There are two popular schools of thought when it comes to the order your should perform resistance exercises. The first technique is called pre-exhaustion, which involves exercising the same muscle or muscle group to the point of muscular failure using a single-joint exercise immediately before a multi-joint exercise (e.g., peck-deck followed by chest press).
Alternatively, the priority system prescribes that complex exercises should be performed first in a training session (i.e., chest press before peck-deck).
In order to assess whether either technique is better, a study was performed on men in their mid-twenties with recreational weight-training experience. Researchers compared upper-body muscle activation, total repetitions, and total work during each technique.
The men performed one set of pre-exhaustion and one set of priority system in a balanced crossover design. The exercises were performed with a weight equal to their 10-rep-max. Therefore, chest press and peck-deck were performed with the same load during both techniques.
Electromyography (EMG) was recorded from the triceps, delts, and pecs during both exercises.
According to the results, there was no significant difference in total work and total repetitions between the two techniques. Likewise, during the peck-deck exercise, no significant EMG change was observed between the two orders. However, tricep activity was significantly higher when chest press was performed after the peck-deck exercise (pre-exhaustion).
The results indicate that performing pre-exhaustion exercise is no more effective in increasing the activation of the prefatigued muscles during the multi-joint exercise. Therefore, there’s no need to do your workouts in any specific order.