Flexibility and Rehab Tips
This is part 2 of a 2-part column. The purpose of part 2 is to provide recommendations for the prescription of eccentric exercises designed to target the shoulder external rotator musculature that are applicable to both the asymptomatic and injured population. The clinical efficacy and biophysiological adaptations discussed in part 1 of this series provides the evidence-based framework for which our recommendations are grounded. Individuals seeking care for their shoulder are often prescribed activity-based interventions ranging from stretching to muscle performance exercises. Rehabilitation professionals often focus on the concentric action of a muscle contraction and reserve exercises that isolate eccentric muscle actions for the athletic population despite compelling evidence in favor of eccentric training.
Numerous methods have been reported for strengthening the external rotators, however, standing and sidelying external rotation exist among the more common exercises prescribed. Training the external rotators requires sufficient proximal scapulae control to gain a favorable outcome when addressing shoulder dysfunction (4). Therefore, individuals performing such exercises should attempt to maintain appropriate scapular position by retracting the scapula toward the spine and inferior as one would do when squeezing the shoulder blades together (Figure 1). Three exercises are described below that may be performed to target eccentric actions of the external rotator musculature (infraspinatus and teres minor) of the shoulder. Moreover, evidence suggests that these exercises will target the supraspinatus musculature as well, thus, it is not necessary to perform additional eccentric exercises in cases where supraspinatus pathology exists (2). These exercises are not recommended to replace one's current exercise prescription but rather to be performed in addition to an existing routine.
SIDELYING EXTERNAL ROTATION
Sidelying external rotation with a dumbbell (Figure 2A and 2B and Supplemental Digital Content 1, http://links.lww.com/SCJ/A110): The participant assumes the sidelying position with the shoulder to be trained up toward the ceiling with the forearm resting on the abdomen while holding a dumbbell. A towel roll is interpositioned between the humerus and lateral trunk to maintain slight abduction and minimize compensatory humerus movement. Additional benefits derived from using a towel roll during external rotator exercises have been discussed in the literature (5). The concentric phase of external rotation is achieved by using the contralateral arm to elevate the weight in the training arm to end-range external rotation (Figure 2A). Once in external rotation, the weight is then slowly lowered (eccentric action) toward the table to the point of the forearm resting on the abdomen (Figure 2B).
STANDING EXTERNAL ROTATION—ARM ADDUCTED TO SIDE
Eccentric exercises for the external rotators may be performed while standing in a manner similar to sidelying. There is no evidence to suggest a difference between the standing and sidelying positions, thus, environment (access to a bench) and equipment (resistance band/cables versus dumbbell) may play the greatest role in position selection. The standing exercise requires the participant to stand with either a resistance band fixed to a surface approximately waist height or cable pulleys adjusted to a comparable level. The exercise is performed with a towel roll interpositioned between the elbow and side and forearm resting on waist with band resistance at the start (Figure 3A and 3B and Supplemental Digital Content 2, http://links.lww.com/SCJ/A111). The concentric phase of external rotation is achieved by using the contralateral arm to rotate the arm out to the side to achieve end-range external rotation (Figure 3A). At this stage, the individual should laterally step to the side to further increase resistance from the band or pulley. Once increased resistance is perceived, the individual slowly allows the arm to return to the start position to complete the eccentric action of this exercise (Figure 3B). When using resistance bands, it should be noted that resistance will increase proportionally to the distance one stands from the anchor point.
STANDING EXTERNAL ROTATION—90/90 POSITION
Standing external rotation with the resistance band or cable at 90° of shoulder elevation is considered an advancement from the aforementioned 2 exercises. This exercise may be best suited for those individuals who have a compulsory assumption of this position, such as throwing athletes or weight-training participants. The exercise (Figure 4A–C and Supplemental Digital Content 3, http://links.lww.com/SCJ/A112) is performed by having the individual stand facing the cable or resistance band, which is anchored to a level slightly below waist height. The individual grasps the band/cable and brings the arm into a position of 90° of abduction while in neutral rotation (Figure 4A). Once in the start position, the individual externally rotates the arm concentrically to achieve the 90/90 position (Figure 4B). Once in the 90/90 position, the individual is requested to step backward 2–4 steps in an effort to increase tension in the band/cable. The band/cable is then lowered back to the start position (Figure 4C) to finish.
