Effects of Lower Extremity and Core Muscles Fatigue Protocols on Landing Mechanics and Performance in Female Athletes

Fatigue decreases muscle strength and functional capacity, disrupting neuromuscular coordination by impairing load control. This negatively impacts the kinetics and kinematics of the ankle, knee, and hip joints, resulting in reduced performance and an increased risk of injury, particularly to the anterior cruciate ligament (ACL). This study aimed to compare the effects of fatigue protocols for lower extremity and core muscles on landing mechanics and performance of female athletes. This study used a cross-sectional, comparative, pretest-posttest design with a control group. A total of 105 female athletes, aged 11 to 49, were selected via convenience and purposive sampling. Participants were divided into three groups: core muscle fatigue, lower extremity muscle fatigue, and a control group. Data were gathered using the Landing Error Scoring System (LESS), Y-Balance, and 45-degree trunk flexion tests. Data were analyzed using descriptive statistics, Shapiro-Wilk test, Levene's test, one-way ANCOVA, and the Bonferroni post hoc test. A P of 0.05 or lower was considered statistically significant. ANCOVA results showed significant differences among the groups for the LESS (P=0.001) and 45 ° trunk flexion test (P=0.001). There was no significant difference between the two experimental groups regarding the LESS (P=1.00). However, a significant difference was observed between the two experimental groups in the trunk flexion test (P=0.001). Fatigue had a greater effect size on landing mechanics (ηp²=0.209) than on the trunk flexion test (ηp²=0.143). However, no significant difference was observed between the groups regarding the Y-Balance Test (P=0.996). The study revealed that fatigue protocols targeting lower extremity and core muscles had a negative impact on kinematic parameters associated with ACL injuries during jump-landing in female athletes. Additionally, core muscle fatigue significantly impacted the 45º trunk flexion test, while lower extremity muscle fatigue had no significant effect on it.