scholarly journals Corticospinal drive does not contribute to increased torque production in the presence of residual force enhancement

2020 ◽  
Author(s):  
Jasmin Frischholz ◽  
Brent J. Raiteri ◽  
Daniel Hahn

AbstractFollowing active muscle stretch, a muscle’s force capacity is increased, which is known as residual force enhancement (rFE). As earlier studies found modulations of cortical excitability in the presence of rFE, this study aimed to test whether corticospinal drive contributes to rFE. Fourteen participants performed submaximal plantar flexion stretch-hold and fixed-end contractions at 30% of their maximal voluntary soleus muscle activity in a dynamometer. During the steady state of the contractions, participants either received subthreshold or suprathreshold transcranial magnetic stimulation (TMS) of their motor cortex while triceps surae muscle responses to stimulation were obtained by electromyography (EMG) and net plantar flexion torque was recorded. B-mode ultrasound imaging was used to confirm muscle stretch during stretch-hold contractions in a subset of participants. Following stretch of the plantar flexors, an average rFE of 7% and 11% was observed for contractions with subthreshold and suprathreshold TMS, respectively. 41-46 milliseconds following subthreshold TMS, triceps surae muscle activity was suppressed by 19-25%, but no difference in suppression was found between contraction conditions. Similarly, the reduction in plantar flexion torque following subthreshold TMS was not different between contraction conditions. Motor evoked potentials, silent periods and superimposed twitches following suprathreshold stimulations were also not different between contraction conditions. As stimulations of the motor cortex by TMS did not result in any differences between stretch-hold and fixed-end contractions, we conclude that corticospinal drive does not contribute to the increased torque production in the presence of rFE following active muscle stretch.New & NoteworthyThis study tested whether corticospinal drive contributes to the increased torque capacity in the presence of rFE. Through subthreshold and suprathreshold TMS of the motor cortex, triceps surae muscle activity was respectively supressed or increased in the presence of rFE and during a reference contraction without rFE. As similar responses were observed between contraction contractions, we conclude that corticospinal drive likely does not contribute to the increased torque capacity in the presence of rFE.

PeerJ ◽  
2022 ◽  
Vol 10 ◽  
pp. e12729
Author(s):  
Jasmin Frischholz ◽  
Brent J. Raiteri ◽  
Andrew G. Cresswell ◽  
Daniel Hahn

Background Following stretch of an active muscle, muscle force is enhanced, which is known as residual force enhancement (rFE). As earlier studies found apparent corticospinal excitability modulations in the presence of rFE, this study aimed to test whether corticospinal excitability modulations contribute to rFE. Methods Fourteen participants performed submaximal plantar flexion stretch-hold and fixed-end contractions at 30% of their maximal voluntary soleus muscle activity in a dynamometer. During the steady state of the contractions, participants either received subthreshold or suprathreshold transcranial magnetic stimulation (TMS) of their motor cortex, while triceps surae muscle responses to stimulation were obtained via electromyography (EMG), and net ankle joint torque was recorded. B-mode ultrasound imaging was used to confirm muscle fascicle stretch during stretch-hold contractions in a subset of participants. Results Following stretch of the plantar flexors, an average rFE of 7% and 11% was observed for contractions with subthreshold and suprathreshold TMS, respectively. 41–46 ms following subthreshold TMS, triceps surae muscle activity was suppressed by 19–25%, but suppression was not significantly different between stretch-hold and fixed-end contractions. Similarly, the reduction in plantar flexion torque following subthreshold TMS was not significantly different between contraction conditions. Motor evoked potentials, silent periods and superimposed twitches following suprathreshold TMS were also not significantly different between contraction conditions. Discussion As TMS of the motor cortex did not result in any differences between stretch-hold and fixed-end contractions, we conclude that rFE is not linked to changes in corticospinal excitability.


2011 ◽  
Vol 21 (5) ◽  
pp. 819-826 ◽  
Author(s):  
Kim Hébert-Losier ◽  
Anthony G. Schneiders ◽  
José A. García ◽  
S. John Sullivan ◽  
Guy G. Simoneau

2007 ◽  
Vol 102 (1) ◽  
pp. 18-25 ◽  
Author(s):  
Gavin J. Pinniger ◽  
Andrew G. Cresswell

Stretch of an activated muscle causes a transient increase in force during the stretch and a sustained, residual force enhancement (RFE) after the stretch. The purpose of this study was to determine whether RFE is present in human muscles under physiologically relevant conditions (i.e., when stretches were applied within the working range of large postural leg muscles and under submaximal voluntary activation). Submaximal voluntary plantar flexion (PFv) and dorsiflexion (DFv) activation was maintained by providing direct visual feedback of the EMG from soleus or tibialis anterior, respectively. RFE was also examined during electrical stimulation of the plantar flexion muscles (PFs). Constant-velocity stretches (15°/s) were applied through a range of motion of 15° using a custom-built ankle torque motor. The muscles remained active throughout the stretch and for at least 10 s after the stretch. In all three activation conditions, the stable joint torque measured 9–10 s after the stretch was greater than the isometric joint torque at the final joint angle. When expressed as a percentage of the isometric torque, RFE values were 7, 13, and 12% for PFv, PFs, DFv, respectively. These findings indicate that RFE is a characteristic of human skeletal muscle and can be observed during submaximal (25%) voluntary activation when stretches are applied on the ascending limb of the force-length curve. Although the underlying mechanisms are unclear, it appears that sarcomere popping and passive force enhancement are insufficient to explain the presence of RFE in these experiments.


