Alejandro Bustamante-Garrido

Background/Objectives: Understanding the factors that influence tendon mechanical properties is essential for optimizing performance and preventing injuries in elite athletes. This study aimed to identify the strongest correlates of the biomechanical properties (frequency, stiffness, logarithmic decrement, relaxation, and creep) in the Achilles and patellar tendons in elite international athletes. Methods: A cross-sectional study was conducted with 111 elite athletes from 11 sports disciplines assessed at a high-performance training center. Tendon properties were measured bilaterally using MyotonPRO. Anthropometric (height, weight, age), demographic (sex, limb dominance defined as the preferred limb for sport-specific activities), and sport-specific variables were analyzed using correlation, multiple regression, and machine learning approaches. Results: Height showed the strongest correlations with tendon frequency and stiffness, particularly for the Achilles tendon (r = 0.52 for frequency; r = 0.53 for stiffness; p ≤ 0.001, large effects). Sex differences were evident across all measures, with men showing higher stiffness and frequency, and women greater relaxation and creep (partial η² = 0.35–0.48, Cohen’s d = 0.84–1.16). Sports discipline explained substantial variance in tendon properties (η² > 0.40), and limb dominance influenced Achilles stiffness, with left-dominant athletes showing higher values (p < 0.05). Age showed minimal associations (r < 0.10). Conclusions: Height, sex, and sports discipline were the strongest correlates of Achilles and patellar tendon mechanical properties in elite athletes, with large and practically meaningful effects across sports. This comprehensive analysis, utilizing multivariate and machine learning approaches, provides insights that can inform individualized training, injury prevention, and performance optimization strategies in high-performance sports.

Background: The isometric mid-thigh pull test (IMTP) is commonly used in sports performance assessment, but it remains underutilized among combat sports athletes. Aims: to evaluate whether Pan-American medalists (PM) showed differences when compared with other athletes (NM) when performing the IMTP. Methods: a total of 72 Karate [n=35 (♀12)] and Taekwondo [n=37 (♀15)] athletes were measured (22.4±3.7 yrs.; 67.4±11.5 Kg; 1.7±0.1 m; 22.1±2.8 kg/m2). From the total, 32 athletes were PM of their specific combat sport (♀11). All participants performed the IMTP 60-90 days before the competition. The following variables were measured: a) Impulse Net at 50; 100; 150 and 200 ms (N*s); b) absolute (N) and relative peak force (PF; N/Kg) and; c) Rating of force development (RFD) at 50; 100; 150 and 200 ms (N/s). Results: PM showed a better performance on absolute (2,398.5±623.1 vs. 2,096.2±559.3 N; p=0.034) and relative PF (34.6±5.0 vs. 31.2±5.1 N/Kg; p=0.006); RFD at 150 (5,273.4±2,670.8 vs. 3,963.4±1,904.2 N/s; p=0.0018) and 200ms (4,870.3±2,184.6 vs. 4,022.1±1,574.8 N/s; p=0.05). Relative PF (Τ=0.249; p=0.011) and RDF at 150 ms (Τ=0.208; p=0.033) showed a positive and significative correlation with the competition result. Conclusion: PM showed a high PF and RFD at 150 and 200 ms. Furthermore, the competition result was correlated with relative PF and RDF at 150 ms. Based on our findings, we recommend that coaches incorporate the IMTP into their evaluation routine for striking athletes. Keywords: martial arts, athletic performance, elite athlete, task performance and analysis.