Preventive and rehabilitation programs include plyometric exercises to promote agility, power, and muscle activation pattern during jumping. These exercises also are known to cause a high mechanical load that increases the risk of a musculoskeletal injury. The knowledge regarding the musculoskeletal damage result from this configuration of exercise can help to elaborate safer and effective training and rehabilitation programs. In this study, the investigators will conduct a clinical trial to determine the acute effect of plyometric exercises on damage caused on different portions of quadriceps and biceps femoral's muscles and tendons of quadriceps, and biceps femoral, and its effects on mechanical properties.

This is a single-arm clinical trial aiming to determine the acute effect of one session of plyometric exercises on quadriceps and biceps femoral musculotendinous properties in healthy individuals.

The sample size was determined using G*Power software considering the application of ANOVA: Repeated measures, between factors, 90% power, alpha 0.05. Data from muscle echo intensity of the rectus femoral by Muddle et al. (2019) were considered for this calculation, with an effect size 0.44. A total of 30 individuals was required for this study.

The outcomes will include the muscle and tendon quality, and mechanical properties of the tendon. The assessments will be performed at three different moments: before exercise, immediately after, and 48 hours after exercise.

The data analysis will be performed per protocol. Generalized estimating equations will be used to identify the effects of time followed by Bonferroni posthoc. When effects are found, effect sizes will be estimated. Missing data will be estimated by statistical analysis.

Inclusion Criteria:

• Who practice physical activity (except jump training);
• No previous lower extremity muscle injury at least 6 months before the recruitment;
• No previous lower extremity ligament or tendon injury or surgery;
• No auditory, vestibular, visual or musculoskeletal injuries or disease that limit the execution of the exercise and assessment protocols;
• No hypertension, cardiovascular, or respiratory disease.

Exclusion Criteria:

• Body mass index greater than 30 kg/m².

The investigators intend to publish the results in an open-access journal, indexed at the Directory of Open Access Journals, with the copyrights transferred to the authors. Details regarding the study's design and statistical plan can be obtained consulting the trial's protocol. Data on other outcomes could be requested contacting the PI.

The individual participant dataset will become available at a public repository up to six months after the first study publication

A simple registration will grant access to study datasets. The website for these files is not defined at the time of registration.

The statistical analyzer will be masking for the time factor.