the aim of the study is to investigate the impact of gender difference on knee proprioception among non specific low back pain young adults.

Low back pain (LBP) is one of the most common musculoskeletal disorders and the leading causes of disability and work absence globally. LBP notonly causes individual suffering, but also a heavy burden to the society. Despite this, up to 85% patients with LBP cannot be clearly diagnosed and are classified as non-specific LBP (NSLBP). Proprioception plays an important role in the planning of precise and coordinated movements, in maintaining balance and controlling body posture. It also exerts its influence on motor learning and re-education. Proprioception deficit has been identified in people with LBP and it has been suggested that these deficits might be associated with causes and mechanisms of LBP. Although the local investigation of proprioception is important, the proprioceptive deficits due to LBP may not be restricted only to the lumbar region. Anatomical and biomechanical associations between the knee and lower back segments imply that the knee might be adversely affected in patients with LBP.

there is a gap in the literature concerning sex differences in the knee joint proprioception. Although biomechanical and hormonal differences between males and females are suspected to be responsible for increasing this incidence.

Inclusion Criteria:

1. Forty-one Patients from each gender participated in the study.
2. Subject's age ranged from 18-26 years old, with Body Mass Index (BMI) less than 30Kg/m2
3. The dominant knees of the subjects (defined as the leg used for kicking) are tested.
4. Pain between three and eight using numerical pain rating scale NPRS, and Oswestry Disability Index score less than 20.
5. All the subjects sign an informed consent form. 6. able to comprehend and follow the examiner's instructions.

Exclusion Criteria:

1. limitation of active and passive knee joint motion.
2. clinical signs of an impairment or abnormality in the knee (such as abnormal range of motion, muscle weakness, or malalignment).
3. injury to the knee that required medical attention.
4. current pain in the knee or previous surgery on the knee.
5. not able to understand and follow the commands of the examiner.

Eighty-two Young Adults (include males and females), ranging in age from 18 to 26, will be included in the study. Individuals will be assigned into 2 groups. Group (A) 41 males with non specific low back pain (B) 41 females with non specific low back pain.