gago

Arndt

Marques

et al. 2019

Clinical Biomechanics

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A B S T R A C TElectromechanical delay (EMD) presumably depends upon both contractile and tensile factors. It has recently been used as an indirect measure of muscle tendon stiffness to study adaptations to stretching and training. The aim of the present study was to investigate whether contractile properties induced by a 6 s maximum voluntary isometric contraction (MVIC) could affect EMD without altering passive muscle tendon stiffness or stiffness index. Plantar flexor twitches were evoked via electrical stimulation of the tibial nerve in eight highly trained male sprinters before and after a 6 s MVIC in passive isometric or passively shortening or lengthening muscles. For each twitch, EMD, twitch contractile properties and SOLM-Wave were measured. Passive muscle tendon stiffness was measured from the slope of the relation between torque and ankle angle during controlled passive dorsal flexion and stiffness index by curve-fitting the torque angle data using a second-order polynomial function. EMD did not differ between isometric, lengthening or shortening movements. EMD was reduced by up to 11.56 ± 5.64% immediately after the MVIC and stayed depressed for up to 60 s after conditioning. Peak twitch torque and rate of torque development were potentiated by up to 119.41 ± 37.15% and 116.06 ± 37.39%, respectively. Rising time was reduced by up to 14.46 ± 7.22%. No significant changes occurred in passive muscle tendon stiffness or stiffness index. Using a conditioning MVIC, it was shown that there was an acute enhancement of contractile muscle properties as well as a significant reduction in EMD with no corresponding changes in stiffness. Therefore, caution should be taken when using and interpreting EMD as a proxy for muscle tendon stiffness.

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Lessons from a tarantula: new insights into myosin interacting-heads motif evolution and its implications on disease

et al. 2017

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Tarantula's leg muscle thick filament is the ideal model for the study of the structure and function of skeletal muscle thick filaments. Its analysis has given rise to a series of structural and functional studies, leading, among other things, to the discovery of the myosin interacting-heads motif (IHM). Further electron microscopy (EM) studies have shown the presence of IHM in frozen-hydrated and negatively stained thick filaments of striated, cardiac, and smooth muscle of bilaterians, most showing the IHM parallel to the filament axis. EM studies on negatively stained heavy meromyosin of different species have shown the presence of IHM on sponges, animals that lack muscle, extending the presence of IHM to metazoans. The IHM evolved about 800 MY ago in the ancestor of Metazoa, and independently with functional differences in the lineage leading to the slime mold Dictyostelium discoideum (Mycetozoa). This motif conveys important functional advantages, such as Ca regulation and ATP energy-saving mechanisms. Recent interest has focused on human IHM structure in order to understand the structural basis underlying various conditions and situations of scientific and medical interest: the hypertrophic and dilated cardiomyopathies, overfeeding control, aging and hormone deprival muscle weakness, drug design for schistosomiasis control, and conditioning exercise physiology for the training of power athletes.

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Passive Muscle Length Changes Affect Twitch Potentiation in Power Athletes

Cited by 9 publications

References 41 publications

Post Activation Potentiation of the Plantarflexors: Implications of Knee Angle Variations

Post Activation Potentiation of the Plantarflexors: Implications of Knee Angle Variations

Effects of post activation potentiation on electromechanical delay

Lessons from a tarantula: new insights into myosin interacting-heads motif evolution and its implications on disease

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