Electromyography (EMG) has long been the clinical and research standard for skeletal muscle activity. Through manipulations of waveforms produced by electrical signals given off by muscle movement, researchers can gain insight into the mechanical properties of the muscular system. In exercise physiology, surface EMG is often used to study effort and usage dynamics of human muscles in an exercise setting. In a recent study by Jenkins et al, researchers observed the activity of the biceps and forearm during dumbbell curls between two groups. One group performed repetitions of curls with lighter weight (relative to their own 1- repetition maximum), and the other used heavier weight, both to the point of failure. The main difference here is that an exercise with a lighter weight can generally be repeated many more times than a heavier weight per set. There are differing views in the fitness community as to whether lifting heavier weights for fewer reps or lighter weights for many reps is more effective for optimal muscle activation. The researchers used a BIOPAC differential EMG amplifier and an MP150 system, combined with AcqKnowledge software to record data. The study shows, as a result of the surface EMG recordings, that there are significant differences in muscle activity in response to these differing methods of training. The total exercise volume, as a product of the weight lifted and reps performed, was similar between groups. However, a noticeable rise in EMG amplitude was recorded in those who performed more reps with light weights, suggesting greater muscle fatigue and activation in these individuals. These results conflict with previous studies performed with leg extensor resistance training, in which more muscle activation was observed in the heavier weight group. Thus the paper concludes that differences in muscle structure and blood flow may alter the effectiveness of different training methods across different muscle groups.