Effect of neuromuscular electrical stimulation on motor cortex excitability upon release of tonic muscle contraction

BACKGROUND: Neuromuscular electrical stimulation (NMES) is a complementary tool for therapeutic exercise for muscle strengthening and may potentially enhance exercise performance. OBJECTIVE: To determine whether high-intensity interval training (HIIT) and continuous aerobic training (CA) coupled with NMES enhance the changes in the eccentric/concentric muscle contraction patterns of hamstring and quadriceps. METHODS: Forty-five healthy sedentary male participants performed cycling training 3 times per week for 8 weeks combined with/without NMES performed at a load equivalent to 65% and 120% of IVO2max (intensity associated with the achievement of maximal oxygen uptake). Anthropometrics, blood lactate measurements, IVO2max, TLimVO2max (time-to-exhaustion) and isokinetic strength parameters were measured at baseline and post-training using a randomized controlled trial. RESULTS: The conventional hamstring-to-quadriceps-ratio (HQR: Hcon/Qcon) at 60∘/s and the Dynamic Control Ratio (DCR: Hecc/Qcon) at 180∘/s significantly increased both in the dominant (D) and non-dominant (ND) limb in the HIIT + NMES group (p< 0.05). There was a positive significant correlation between the individual changes in D HQR at 60∘/s and IVO2max (r= 0.94, p= 0.005) and the DCR at 180∘/s and TLimVO2max (r= 0.90, p= 0.015), respectively. CONCLUSIONS: The increases in the eccentric muscle contraction and DCR following HIIT + NMES seem to improve fatigue tolerance, cause less fatigue and oxidative stress on the lower limb during pedaling at high intensities.

Download Full-text

Neural mechanisms underlying the changes in ipsilateral primary motor cortex excitability during unilateral rhythmic muscle contraction

Behavioural Brain Research ◽

10.1016/j.bbr.2012.10.053 ◽

2013 ◽

Vol 240 ◽

pp. 33-45 ◽

Cited By ~ 15

Author(s):

Kazumasa Uehara ◽

Takuya Morishita ◽

Shinji Kubota ◽

Kozo Funase

Keyword(s):

Motor Cortex ◽

Muscle Contraction ◽

Primary Motor Cortex ◽

Neural Mechanisms ◽

Motor Cortex Excitability

Download Full-text

Effects of electrode size and placement on comfort and efficiency during low-intensity neuromuscular electrical stimulation of quadriceps, hamstrings and gluteal muscles

BMC Sports Science Medicine and Rehabilitation ◽

10.1186/s13102-022-00403-7 ◽

2022 ◽

Vol 14 (1) ◽

Author(s):

J. Flodin ◽

R. Juthberg ◽

P. W. Ackermann

Keyword(s):

Electrical Stimulation ◽

Muscle Contraction ◽

Current Density ◽

Rating Scale ◽

Numerical Rating Scale ◽

Neuromuscular Electrical Stimulation ◽

Gluteus Maximus ◽

Major Drawback ◽

Electrode Size ◽

Low Intensity

Abstract Background Neuromuscular electrical stimulation (NMES) may prevent muscle atrophy, accelerate rehabilitation and enhance blood circulation. Yet, one major drawback is that patient compliance is impeded by the discomfort experienced. It is well-known that the size and placement of electrodes affect the comfort and effect during high-intensity NMES. However, during low-intensity NMES the effects of electrode size/placement are mostly unknown. Therefore, the purpose of this study was to investigate how electrode size and pragmatic placement affect comfort and effect of low-intensity NMES in the thigh and gluteal muscles. Methods On 15 healthy participants, NMES-intensity (mA) was increased until visible muscle contraction, applied with three electrode sizes (2 × 2 cm, 5 × 5 cm, 5 × 9 cm), in three different configurations on quadriceps and hamstrings (short-transverse (ST), long-transverse (LT), longitudinal (L)) and two configurations on gluteus maximus (short-longitudinal (SL) and long-longitudinal (LL)). Current–density (mA/cm2) required for contraction was calculated for each electrode size. Comfort was assessed with a numerical rating scale (NRS, 0–10). Significance was set to p < 0.05 and values were expressed as median (inter-quartile range). Results On quadriceps the LT-placement exhibited significantly better comfort and lower current intensity than the ST- and L-placements. On hamstrings the L-placement resulted in the best comfort together with the lowest intensity. On gluteus maximus the LL-placement demonstrated better comfort and required less intensity than SL-placement. On all muscles, the 5 × 5 cm and 5 × 9 cm electrodes were significantly more comfortable and required less current–density for contraction than the 2 × 2 cm electrode. Conclusion During low-intensity NMES-treatment, an optimized electrode size and practical placement on each individual muscle of quadriceps, hamstrings and gluteals is crucial for comfort and intensity needed for muscle contraction.

