## 4 Discussion
LBP is common in rhythmic gymnasts due to extreme spinal hyperextension and repetitive loading, often developing in adolescence (10-18 years) and persisting into adulthood (20-30 years) due to chronic stress [36; 37]. Physiologically, younger gymnasts (10-18 years) are vulnerable to growth-related injuries such as apophyseal injuries and stress fractures [38], while older gymnasts (20-30 years) may suffer from degenerative changes and cumulative musculoskeletal stress [39]. A key limitation of this study is the wide age range (10 to 30 years) among elite rhythmic gymnasts, which introduces variability in maturation, height, and technique, potentially influencing jump performance outcomes. However, in our study, the mean age of both groups was 13.8 years old, with no significant differences between them, and only one participant was 27 years old. Despite the broad inclusion criteria, the sample was predominantly composed of adolescent gymnasts, which helps reduce the impact of extreme age-related differences. Nevertheless, younger gymnasts (10-18 years) are still undergoing growth and neuromuscular development, which can affect their ability to generate Maximal Force and optimize jump biomechanics [38]. In contrast, older gymnasts (20-30 years) typically have greater muscle strength, coordination, and refined technique, which may enhance jump performance [39]. Differences in limb length, muscle mass, and motor control strategies between younger and older gymnasts could influence jump variables such as maximal speed, height, and force production. Although only one participant was significantly older, her results may have slightly skewed overall performance trends. Future studies should consider narrower age groups or statistical adjustments for maturational differences to ensure more homogeneous comparisons. Moreover, great variability of height was observed between Mezieres and Isostretching groups, suggesting different anthropometric profiles among participants. Although this difference was not statistically significant, height differences could influence jump performance, namely due to limb length, segmental leverage, and force application, which, in turn, influence neuromuscular efficiency and movement biomechanics. Given that height can impact countermovement jump (CMJ) performance by altering the stretch-shortening cycle and force production mechanics, this variability should be considered a potential limitation of the study [40; 41]. Future research should consider whether controlling for height variability in postural therapy interventions could help further refine the understanding of neuromuscular adaptations in rhythmic gymnasts with low back pain. Another limitation of this study is also the relatively small sample size (\(n=17\)), which may restrict the generalizability of the findings. Additionally, the limited sample size in this study may have impacted the statistical power, reducing the ability to detect small but meaningful differences in performance outcomes. A small sample size increases the risk of Type II errors, making it difficult to generalize findings to the broader population of elite rhythmic gymnasts. A larger sample should be selected in future studies to improve statistical power and ensure more reliable comparisons between groups. A larger, more diverse cohort would allow for subgroup analyses based on maturational status, helping to better understand the effects of age-related differences on jump performance. Additionally, longitudinal studies tracking gymnasts over time could provide further insights into how maturation, training adaptations, and injury history influence performance metrics. Moreover, the study duration (24 weeks) might not be sufficient to capture long-term adaptations in pain management and athletic performance. Future research should consider larger cohorts and extended intervention periods to validate these results.