Becker muscular dystrophy (BMD) presents with limb-girdle distribution of muscle weakness similar to limb girdle muscular dystrophies (LGMDs). To facilitate the differential diagnosis and direct genetic testing clinical markers indicating towards BMD could be helpful in the diagnostic process. We investigated if a combination of muscle testing and MRI could provide a diagnostic marker. Quantitative muscle testing of hip-flexors and extensors, knee-flexors and extensors was performed. To minimize confounding effects of age and weight, mean z-scores for muscle strength of the individual groups was calculated. On 3T MRI the gluteus maximus, iliopsoas, vastus lateralis, medialis and intermedius, rectus femoris, biceps femoris long and short head, semimembranosus, semitendinosus and sartorius were scored for fatty infiltration: 1=normal, 2=fatty streaks, 3=<30%, 4=30–60% and 5=>60%. Eleven patients (mean age 39years, range 20–63) with variable symptoms ranging from no motor symptoms (n=3) to wheelchair dependence (n=1) were tested. Ten patients had negative z-scores and all had fatty infiltration on MRI. Overall knee extension showed the lowest z-score followed by knee flexion, hip extension, while hip flexion was relatively spared. In terms of fatty infiltration the biceps femoris long head was most severely affected and the iliopsoas least. Evaluation of the mean fatty infiltration score of the tested groups showed the highest mean fat score for hip extension muscles followed by knee flexion, knee extension, while hip flexion again appeared relatively spared. We show that in BMD patients hip flexion is spared compared to the other investigated muscles, which is mirrored by the MRI. This could be a valuable clue in the clinical setting as in LGMDs like type 2L and 2A, relatively common in the Netherlands, hip flexion is usually clearly affected. Thus, spared hip flexion on muscle testing or MRI in males with LGMD patters of weakness points to a diagnosis of BMD.