This completed observational repeated-measures study examined the relationship between field-based physical and temporal measures and pitch velocity in adolescent baseball pitchers. Six adolescent pitchers were assessed repeatedly over five weeks. The assessment battery included rotational medicine-ball throw distance, countermovement jump height, 30 m sprint time, shoulder flexibility, temporal characteristics of two operational wind-up phases, and pitch velocity measured with a sports radar. No experimental intervention or modification of the athletes' usual training was implemented.

Pitch velocity is a relevant performance indicator in baseball pitching, particularly during adolescent development, when physical capacities, technical refinement, and sport-specific skill acquisition occur simultaneously. This completed observational study was designed to explore whether field-based measures of explosive strength, shoulder flexibility, sprint performance, and wind-up temporal organization were associated with pitch velocity in adolescent baseball pitchers.

The study used a quantitative, non-experimental, descriptive-correlational, longitudinal repeated-measures design. Six adolescent baseball pitchers were assessed once per week over approximately five weeks, yielding repeated observations nested within each athlete. The study did not involve an assigned intervention, randomization, treatment allocation, or modification of the athletes' usual training process.

The field-based assessment battery included rotational medicine-ball throw distance as an indicator of upper-body rotational explosive performance, countermovement jump height as an indicator of lower-body explosive performance, 30 m flying sprint time as an indicator of sprint performance, shoulder flexibility assessed through a behind-the-back shoulder mobility test, temporal analysis of two operational phases of the pitching wind-up using video, and pitch velocity measured with a sports radar. Wind-up phase 1 was operationally defined as the interval from maximal knee elevation to bilateral foot contact, whereas wind-up phase 2 was defined as the interval from bilateral foot contact to frontal orientation toward the target.

The main analytical purpose was to describe the magnitude and direction of the associations between the field-based measures and pitch velocity while accounting for the repeated-measures structure of the data. Analyses were planned using descriptive statistics and association models appropriate for repeated observations within participants, including mixed-effects models or exploratory correlation procedures when required by the sample size.

Inclusion Criteria:

• Male adolescent baseball players aged 13 to 14 years.
• Regular pitchers or players who performed regular pitching duties within an organized baseball training process.
• Regular participation in baseball training during the assessment period.
• Ability to complete field-based jumping, sprinting, shoulder flexibility, pitching, and video-based wind-up assessments.
• Parent or legal guardian consent and participant assent.

Exclusion Criteria:

• Active musculoskeletal injury, relevant pain, or medical restriction limiting participation in jumping, sprinting, or pitching assessments.
• Ongoing physical rehabilitation at the time of assessment.
• Medical contraindication for performing physical efforts consistent with regular baseball practice.
• Insufficient attendance to complete the minimum repeated-measures record required for analysis.
• Withdrawal of parent/legal guardian consent or participant assent.

The study population consisted of male adolescent baseball pitchers aged 13 to 14 years from an organized youth baseball training process in Antioquia, Colombia. Participants were healthy athletes involved in regular baseball practice and were assessed using field-based physical, biomechanical, and performance measures related to pitch velocity.

Individual participant data will not be shared because the study involved minors and a small sport-specific sample, which may increase the risk of indirect identification. Results will be reported only in aggregate form.