This study aimed to measure the associative and predictive strength of biomechanical variables of the countermovement jump (CMJ) and squat jump (SJ), and performance of the bandal-chagi kick performed with the dominant (D) rear lower limb in elite Taekwondo Athletes. For this, a total of 27 international level athletes (15 males and 12 females) performed the CMJ and SJ on two force platforms. The bandal-chagi was monitored using a motion capture system (VICON). The main results indicated that non-dominant (ND) Stiffness for the CMJ showed predictive power alone (p=0.048) or in combination with eccentric breaking rating of force development (RFD) (p=0.031) for total hip angular speed. Takeoff peak force/BM for the SJ predicted total time (p=0.002). Concentric RFD/BM predicted total linear foot acceleration, either alone (p=0.001) or with vertical speed at takeoff (p=0.042). The total hip angular acceleration predictor was takeoff peak force D alone (p=0.019) or in combination with peak power/BM (p=0.041). In conclusion, CMJ and SJ tests showed specific associations with TKD kick performance. These analyses in this study indicated that they are good predictors for TKD athletes, producing results consistent with the participants’ levels. Keywords: Martial arts, Biomechanical Phenomena, Time-motion studies, Kinanthropometry, Motion Capture.

Background: Uchi-mata is one of the most frequently used throwing techniques in judo, yet little is known about the kinematic factors distinguishing specialists from non-specialists. This study compared lower-limb kinematics during uchi-mata across its three phases in elite judokas. Methods: Forty athletes (12 female, 28 male; 24.5 ± 5.9 years) were classified as specialists (n = 20) or non-specialists (n = 20). Photogrammetry assessed hip, knee, and foot displacement, velocity, acceleration, and timing during the Approach, Turning, and Throw phases. Analyses were performed using mixed-effects models with group, phase, and sex as fixed effects, plus exploratory multivariate tests (p < 0.05). Results: Specialists executed faster movements in the Approach (p = 0.036, d = 0.69) and Throw phases (p = 0.010, d = 0.85), showed greater hip displacement during Approach (p = 0.008, d = 0.89), and achieved superior knee and foot displacement in Throw (p = 0.005 and p = 0.003). Final positioning also differed, with specialists displaying higher knee (98.5 ± 14.5 vs. 86.3 ± 17.8 cm, p ≤ 0.001) and foot (121.0 ± 19.7 vs. 104.4 ± 27.4 cm, p = 0.034) heights, but lower hip position (61.9 ± 4.2 vs. 75.6 ± 7.5 cm, p = 0.021). Sex showed no significant effects or interactions, indicating that these group differences were consistent across male and female athletes. Conclusions: Uchi-mata specialists demonstrated superior displacement and velocity control, particularly in the Approach and Throw phases, reflecting greater neuromuscular coordination and efficiency. These findings provide practical markers for coaches and athletes to guide training focused on mobility, strength, and technical drills that enhance hip, knee, and foot displacement, supporting the optimization of uchi-mata performance in elite judo.

This study investigated the relationship between variables of the deep squat jump (DSJ) and the Abalakov jump (ABK) and the performance of the rear leg roundhouse kick in elite combat sport athletes. Twenty-seven elite taekwondo athletes (12 females) performed three attempts of each movement: DSJ and ABK (measured with Pasco® force platforms), and the roundhouse kick (analyzed with Vicon® motion capture systems). The key findings demonstrated that specific force and power metrics from the jumps are significant predictors of kicking kinematics. For the DSJ, the rate of force development (RFD) in the first 100 ms of the concentric phase (RFDcon) was a primary predictor, independently explaining 21% of the variance in linear foot velocity (p=0.009) and 30.3% in linear foot acceleration (p=0.003). Furthermore, for the non-dominant (stance) limb, takeoff peak force independently predicted angular hip acceleration (R²=0.144, p=0.029). For the ABK, the eccentric braking RFD at 100 ms (RFDecc) emerged as a strong predictor, accounting for 24% of the variance in angular hip acceleration (p=0.006). In conclusion, this study validates the DSJ and ABK as practical tools for assessing qualities critical to roundhouse kick performance. Coaches should prioritize monitoring RFDcon and stance limb strength during a DSJ, as well as the RFDecc during an ABK, to evaluate and train for improved kicking power.