When progressing an exercise, there are several avenues we can take. If we are progressing strength exercises, we can manipulate the resistance, velocity, sets, repetitions, rest time, or total volume. When developing energy systems, we may choose to manipulate the work-to-rest ratio, resistance, or the implement (Assault Bike, Concept2 Rower, VersaClimber, etc.). The options we have for progressing or regressing an exercise are virtually endless, however, we sometimes forget that manipulating the posture used while performing the exercise is also an option.
Resisted chops are a great way to teach our athletes core stability and kinetic linking. When we manipulate the athlete’s posture, we alter their base of support and change the height of their center of mass to further challenge their stability. The athlete’s base of support can be thought of as the points of contact between the athlete and the supporting surface. The wider the base of support, the easier it is for the athlete to balance. Center of mass, on the other hand, is defined as the mean position of matter in the body (2). In humans, the center of mass lies just anterior to the sacrum while we are in anatomical position; this point changes as we transition to different postures, such as lying down, sitting, or kneeling (4). Due to the effects of gravity, our stability is challenged as we progress from a lower center of mass to a higher one.
While performing a tall kneeling sweeping chop, we have a wide base of support that includes four points of contact between ourselves and the ground: both knees and both feet. This position also requires a low center of mass. If we were to connect our four points of contact with our center of mass it would form the shape of a pyramid, a very stable structure.
We can then progress to a half kneeling position to increase the stability demands of the exercise. In this position, the center of mass remains low, however, the base of support is altered. Our four points of contact are reduced to three and our base becomes more narrow.
As we progress to a high split position, we raise the center of mass, further increasing the stability demands of the exercise. We also decrease our points of contact with the ground once again, this time from three points of contact to two.
Finally, we raise our center of mass even further while reducing our base of support once more, this time from two points of contact to one. If we were to connect these two points, it would resemble the shape of the Washington Monument. Obviously, this is a much less stable structure than a pyramid.
Active Shoulder External Rotation
Teaching an overhead athlete how to control their extreme ranges of motion can play an important role in improving performance and mitigating the risk of injury. Possessing active control of shoulder external rotation is of particular importance, as the overhead throwing motion requires upwards of 165 degrees of external rotation (3). One of my favorite ways to teach overhead athletes to do this is by simply having them actively externally rotate their shoulder to end range while focusing on keeping the head of the humerus centered in the glenohumeral joint. Once again, we can use posture as a progression.
We can start by performing this exercise in a supine position, where gravity is assisting with the motion at the shoulder and the stability demands of the rest of the body are essentially nonexistent.
Supine is then progressed to a prone position, where gravity is resisting the motion of external rotation at the shoulder, although, once again, the stability demands of the rest of the body are essentially nonexistent. This makes the exercise more challenging for the athlete at the shoulder but does not require them to have to focus on the rest of the kinetic chain.
Next, we could progress to a half kneeling position. In this position, the effects of gravity have a net zero effect at the shoulder while the stability demands of the rest of the body are increased. This position forces the athlete to stabilize the pelvis and control for compensations, such as lumbar hyperextension, while performing the movement of external rotation at the shoulder. This is very similar to the demands required of overhead athletes in their respective sports.
Finally, we could progress to a split stance position. In this position, the effects of gravity at the shoulder remain the same, however, the stability demands of the rest of the body are once again increased, as we decrease our points of contact with the ground and raise our center of mass.
There are lots of options when it comes to progressing an exercise. Lots of discussion has been made regarding the manipulation of sets, repetitions, and rest time for achieving a specific adaption. Another option includes taking into consideration the effects that gravity have on the body. By progressing through different postures, we can alter the base of support and center of mass, increasing the stability demands of an exercise in order to create a greater challenge for our athletes.
Base of support. Physiopedia. (n.d.). Retrieved December 12, 2021, from https://www.physio-pedia.com/Base_of_Support.
Centre of Gravity. Physiopedia. (n.d.). Retrieved December 12, 2021, from https://www.physio-pedia.com/Centre_of_Gravity.
Fleisig GS, Andrews JR, Dillman CJ, Escamilla RF. Kinetics of baseball pitching with implications about injury mechanisms. Am J Sports Med. 1995;23(2):233-9.
Le Huec JC, Saddiki R, Franke J, Rigal J, Aunoble S. Equilibrium of the human body and the gravity line: the basics. Eur Spine J. 2011 Sep;20 Suppl 5(Suppl 5):558-63.