Attenuation of the effect of remote muscle contraction on the soleus H-reflex during plantar flexion

2005 ◽  
Vol 116 (6) ◽  
pp. 1362-1369 ◽  
Author(s):  
T. Tazoe ◽  
T. Kida ◽  
T. Wasaka ◽  
M. Sakamoto ◽  
T. Nakajima ◽  
...  
Keyword(s):  
Muscle Contraction ◽  
Plantar Flexion ◽  
H Reflex

scholarly journals Evidence that a higher ATP cost of muscular contraction contributes to the lower mechanical efficiency associated with COPD: preliminary findings

2011 ◽  
Vol 300 (5) ◽  
pp. R1142-R1147 ◽  
Author(s):  
Gwenael Layec ◽  
Luke J. Haseler ◽  
Jan Hoff ◽  
Russell S. Richardson
Keyword(s):  
Skeletal Muscle ◽  
Muscle Contraction ◽  
Energy Cost ◽  
Plantar Flexion ◽  
Mechanical Efficiency ◽  
Exercise Intolerance ◽  
Chronic Obstructive ◽  
Small Subset ◽  
Resonance Spectroscopy ◽  
Muscle Energetics

Impaired metabolism in peripheral skeletal muscles potentially contributes to exercise intolerance in chronic obstructive pulmonary disease (COPD). We used 31P-magnetic resonance spectroscopy (31P-MRS) to examine the energy cost and skeletal muscle energetics in six patients with COPD during dynamic plantar flexion exercise compared with six well-matched healthy control subjects. Patients with COPD displayed a higher energy cost of muscle contraction compared with the controls (control: 6.1 ± 3.1% of rest·min−1·W−1, COPD: 13.6 ± 8.3% of rest·min−1·W−1, P = 0.01). Although, the initial phosphocreatine resynthesis rate was also significantly attenuated in patients with COPD compared with controls (control: 74 ± 17% of rest/min, COPD: 52 ± 13% of rest/min, P = 0.04), when scaled to power output, oxidative ATP synthesis was similar between groups (6.5 ± 2.3% of rest·min−1·W−1 in control and 7.8 ± 3.9% of rest·min−1·W−1 in COPD, P = 0.52). Therefore, our results reveal, for the first time that in a small subset of patients with COPD a higher ATP cost of muscle contraction may substantially contribute to the lower mechanical efficiency previously reported in this population. In addition, it appears that some patients with COPD have preserved mitochondrial function and normal energy supply in lower limb skeletal muscle.

Postactivation Potentiation of Force Is Independent of H-Reflex Excitability

2008 ◽  
Vol 3 (2) ◽  
pp. 219-231 ◽  
Author(s):  
Matthew J. Hodgson ◽  
David Docherty ◽  
E. Paul Zehr
Keyword(s):  
Isometric Force ◽  
Plantar Flexion ◽  
Force Production ◽  
H Reflex ◽  
Postactivation Potentiation ◽  
Neural Excitability ◽  
Reflex Excitability ◽  
Before And After ◽  
History Of ◽  
A Minor

The contractile history of muscle can potentiate electrically evoked force production. A link to voluntary force production, related in part to an increase in reflex excitability, has been suggested.Purpose:Our purpose was to quantify the effect of postactivation potentiation on voluntary force production and spinal H-reflex excitability during explosive plantar fexion actions.Methods:Plantar flexor twitch torque, soleus H-reflex amplitudes, and the rate of force development of explosive plantar fexion were measured before and after 4 separate conditioning trials (3 × 5 s maximal contractions).Results:Twitch torque and rate of force production during voluntary explosive plantar flexion were significantly increased (P < .05) while H-reflex amplitudes remained unchanged. Although twitch torque was significantly higher after conditioning, leading to a small increase in the rate of voluntary force production, this was unrelated to changes in reflex excitability.Conclusion:We conclude that postactivation potentiation may result in a minor increase in the rate of voluntary isometric force production that is unrelated to neural excitability.