Author(s):  
Nathan L. Lehr ◽  
William H. Clark ◽  
Michael D. Lewek ◽  
Jason R. Franz

The triceps surae muscle tendon unit is comprised of the lateral and medial gastrocnemius (MG) and soleus (SOL) muscles and three in series elastic “subtendons” that form the Achilles tendon. Comparative literature and our own in vivo evidence suggests that sliding between adjacent subtendons may facilitate independent muscle actuation. We aim to more clearly define the relation between individual muscle activation and subtendon tissue displacements. Here, during fixed-end contractions, electrical muscle stimulation controlled the magnitude of force transmitted via individual triceps surae muscles while ultrasound imaging recorded resultant subtendon tissue displacements. We hypothesized that MG and SOL stimulation would elicit larger displacements in their associated subtendon. 10 young adults completed 4 experimental activations at 3 ankle angles (-20°, 0°, 20°) with knee flexed to approximately 20°: MG stimulation (STIMMG), SOL stimulation (STIMSOL), combined stimulation, and volitional contraction. At 20° plantarflexion, STIMSOL elicited 49% larger tendon non-uniformity (SOL – MG subtendon tissue displacement) than that of STIMMG (p=0.004). For STIMSOL, a one-way post-hoc ANOVA revealed a significant main effect of ankle angle (p=0.009) on Achilles tendon non-uniformity. However, peak tendon non-uniformity decreased by an average of 61% from plantarflexion to dorsiflexion, likely due to an increase in passive tension. Our results suggest that localized tissue displacements within the Achilles tendon respond in anatomically consistent ways to differential patterns of triceps surae muscle activation, but these relations are highly susceptible to ankle angle. This in vivo evidence points to at least some mechanical independence in actuation between the human triceps surae muscle-subtendon units.


1989 ◽  
Vol 66 (4) ◽  
pp. 1976-1983 ◽  
Author(s):  
Y. Yamazaki ◽  
M. Suzuki ◽  
T. Mano

The relationships between neuromuscular performance and biomechanical variables were studied in maximum vertical jumps to examine the factors influencing the performance of a noncountermovement jump. Keeping their knee and hip joint fully extended, five healthy subjects performed four kinds of noncountermovement jumps and one countermovement jump, during which ankle joint angle, platform force, and surface electromyograms of a triceps surae muscle were recorded. In the four noncountermovement jumps, the magnitude of activation and force at the onset of a shortening contraction of the triceps surae muscle were controlled at four different levels. Performance parameters of the noncountermovement jumps, maximum angular velocity of the ankle angle and flight time, correlated with the platform force at the onset of the plantar flexion. Furthermore the integrated electromyograms of the triceps surae muscle before the plantar flexion were correlated with the maximum angular velocity of the ankle angle and the force at the plantar flexion onset. The findings suggest that the efficient utilization of the muscle characteristic contributes to an enhancement of the noncountermovement jump.


2020 ◽  
Vol 8 (10) ◽  
pp. 232596712095691
Author(s):  
Rubén Sánchez-Gómez ◽  
Ricardo Becerro-de-Bengoa-Vallejo ◽  
Carlos Romero Morales ◽  
Marta Elena Losa-Iglesias ◽  
Aitor Castrillo de la Fuente ◽  
...  

