The study sample included 40 participants (n = 40), with 27 males and 13 females’ taekwondo athletes, from middle and high schools in Gangwon Province, South Korea. The adolescent taekwondo athletes who participated in the experiment fully understood the purpose and procedure of the study and volunteered to participate in the experiment. The characteristics of experimental subjects are shown in Table 2.

Dominance was identified through a self-report question asking which leg the athlete prefers to use when executing a Taekwondo kick (e.g., roundhouse or back kick), which is a standard criterion in martial arts research (9).

To clarify test order and timing, a flow chart of the full testing protocol has been added (Figure 1), showing the sequence of warm-up, isokinetic strength testing (knee, then ankle), followed by a 20-minute rest and Y-balance testing.

Sample size was determined using G*Power 3.1 software (30, 31). with an effect size of 0.4(Cohen’s f), power of 0.80, and alpha of 0.05 for ANOVA repeated measures, indicating that a minimum of 36 participants was required. We recruited 40 to account for potential dropouts.

The SPSS 26.0 program was used to calculate the mean (M) and standard deviation (SD) of all data. The isokinetic muscle function and Y balance of dominant and non-dominant lower limbs of Taekwondo athletes were analyzed by independent sample T-test. Chi-square tests were used to analyze the correlation between dominant and non-dominant lower extremity injuries. All statistical significance levels were set at p < 0.05.

The isokinetic muscle function test results of dominant and non-dominant lower extremity knee joint of adolescent taekwondo athletes are shown in Table 3. At 60°/s, the left dominant lower extremity (LDLE) group shows significantly higher muscle function values in the left extensor compared to the right dominant lower extremity (RDLE) group (p = 0.025). At 180°/s, the differences in muscle function values between the RDLE and LDLE groups are not statistically significant (p = 0.164).

Figure 2 illustrates that the peak torque of the left knee extensor in the RDLE group was 174.5 ± 55.6 Nm, while in the LDLE group it was 183.8 ± 34.5 Nm, with a significant difference (p = 0.025). This result indicates that the left-dominant lower extremity group demonstrated superior isokinetic extensor strength at 60°/s.

The isokinetic muscle function test results of ankle joint of dominant and non-dominant lower limbs of adolescent taekwondo athletes are shown in Table 4. At 60°/s, most p-values were greater than 0.05, indicating no significant difference between the RDLE and LDLE groups in these muscle functions. However, at 180°/s, the p-values for right and left plantar flexion were both p < 0.01, indicating a statistically significant difference between the two groups. Specifically, the LDLE group has higher muscle function values in these aspects compared to the RDLE group.

Figure 3 visually confirms the greater plantar flexion strength of the LDLE group at 180°/s. The isokinetic muscle function of the ankle joint in adolescent taekwondo athletes shows some differences between the dominant and non—dominant lower limbs, especially at higher velocities (180°/s). The LDLE group tends to have higher muscle function in certain aspects, which may have implications for training and injury prevention strategies.

The Y-balance test results are shown in Table 5. All p-values were greater than 0.05, indicating no statistically significant differences between the dominant and non-dominant lower limbs in terms of balance performance. However, the p-values for “Right Rear Outer” (0.096) and “Left Rear Outer” (0.059) suggest a trend toward a difference, with the left dominant lower extremity performing slightly better in the outer rear balance directions.

Overall, there are no significant differences in the Y-balance test results between the right and left dominant lower extremities in these adolescent taekwondo athletes. The data suggest that both limbs demonstrate similar balance capabilities, with some indications of potential slight differences in rear outer balance.

The relationship between injuries in the dominant and non-dominant lower limbs is presented in Table 6. By analyzing the correlation between dominant lower limb injury and non-dominant lower limb injury of adolescent taekwondo athletes, it was found that there was a significant statistical difference between them (p < 0.01).In terms of dominant and non-dominant lower extremity injuries, athletes with the right dominant leg had a 24% chance of sustaining a right leg injury, while athletes with a left dominant leg had a 20% chance of sustaining a left leg injury.

