Sprint and jump abilities are considered basic skills that are regularly evaluated in training and school contexts. The correlations between these two skills have previously been established in adults and adolescents, but they have not been fully assessed in children. The present study aimed to explore sprinting and jumping ability in prepubertal boys and girls. Thirty-one prepubertal individuals (aged 8–11 years) were assessed during sprinting for different distances (5, 10, and 20 m) and using different vertical and horizontal jump modalities (squat jump, countermovement jump, broad jump, and hop test). Correlations between the different results were tested. Strong correlations were found between vertical jump and sprint performances, especially over short distances. These results suggested that vertical jump tests are more sensitive than horizontal jumps to reveal acceleration capacity in children.

Introduction: This study aimed to compare the influence of the knee and hip joint angles on the quadriceps muscles and tendon shear wave velocity (SWV) between men and prepubertal boys. Methods: Ten prepubertal boys and ten men participated in one experimental session, which included SWV measurements at rest for the vastus lateralis (VL), the rectus femoris (RF), and the patellar tendon (PT). Each volunteer was tested in ten randomized positions, including five knee joint angles (30, 50, 70, 90, and 110°, 0° = full extension) and two hip joint angles (0° and 80°, 0° = full extension). The SWV values were analyzed independently with a three‐way ANOVA, while considering the knee angle, hip angle, and the age group. Results: Significant knee angle × age interactions were observed for VL ( p = 0.008), RF ( p = 0.008), and PT ( p < 0.001). Boys and men did not present a difference in VL and RF SWV. However, boys exhibited significantly lower PT SWV values than men from a 30° to 90° knee flexion angle ( p < 0.001). Additionally, a hip angle × knee angle interaction ( p < 0.001) has been observed for RF SWV and highlighted greater values with a 0° hip joint angle, whatever the knee joint angles. Conclusion: These results suggested that boys and men present similar muscle elastic properties in VL and RF. However, lower SWV was observed for PT in boys up to 90° knee joint flexion.

This study aimed to compare the effects of a fatiguing concentric exercise on the myotendinous mechanical properties of the knee extensors between men and prepubertal boys. Ten prepubertal boys and 10 men performed a fatiguing exercise consisting of five sets of 20 maximal isokinetic concentric knee extensor contractions. Before the exercise, the mechanical properties of the vastus lateralis (VL), the rectus femoris (RF), and the patellar tendon (PT) were assessed using shear wave elastography to measure the shear wave velocity (SWV) at 70° of knee joint flexion for PT and 70° and 110° for VL and RF. The tests also included maximal voluntary isometric (MVIC) and concentric (MVCC) contractions. These measurements were repeated after the exercise (Post), 30 min after (Post30), and 48 h after (Post48 h). Significant main time effects were observed for SWV VL 70° ( p = 0.007) and RF 70° ( p < 0.001), with lower values at Post compared to Pre. No age effect or interaction were observed for VL and RF SWV 70°. For SWV PT, a main age effect was observed, highlighting lower values for boys ( p < 0.001), without a time effect or interaction. A significant decreased MVIC was observed for men at post, returning to baseline at Post30, whereas no changes in MVIC were observed in boys. These findings suggest that, under acute conditions, maximal concentric contractions induce comparable changes in myotendinous mechanical properties between prepubertal boys and men, while men exhibit a greater force production decline.