Purpose: The purpose of the study was to investigate effect 4 and 8 wk electromyostimulation (EMS) training on both muscular neural adaptations knee extensor muscles. Methods: Twenty males were divided into electrostimulated group (EG, N = 12) control (CG, 8). program consisted 32 sessions isometric EMS over an 8-wk period. All subjects tested at baseline (B) retested after (WK4) (WK8) training. EMG activity muscle activation obtained under maximal voluntary contractions (MVC) used assess...

Abstract The aim of the present study was to further confirm validity measurements for characterizing neuromuscular alterations by establishing their reliability both before and after fatigue. Thirteen men (28 ± 5 years) volunteered participate in two separate identical sessions requiring performance a sustained maximal voluntary contraction (MVC) with quadriceps muscle 2 min. MVC transcutaneous electrical stimulations were used immediately fatiguing investigate torque, central activation,...

The purpose of this study was to investigate whether the voluntary neural drive and excitability reflex arc could be modulated by training, even in old age. To aim, effects a 16-wk strengthening program on plantar flexor activation (VA) maximum Hoffman (H(max))-to-maximum M wave (M(max)) ratio were investigated 14 elderly men (65-80 yr). After isometric contraction (MVC) increased 18% (P < 0.05) weight-lifting ability 24% 0.001). Twitch time decreased 8% 0.01), but no changes half relaxation...

This study is the first in which measurements of thickness, fascicle angle and length, tendon elongation were combined to examine impact eccentric strength training on both muscle architecture tendinous structures. Eighteen healthy male subjects divided into an group (n = 10) a control 8). The program consisted 18 sessions exercises over 7-week period. All tested at baseline after last session. Using ultrasound imaging, length thickness medial gastrocnemius (MG) analyzed rest (i.e.,...

Key points While a consensus has now been reached on the effect of motor imagery (MI) – mental simulation an action cortical areas, less is known about its impact spinal structures. The current study, using H‐reflex conditioning paradigms, examined 20 min MI practice several mechanisms plantar flexor muscles. We observed modulations presynaptic circuitry while imagining, which was even more pronounced following acute session practice. suggested that small output generated during may reach...

The effect of time day on the neural activation and contractile properties human adductor pollicis muscle was investigated in 13 healthy subjects. Two different times were chosen, corresponding to minimum (7 h) maximum (18 levels strength. force produced compared with associated electromyographic (EMG) activity during voluntary electrically induced contractions order determine whether peripheral or central mechanisms play a dominant role diurnal fluctuation. results indicated that...

The study was conducted first, to determine the possibility of a dichotomy between circadian rhythm maximal torque production knee extensors dominant and non-dominant legs, second, whether possible could be linked change in downward drive central nervous system and/or phenomena prevailing at muscular level. leg defined as one with which subjects spontaneously kick football. Tests were performed 06:00, 10:00, 14:00, 18:00, 22:00 h. To distinguish neural mechanisms that influence muscle...

This study was designed to investigate the modulations of H-reflex and V-wave responses during passive maximal active dynamic actions. Experiments were performed on 16 healthy males [age: 24 +/- 4 (SD) yr]. Maximal H-reflexes (Hmax) M-waves (MmaxR) evoked at same muscle length isometric, shortening lengthening actions voluntary concentric, eccentric plantar-flexion. In all contraction types, supra-maximal stimulus intensity used evoke superimposed M wave (MmaxA) V (V) soleus muscle. At rest,...

The aim of this study was to compare the mechanical and electromyographic (EMG) characteristics soleus motor units activated during maximal H reflex direct M response among subjects with different histories physical activity. Power-trained athletes produced stronger twitches, a higher rate twitch tension buildup relaxation, than their endurance counterparts for both H-reflex M-wave responses. H-reflex-to-maximal ratios force output (twitch) EMG wave amplitude were significantly lower in...

The aim of this study was to compare the use transcutaneous vs. motor nerve stimulation in evaluation low-frequency fatigue. Nine female and eleven male subjects, all physically active, performed a 30-min downhill run on motorized treadmill. Knee extensor muscle contractile characteristics were measured before, immediately after (Post), 30 min fatiguing exercise (Post30) by using single twitches 0.5-s tetani at 20 Hz (P20) 80 (P80). P20-to-P80 ratio calculated. Electrical stimulations...

Whether the involvement of motor units is different between surface neuromuscular electrostimulation and voluntary activation remains an unresolved issue. The aim this pilot study was to verify if unit during nonselective/random (i.e., without obvious sequencing related fibre type), as recently suggested by Gregory Bickel [6]. Sixteen healthy men randomly performed submaximal isometric contractions (10-s duration) quadriceps femoris muscle at 20, 40 60 % maximal torque under both stimulated...

