The purpose of this study was to investigate variations in T2 relaxation time in normal human lumbar muscles caused by inertia barbell training. Thirty undergraduate healthy males (mean age=19 ± 1.2 years, weight=72 ± 10.0 kilograms, height=1.78 ± 0.1 meters) were recruited to participate in this study. Subjects were randomly assigned into 2 groups: an inertia barbell training group (IBTG) (n=15) and a normal barbell-training group (NBTG) (n=15). All subjects participated in lumbar flexion and extension muscle strength training for 1 hour per time, 3 times per week for a total of 8 weeks. The lumbar of each participant was scanned before and after the experiment using a 3.0T superconductive magnetic resonance imaging system. The T2 values measured after intervention were significantly different compared to the T2 values measured before the experiment in both the IBTG and NBTG groups (p<0.001). After intervention, there was no significant difference in T2 values between the IBTG and NBTG groups (p = 0.17). The (△ T2) / T2 percentage was significantly different in the IBTG group (p<0.01). This study demonstrated that 8 weeks of strength training led to significant improvements in the values for T2 relaxation time of the lumbar muscles. Furthermore, the (△ T2) / T2 percentage for IBTG was higher than that for NBTG, which suggested that lumbar muscle activity increased more with inertial barbell training.