Exercise prescription of repetitions, sets, and frequency may vary dependent on the individual, shoulder condition, and desired effects of the intervention. A specific protocol consisting of 3 sets of 15 repetitions has been reported as efficacious when performed daily for the population with shoulder disorders. It is not unreasonable for individuals to begin with fewer repetitions per set if they are unfamiliar with eccentric training, as professional judgment should supersede any external recommendations. The load of an eccentric exercise should generally be greater than what would be selected for concentric exercises given the ability of an eccentric contraction to elicit greater muscular force (6).
There are no specific dosing guidelines for prescribing eccentric exercises in the asymptomatic population desiring to facilitate hypertrophy. Thus, it is recommended that the prescription adheres to standard resistance training guidelines with the addition of eccentric repetitions at the conclusion of each set as tolerated. Specifically, for hypertrophy, it is recommended that an individual perform each exercise with a resistance that allows between 6 and 12 normal concentric/eccentric repetitions for approximately 3–6 sets. When adding isolated eccentric exercises to the routine, we suggest adding 2–3 repetitions at the conclusion of each set at first and progress as tolerated. Progression beyond 6–12 repetitions at conclusion of a traditional set is often an indication that the resistance needs to be increased. In regard to frequency it is advised that traditional training guidelines for rest are respected to allow adequate time for repair.
Rest time between sets is often similar for the symptomatic and asymptomatic populations. Rest must be sufficient so that the patient is able to complete the subsequent set without lowering the resistance level. Individuals often experience a greater level of delayed onset muscle soreness (DOMS) after eccentric exercise compared with concentric exercise (3). DOMS is not routinely an indication to modify dosing when the intention of the intervention is to facilitate healing in shoulder disorders. However, to obtain maximal muscle tissue healing, the progression of load should be withheld until the effects of delayed onset muscle soreness are minimal.
The exercises recommended in this column are applicable to both the asymptomatic and injured population. Rehabilitation specialists and strength and conditioning professionals are encouraged to incorporate these exercises into their patient and client routines as appropriate beginning with more conservative exercises such as the sidelying and standing external rotation with arm at side in an effort to prevent unnecessary soreness and injury. While the health and fitness benefits attributed to eccentric training are well known, participation may not be without risk. Individuals with an active shoulder injury should consult with an appropriate medical professional before beginning these or any exercise program.
1. Baechle TR, Earle RW. Essentials of Strength Training and Conditioning (3rd ed). Champaign, IL: Human Kinetics, 2008. pp. 406.
2. Boettcher CE, Ginn KA, Cathers I. Which is the optimal exercise to strengthen supraspinatus? Med Sci Sports Exerc 41: 1979–1983, 2009.
3. Clarkson PM, Hubal MJ. Exercise-induced muscle damage in humans. Am J Phys Med Rehabil 81: 52–69, 2002.
4. Cools AM, Dewitte V, Lanszweert F, Notebaert D, Roets A, Soetens B, Cagnie B, Witvrouw EE. Rehabilitation of scapular muscle balance: Which exercises to prescribe? Am J Sports Med 35: 1744–1751, 2007.
5. Kolber MJ, Beekhuizen KS, Santore T, Fiers H. Implications for specific shoulder positioning during external rotator strengthening. Strength Cond J 30: 12–16, 2008.
6. Ojasto T, Häkkinen K. Effects of different accentuated eccentric load levels in eccentric-concentric actions on acute neuromuscular, maximal force, and power responses. J Strength Cond Res 23: 996–1004, 2009.