Download Full-text

Does Transvaginal Neuromuscular Electrical Stimulation Elicit a Pelvic Floor Muscle Contraction? A Pilot Study Using Ultrasonography in Healthy Women

Journal of Womenʼs Health Physical Therapy ◽

10.1097/jwh.0b013e318260dd24 ◽

2012 ◽

Vol 36 (2) ◽

pp. 102-107

Author(s):

Ruth M. Maher ◽

Dawn M. Hayes

Keyword(s):

Electrical Stimulation ◽

Pilot Study ◽

Pelvic Floor ◽

Muscle Contraction ◽

Pelvic Floor Muscle ◽

Neuromuscular Electrical Stimulation ◽

Pelvic Floor Muscle Contraction ◽

Healthy Women

Download Full-text

Ultrasonographic Detection of Vastus Intermedius Muscle Contraction During Surface Neuromuscular Electrical Stimulation

Ultrasound in Medicine & Biology ◽

10.1016/j.ultrasmedbio.2011.05.117 ◽

2011 ◽

Vol 37 (8) ◽

pp. S22

Author(s):

L. Kneisz ◽

M. Krenn ◽

C. Hanc ◽

W. Mayr ◽

C. Kollmann

Keyword(s):

Electrical Stimulation ◽

Muscle Contraction ◽

Neuromuscular Electrical Stimulation ◽

Vastus Intermedius

Download Full-text

Ultrasound stimulation of the motor cortex during tonic muscle contraction

10.1101/2021.05.03.442483 ◽

2021 ◽

Author(s):

Ian Szwast Heimbuch ◽

Tiffany Fan ◽

Allan Wu ◽

Guido C Faas ◽

Andrew C Charles ◽

...

Keyword(s):

Transcranial Magnetic Stimulation ◽

Motor Cortex ◽

Muscle Contraction ◽

Magnetic Stimulation ◽

Primary Motor Cortex ◽

Silent Period ◽

Transcranial Ultrasound ◽

Emg Activity ◽

Ultrasound Stimulation ◽

Tonic Muscle

Transcranial ultrasound stimulation (tUS) shows potential as a noninvasive brain stimulation (NIBS) technique, offering increased spatial precision compared to other NIBS techniques. However, its reported effects on primary motor cortex (M1) are limited. We aimed to better understand tUS effects in human M1 by performing tUS of the hand area of M1 (M1hand) during tonic muscle contraction of the index finger. Stimulation during muscle contraction was chosen because of the transcranial magnetic stimulation-induced phenomenon known as cortical silent period (cSP), in which transcranial magnetic stimulation (TMS) of M1hand involuntarily suppresses voluntary motor activity. Since cSP is widely considered an inhibitory phenomenon, it presents an ideal parallel for tUS, which has often been proposed to preferentially influence inhibitory interneurons. Recording electromyography (EMG) of the first dorsal interosseous (FDI) muscle, we investigated effects on muscle activity both during and after tUS. We found no change in FDI EMG activity concurrent with tUS stimulation. Using single-pulse TMS, we found no difference in M1 excitability before versus after sparsely repetitive tUS exposure. Using acoustic simulations in models made from structural MRI of the participants that matched the experimental setups, we estimated in-brain pressures and generated an estimate of cumulative tUS exposure experienced by M1hand for each subject. We were unable to find any correlation between cumulative M1hand exposure and M1 excitability change. We also present data that suggest a TMS-induced MEP always preceded a near-threshold cSP.

Download Full-text