This is a two-group randomized clinical trial (includes an experimental and a placebo group) to verify the effects of the Myofascial Reorganization (RMF) compared to the placebo-RMF technique on running performance and thermographic, biomechanical, and viscoelastic proprieties of lower limbs of male triathletes. Data collection will be carried out one week before the first intervention session, and one week after the last intervention session. Anthropometric characteristics (height and weight), lower limbs, and biomechanical, viscoelastic, and thermographic properties will be collected before any exercise tests. After this, the athlete will be submitted to: a 10-minute protocol to verify running economy on the treadmill, followed by an incremental test on the treadmill, and a time to exhaustion test. Evaluation procedures will carried out one week before (0 weeks) and one week after (7th week) the experimental/placebo intervention. Intervention sessions will occur during six weeks, twice a week, each session lasting up to 30 minutes.

1. This study was approved by the Ethical Committee involving Research with Human Beings of the University of Santa Catarina (UDESC) under protocol number 56498722.1.0000.0118. Consolidated Standards of Reporting Trials will be followed.

2.1 General objectives: to verify the effects of the Myofascial Reorganization (RMF) technique compared to the placebo-RMF technique on running performance and thermographic, biomechanical, and viscoelastic proprieties of lower limbs of athletes.

2.2 Specific objectives: intragroup and intergroup comparisons of running-related performance variables, lower limb skin temperature, and biomechanical and viscoelastic properties.

3. Sample: Athletes volunteers living in Florianópolis, SC, Brazil, if they meet inclusion criteria and do not meet exclusion criteria.

4. Sampling: will be non-probabilistic by convenience and snowball (participants will be recruited by social media, flyers, and by referral of other participants).

5. Data collection procedures: the athletes will be evaluated before (0 weeks) and after (7 weeks) a 6-week intervention protocol.

5.1 Anthropometric measures: height (centimeters) will be collected using a stadiometer, and body mass (kilograms) will be measured using a weighting balance.

5.2 Lower limb skin temperature: Thermographic characteristics of lower limbs will be measured in a dark and controlled room, at an ambient temperature of 24°C(±1°) and relative air humidity of 50%, after 15 minutes of acclimatation. Anterior and posterior lower limb regions of interest will be included.

5.3 Biomechanical and viscoelastic properties:

Biomechanical and viscoelastic properties State of tension, biomechanical and viscoelastic properties of the myofascial tissue of lower limbs and thoracolumbar region will be assessed using a non-invasive digital palpation device. These properties will be:

• F: Frequency
• S: Dynamic Stiffness
• D: logarithmic decrement
• R: Relaxation time,
• C: Creep. These measures will be taken bilaterally on the anterior and posterior regions of the tights, the iliotibial tract, and the thoracolumbar region.

5.4 Performance-related tests: all exercise tests to analyze running performance-related variables will be carried out on a treadmill while monitoring the heart rate using a frequency meter and analyzing the gas exchange parameters using a gas analyzer in an open circuit breath-by-breath.

5.4.1 Running Economy: is the oxygen consumption at a common velocity, chosen to be under the first lactate threshold. The athletes will run at a constant velocity of 7 kilometers per hour while measuring their oxygen consumption (VO2) and monitoring the heart rate, for 10 minutes.

5.4.3 Incremental 3-minute graded test: The maximal volume of oxygen consumption (VO2 max), the maximal velocity of the incremental test, and lactate thresholds will be determined by an incremental graded test until volitional exhaustion, using stages of 3min, and an increment of 1km/h per stage, with a slope of 1% on the treadmill. Between each stage, capillary blood from the ear lobe will be collected to determine lactate blood concentrations. The perceived effort will be measured using the 10-point scale for perceived effort.

5.4.4 Lactate thresholds: blood lactate concentrations [bLa] will be derived from blood samples collected from the ear lobe during the incremental test, and the first (LT1) and the second lactate threshold (LT2) will be determined.

5.4.5 Time to Exhaustion Test: to determine the time to exhaustion in a maximal effort and as a verification of the VO2max. After the 20-minute rest after the incremental test, a re-warm of 3 minutes will be taken at a velocity of 50% of the maximal velocity reached by the incremental test. Then, the athlete will perform the test at 100% of the maximal velocity, until volitional exhaustion.