Background: The triceps surae muscle has been identified with propulsion during running gait, and typical heel-lift orthotics (THOs) have been used to treat some sports injuries of this structural-biomechanical unit. The effects of a novel propulsion heel-lift orthotic (PHO) on surface electromyography (EMG) activity of the gastrocnemius during a full cycle of running have yet to be tested. Purpose/Hypothesis: We aimed to assess EMG changes in gastrocnemius medialis and lateralis muscle activity when wearing THOs, PHOs, or neutral sports shoes only (SO) during running. We hypothesized that EMG activity of the triceps surae muscle would be lower for PHOs than THOs or SO during running. Study Design: Controlled laboratory study. Methods: A total of 26 healthy, regular recreational runners of both sexes (mean age, 33.58 ± 6.02 years) with a neutral Foot Posture Index and rearfoot strike pattern were recruited to run on a treadmill at 9 km/h using aleatory THOs of 6 and 9 mm, PHOs, and SO while EMG activity of the gastrocnemius medialis and lateralis muscles was recorded over a 30-second period. Intraclass correlation coefficients were calculated to assess reliability. Results: The intraclass correlation coefficient values indicated near perfect reliability, ranging from 0.801 for 6-mm THOs to 0.959 for SO in the gastrocnemius lateralis muscle. EMG activity of the gastrocnemius lateralis muscle was greater for PHOs (25.516 ± 4.780 mV) than for SO (23.140 ± 4.150 mV) ( P < .05), but EMG activity of the gastrocnemius medialis muscle did not show any statistically significant difference between conditions (23.130 ± 2.980 mV vs 26.315 ± 2.930 mV, respectively) ( P = .3). Conclusion: A novel PHO may increase muscle activity of the gastrocnemius lateralis during a full cycle of running gait; consequently, its prescription to treat triceps surae muscle injuries is cautioned. Clinical Relevance: The prescription of novel PHOs could increase EMG activity, which has not been previously described.


2012 ◽  
Vol 26 (11) ◽  
pp. 3124-3133 ◽  
Author(s):  
Kim Hébert-Losier ◽  
Anthony G. Schneiders ◽  
José A. García ◽  
S. John Sullivan ◽  
Guy G. Simoneau

2019 ◽  
Vol 317 (3) ◽  
pp. R369-R378 ◽  
Author(s):  
Korynne S. Rollins ◽  
Tyler D. Hopkins ◽  
Alec L. Butenas ◽  
Kennedy P. Felice ◽  
Carl J. Ade ◽  
...  

Passive limb movement and limb muscle stretch in humans and animals are common experimental strategies used to investigate activation of the muscle mechanoreflex independent of contraction-induced metabolite production. Cyclooxygenase (COX) metabolites, however, are produced by skeletal muscle stretch in vitro and have been found to impact various models of mechanoreflex activation. Whether COX metabolites influence the decerebrate rat triceps surae muscle stretch mechanoreflex model remains unknown. We examined the effect of rat triceps surae muscle stretch on the interstitial concentration of the COX metabolite prostaglandin E2 (PGE2). Interstitial PGE2 concentration was increased above baseline values by 4 min of both static (38% increase, P = 0.01) and dynamic (56% increase, P < 0.01) triceps surae muscle stretch ( n = 10). The 4-min protocol was required to collect enough microdialysis fluid for PGE2 detection. The finding that skeletal muscle stretch in vivo was capable of producing COX metabolites prompted the hypothesis that intra-arterial administration of the COX inhibitor indomethacin (1 mg/kg) would reduce the pressor and cardioaccelerator responses evoked during 30 s (the duration most commonly used in the rat mechanoreflex model) of static and dynamic rat triceps surae muscle stretch. We found that indomethacin had no effect ( P > 0.05, n = 9) on the pressor or cardioaccelerator response during 30 s of either static or dynamic stretch. We conclude that, despite the possibility of increased COX metabolite concentration, COX metabolites do not activate or sensitize thin-fiber muscle afferents stimulated during 30 s of static or dynamic hindlimb skeletal muscle stretch in healthy rats.


2010 ◽  
Vol 103 (3) ◽  
pp. 1262-1274 ◽  
Author(s):  
R. af Klint ◽  
N. J. Cronin ◽  
M. Ishikawa ◽  
T. Sinkjaer ◽  
M. J. Grey

Plantar flexor series elasticity can be used to dissociate muscle–fascicle and muscle–tendon behavior and thus afferent feedback during human walking. We used electromyography (EMG) and high-speed ultrasonography concomitantly to monitor muscle activity and muscle fascicle behavior in 19 healthy volunteers as they walked across a platform. On random trials, the platform was dropped (8 cm, 0.9 g acceleration) or held at a small inclination (up to ±3° in the parasagittal plane) with respect to level ground. Dropping the platform in the mid and late phases of stance produced a depression in the soleus muscle activity with an onset latency of about 50 ms. The reduction in ground reaction force also unloaded the plantar flexor muscles. The soleus muscle fascicles shortened with a minimum delay of 14 ms. Small variations in platform inclination produced significant changes in triceps surae muscle activity; EMG increased when stepping on an inclined surface and decreased when stepping on a declined surface. This sensory modulation of the locomotor output was concomitant with changes in triceps surae muscle fascicle and gastrocnemius tendon length. Assuming that afferent activity correlates to these mechanical changes, our results indicate that within-step sensory feedback from the plantar flexor muscles automatically adjusts muscle activity to compensate for small ground irregularities. The delayed onset of muscle fascicle movement after dropping the platform indicates that at least the initial part of the soleus depression is more likely mediated by a decrease in force feedback than length-sensitive feedback, indicating that force feedback contributes to the locomotor activity in human walking.


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