This is a great article from the National Counsel on Strength and Fitness on correcting injuries acquired from continued machine, or symmetrical training.
Using Asymmetrical Exercise to Correct Bilateral Training Problems
By: NCSF on: Feb 24 2011
Many of the common ailments and skeletal inefficiencies that affect athletes and fitness enthusiasts are actually created by the activities they engage in on a routine basis. Strength and fitness training facilities alike provide numerous machines and equipment to stress the body for what seems to be better performance. Cardiovascular machines help to improve heart and vascular efficiency, selectorized machines help develop bigger muscles and bilateral symmetrical exercises like the squat can produce impressive improvements in strength. So if all these benefits are yielded from a fitness facility or traditional exercise approach than how may they also contribute to musculoskeletal problems?
The human body functions in a three hundred and sixty degree world and as such requires a balance of integrated muscles working together to accelerate, decelerate and stabilize the skeleton at various angles and ranges. Machines and symmetrical training create an unnatural environmental stress. This causes adaptations to a stress that is not consistent with the body’s design. In many cases, as the adaptations become more pronounced they create faulty movement patterns. Certainly the bench, spin bike and back squat exercise have a place in effective training but without the proper adjuncts these same exercises can actually lead to problems. Heavy bench press, when chronically applied without preventative therapies leads to posterior glenohumeral capsule tightness and contributes to forward humeral head migration and internal rotation. Spinning and stairclimber habitualness lead to tight hip flexors, squatting without proper trunk engagement leads to back/front imbalances in the trunk. For these and other exercises it makes sense to identify the common overuse adaptations and create programmatic balance to ensure the common daily fitness effort does not lead down the wrong path.
One of the easiest ways to prevent the problems of bilateral over training is to add unilateral activities to offset negative adaptations. Likewise the best way to correct the problems with symmetrical work is to use asymmetrical exercises as well. Although unilateral can be argued to be asymmetrical there are underlying differences. A dumbbell Romanian deadlift from single leg stance is unilateral training for the hamstring; if only one dumbbell was used it becomes asymmetrical as the load across the midline is unbalanced. Unilateral training is most useful for improving range of motion and stability in the muscles around a joint, whereas asymmetrical training is designed to enhance stabilizers across the kinetic chain. A Bulgarian of single leg squat (back leg on a bench) holding two dumbbells is unilateral and places greater range in the hip flexors and extensors than a traditional squat with less trunk stability. It also increases the stability requirements for the ankle and knee as the base of support is small. A suitcase deadlift (one sided load) or a squat with a sand bag on one shoulder is asymmetrical and dramatically increases the spinal stabilizers to keep the trunk in alignment. Since many people perform the squat with inefficient form, as they lose their pelvic floor and TVA engagement only to have the erector spinae or rectus abdominis take over and change the sacrum angle, the asymmetrical squat may be used to help address the muscles being missed. Likewise if flexibility and localized instability are a problem than it makes sense to switch the bilateral RDL to a unilateral lift.
There are many ways to make exercise adjustments but they have to make sense and function purposefully. Too much variation and the exercise becomes a circus as is seen in some “functional” training videos. Fundamental movements with premeditated progressions will provide the positive outcomes without the risk of injury or use of sloppy movement patterns.
Try to include full body exercises in your routine that do not involve machines, to use the natural full range of movement your body possesses. Also remember to include at least 30 minutes of flexibility training to ease tendon stress and relax contracted muscles.