Effects of postural and voluntary muscle contraction on modulation of the soleus H reflex by transcranial magnetic stimulation

2015 ◽  
Vol 233 (12) ◽  
pp. 3425-3431 ◽  
Author(s):  
Jessica Guzmán-López ◽  
Aikaterini Selvi ◽  
Núria Solà-Valls ◽  
Jordi Casanova-Molla ◽  
Josep Valls-Solé
Keyword(s):  
Transcranial Magnetic Stimulation ◽  
Muscle Contraction ◽  
Magnetic Stimulation ◽  
H Reflex ◽  
Voluntary Muscle ◽  
Voluntary Muscle Contraction

Cyclic H-Reflex Modulation in Resting Forearm Related to Contractions of Foot Movers, Not to Foot Movement

2003 ◽  
Vol 90 (1) ◽  
pp. 81-88 ◽  
Author(s):  
Gabriella Cerri ◽  
Paola Borroni ◽  
Fausto Baldissera
Keyword(s):  
Plantar Flexion ◽  
Motor Command ◽  
H Reflex ◽  
Reflex Modulation ◽  
Phase Coupling ◽  
Foot Kinematics ◽  
Reflex Excitability ◽  
Movement Frequency ◽  
Before And After ◽  
Foot Loading

During rhythmic voluntary oscillations of the foot, the excitability of the H-reflex in the Flexor Carpi Radialis (FCR) muscle of the resting prone forearm increases during the foot plantar-flexion and decreases during dorsiflexion. It is known that, when the two extremities are moved together, isodirectional (in-phase) coupling is the preferred form of movement association. Thus the above pattern of the H-reflex excitability modulation may favor the preferred coupling between the two limbs. To gain some clues about its origin, FCR H-reflex excitability was tested before and after modifying the phase relations between the activation [electromyogram (EMG)] of foot movers and foot movement, either by loading of the foot or by changing the movement frequency. After foot loading, the movement cycle was consistently delayed with respect to the onset of the EMG in Soleus (Sol) or Tibialis Anterior (TA) muscles. Simultaneously, the FCR H-reflex modulation advanced by that same amount with respect to the foot movement, thus remaining phase-locked to the EMG onsets. Similarly, when movement frequency was varied step-wise between 1.0 and 2.0 Hz, the foot movement was progressively delayed with respect to both the EMG onset (Sol and TA) and the FCR H-reflex modulation, so that the phase relation between the motor command to the foot and the H-modulation in the forearm remained constant. These results suggest that modulation of H-reflex in the forearm is tied to leg muscle contraction, rather than to foot kinematics, and point to a central, rather than kinesthetic, origin for the modulation.

scholarly journals Lifelong strength training mitigates the age-related decline in efferent drive

2016 ◽  
Vol 121 (2) ◽  
pp. 415-423 ◽  
Author(s):  
Runar Unhjem ◽  
Mona Nygård ◽  
Lene T. van den Hoven ◽  
Simranjit K. Sidhu ◽  
Jan Hoff ◽  
...  
Keyword(s):  
Strength Training ◽  
Plantar Flexion ◽  
H Reflex ◽  
Voluntary Activation ◽  
M Wave ◽  
Reflex Amplitude ◽  
Age Related ◽  
Musculus Soleus ◽  
V Wave ◽  
Voluntary Contractions

Recently, we documented age-related attenuation of efferent drive to contracting skeletal muscle. It remains elusive if this indication of reduced muscle strength is present with lifelong strength training. For this purpose, we examined evoked potentials in the calf muscles of 11 [71 ± 4 (SD) yr] strength-trained master athletes (MA) contrasted with 10 (71 ± 4 yr) sedentary (SO) and 11 (73 ± 6 yr) recreationally active (AO) old subjects, as well as 9 (22 ± 2 yr) young controls. As expected, MA had higher leg press maximal strength (MA, 185 ± 32 kg; AO, 128 ± 15 kg; SO, 106 ± 11 kg; young, 147 ± 22 kg, P < 0.01) and rate of force development (MA, 5,588 ± 2,488 N/s; AO, 2,156 ± 1,100 N/s; SO, 2,011 ± 825 N/s; young, 3,663 ± 1,140 N/s, P < 0.05) than the other groups. MA also exhibited higher musculus soleus normalized V waves during maximal voluntary contractions (MVC) [maximal V wave amplitude/maximal M wave during MVC (Vsup/Msup); 0.28 ± 0.15] than AO (0.13 ± 0.06, P < 0.01) and SO (0.11 ± 0.05, P < 0.01), yet lower than young (0.45 ± 0.12, P < 0.01). No differences were apparent between the old groups in H reflex recorded at rest or during MVC [maximal H reflex amplitude/maximal M wave during rest (Hmax/Mmax); maximal H reflex amplitude during MVC/maximal M wave during MVC (Hsup/Msup)], and all were lower ( P < 0.01) than young. MA (34.4 ± 2.1 ms) had shorter ( P < 0.05) H reflex latency compared with AO (36.4 ± 3.7 ms) and SO (37.3 ± 3.2 ms), but longer ( P < 0.01) than young (30.7 ± 2.0 ms). Using interpolated twitch analysis, MA (89 ± 7%) had plantar flexion voluntary activation similar to young (90 ± 6%), and this was higher ( P < 0.05), or tended to be higher ( P = 0.06–0.09), than SO (83 ± 10%) and AO (84 ± 5%). These observations suggest that lifelong strength training has a protective effect against age-related attenuation of efferent drive. In contrast, no beneficial effect seems to derive from habitual recreational activity, indicating that strength training may be particularly beneficial for counteracting age-related loss of neuromuscular function.

