8.0 Reaching Forward with Outstretched Arm Standing
The reaching component of the Berg is also found in its own test, the Functional Reach. It provides information about the balance. This component tests the strength of the extensors and eccentric motion of the hips in order to control the forward bending of the body at the hip joint. As the hip joint flexes and the center of gravity moves towards the anterior portion of the base support there is also a shift backwards by the core in order to maintain the base support center of gravity. If the body segments can complete these critical tasks, then the relationship of the COG and BOS is supported and the performer stays upright. As the arms reach out further, flexion at the hip occurs.Each score in the component provides valuable information regarding the state of the body segments and data to organize a successful change effort.
When the performer “loses balance while trying/requires external support” the body segments are not adequate to produce the critical task of the maintaining the COG over the BOS. This is similar to the earlier components that examined the capacity of the neuromuscular system to produce static stability. Without adequate control of static balance to begin a forward motion the performer will lose balance or attempt only with upper extremity support. Going further in the test would be likely counterproductive and possibly dangerous. Returning the upright posture of the lower extremities into extension and the pelvis into neutral maybe enough to regain the static control desired. Clearly there is work to be done at the supportive critical tasks and a regression to the basics is the best move forward.
When the performer “reaches forward but needs supervision” the body has developed through adequate posture and strength to maintain the static balance and to begin tentatively to extend the upper extremity away from the COG. As the arm extends this shifts the COM anteriorly. The body reacts by producing an extension moment on the lumbar spine as a counter force. Typically this looks like lumbar spine flexion as the performer reaches out to attempting to maintain the COG over the BOS without moving. This tug of war provides stability however ultimately limits the capacity of the body segments to support dynamic control of the COG within the BOS.
When the performer “can reach forward 5 cm (2 inches)” the observer would recognize the shift of the COG to edge of BOS by transferring body weight on to the metatarsal heads. As the reach proceeds the BOS begins to change from the full foot to the rise of the heels on to the metatarsal heads. Predictably the performer will be straining as strong gastrocsoleus is required as a counter force. The problem solving approach would be to seek to enhance the lower extremity strength to counter the forward motion, or to improve the posterior chain to again pull the body back. Instead the loss of balance indicates that the COG has left the BOS, most likely moving anterior of the BOS.
However no matter how strong the lower extremities are, completing the “can reach forward 12 cm (5 inches)” and “can reach forward confidently 25 cm (10 inches)” will not be attainable. What is required is a critical task to maintain the COG over BOS. The key is the standing hip hinge. Ironically in order to reach more forward, must be better at maintaining the COG above the BOS through the use of posterior weight shift. The hip hinge has been present before, however in the seated position and as a critical task of the sit to stand to sit components. In the standing symmetrical position utilized for this test, different body segments are contributing to the movement in different ways. Knee extension is required to perform this test and as such requires adequate biceps femoris length to attain the knee extension position. This is not enough to complete the test however, as the biceps femoris must also be flexible and strong enough to assist in controlling the anterior pelvic tilt that is part of the hip hinge movement.
Without adequate length and/or strength the biceps femoris through its origin on the ischial tuberosities will limit the anterior pelvic rotation and initiate a posterior pelvic tilt. As this occurs the lumbar spine will be forced from the extended position into relative flexion, resulting in loss of control of the posterior weight shift maintaining the COG within the BOS. The posterior weight shift to assist the forward reach will be impossible to complete, resulting in a loss of balance.
Within the context of hierarchies of critical tasks it is best to step down to the level of the squat progressions to practice the hip hinge. Using the standing hip hinge to initiate stand to sit, variations on theme can be used to enhance biceps femoris length and eccentric control. Control of the COG with this new available mobility can be practiced with the anterior weight shift in the seated position. From there the BOS is changed to symmetrical stance and the hip hinge with the posterior weight shift introduced.