I guess it really comes down to this: the difference between a biomechanical system versus an implement-forward thought system.
And the difference is quite simple: our system relies on the demand for specific muscle, movement, and adaption outcomes. An implement-forward system relies on the presence of certain tools (like a dumbbell, for instance) and then builds workouts around the tools at hand.
The problem with an implement-forward system is that it resembles a square peg and round hole, for a few reasons.
Fewer Options
The first is that implement-forward systems leave no options when things don’t go as planned. Sometimes, exercises are going to feel weird, won’t be a great fit, or just aren’t vibing. If your training is implement-forward, you’re left with two options: hit it or quit it.
Overloading
This leads right into the next point, which is that implement-forward systems, since they don’t leave much room for accommodation, present the possibility of overloading certain tissues while neglecting others. For example, a barbell-only program has us performing, roughly, just a few variations for each exercise group. It might be helpful to include some dumbbells, kettlebells, or bodyweight exercises to attack the tissues in a slightly different way.
Left on the Table
And for the third point, neglecting certain loading schemes means we’re leaving improvements on the table via both actual stimulus and technical improvements by means of varied practice. Being able to stimulate our body in a variety of ways will build a more versatile, robust, resilient body.
What We Do Instead
In a biomechanical system, we approach things a little differently. Instead of building workouts and programs around the equipment we have, we use the principles of biomechanics and exercise physiology to determine first what we need to accomplish before deciding how we’ll accomplish it (e.g. with a dumbbell, barbell, bodyweight, band, bike, rower, sled, treadmill, etc).
This means, for instance, a bilateral squat-priority exercise (a great builder for the quads, hamstrings, glutes, adductors, and torso) could be a goblet squat. But it could also be a safety bar squat, back squat, split squat, sled push, hack squat, reverse lunge, bulgarian, or hip thrust. It just truly depends on an individual.
We can also approach things through the lens of muscle groups, like the quadriceps, which leaves us with a host of different exercises to incorporate. Or maybe we just need a max-effort lower body movement, which could be a squat, deadlift, plyometric, or bike sprint.
It just really depends.
And we always want as much flexibility as we can round up in order to personalize workouts on the smallest levels.