Exercise selection is one of the most important variables in a weekly strength training program. In general, individuals should look for multi joint (ex. lat pulldown) exercises instead of single joint exercises (barbell curl). At our Boulder Physical Therapy practice we recommend participants select one exercise from each of the following categories: vertical push, vertical pull, horizontal push, horizontal pull, squat, and hinge. Importantly, participants should be able to perform these exercises both safely and effectively allowing them to make adjustments to the intensity (weight lifted) as they become stronger.
Although a case can be made for exercise variation/change, in high level athletes (periodization) and participants returning from injury, the majority of individuals can continue with a given exercise as long as the prescription changes (more challenging) as they become stronger and more fit. Some in the field recommend changing exercises and repetitions/sets to avoid adaptation of the body (plateau) to the given stresses of exercise. A new research study examines the impact of consistent vs. changing exercise prescriptions on strength and muscle size.
Authors randomized men with at least 2 years of resistance training (3/week) experience to one of two training groups (Baz-Valle et al. PLoS ONE. 2019). Each individual performed strength training (3 sets of 6 exercises) 3 days per week for 8 weeks. The first group performed the same 6 exercises at each exercise session while the experimental group had their 6 exercises randomly selected by an exercise app at each session. Exercises were mainly multi joint in nature involving the upper and lower body (ex. bench press, squat). Authors found groups demonstrated upper and lower body strength and muscle size increases over the 8 weeks, but no differences were found between the consistent and varying programs. Interestingly, the participants whose program changed reported higher levels of intrinsic motivation compared to the controlled group.
In short, among trained individuals changing known exercises does not deter from the effects of strength training and may enhance motivation to perform exercises. We often recommend moving laterally with exercises (bench press to dumbell bench press or push up) to maintain the general intent of the exercise, but with a slight twist to keep it fun and interesting.