2D Key-Event Joint Angles Across Phases of the Badminton Overhead Smash in Elite Colombian Players

Federal University of Vicosa4 enrolled

Overview

Phase-based descriptions of the badminton overhead smash can support coach-relevant feedback when laboratory motion capture is impractical. This cross-sectional exploratory case series characterises dominant-side, two-dimensional key-event joint-angle configurations (knee, hip, shoulder, elbow) across five phases (preparation, start, acceleration, impact, termination) in elite Colombian players from the Antioquia Badminton League. Athletes performed three maximal-effort smashes; one trial per athlete was selected for analysis using pre-defined visibility criteria, and one key-event frame per phase was digitised in Kinovea. Outcomes are descriptive phase-specific angle values and between-athlete dispersion metrics. The study is retrospectively registered for transparency.

Badminton overhead smash performance depends on coordinated whole-body contributions and is often judged qualitatively in applied settings. This study provides a field-based, minimal-equipment description of dominant-side planar joint-angle configurations across five technical phases of the overhead smash using a single lateral high-speed camera. Five elite athletes (men n=4; woman n=1) from the Antioquia Badminton League were recorded at 240 frames·s-¹ during maximal-effort smashes. Phases were defined as preparation (F1), start (F2), acceleration (F3), impact (F4), and termination (F5), with one key-event frame selected per phase. Knee, hip, shoulder, and elbow internal angles were extracted via three-point definitions in Kinovea. Data are reported descriptively (male subgroup as mean±SD and CV%; female case descriptively). The intention is to offer coach-interpretable phase references and to identify phases with higher inter-individual dispersion.

Study Type

OBSERVATIONAL

Enrollment

Conditions

Sports Performance Biomechanics

Eligibility

Sex: ALLMin age: 18 Years

Medical Language ↔ Plain English

Inclusion Criteria: * 5 years of organised badminton experience * Current Antioquia Badminton League affiliation * Competitive participation in ≥5 federated tournaments * Previous selection to a representative team at least at national level * Able to execute maximal-effort overhead smashes on the testing day Exclusion Criteria: * Pain or musculoskeletal complaints affecting upper limb, trunk, or lower limb on the testing day * Any condition preventing maximal-effort overhead smashes

Outcomes

Primary Outcomes

2D sagittal-plane joint angles at key events during the smash (knee, hip, shoulder, elbow)

Internal joint angles (degrees) for the knee, hip, shoulder, and elbow computed using three-point (planar) definitions at five pre-defined key-event frames (F1-F5) spanning the smash phases. Angles will be extracted from lateral high-speed video after landmark digitisation in Kinovea using pre-specified anatomical landmarks and segment definitions. Data will be reported as mean (SD) for each joint and key-event frame; larger values indicate more extended joint configurations.

Time frame: Baseline (Visit 1; up to 30 minutes)

Secondary Outcomes

Between-participant variability (SD and CV%) of 2D sagittal-plane joint angles by key-event frame and joint

Between-participant dispersion of the 2D sagittal-plane joint angles (knee, hip, shoulder, elbow) at each pre-defined key-event frame (F1-F5). Variability will be summarized as (i) standard deviation (SD, degrees) and (ii) coefficient of variation (CV%, 100×SD/mean) across participants for each joint × key-event frame. Variability will be reported for the overall sample and, if applicable, stratified by sex as a pre-specified exploratory analysis.