6 Groups and Interventions

After an evaluation (0 weeks), the participants will be randomized into one of the two groups: (a) Myofascial Reorganization (RMF) or (b) PLACEBO Myofascial Reorganization (RMFplacebo). They will be blinded to the group of intervention. The randomization will be enrolled using sealed envelopes, and the allocation will be carried out in blocks of 4 by a non-investigator.Both groups will receive 6 weeks of experimental/placebo intervention, twice a week. Each session will last approximately 30 minutes. The RMF group will receive a specific mechanical load directed to the fascial system (real technique) while the placebo group will receive a simulation of the technique (a light touch to the skin), added to lower limb voluntary movements. The real technique consists of a specific 45° oblique mechanical load applied to the fascial system, and it includes an additional shear load provoked passively (by the therapist) and then actively (provoked by the participant's voluntary movement).The re-tests will be carried out one week after the last session of intervention (in the 7th week).RMF will be applied:

6.1. Thoracolumbar fascia insertion: using one proximal hand (closer to the participant's head) and a distal hand (closer to the participant's feet). Proximal hand - three fingers on the iliolumbar ligament. Distal hand - three fingers on the lateral edge of the sacrum. Passive load (first stage): the therapist applies a progressive then sustained oblique 45° load with both hands, directing the force vector to the pelvis center, with additional craniocaudal shear load, using the fingers, both hands working synchronically. Active load (second stage): the participant, lying in the supine position, contralateral and ipsilateral lower limbs initially relaxed, both feet placed in the stretcher and hips, and knees flexed at 90°/90°, hands on the thorax, starts, with ipsilateral lower limb will perform an active movement: (a) hip external rotation, added to dorsal flexion of the ankle, and flexion of the knee, and hip joints; (b) followed by the movement of hip internal rotation added to plantar flexion of the ankle, and extension knee, and hip joints.

6.2. Abdominal muscles fascia: The therapist's hands are placed on a virtual triangle formed by the anterior iliac spine, the umbilical scar, and the pubic symphysis, closer to the insertion of the abdominis muscles on the pelvis, where the fascia of rectus abdominis muscle and the obliques muscles separate. First stage: the therapist's fingers will be directed to the center of the pelvis, the hands working synchronically. The therapist applies a progressive mechanical oblique load directing the force vector to the pelvis center, adding a subsequent shear load in the craniocaudal direction, with both hands working synchronically. The participant lies on the stretcher in supine, contralateral, and ipsilateral lower limbs initially relaxed, both feet placed in the stretcher, hips, and knees flexed at 90°/90°, and the hands on the thorax. In the second stage, the participant will add ante/retroversion of the pelvis to promote the active shear load.

6.3. Quadriceps femoris muscle: The therapist will use a proximal and a distal hand. Proximal hand: acting as an anchor - the hypothenar region in parallel with the lateral side of the participant, contemplating the surface between both anterior and inferior iliac spines; to perform that anchor, the therapist will bring the skin excess and apply a soft and sustained mechanical load until they find the fascial barrier. Distal hand: the therapist's hand will embrace the distal portion of the tight, contemplating the patella, the first finger on the lateral side of the knee region, and the other fingers on the medial side; the fingers will create an anchor, promoting an "intention" to separate the quadriceps femoris muscle from the iliotibial tract and the insertion of the sartorius, gracious and semitendinosus muscles. At the same time, using these fingers, the caudal hand will apply the mechanical load with the subsequent shear load. First stage: the mechanical oblique load is applied with a subsequent shear load in the proximal-distal direction. Second stage: passive shear load is replaced by the active shear load (movement with the ipsilateral lower limb). The participant will be in the supine position. The ipsilateral lower limb lies on the therapist's tight (that acts as a cushion, under the knee region), knee flexed between 40° and 50°, foot resting on the stretcher. The contralateral lower limb: foot resting on the stretcher, keeping 90°/90° hip and knee flexion. The ipsilateral will perform, slowly and with a short range of motion, cycles of knee flexion added to dorsiflexion, followed by knee extension and plantar flexion. The cycle is repeated during the stage time.

6.4. a. Fascia lata tensor muscle and iliotibial tract: the therapist will place one hand right beside the other, with the thumbs relaxed, and the other fingers semi-flexed as if the hands formed a "C". The hands will mirror each other, the carpi bones of the right hand almost touching the ones of the left hand. Both hands will be placed on the supra-trochanteric region. Stage one: The load will be applied using the hypothenar region of the right and left hands and the lateral surface of the 5th right and left fingers. The mechanical oblique load will be directed to the center of the pelvis and knee, with a passive shear load in the mediolateral direction. Stage two: the participant will be in lateral decubitus, relaxed, with the ipsilateral hip in light flexion, the knee in extension, and the contralateral lower limb with hip and knee flexed at 90°/90°. The ipsilateral lower limb executes a hip and knee flexion added to ankle dorsal flexion, then a hip and knee extension added to an ankle plantar flexion, repeatedly.