From Table 6, in the RDLE group, the frequency of right leg injuries is higher, while the frequency of Left leg injuries is 0. In the LDLE group, the frequency of left leg injuries is higher, while the frequency of right leg injuries is 0. The p-value < 0.01 indicates a significant correlation between dominant lower—limb injuries and non—dominant lower—limb injuries in the RDLE group. The results show that there is a correlation between dominant lower—limb injuries and non—dominant lower—limb injuries among adolescent taekwondo athletes. Specifically, athletes in the RDLE group are more likely to have right—leg injuries, while athletes in the LDLE group are more likely to have left leg injuries.

Isokinetic muscle function assessment of the knee joint is a reliable and objective method for evaluating muscle performance, including strength, power, and endurance, and is widely used in injury prediction and rehabilitation (32, 33). In sports with strong unilateral movements, such as badminton, golf, and tennis, athletes often exhibit higher rates of muscle imbalance (10). While numerous studies have investigated the isokinetic knee muscle strength of adolescent Taekwondo athletes, focusing on bilateral and ipsilateral proportions (34–38). However, research specifically addressing lower limb asymmetry and the balance between the dominant and non-dominant legs in Taekwondo remains limited.

In this study, no significant difference was observed in isometric muscle strength between the right dominant lower extremity (RDLE) and left dominant lower extremity (LDLE) at angular velocities of 60° and 180°. However, the LDLE group exhibited greater maximum muscle strength and average extensor power compared to the RDLE group. Specifically, the extensor strength in the LDLE group was significantly higher than in the RDLE group, contrasting with findings by Harbili et al. (39), who reported no bilateral asymmetry in knee joint strength among competitive Taekwondo athletes. Conversely, Čular et al. (21) observed significant differences in muscle strength between the left and right sides in both competitive and non-competitive Taekwondo athletes. In addition, studies have shown that differences in lower limb isokinetic muscle strength are also observed in some healthy populations, and these variations have been associated with age and gender factors (40). This inconsistency could reflect differences in athlete age, experience, or training emphasis. For example, adolescent athletes may experience greater asymmetry due to neuromuscular immaturity and incomplete physical development (41). It is important to note that while a speculative interpretation suggests the smaller number of LDLE athletes might result from long-term training against RDLE opponents, this remains hypothetical and should be tested in future studies. The study revealed that the left-right ratio of extensor muscle strength was 10.4% in the RDLE group and 7.9% in the LDLE group, while the bilateral leg differences in flexor muscle strength in the LDLE group was 6.7%. These findings suggest a higher potential for injury in both dominant and non-dominant lower limbs, as muscle strength differences exceeding 10% are associated with increased injury rates (42–44). The significant differences in extensor strength between the two groups and in flexor strength within the LDLE group highlight the need for intervention strategies to improve bilateral muscle balance in adolescent Taekwondo athletes.

Although no difference was found in the ipsilateral muscle strength ratio between the RDLE and LDLE groups, the ratio in both groups was significantly below 60%. The LDLE group exhibited a notable difference between the dominant and non-dominant sides. While well-trained athletes typically show minimal differences in ipsilateral muscle strength ratios (45), these findings align with observations in teenage male soccer players at lower training levels (32, 46). The observed disparities in lower extremity strength ratios may stem from musculoskeletal immaturity and underdeveloped neuromuscular control in adolescent Taekwondo athletes.

Taekwondo athletes are constantly jumping, stepping, attacking, and defending; therefore, the ankle joint is frequently subjected to external forces. Strengthening ankle joint muscles is essential for maintaining stability and reducing injury risk. When the torque ratio of ankle dorsiflexion to plantarflexion is about 30%–40%, the muscle strength balance between agonists and antagonists is considered optimal (47). Therefore, enhancing dorsiflexor strength plays a crucial role in injury prevention.

Under the condition of 60°/s angular velocity, no significant differences in ankle muscle strength were found between dominant and non-dominant limbs. However, at 180°/s angular velocity, the LDLE group had significantly higher dorsiflexion difference on the dominant ankle than the RDLE group. The mechanical implications of such dorsiflexor dominance suggest reduced joint stiffness during landing, potentially increasing ankle sprain susceptibility (48). The difference in the maximum strength ratio of the plantar flexors and dorsiflexors of the dominant and non-dominant ankles may be associated with an increased incidence of injury to the right ankle, as the maximum strength ratio of the left ankle is 30%–40%, while that of the right ankle is less than 20%.

