Local vibration is a non-invasive neuromuscular stimulation modality used in training and rehabilitation for its effects on neuromuscular function, particularly its ability to induce nervous adaptations. Its passive application is particularly useful in cases of motor deficit or immobilization. Several studies, including our own, have shown that vibration protocols over several weeks can induce significant gains in muscle strength, particularly in the knee extensors. However, the parameters of application remain heterogeneous, particularly with regard to the duration of the interventions. With this in mind, a prospective controlled study is being conducted in healthy subjects, comparing four modalities of local vibration intervention targeting the knee extensors: an intensive vibration protocol over 5 consecutive days (1 session of 30 or 60 minutes per day) and a protocol spread over 4 weeks at a rate of 3 weekly sessions of 30 or 60 minutes). The objective is to evaluate and compare their immediate and delayed effects on force production and corticospinal properties. The results of this study will thus help optimize recommendations regarding the use of local vibration in muscle strengthening and neuromuscular reconditioning strategies.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
OTHER
Masking
NONE
Enrollment
72
The vibrations will be delivered using the Vibramoov Physio device, positioned directly on the quadriceps muscle. The participant will be seated comfortably and will remain at rest throughout the session. The vibration settings will be set to an amplitude of 1 mm and a frequency of 100 Hz.
CHU de Saint-Etienne
Saint-Etienne, France
Compare the effect of the duration of a local vibration program (5 days vs 4 weeks), as well as the effect of the duration of the sessions (30 min vs 60 min) on the gain in knee extension strength in healthy volunteers.
The primary endpoint will be the relative change in maximum isometric strength of the knee extensors (expressed as a percentage increased), assessed using an isokinetic dynamometer.
Time frame: Five times: before the procedure (baseline); at the end of the procedure (day 21 or day 42 depending on the group); then 1 week (day 28 or day 49), 1 month (day 49 or day 70), and 3 months (day 105 or day 126) after the procedure.
Compare the effect of the duration of a local vibration program (5 days vs 4 weeks), as well as the effect of the duration of the sessions (30 min vs 60 min) on functional motor abilities and, more specifically, maximum voluntary strength
Strength (Nm) will be assessed on an isokinetic dynamometer. Two concentric contraction speeds will be tested: 60°/s and 180°/s (also assessed for the contralateral leg).
Time frame: Five times: before the intervention (baseline); at the end of the intervention (day 21 or day 42 depending on the group); then 1 week (day 28 or day 49), 1 month (day 49 or day 70) and 3 months (day 105 or day 126) after the intervention.
Compare the effect of the duration of a local vibration program (5 days vs 4 weeks), as well as the effect of the duration of the sessions (30 min vs 60 min) on functional motor skills and, more specifically, jumping performance.
Jumping performance (height, in cm) will be assessed using validated vertical jump tests: Squat Jump and Counter Movement Jump.
Time frame: Five times: before the intervention (baseline); at the end of the intervention (day 21 or day 42 depending on the group); then 1 week (day 28 or day 49), 1 month (day 49 or day 70) and 3 months (day 105 or day 126) after the intervention.
Compare the effect of the duration of a local vibration program (5 days vs 4 weeks), as well as the effect of the duration of the sessions (30 min vs 60 min) on functional motor skills and, more specifically, the rate of force development (RFD)
The RFD (expressed in N/s), an indicator of explosive strength, will be assessed for the knee extensor muscles from the initial phases of isometric contraction on an isokinetic dynamometer.
Time frame: Five times: before the intervention (baseline); at the end of the intervention (day 21 or day 42 depending on the group); then 1 week (day 28 or day 49), 1 month (day 49 or day 70) and 3 months (day 105 or day 126) after the intervention.
Compare the effect of the duration of a local vibration program (5 days vs 4 weeks), as well as the effect of the duration of the sessions (30 min vs 60 min) on corticospinal properties and, more specifically, on the level of voluntary activation
The level of voluntary activation (in %) will be determined by the increase in force obtained following electrical nerve stimulation during a maximum voluntary isometric contraction. An electrical stimulator will deliver rectangular electrical pulses (400 V max, pulse duration: 1 ms) to the femoral nerve through the skin.
Time frame: Five times: before the intervention (baseline); at the end of the intervention (day 21 or day 42 depending on the group); then 1 week (day 28 or day 49), 1 month (day 49 or day 70) and 3 months (day 105 or day 126) after the intervention.
Compare the effect of the duration of a local vibration program (5 days vs 4 weeks), as well as the effect of the duration of the sessions (30 min vs 60 min) on corticospinal properties and, more specifically, corticospinal excitability.
Cortico-spinal excitability will be assessed using electromyographic responses (motor evoked potentials, in mV) elicited by transcranial magnetic stimulation.
Time frame: Five times: before the intervention (baseline); at the end of the intervention (day 21 or day 42 depending on the group); then 1 week (day 28 or day 49), 1 month (day 49 or day 70) and 3 months (day 105 or day 126) after the intervention.
Compare the effect of the duration of a local vibration program (5 days vs 4 weeks), as well as the effect of the duration of the sessions (30 min vs 60 min) on corticospinal properties and, more specifically, spinal excitability
Spinal excitability (in mV) will be assessed by recording electromyographic responses evoked by electrical stimulation at the femoral nerve and spinal cord (thoracic motor evoked potentials).
Time frame: Five times: before the intervention (baseline); at the end of the intervention (day 21 or day 42 depending on the group); then 1 week (day 28 or day 49), 1 month (day 49 or day 70) and 3 months (day 105 or day 126) after the intervention.
Compare the effect of the duration of a local vibration program (5 days vs 4 weeks), as well as the effect of the duration of the sessions (30 min vs 60 min) on corticospinal properties and, more specifically, cortical activation of sensorimotor areas.
Cortical activation of sensorimotor areas will be assessed by recording the electroencephalographic signal during submaximal isometric contractions. A flexible 64-electrode cap will be placed on the subject's head and a gel will be applied to improve signal reception. The signal will be recorded at rest during a 3-minute period of muscle inactivity, then during a 30-minute vibration session.
Time frame: Five times: before the intervention (baseline); at the end of the intervention (day 21 or day 42 depending on the group); then 1 week (day 28 or day 49), 1 month (day 49 or day 70) and 3 months (day 105 or day 126) after the intervention.
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