Step inside any gym on a Saturday mid morning and you will see a bunch of people doing what they are good at and what they know how to do. You will see people bench pressing, squatting, doing body parts with seated machines, people on ellipticals and treadmills. There is nothing wrong with these exercise selections but done over and over for a set amount of time and workouts is not the best for human movement.
Traditional bilateral movements (squats, deadlift, barbell benches, leg press etc) repeated under load can add great strength and muscle mass but if there is not appropriate programming in an exercise routine this can lead to tissue overuse, poor tissue adaptation, pain, and injury. This is due to the fact that we are putting asymmetrical structures and systems and driving it to be symmetrical over and over. As we are driving the system to remain symmetrical we most likely are putting the system into extension patterns that leads to compression on the system. This repeated stress causes lower back pain and poor movement strategies. Taking the squat as our example, loading either the front or the back the bodies strategy is to lift the ribs up and keep the chest up and the torso vertical this also pulls the lumbar (lower) spine forward leading to the posterior compression of the lower back and putting stress on the discs, this is where people get slipped discs. Now take that and load it 2-3 times a week with constant resistance and tension and you are bound for some trouble.
We need to always respect that the human body is designed and constructed asymmetrically, so trying to always jam a square peg in a round hole will have its issues, learning to offset the asymmetries will go a long way for you. (See Asymmetrical post) That is step one, the next thing we need to do is to learn to get away from the machines and bilateral movements in the gym and our workouts, and get onto a single leg and perform unilateral movements. This helps take the tension out of the chains of muscles we are constantly putting demand on.
The ability to shift into each hip is critical for movement, sports and daily life, and that helps us orient over one leg, stay balanced and controlled and then perform a task, most often seen is a lack of stability of the hip and shifting, people are not accustomed to their body performing such movement, the right side will be good, but the left side will feel foreign to them or shifting into both hips could not be great. The ability to turn and rotate at the lumbosacral area is very important in inhibiting muscle chains that are overactive due to our asymmetries and patterns.
Many people struggle to find variations in their workouts, and will constantly go to movements that they are good at and can perform well, this is just nature but more often than not we need to create variability in our workouts, variability in our movement patterns so it is always a good time to add some unilateral work in. For the lower body it is pretty simple: take the movements that you perform bilaterally, squat, deadlift, leg press, seated leg exercises, take them and perform the lift on a single leg, single leg deadlift, split squats, lunges etc. There are numerous exercises that are single leg focus.
The work on a single leg will help you perform better, create flow through the human body, take tension off certain muscle chains, give you more training adaptations, more muscle, more mobility, more degrees of movement. Try a microcycle of unilateral upper and lower body work, increase the load on each side and you will see your bilateral lifts improve.
An example of this would look like,
Sets Reps
A1. Step Ups 4 5 each leg
A2. Alternating DB Bench Press 4 6 each arm
B1. Lateral Lunges 3 6 each
B2. SIngle Arm Lat Pulldown 3 10 each
C1. Single Leg Deadlift 3 8 each
C2. Alternating Cable Row 3 8 each