scholarly journals Effects of Vibration Rolling with and without Dynamic Muscle Contraction on Ankle Range of Motion, Proprioception, Muscle Strength and Agility in Young Adults: A Crossover Study

2020 ◽  
Vol 17 (1) ◽  
pp. 354 ◽  
Author(s):  
Bo-Jhang Lyu ◽  
Chia-Lun Lee ◽  
Wen-Dien Chang ◽  
Nai-Jen Chang
Keyword(s):  
Young Adults ◽  
Muscle Strength ◽  
Muscle Contraction ◽  
Range Of Motion ◽  
Exercise Performance ◽  
Plantar Flexion ◽  
Ankle Dorsiflexion ◽  
Plantar Flexor ◽  
Flexor Muscle ◽  
Warm Up

Vibration rolling (VR) has emerged as a self-myofascial release (SMR) tool to aid exercise performance when warming up. However, the benefits of VR on exercise performance when combined with dynamic muscle contraction are unclear. The purpose of this study was to investigate the immediate effects of the combination of VR with dynamic muscle contraction (DVR), VR, and static stretching (SS) during warm-up on range of motion (ROM), proprioception, muscle strength of the ankle, and agility in young adults. In this crossover design study, 20 recreationally active adults without musculoskeletal disorders completed three test sessions in a randomized order, with 48 h of rest between each session. Participants completed one warm-up intervention and its measurements on the same day; different warm-up interventions and measurements were performed on each of the three days. The measurements included ankle dorsiflexion and plantarflexion ROM, ankle joint proprioception, muscle strength, and agility. After DVR and VR intervention, ankle dorsiflexion ROM (both DVR and VR, p < 0.001), plantarflexion ROM (both DVR and VR, p < 0.001), plantar flexor muscle strength (DVR, p = 0.007; VR, p < 0.001), and agility (DVR, p = 0.016; VR, p = 0.007) significantly improved; after SS intervention, ankle dorsiflexion and plantar flexion ROM (dorsiflexion, p < 0.001; plantar flexion, p = 0.009) significantly improved, but muscle strength and agility were not enhanced. Compared with SS, DVR and VR significantly improved ankle plantar flexor muscle strength (p = 0.008 and p = 0.001, respectively). Furthermore, DVR significantly improved ankle dorsiflexion compared with VR (p < 0.001) and SS (p < 0.001). In conclusion, either DVR, VR, or SS increased ankle ROM, but only DVR and VR increased muscle strength and agility. In addition, DVR produced considerable increases in ankle dorsiflexion. These findings may have implications for warm-up prescription and implementation in both rehabilitative and athletic practice settings.

Postactivation Depression of the Soleus H Reflex Measured Using Threshold Tracking

2008 ◽  
Vol 100 (6) ◽  
pp. 3275-3284 ◽  
Author(s):  
Penelope A. McNulty ◽  
Stacey K. Jankelowitz ◽  
Tanya M. Wiendels ◽  
David Burke
Keyword(s):  
Plantar Flexion ◽  
H Reflex ◽  
Homosynaptic Depression ◽  
Threshold Tracking ◽  
Nonlinear Input ◽  
The Face ◽  
Reflex Gain ◽  
Afferent Inputs ◽  
Voluntary Contractions ◽  
Postactivation Depression

The interpretation of changes in the soleus H reflex is problematic in the face of reflex gain changes, a nonlinear input/output relationship for the motoneuron pool, and a nonhomogeneous response of different motoneurons to afferent inputs. By altering the stimulus intensity to maintain a constant reflex output, threshold tracking allows a relatively constant population of α-motoneurons to be studied. This approach was used to examine postactivation (“homosynaptic”) depression of the H reflex (HD) in 23 neurologically healthy subjects. The H reflex was elicited by tibial nerve stimulation at 0.05, 0.1, 0.3, 1, and 2 Hz at rest and during voluntary plantar flexion at 2.5, 5, and 10% of maximum. A computerized threshold tracking procedure was used to set the current needed to generate a target H reflex 10% of Mmax. The current needed to produce the target reflex increased with stimulus rate but not significantly beyond 1 Hz. In three subjects, the current needed to produce H reflexes of 5, 10, 15, and 20% Mmax at 0.3, 1, and 2 Hz increased with rate and with the size of the test H reflex. HD was significantly reduced during voluntary contractions. Using threshold tracking, HD was maximal at lower frequencies than previously emphasized, probably because HD is greater the larger the test H reflex. This would reinforce the greater sensitivity of small motoneurons to reflex inputs.

