The aim of this study was to provide comparative data on a slow versus a traditional supervised resistance training in an obese female population. Forty obese female patients admitted to our rehabilitation hospital were assigned randomly to a slow training group (ST group; mean age: 47.44 years, mean BMI: 38.53 kg/m2) and a traditional training group (TT group; mean age: 54.34 years, mean BMI: 39.37 kg/m2). The ST protocol included five repetitions for five consecutive bouts on the leg press and extension machine. The duration of each repetition (concentric+eccentric phases) was 6 s for leg press and 5 s for leg extension. The initial load was 50% of the one repetition maximum and then gradually reduced by 20% for each bout. The TT protocol included six consecutive repetitions for five bouts on the leg press and leg extension with 80% of the one repetition maximum load. Both groups performed 10 sessions. All of the patients were assessed by a visual analogue scale for pain, a Borg scale for subjective fatigue, and an isokinetic strength test. Statistically significant strength improvements were observed in both groups. In ST group statistically significant improvements in visual analogue scale scores for knee pain were found at post, larger than that observed in TT group. Subjectively perceived fatigue on the Borg scale decreased more at post in ST group in comparison with TT group. Our preliminary data suggest that ST may represent a preferential strengthening method in obese patients as it can lead to significant strength gains with a relatively lower loading effect on the knee, and hence reduced perception of pain.