Use of motor cortex stimulation to measure simultaneously the changes in dynamic muscle properties and voluntary activation in human muscles

2007 ◽  
Vol 102 (5) ◽  
pp. 1756-1766 ◽  
Author(s):  
Gabrielle Todd ◽  
Janet L. Taylor ◽  
Jane E. Butler ◽  
Peter G. Martin ◽  
Robert B. Gorman ◽  
...  
Keyword(s):  
Motor Cortex ◽  
Muscle Contraction ◽  
Motor Nerve ◽  
Contractile Properties ◽  
Voluntary Activation ◽  
Relaxation Rates ◽  
Muscle Contractile Properties ◽  
Fatigued Muscle ◽  
Voluntary Contractions ◽  
Muscle Contractile

Force responses to transcranial magnetic stimulation of motor cortex (TMS) during exercise provide information about voluntary activation and contractile properties of the muscle. Here, TMS-generated twitches and muscle relaxation during the TMS-evoked silent period were measured in fresh, heated, and fatigued muscle. Subjects performed isometric contractions of elbow flexors in two studies. Torque and EMG were recorded from elbow flexor and extensor muscles. One study ( n = 6) measured muscle contraction times and relaxation rates during brief maximal and submaximal contractions in fresh and fatigued muscle. Another study ( n = 7) aimed to 1) assess the reproducibility of muscle contractile properties during brief voluntary contractions in fresh muscle, 2) validate the technique for contractile properties in passively heated muscle, and 3) apply the technique to study contractile properties during sustained maximal voluntary contractions. In both studies, muscle contractile properties during voluntary contractions were compared with the resting twitch evoked by motor nerve stimulation. Measurement of muscle contractile properties during voluntary contractions is reproducible in fresh muscle and reveals faster and slower muscle relaxation rates in heated and fatigued muscle, respectively. The technique is more sensitive to altered muscle state than the traditional motor nerve resting twitch. Use of TMS during sustained maximal contractions reveals slowing of muscle contraction and relaxation with different time courses and a decline in voluntary activation. Voluntary output from the motor cortex becomes insufficient to maintain complete activation of muscle, although slowing of muscle contraction and relaxation indicates that lower motor unit firing rates are required for fusion of force.

scholarly journals Thermal Sensitivity of Swimming Performance and Muscle Contraction in Northern and Southern Populations of Tree Frogs (Hyla Crucifer)

1989 ◽  
Vol 142 (1) ◽  
pp. 357-372 ◽  
Author(s):  
HENRY B. JOHN-ALDER ◽  
M. CHRISTOPHER BARNHART ◽  
ALBERT F. BENNETT
Keyword(s):  
Muscle Contraction ◽  
Contractile Properties ◽  
Swimming Velocity ◽  
Tree Frog ◽  
Contraction Time ◽  
Thermal Dependence ◽  
Stroke Frequency ◽  
Muscle Contractile Properties ◽  
Muscle Contractile ◽  
Tetanic Tension

The effects of temperature on sprint swimming ability and muscle contractile properties were examined in northern and southern populations of the holarctic tree frog, Hyla crucifer Wied-Neuwied, acclimated to 20–23°C. Maximal swimming velocities of 29 (southern) and 32 (northern) cms−1 and stroke frequencies of 4.1 (southern) and 5.5 (northern) strokes s−1 were attained at 30°C, and maximal stroke lengths (i.e. distance moved per stroke) of 8.0 (southern) and 7.4 (northern) cm at 20°C. The thermal dependence of swimming velocity decreases with increasing temperature (e.g. Q10 = 4.0 from 6 to 10°C, 1.2 from 20 to 30°C), as reported for locomotion in other ectothermic vertebrates. Over a temperature range of l.5-30°C, velocity increases by a factor of 5.5, frequency by a factor of 4, and length by a factor of 1.7. Thus, increased velocity at higher temperatures can be attributed mostly to increased stroke frequency; increments in stroke length contribute less. Muscle contractile properties have similar thermal dependencies to those of other vertebrates: rate processes [including twitch time-to-peak tension (TPT), twitch half-relaxation time (RT½), maximal rate of tetanic tension development and isotonic shortening velocity] are much more sensitive to temperature than is force generation (twitch and tetanic tension). Below 8°C, stroke frequency is limited by twitch contraction time (TPT + RT½), and leg extension in a swimming stroke by TPT. At higher temperatures, the thermal dependence of stroke time is lower than that of contraction time. Neither locomotor nor muscle contractile properties are different between the two populations (except for twitch tension at low temperatures). Inflexibility in the thermal dependence of muscle contraction and locomotion in this species may help to explain differences in breeding phenologies between northern and southern populations.

