Background: The role of levator ani muscle (LAM) dysfunction in female stress urinary incontinence (SUI) is not known. Purpose: To determine whether LAM function is associated with SUI severity, and whether changes in LAM function induced through pelvic floor muscle training (PFMT) are associated with improvements in SUI in females. Methods: Females with SUI were recruited from urogynaecology and physiotherapy clinics. LAM function was evaluated using ultrasound imaging (USI) and manual palpation (PERFECT-Scheme) before and after participants underwent a 12-week PFMT program. SUI severity was assessed using the ICIQ-FLUTS-UI and a 30-minute pad test(30MPT). Results: At baseline (n=97), lower 30MPT was weakly associated with higher bladder neck position(ρs=-0.209,p=0.044) yet with lower PERFECT-Scheme outcomes(overall ρs=0.206, repeated maximum voluntary contractions (MVCs):ρs=0.203, power/motor control ρs=0.214,p<0.05) except perineal lift during coughing was associated with lower ICIQ-FLUTS-UI. All measures of SUI and LAM function were significantly improved after the PFMT intervention (p<0.05). Greater improvements in ICIQ-FLUTS-UI were associated with greater reductions in levator plate length during MVC (ρs=0.238,p=0.041) yet with less improvement in the ability to repeat MVCs(ρs=0.303,p=0.009). Greater improvements in the 30MPT were associated with more bladder neck elevation(ρs=-0.261,p=0.027) and greater reductions in levator plate length(ρs=0.292,p=0.016) during MVC. Conclusion: Improvements in bladder neck support and elevation during MVC show weak associations with improvement in SUI signs and symptoms. Implications: While associations are weak, improved bladder neck support and elevation during MVC may play a role in improving continence function among females with SUI. The PERFECT-Scheme provides limited information on LAM function relevant to SUI or PFMT outcomes.