Author(s): CHOU, T., CHOU, P., Institution: KAOHSIUNG MEDICAL UNIVERSITY, Country: TAIWAN, Abstract-ID: 1023

INTRODUCTION:
Lower-limb landing mechanics are critical factors associated with anterior cruciate ligament (ACL) injury risk. While muscle strength and jump tests are standard clinical assessments for return-to-sport, the relationships between strength capacity, jump performance, and landing characteristics remain unclear. This study investigated the associations between knee strength, jump performance, and landing load/asymmetry indices in healthy female basketball players.
METHODS:
Twenty healthy female basketball players (age: 21.95 +/- 2.87 years; height: 1.65 +/- 0.08 m; body mass: 60.8 +/- 9.74 kg; playing experience: 8.65 +/- 3.69 years; Tegner activity scale: 6.5 +/- 0.89) participated. Participants performed isokinetic knee strength tests at 60 deg/s and 180 deg/s on the dominant limb to measure isokinetic peak torque. Isometric tests were performed with knee extension at 70 deg and flexion at 20 deg to calculate the rate of torque development (RTD) at 0-100 ms and 0-200 ms intervals. Force plate-based jump assessments included countermovement jump (CMJ), squat jump (SJ), and drop jump (DJ) from a 0.35-m box. Variables included jump performance, RTD, and landing load/asymmetry indices. Spearman's rank correlation was used for analysis (alpha = 0.05).
RESULTS:
During the DJ task, modified Reactive Strength Index (mRSI) showed a significant positive correlation with relative peak landing force (r = 0.566, p = 0.009), and time to take-off was positively correlated with landing stiffness (r = 0.466, p = 0.038). No significant associations were observed during CMJ and SJ tasks. Notably, although isometric RTD (0-100 ms and 0-200 ms) showed moderate positive correlations with isokinetic knee extensor peak torque (r = 0.46-0.69, p < 0.05), neither isometric RTD nor isokinetic peak torque variables were significantly associated with landing load or asymmetry indices.
CONCLUSION:
The findings suggest that reactive jump ability may better reflect neuromuscular control demands during landing compared with isolated force production capacity. The correlation between mRSI and landing force indicates that athletes with higher reactive strength may adopt distinct landing strategies to manage impact loads. These results suggest that isolated knee strength and RTD measures, while indicative of maximal and explosive force capacity, do not sufficiently represent the dynamic control required for landing. Therefore, for jumping athletes following ACL reconstruction, reactive jump assessments such as the DJ are more suitable evaluation tools for return-to-sport readiness than isolated strength measures alone.