Alterations in Contractile Properties of Tongue Muscles in Old Rats

2005 ◽  
Vol 114 (10) ◽  
pp. 799-803 ◽  
Author(s):  
Fumikazu Ota ◽  
Nadine P. Connor ◽  
Richard Konopacki
Keyword(s):  
Muscle Contraction ◽  
Vital Role ◽  
Contractile Properties ◽  
Brown Norway ◽  
Tongue Muscle ◽  
Fischer 344 ◽  
Muscle Contractile Properties ◽  
Age Related ◽  
Old Rats ◽  
Muscle Contractile

Objectives: Fatigue and weakness are well-known signs of aging that are related to sarcopenia, or loss of skeletal muscle mass, organization, and strength. Sarcopenia may affect swallowing. The tongue plays a vital role in swallowing, but there is limited knowledge regarding age-related changes in lingual muscle contractile properties. Our purpose was to determine whether alterations in tongue force, temporal features of tongue muscle contraction, and fatigability are manifested as a function of aging in old rats. Methods: We evaluated tongue muscle contractile properties in young and old Fischer 344/Brown Norway rats. Contractions were elicited via bilateral electrical stimulation of the hypoglossal nerves. Results: Maximum tongue forces and fatigability were not significantly altered in old animals, but aging was associated with significantly longer twitch contraction time and longer half-decay recovery time intervals (p <.01). Conclusions: The results indicated that old animals generated sufficient maximum tongue forces, but were slower in achieving these forces than young animals. These findings are consistent with reports of altered temporal parameters of tongue actions during swallowing in humans, and suggest that a disruption in the timing of muscle contraction onset and recovery may contribute to the altered tongue kinetics observed with aging.

scholarly journals Choline-Based Multi-Ingredient Supplementation Can Improve Explosive Strength during a Fatiguing Task

2021 ◽  
Vol 18 (21) ◽  
pp. 11400
Author(s):  
Matthew Gage ◽  
Kevin Phillips ◽  
Byungjoo Noh ◽  
Tejin Yoon
Keyword(s):  
Physical Performance ◽  
Knee Extensor ◽  
Performance Testing ◽  
Contractile Properties ◽  
Voluntary Activation ◽  
Double Blind ◽  
Muscle Contractile Properties ◽  
Explosive Strength ◽  
Muscle Contractile ◽  
Fatiguing Contractions

Various choline-based multi-ingredient supplementations (CMS) have been suggested in the current market, but the research is limited. The purpose of this study was to investigate the acute effect of a CMS on physical performance. Fourteen male college football players (20.4 ± 1.0 years) participated in a randomized double-blind crossover experiment separated by 7 days. Subjects were given a CMS or a placebo 60 min before physical performance testing measures, including maximum vertical jumps, maximum voluntary isometric contractions (MVIC), maximal voluntary concentric contractions (MVCC), and fatiguing contractions. Four MVICs and seven sets of two MVCCs at various loads (1 N·m to 60% MVIC torque) were performed with the knee extensor muscles while seated on a dynamometer before and after the fatiguing tasks. During the fatiguing tasks, 120 MVCCs (4 sets × 30 reps) were performed with a load equivalent to 20% MVIC. Twitch interpolation technique was used to assess muscle contractile properties and voluntary activation. No significant differences were seen at baseline between sessions for all testing measures including vertical jump height, strength, power, muscle contractile properties and voluntary activation. Rate of torque development and impulse was higher in supplemental session compared to control session throughout the fatiguing contractions (p = 0.018, p < 0.001, respectively). Acute CMS can improve explosive strength by delaying the onset of fatigue.

scholarly journals Locomotor exercise induces long-lasting impairments in the capacity of the human motor cortex to voluntarily activate knee extensor muscles

2009 ◽  
Vol 106 (2) ◽  
pp. 556-565 ◽  
Author(s):  
Simranjit K. Sidhu ◽  
David J. Bentley ◽  
Timothy J. Carroll
Keyword(s):  
Motor Cortex ◽  
Motor Nerve ◽  
Maximum Voluntary Contraction ◽  
Voluntary Activation ◽  
Exercise Session ◽  
Knee Extensors ◽  
Central Component ◽  
Control Session ◽  
Cycling Exercise ◽  
Human Motor Cortex

Muscle fatigue is a reduction in the capacity to exert force and may involve a “central” component originating in the brain and/or spinal cord. Here we examined whether supraspinal factors contribute to impaired central drive after locomotor endurance exercise. On 2 separate days, 10 moderately active individuals completed a locomotor cycling exercise session or a control session. Brief (2 s) and sustained (30 s) isometric knee extension contractions were completed before and after locomotor exercise consisting of eight, 5-min bouts of cycling at 80% of maximum workload. In the control session, subjects completed the isometric contractions in a rested state. Twitch responses to supramaximal motor nerve stimulation and transcranial magnetic stimulation were obtained to assess peripheral force-generating capacity and voluntary activation. Maximum voluntary contraction (MVC) force during brief contractions decreased by 23 ± 6.3% after cycling exercise and remained 12 ± 2.8% below baseline 45 min later ( F1,9 > 15.5; P < 0.01). Resting twitch amplitudes declined by ∼45% ( F1,9 = 28.3; P < 0.001). Cortical voluntary activation declined from 90.6 ± 1.6% at baseline to 80.6 ± 2.1% after exercise ( F1,9 = 28.0; P < 0.001) and remained significantly reduced relative to control 30–45 min later (80.6 ± 3.4%; F1,9 = 10.7; P < 0.01). Thus locomotor exercise caused a long-lasting impairment in the capacity of the motor cortex to drive the knee extensors. Force was reduced more during sustained MVC after locomotor exercise than in the control session. Peripheral mechanisms contributed relatively more to this force reduction in the control session, whereas supraspinal fatigue played a greater role in sustained MVC reduction after locomotor exercise.