6.4. b. Fascia lata tensor muscle and iliotibial tract: the therapist will use a medial hand (placed on the medial side of the knee), acting as an anchor, and one lateral hand (lateral side of the knee), that will apply the mechanical load. Anchor (medial hand): the thumb embraces medial the region of the knee. Mechanical load (lateral hand): on the lateral region of the tight, 5cm above the articular line, on the insertion of the iliotibial tract; the hypothenar region of the hand will apply the load 5cm above the joint line of the knee (the distal third of the iliotibial tract). Stage one: The lateral hand applies the mechanical oblique load, vector directed to the center of the pelvis, and to the ceiling, with the shear load applied in the mediolateral direction. Stage two: the participant, already in lateral decubitus, with the contralateral lower limb in 90/90° hip and knee flexion, and the ipsilateral initially, the hip in light flexion, and the knee in extension will perform a very short range of motion of hip internal rotation and then returns to the initial position, repeatedly, with the ipsilateral lower limb.

6.4. c. Fascia lata tensor muscle and iliotibial tract: from the abovementioned position, only the second stage (active shear load) is repeated, but the therapist's mechanical load hand (lateral hand) is now on the proximal insertion of the iliotibial tract.

6.5 Hamstrings muscles: The participant will be in the supine position, contralateral lower limb with the foot resting on the stretcher, keeping the hip and the knee flexed at 90°/90°. The participant's ipsilateral knee initially rested on the therapist's shoulder. The therapist uses one hand to stabilize the participant's knee, and the other hand, to promote the mechanical load. Stabilizing hand: on the distal region of the thigh, involving the knee and stabilizing the participant's limb. Mechanical load hand: the therapist will apply the mechanical load using the diaphysis of the distal phalanges; on the proximal third of the tight, close to the insertion of the ipsilateral hamstring muscles. Stage one: progressive then sustained 45° oblique load, force vector directed to the center of the pelvis added to a shear load in the proximal-distal direction (from the ischiatic bone to the knee, repeatedly). Stage two: the participant's ipsilateral lower limb performs knee flexion/extension (not full extension).

6.6 Adductor muscles: The participant will be in the supine position. The Ipsilateral lower limb with the foot resting on the stretcher, the tight resting against the therapist's tight, maintaining a hip and knee flexion of approximately 60°/60°, and slight hip external rotation. The contralateral lower limb with the foot resting in the stretcher, maintaining 90°/90° of hip and knee flexion. The therapist will use one hand as an anchor, while the other applies the mechanical load. Anchor: the thumb performs an oblique 45°load directed to the center of the pelvis, on the region that designs a virtual triangle formed by the umbilical scar, the anterior superior iliac spine, and the pubic symphysis. Hand of the mechanical load: performing thumb opponency while the second and third fingers remain together, in interphalangeal and metacarpophalangeal flexion, forming a "C", this hand promotes a continuous mechanical load, 15cm distant to the pubic symphysis. Stage one: progressive then sustained 45° oblique load, force vector directed to the center of the pelvis, with additional shear load on the proximal-distal direction (from the pelvis to the knee, and vice-versa). Stage two: the participant will perform, with the ipsilateral lower limb, hip internal/external rotation repeatedly.

The placebo technique will repeat all the stages, except the therapist will apply a light touch to the skin during stages one and two. The movements of stage two will be performed.

7Statistical Analysis The data will be processed using IBM Statistical Package for the Social Sciences version 20.0. The Shapiro-Wilk test will determine the normality of data, and an analysis of variance (ANOVA) 2x2 will be conducted to compare between conditions (experimental/placebo) and between the baseline (0 weeks) and post-intervention (7th week). All analyses will be bidirectional and set to a significance level of (p<0,05). The effect size will be conducted.

Inclusion Criteria:

• Athletes
• Age between 18 and 45 years
• 2 years of competitive experience
• Non-smokers
• Training at least 3 times/week intending to compete in at least local competitions
• No presenting lower limb surgery in the last 12 months
• Not presenting lower limb injury in the last 6 months
• Not presenting cerebellar diseases that limit sportive practice
• Not presenting brain diseases that limit sportive practice
• Not presenting musculoskeletal diseases that limit sportive practice
• Not presenting signs of rhabdomyolysis
• Not presenting systemic conditions that limit sportive practice
• Not presenting metabolic that limits sports practice
• Not presenting autoimmune conditions;
• Not presenting cardiac conditions.

Exclusion Criteria:

• Not accomplishing 83,3% (10 of 12 sessions) of the proposed experimental/placebo protocol
• Not presenting themselves on the re-test day
• Developing a lower limb musculoskeletal injury during the study's ongoing period.
• Developing a back injury during the study's ongoing period?
• Developing central or peripheral nervous system conditions during the study's ongoing period.

Participants will be blinded to which group they will belong, as they never had contact to the technique investigated. The statistical analysis will be blinded as well, and the statistical will not know which is the experimental or the placebo group.