This arm only received the Neuromuscular and Muscular Electrical Stimulation (NMES) intervention.

This arm received the intervention with NMES and Blood flow restriction (BFR).

Consisting of the use of NMES (biphasic symmetrical pulse, bipolar mode, 50Hz frequency, pulse duration 300 μs at 1:1 ratio) (S82®; Enraf-Nonius BV, Rotterdam, The Netherlands). The self-adhesive electrodes (8x5 cm2 Pals Platinum © type, Axelgaard Manufacturing Co. Ltd, Fallbrook, CA, USA) were placed on the quadriceps muscle. The positives electrodes placed distally on the rectus anterior and vastus externus and negative electrodes were placed proximally on the rectus anterior and vastus internus. The over current program consisted of 8 seconds (s) of work (ON phase) and 8 seconds of rest (OFF phase). The overcurrent program in the ON phase had a rise time of 2 s, a hold time of 4 s and a fall time of 2 s. The intensity of the electric current was increased to the maximum perceived tolerance, achieving a clear contraction without producing fatigue.

It was performed using an isokinetic dynamometer (Kineo, Globus, Codognè, Italy). The maximum peak force that the user can perform was measured by means of the concentric-eccentric isokinetic force test. The patient is placed seated on the seat of the machine and with the dominant lower limb, performs 5 contractions with the maximum force, obtaining the concentric and eccentric peak force.

It was performed by means of the thigh perimeter, using a tape measure. The superior pole of the patella is selected as an anatomical reference point and four segments are marked from it, located at 5, 10, 15 and 20 centimeters respectively (95). Subsequently, placing the beginning of the measuring tape at the mark of the segment in question, the thigh is encircled keeping the beginning of the tape fixed, which will coincide with a measurement of the tape when it is reached. This measurement is taken before the start of the quadriceps work with the knee extension exercise and at the end of the 15 minutes of rest after this work.

It was performed through the ability to perceive and reproduce an articular angle previously represented and explained passively. The angles are photographed and measured using the SAPO® computer program, by means of the placement of four marked points on the greater trochanter, lateral epicondyle of the femur, head of the fibula and peroneal malleolus. To perform this procedure, the user must memorize two positions, knee flexion of 90º and knee flexion of 135º, taking 3 photographs of each position in both seated and prone positions.