Author(s): XU, Y., GU, Y., Institution: NINGBO UNIVERSITY, Country: CHINA, Abstract-ID: 713

INTRODUCTION:
The kipping bar muscle-up constitutes a multifaceted, multi-joint maneuver that significantly augments upper-body explosiveness and neuromuscular synergy, yet demands intricately honed technique and entails notable injury risks. To elevate acquisition efficacy without escalating training volume, a posture-oriented approach designates the high-hang power snatch as a plausible antagonist. By analyzing biomechanical trajectories via machine learning, this study seeks to quantify their antagonistic nexus and refine training methodologies.
METHODS:
Eight males (21.2±1.2 yrs, 175.6±2.2 cm, 70.3±6.6 kg), able to perform ≥5 kipping bar muscle-ups and a ≥60 kg snatch 1RM, participated. Over six test days, bar muscle-ups or snatches (20–60 kg) were alternated in five sets of three reps, with two-day intervals. Warm-up involved brief cycling and stretching; main tests used five sets×3 reps and three-minute rests. Xsens and Gymaware captured displacement, velocity, angles, force, power, and work. Paired t-tests (Jamovi, α=0.05) compared temporal and kinematic data, while SPM1D analyzed time-series. DTW examined reversed snatch data for antagonistic joint motion; Python scripts executed SPM1D and DTW.
RESULTS:
Barbell displacement during snatches markedly surpassed body COM displacement in kipping muscle-ups (p<0.001), with no significant difference in total movement time (p>0.05). Although the 20 kg snatch required less time than muscle-ups (p<0.05), peak power and relative force showed no significant discrepancy (p>0.05). Notably, the 40 kg snatch produced the highest velocity (3.05±0.08 m/s), power (3201.03±1061.52 J/s), and relative force (14.84±2.86 N/kg), closely paralleling muscle-ups. While muscle-ups had the largest shoulder range (e.g., frontal plane 26.53±3.59°–122.25±0.94°), the 60 kg snatch exceeded other loads (16.63±1.14°–140.51±3.97°). Elbow motion at 40 kg most resembled muscle-ups. SPM1D revealed minimal time-series discrepancies in velocity and power. DTW analysis indicated a 63.18% reduction in distance for the 30 kg snatch upon sequence reversal, underscoring reversed kinematic patterns that better align with the muscle-up profile.
CONCLUSION:
The results revealed that the barbell high-hang power snatch exhibits an antagonistic relationship with the kipping bar muscle-up in specific degrees of freedom—namely shoulder abduction-adduction, rotation, flexion-extension, and elbow rotation. Notably, a 40 kg snatch (61.5% 1RM) produced the highest peak velocity, peak power, and relative force, closely approximating the muscle-up profile. By contrast, 20 kg and 30 kg snatches (30.8% and 46.2% 1RM) demonstrated the strongest antagonistic joint kinematics per DTW analysis, suggesting lighter loads may be preferable for technique training or injury prevention. Overall, to boost explosive strength, loads near 60% 1RM are advisable; while to refine muscle-up technique or accommodate joint limitations, lighter loads constitute a safer, more effective antagonistic alternative.