The aim of the study was to use combined longitudinal measurements soleus (SOL) and gastrocnemii evoked V-wave H-reflex responses determine site adaptations within central nervous system induced by 5 wk neuromuscular electrical stimulation (NMES) training plantar flexor muscles. Nineteen healthy males subjects were divided into a electrostimulated group (n = 12) control 7). program consisted 15 sessions isometric NMES over 5-wk period. All tested before after SOL, lateral gastrocnemius (LG),...

Purpose: The aim of the study was to use eccentric strength training plantar flexor muscles investigate plasticity spinal reflexes during maximal voluntary isometric, concentric, and contractions. Methods: Eighteen healthy male subjects were divided into an group (N = 10) a control 8). program consisted 18 sessions exercise for 7-wk period. All tested before, during, after program. Soleus (SOL) medial gastrocnemius (MG) (H-reflex V-wave) M-waves evoked at same angular position passive...

This study was designed to investigate the cortical and spinal mechanisms involved in modulations of neural activation during lengthening compared with isometric shortening maximal voluntary contractions (MVCs). Two muscles susceptible different adjustments at level, soleus (SOL) medial gastrocnemius (MG), were compared. Twelve healthy males participated least two experimental sessions assess corticospinal excitabilities. We modulation motor evoked potentials (MEPs) response transcranial...

It is well known that centre of pressure (CoP) displacement correlates negatively with the maximal isometric torque (MIT) ankle muscles. This relationship has never been investigated in elderly fallers. The purpose this study was thus to analyse between MIT muscles and CoP upright stance a sample aged 18 90 years old included aim identify threshold below which balance compromised. Plantar flexors (PF) dorsal (DF) were measured volunteers: 21 healthy young adults (age: 24.1 ± 5.0), 12...

Motor imagery (MI) is the mental simulation of movement, without corresponding muscle contraction. Whereas activation cortical motor areas during MI established, involvement spinal structures still under debate. We used original and complementary techniques to probe influence on structures. Amplitude motor-evoked potentials (MEPs), cervico-medullary-evoked (CMEPs), Hoffmann (H)-reflexes flexor carpi radialis (FCR) triceps surae muscles was measured in young, healthy subjects at rest MI....

Neuromuscular adaptations of the plantar flexor muscles were assessed before and subsequent to short-term electromyostimulation (EMS) training. Eight subjects underwent 16 sessions isometric EMS training over 4 wk. Surface electromyographic (EMG) activity torque obtained under maximal voluntary electrically evoked contractions analyzed distinguish neural from contractile changes. After training, significantly increased conditions at angle (+8.1%, P < 0.05) two eccentric velocities considered...

AbstractThe influence of time day on elbow flexion torque was studied. Thirteen physical education students, 7 males and 6 females, made maximal submaximal isometric contractions at 90° flexors using a dynamometer. The developed measured each contraction. myoelectric activity the biceps muscle also same by surface electromyography (EMG) quantified from root mean square (RMS) activity. Torque EMGs were 6:00, 9:00, 12:00, 15:00, 18:00, 21:00, 24:00 h over day. Oral temperature before test...

Graphical Abstract figure legend HCN channels play an evolutionarily conserved pacemaker role in renal pelvic smooth muscle (RPSM) of lower and higher order mammals. The function hyperpolarization-activated cation (HCN) pacemakers remains controversial. Renal trigger contractions that expel waste from the kidney, have been localized to these tissues. To date, however, mechanisms underlying RPSM activity remain elusive. was investigated both (top left) (bottom mammalian models, which exhibit...

PICHON, F., J-C. CHATARD, A. MARTIN, and G. COMETTI. Electrical stimulation swimming performance. Med. Sci. Sports Exerc., Vol. 27, No. 12, pp. 1671–1676, 1995. The purpose of the study was to examine influence a 3-wk period electrostimulation training on strength latissimus dorsi m. performances 14 competitive swimmers divided into 7 electrostimulated (EG) control (CG). peak torques registered during flexion-extension arm determined with help an isokinetic dynamometer at different...

The effect of aging on mechanical and electromyographic characteristics ankle joint muscles was investigated in 11 young (mean age 24 years) 12 elderly 77 males. Maximal submaximal isometric voluntary torques were measured during plantarflexion dorsiflexion. Electromyographic activities triceps surae tibialis anterior recorded. group developed equal maximal dorsiflexion (42 vs 45 N.m, p >.05), but plantarflexion, the weaker (80 132 <.001) presented a decreased twitch amplitude (11 16 N.m)...

This study was designed to investigate the effect of ageing on mechanical and electromyographic (EMG) characteristics soleus motor units (MUs) activated by maximal Hoffmann reflex (Hmax) direct muscle compound action potential (Mmax). Eleven young (mean age 25 +/- 4 years) ten elderly 73 5 males took part in this investigation. The senior group presented lower amplitudes Mmax (-57 %, P < 0.001) Hmax (-68 waves compared younger population. These were associated with a depression relative...