Soft Tissue Stiffness and Functional Knee Outcomes in Female Handball Players Following a Knee Injury: A Cross-Sectional Study

<b>Background/Objectives</b>: The aim of our study was to evaluate the transverse stiffness of selected soft tissues in the knee joint region on the previously injured and uninjured sides of female handball players and non-athlete women, in the lying and standing positions, and to investigate the relationship between stiffness, age, sporting practice, and clinical assessments of the knees. <b>Methods</b>: A total of 25 young female handball players (the SPORT group) and 27 healthy non-athletic individuals (the CONTROL group) were examined. The MyotonPRO device was used to measure the stiffness of the patellar tendon (PT), rectus femoris (RF), and biceps femoris (BF) muscles on both sides and in both positions. The function of the knee joints was clinically assessed using the Knee Outcome Survey-Sports Activities Scale and the Lysholm Knee Scoring Scale. <b>Results</b>: ANOVA indicated a significant effect of group (<i>p</i> < 0.003) on the PT's stiffness, and a significant effect of position (<i>p</i> < 0.0001) on the PT, RF, and BF muscle stiffness. The SPORT group demonstrated significantly higher PT transverse stiffness when lying down (<i>p</i> < 0.01), but not when sitting up (<i>p</i> > 0.05), compared to the CONTROL group. Significant negative correlations were found between PT stiffness and both clinical scales in the SPORT group (rho from -0.39 to -0.71, <i>p</i> < 0.05). <b>Conclusions</b>: In female handball players, only the patellar tendon transverse stiffness was higher than in the control group. While this higher stiffness could indicate an adaptive rebuilding process, it was negatively correlated with the clinical assessment of joint function, meaning poorer knee joint function.