Collapse of medial longitudinal arch is known as flat foot. If the arch collapses in weight bearing position it is called and flexible flat feet. In weight bearing activities, excessive foot pronation can occur. Iliopsoas is positioned anteriorly to the hip which is a flexor of hip which pulls femur towards pelvis or pelvis towards femur. when latter movement, iliopsoas can cause anterior tilt resulting in increased lordosis. in weight bearing position in flexible flat feet, subtalar hyper pronation occurs which leads to internal rotation of tibia and femur which contributes to anterior pelvic tilt which is associated with tightness of iliopsoas muscle. Bilateral flat feet also results in more proximal lower limb dysfunctions which affects core stability.

Therefore, weakness or imbalance in these muscles may contribute to collapse of medial longitudinal arch of foot and development of flexible flat feet. It is crucial to understand the relationship between core endurance, iliopsoas flexibility and navicular drop test in individuals with bilateral flat feet to develop effective preventive and therapeutic interventions. 

The aim is the study evaluation and relationship of core endurance, iliopsoas flexibility, and the navicular drop test in young adults with bilateral flat feet. The objectives of the study are to: 1) To assess navicular drop in young adults with bilateral flexible flat feet using navicular drop test. 2) To assess iliopsoas flexibility in young adults with bilateral flexible flat feet using Thomas test. 3) To assess core endurance in young adults with bilateral flexible flat feet using Mc gill core endurance test. 4) To compare iliopsoas flexibility and core endurance in young adults with bilateral flexible flat feet using Mc gill core endurance test. 5) Determine the relationship between core endurance, iliopsoas flexibility, and the navicular drop test in young adults with bilateral flexible flat feet. Outcome measures used will be Navicular drop test for assessing flexible flat feet, Iliopsoas tightness using Thomas test and muscle length using bubble inclinometer, Core endurance will be measured using Mc gill core endurance test. All the data obtained from the participants will be kept confidential. The data will be stored in excel sheets for analysis. Graph pad or SPSS software will be used for analysis. If data passes normality, parametric (spearman correlation) test will be used. If data does not pass normality, non-parametric (Pearson correlation coefficient) test will be used.