It could be argued that one first ask the purpose of an exercise. If we wish to teach individuals exercise, which enhances their ability to perform activities of daily living, for example, it would seem reasonable to implement those exercises, which acknowledges the aforementioned outcome goal. Pushing objects, dynamically or statically, could be seen as a motion that is required in an individuals’ life. Raising the arms out to the side, and back down again, could be seen as something done less often (i.e., less functional).
We could also look at an exercise as a means of enhancing intrinsic factors (i.e., biomechanical, neuromuscular, physiological) of a joint and movement pattern (Page, Lardner, & Frank, 2010). For example, we may wish to enhance stability of a shoulder that has been injured or dysfunctional. Perhaps the scapular stabilizers are firing in a non-synchronized fashion, and over-facilitated and under-facilitated stabilizers exist about the scapula. If we continue with this example, it can be shown that some exercises provide more neurological nourishment than others, building a case for the choice and value of exercise.
The sensorimotor system plays an important role in producing shoulder muscle coordination; it has been demonstrated that shoulder instability/dysfunction is due to a loss in both mechanical and sensorimotor element (Khosro & Simin, 2013). If we consider the push-up (under the assumption it is coached correctly, and implemented appropriately along a shoulder stability/strengthening progression), Khosro and Simin (2013) reported that the push-up can offer the right inputs to the stabilizers of the scapula; Khosro and Simin (2013) also noted that there is a considerable amount of research indicating that closed kinetic chain (CKC) exercises (i.e., push-up) are safer and more efficient than open kinetic chain (OKC) exercises (i.e., lateral raises), especially in the early stage of rehabilitation. The researchers continued by stating that during CKC exercises, compressive force, which is the result of terminal limb section stabilization, decreases the amount of shear force in active joints. During OKC exercises, the shear stress present during movement exposes the joints and muscles to risk (Khosro & Simin, 2013).
In conclusion, evidence suggests that some exercises are more functional and safer than others. Thus, it is imperative to always ask why one performs an exercise, and what it is intended to produce. Such questions allow the opportunity to provide exercise prescriptions predicated on a clearly defined purpose.
References
Khosro, K.K., & Simin, B.A. (2013). The effect of base of support stability on shoulder muscle activity during closed kinematic chain exercises. Journal of Bodywork and Movement Therapies, 18(2), 233-238.
Page, P., Lardner, R., & Frank, C. (2010). Assessment and treatment of muscle imbalances: The Janda approach.Champaign, IL: Human Kinetics.
-Michael McIsaac