Neuromodulation in Patients With Hamstring Shortening

The flexibility of the hamstrings is a very important component both for general health and when exercising. The lack of hamstring flexibility has been related to the increase in the likelihood of suffering a large number of musculoskeletal pathologies, due to the possibility of causing important muscle imbalances, which include lumbar spine pathologies, such as disc hernias or spondyloarthrosis. In addition, the decrease in the flexibility of the hamstring musculature is also related to the increased likelihood of suffering muscle strains, patellar tendon tendinopathies, femoropatellar syndrome and decreased lumbopelvic rhythm. Clinically, an invasive technique has appeared, known as Ultrasound-guided Percutaneous Neuromodulation (PNM). This minimally invasive intervention consists in the application of a percutaneous electrical stimulation (PES) through an acupuncture needle-like electrode that is placed in close proximity to the nerve or motor point of the muscle with ultrasound guidance. At the clinical level, the PES is always used with the therapeutic aim of relieving chronic pain and neuropathic pain. Similarly, in sports, PES is used with the aim of improving muscular activity. Therefore, according to the characteristics and the therapeutic benefits of this technique, further research is needed to discover multiple clinical indications. The aim of this study was to examine the effects on flexibility and strength of an ultrasound-guided percutaneous neuromodulation intervention in patients with shortening of the hamstring muscles.

Subjects were treated only once. Specifically, this consisted in the application of a square wave biphasic electrical current, with 10 Hz frequency, a 250µs pulse width, and the maximal tolerable intensity to cause an exacerbated muscle contraction for a total of 1.5 mins, according to the protocol (Valera & Minaya). The subjects were lying prone in decubitus. The middle part of the sciatic nerve was located using an ultrasound machine (cross section), then an acupuncture needle (0.30 mm x 40 mm) was inserted in a short axis approach, perpendicular to the surface of the skin, to the perineurium of the sciatic nerve.

The subjects were lying prone in decubitus. The same puncture protocol was performed on the sciatic nerve for 1.5 minutes, but without the application of electricity.

It's a new intervention of sport physiotherapy. It´s an invasive technique. It is necessary an ultrasound

Change from Passive Knee Extension 90º [PKE 90º] [Hamstring Flexibility test] 5 minutes after intervention

Passive Knee Extension with hip 90º. The examiner will measure the popliteal angle (between the femur and the tibia) with a goniometer.

The sit and reach test is a common measure of flexibility of the lower back and hamstring muscles. Using a standard sit and reach box, the participant sat on the floor with shoes on, and fully extended one leg so that the sole of the foot was flat against the end of the box. She then extended her arms forward, placing one hand on top of the other. With palms down, she reached forward sling hands along the measuring scale as far as possible without bending the knee of the extended leg.

Change from Stand and Reach Flexibility Test [Hamstring Flexibility test] 5 minutes after intervention

The volunteer standing with his knees extended tries to touch the ground with his extended hands. The examiner will measure with a ruler the distance in centimeters between the floor and the tips of fingers.

Inclusion Criteria: over 18 years to practice some sports activity 2 or more times a week get less than 70º in PKE (Passive Knee Extension) with hip 90º Exclusion Criteria: any previous surgery or acute trauma in the back or lower extremity. pain at the time of performing the assessment tests belonephobia anticoagulant consumption pregnancy hemorrhagic disorders immunosuppression inability to understand or carry out evaluations