The maximum torque ratio between plantarflexors and dorsiflexors was less than 20% in the right ankle but fell within the optimal 30%–40% range in the left ankle. This imbalance may indicate a greater susceptibility to right ankle injuries. This interpretation is consistent with previous findings in volleyball players, where the non-dominant ankle showed lower strength at 60°/s angular velocity (28). Although these findings suggest potential injury risk, they should be interpreted with caution due to the lack of direct injury data. Further research with biomechanical and longitudinal injury tracking is recommended.

The Y Balance Test (YBT) is a widely utilized tool for assessing proprioception, stability, balance, and symmetrical balance of the body. A reach difference greater than 4 cm between sides is associated with a 2.5-fold increase in lower limb injury risk (49), while composite scores below 89% indicate reduced dynamic stability. While some studies have reported that male athletes tend to achieve higher composite YBT scores compared to female athletes (50), there is limited research on differences in YBT performance among athletes from various sports disciplines. This gap highlights the need for sport-specific analyses to better understand the relationship between balance performance and injury risk.

In this study, no significant differences were observed between RDLE and LDLE groups. However, the composite scores for both were below 85%, and side-to-side differences were below 4 cm. While the reach difference may not independently indicate risk, the consistently low composite scores are concerning. These results may suggest deficits in neuromuscular control and postural stability, particularly since adolescent athletes are still developing proprioceptive function (51, 52). Importantly, although no statistical difference was found between groups, the absolute YBT performance level was poor, indicating a potentially high injury risk. This underscores the need for incorporating targeted dynamic balance and neuromuscular training in Taekwondo development programs (53).

In conclusion, the YBT results from this study indicate a potential increased risk of lower limb injury among the participants, as evidenced by composite scores below 85% and side-to-side reach differences within the critical threshold. These findings underscore the need for targeted balance training and injury prevention strategies, particularly in populations with similar performance profiles. Speculation on causality—for instance, linking low YBT performance directly to training asymmetry—should be framed as hypothesis-generating rather than conclusive. Longitudinal studies would help establish the predictive value of YBT scores more clearly. Future research should explore sport-specific differences in YBT performance to further refine injury risk assessment and prevention protocols.

Injury analysis revealed differing patterns between the RDLE and LDLE groups. The RDLE group had more right-side injuries, while the LDLE group had more left-side injuries, suggesting limb dominance may influence injury site.

These findings are consistent with previous studies. For example, Haddad et al. (54) showed that limb dominance impacts knee and ankle injury distribution. Neuromuscular asymmetry and load distribution may be key contributing factors, particularly in sports requiring unilateral skills.

However, this conclusion remains correlational. The cross-sectional nature of this study limits causal inference, and future prospective studies are needed. Additionally, Zhao et al. (55) emphasized that asymmetrical strength and coordination are injury risk factors, supporting our recommendation to improve bilateral symmetry. Targeted training such as unilateral strength and balance exercises may improve neuromuscular control (56), especially in adolescent athletes with clear limb dominance. This could reduce future injury incidence by enhancing motor control and joint stabilization.

In conclusion, the correlation between limb dominance and injury patterns in adolescent Taekwondo athletes highlights the importance of evaluating bilateral and ipsilateral balance ratios. These findings provide valuable insights for developing tailored training and injury prevention programs aimed at reducing the risk of lower limb injuries in this population.

This study has several limitations that should be considered when interpreting the findings. First, the cross-sectional design prevents causal inference, making it unclear whether the observed muscle imbalances and balance performance are causes or consequences of injury. Longitudinal research is needed to explore the developmental trajectory of these factors and their long-term relationship with Taekwondo training. Additionally, the retrospective injury data based on self-reports and athlete records may be subject to recall bias, affecting the reliability of injury type, frequency, and timing. Future studies employing prospective tracking and standardized diagnostic methods are recommended to enhance data accuracy.

Second, the homogeneity of the sample—limited to South Korean adolescent Taekwondo athletes—reduces the generalizability of the results to other age groups, sports, or cultural contexts. The absence of a control group also limits the ability to discern whether the observed patterns are unique to Taekwondo or reflective of general adolescent development. Including diverse athletic populations and non-athlete controls in future research would help clarify the sport-specific effects of Taekwondo training.