Effects of selenium supplementation on the muscle contractile properties, fatigue and antioxidant enzymes activities of gastrocnemius muscles in trained and untrained rats

2011 ◽  
Vol 1 (4) ◽  
pp. 226-232
Author(s):  
Mohanad R. Alwan ◽  
Oleksandr Krasilshchikov ◽  
Tengku Muzaffar Bin ◽  
Tengku Mohamad Shihabudin
Keyword(s):  
Lipid Peroxidation ◽  
Selenium Supplementation ◽  
Contractile Properties ◽  
Muscle Contractile Properties ◽  
Body Weights ◽  
Jumping Exercise ◽  
Antioxidant Enzymes Activities ◽  
Gastrocnemius Muscles ◽  
Muscle Contractile ◽  
Tetanic Tension

Selenium (Se) is an important component of cellular seleno Ã¢â‚¬Âcompounds andan integral component of glutathione Peroxidase (GPx), which catalyzes thereduction of harmful radicals produced during muscular exercise. The currentstudy was carried out to evaluate the muscle contractile properties andfatigue resistance of gastrocnemius muscle under selenium supplementationschemes in sedentary and exercise protocols as well as measure the antioxidantenzymes activity and lipid peroxidation. Rats were divided into fourgroups; sedentary Selenium supplementation (S), exercise Selenium (SE)groups, sedentary control (SC) and exercise control (EC) groups. The ratswere fed with 80 μg/kg body weights selenium for six weeks. The exerciseprotocol consisted the 40 jumps up to the height of 40 cm for 6 Ã¢â‚¬Âweek. Themuscle fatigue protocol consisted the trains of pulses of 40 Hz at every secondfor at least 2 min. Significant (P<0.05) increase was observed in treatedgroups than control in the muscle contractile properties like twitch tension(Pt), contraction time (CT) and twitch/tetanic tension Ratio (Pt/Po Ratio),tetanic tension (Po) and EMG amplitude. Decreased EMG failure and increasedfatigue index were observed in ES group. Moreover, a significant(P<0.05) increase and decrease in the GPx activity and lipid peroxidation respectivelywas also reported than SC and EC group. While there were nochanges reported in the activity of CAT and SOD enzymes. This study revealedthat the Se with jumping exercise induces muscle contractile propertiesand decreases the muscular fatigue.

scholarly journals Muscle Contractile Properties Measured at Submaximal Electrical Amplitudes and Not at Supramaximal Amplitudes Are Associated with Repeated Sprint Performance and Fatigue Markers

2021 ◽  
Vol 18 (21) ◽  
pp. 11689
Author(s):  
Alejandro Muñoz-López ◽  
Moisés de Hoyo ◽  
Borja Sañudo
Keyword(s):  
Rectus Femoris ◽  
Peak Torque ◽  
Sprint Performance ◽  
Contractile Properties ◽  
Practical Significance ◽  
Contraction Time ◽  
Repeated Sprints ◽  
Muscle Contractile Properties ◽  
Repeated Sprint ◽  
Muscle Contractile

Background: The present study analyzes the associations between the muscle contractile properties (MCP) measured at different neuromuscular electrical stimulation amplitudes (NMESa) and the performance or transient fatigue after a bout of repeated sprints. Methods: Seventeen physically active male subjects performed six repeated sprints of 30 m with 30 s of passive recovery. Capillary blood creatine kinase (CK) concentration, knee extension or flexion isometric peak torque, tensiomyography, and repeated sprint performance were assessed. Results: Muscle displacement and contraction time were different in relation to the NMESa used in the rectus femoris and biceps femoris muscles. At rest, significant (p < 0.05) associations were found between muscle displacement and the loss of time in the repeated sprints (sprint performance) at 20 or 40 mA in the rectus femoris. At post +24 h or +48 h, the highest significant associations were found between the muscle displacement or the contraction time and CK or peak torques also at submaximal amplitudes (20 mA). The NMESa which elicits the peak muscle displacement showed lack of practical significance. Conclusion: Although MCP are typically assessed in tensiomyography using the NMESa that elicit peak muscle displacement, a submaximal NMESa may have a higher potential practical application to assess neuromuscular fatigue in response to repeated sprints.

Tensiomyographic changes of muscle contractile properties in individuals with lower-limb amputation

2021 ◽  
Vol Publish Ahead of Print ◽  
Author(s):  
Hironori Fujishita ◽  
Noriaki Maeda ◽  
Yukio Urabe ◽  
Makoto Komiya ◽  
Shogo Sakai ◽  
...  
Keyword(s):  
Lower Limb ◽  
Contractile Properties ◽  
Lower Limb Amputation ◽  
Limb Amputation ◽  
Muscle Contractile Properties ◽  
Muscle Contractile
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