The Immediate Effects of Spinal Manipulative Therapy on Kinetic and Kinematic Symmetry.

Athletes have been exposed to an ever increasing training load and subsequent biomechanical overload due to a constant demand for performance enhancement. As a result, it is observed an increased rate of musculoskeletal problems, including spinal biomechanical dysfunctions that are often asymptomatic. These dysfunctions are believed to negatively influence a wide range of mechanical and physiological parameters such as muscle strength, range of motion, and symmetry, what could potentially influence sports performance.

Spinal Manipulative Therapy (SMT) is a safe and effective therapy for musculoskeletal disorders that has been increasingly utilized in sports. SMT purpose is to correct spinal joints biomechanical dysfunctions using a high-velocity, low-amplitude movement, applied at the paraphysiological space, beyond the passive joint range of motion.

Kinetic and kinematic symmetry can be measured in commonly utilized physical functional tests often used as indicators of athlete's performance. Symmetry Index calculation is used to verify bilateral asymmetries in static and dynamic tests.

Therefore, the objective of this randomized controlled trial study is to measure the immediate effects of lumbar SMT on kinetic and kinematic symmetry of asymptomatic athletes, through of the use of three commonly used functional tests: Static posture, Free Squat, and Countermovement Jump (CMJ) are often used as indicators of athlete's performance. These quantitative data is important to assess training effectiveness and prevention/ rehabilitation programs outcomes. To our knowledge this is the first study on literature that measured the immediate effects of SMT on kinetic and kinematic symmetry.

Eligibility Criteria:
Inclusion criteria

The inclusion criteria for sample followed the assumptions below:

* All young student participants had to be of both sexes, age between 18-35 years old.
* All participants had to be pain free or asymptomatic, with regards to low back pain, in order to create homogeneity within the study sample.
* All participants had to have at least a minimal score, (low level) of physical activity, evaluated by (IPAQ) questionnaire (International Physical Activity Questionnaire). This was done on the argument that the minimal score, already shows that the participants were minimally physically active. This also contributed in an indirect way to assure a certain degree of sample homogeneity, scoring the minimal level of physical activity to include in the study;
* All participants were required to show the subluxations or vertebral dysfunctions in their lumbar spine, detected by motion palpation. Through the purposive sampling, was allowed participants to officially take part in the study.

Exclusion Criteria:

The exclusion criteria for sample followed the assumptions below:

* Participants who received medical, surgical or in addition manual interventions prior or during the study, were immediately excluded.
* Participants who presented with any contraindications to manipulation on spine, which included but was not limited to osteomyelitis, tuberculosis, infectious arthritis, disc extrusion, hemangioma, vertebral malignancy and advanced spondylolisthesis
* Participants who have participating of sports competitions or change in training routine during the collecting data, was immediately withdraw from the study.;
* Participants with no vertebral dysfunction in the palpated lumbar joints were excluded of the study;
* Participants who did not sign the informed consent form, or not agree of the conditions, or did not have conditions to compromise with the schedule, were immediately withdraw from the study.