Increased spinal reflex excitability is not associated with neural plasticity underlying the cross-education effect

2006 ◽  
Vol 100 (1) ◽  
pp. 83-90 ◽  
Author(s):  
Olle Lagerquist ◽  
E. Paul Zehr ◽  
David Docherty
Keyword(s):  
Strength Training ◽  
Plantar Flexion ◽  
Exercise Group ◽  
H Reflex ◽  
Spinal Reflex ◽  
Control Group ◽  
M Wave ◽  
Education Effect ◽  
Cross Education ◽  
The Cross

The purpose of this study was to examine the effects of a 5-wk unilateral, isometric strength-training program on plasticity in the spinal Hoffmann (H-) reflex in both the trained and untrained legs. Sixteen participants, 22–42 yr old, were assigned to either a control ( n = 6) or an exercise group ( n = 10). Both groups were tested for plantar flexion maximal voluntary isometric contractions (MVIC) and soleus H-reflex amplitude in both limbs, at the beginning and at the end of a 5-wk interval. Participants in the exercise group showed significantly increased MVIC in both legs after training ( P < 0.05), whereas strength was unchanged in the control group for either leg. Subjects in the exercise group displayed increased ( P < 0.05) H-reflex amplitudes on the ascending limb of the recruitment curve (at an equivalent M wave of 5% of the maximal M wave, HA) only in the trained leg. Maximal H-reflex and M-wave remained unchanged with training. Increased amplitude of HA in the trained limb concurrent with increased strength suggests that spinal mechanisms may underlie the changes in strength, possibly because of increased α-motoneuronal excitability or reduced presynaptic inhibition. Despite a similar increase in strength in the contralateral limb of the exercise group, HA amplitude was unchanged. We conclude that the cross-education effect of strength training may be due to supraspinal to a greater extent than spinal mechanisms.

Neural adaptation to resistance training: changes in evoked V-wave and H-reflex responses

2002 ◽  
Vol 92 (6) ◽  
pp. 2309-2318 ◽  
Author(s):  
Per Aagaard ◽  
Erik B. Simonsen ◽  
Jesper L. Andersen ◽  
Peter Magnusson ◽  
Poul Dyhre-Poulsen
Keyword(s):  
Resistance Training ◽  
Muscle Strength ◽  
Muscle Contraction ◽  
Presynaptic Inhibition ◽  
H Reflex ◽  
Neural Adaptation ◽  
Reflex Amplitude ◽  
Reflex Responses ◽  
Adaptation Mechanisms ◽  
V Wave

Combined V-wave and Hoffmann (H) reflex measurements were performed during maximal muscle contraction to examine the neural adaptation mechanisms induced by resistance training. The H-reflex can be used to assess the excitability of spinal α-motoneurons, while also reflecting transmission efficiency (i.e., presynaptic inhibition) in Ia afferent synapses. Furthermore, the V-wave reflects the overall magnitude of efferent motor output from the α-motoneuron pool because of activation from descending central pathways. Fourteen male subjects participated in 14 wk of resistance training that involved heavy weight-lifting exercises for the muscles of the leg. Evoked V-wave, H-reflex, and maximal M-wave (Mmax) responses were recorded before and after training in the soleus muscle during maximal isometric ramp contractions. Maximal isometric, concentric, and eccentric muscle strength was measured by use of isokinetic dynamometry. V-wave amplitude increased ∼50% with training ( P < 0.01) from 3.19 ± 0.43 to 4.86 ± 0.43 mV, or from 0.308 ± 0.048 to 0.478 ± 0.034 when expressed relative to Mmax (± SE). H-reflex amplitude increased ∼20% ( P < 0.05) from 5.37 ± 0.41 to 6.24 ± 0.49 mV, or from 0.514 ± 0.032 to 0.609 ± 0.025 when normalized to Mmax. In contrast, resting H-reflex amplitude remained unchanged with training (0.503 ± 0.059 vs. 0.499 ± 0.063). Likewise, no change occurred in Mmax (10.78 ± 0.86 vs. 10.21 ± 0.66 mV). Maximal muscle strength increased 23–30% ( P < 0.05). In conclusion, increases in evoked V-wave and H-reflex responses were observed during maximal muscle contraction after resistance training. Collectively, the present data suggest that the increase in motoneuronal output induced by resistance training may comprise both supraspinal and spinal adaptation mechanisms (i.e., increased central motor drive, elevated motoneuron excitability, reduced presynaptic inhibition).

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