Functionally Specific Shoulder Rehabilitation
Column-editor : R. Barry Dale
The Relationship Between Surface Electromyographic Activity and Torque Production of the Infraspinatus Muscle in Shoulder Rehabilitation Exercises
Bill Stodart, Maria Cup, and Curtis Kindel
relationship between surface EMG activity and isometric torque production of the infraspinatus in selected shoulder rehabilitation exercises. Comprising the posterior rotator cuff, infraspinatus and teres minor provide glenohumeral external rotation (ER), which functionally helps to clear the greater
Innovative Tools for Shoulder Rehabilitation
Robert T. Floyd, Kurt R. Behrhorst, and Stacey D. Walters
Shoulder- and Back-Muscle Activation During Shoulder Abduction and Flexion Using a Bodyblade Pro Versus Dumbbells
Joseph S. Parry, Rachel Straub, and Daniel J. Cipriani
The Bodyblade Pro is used for shoulder rehabilitation after injury. Resistance is provided by blade oscillations—faster oscillations or higher speeds correspond to greater resistance. However, research supporting the Bodyblade Pro’s use is scarce, particularly in comparison with dumbbell training.
To compare muscle activity, using electromyography (EMG), in the back and shoulder regions during shoulder exercises with the Bodyblade Pro vs dumbbells.
Randomized crossover study.
San Diego State University biomechanics laboratory.
11 healthy male subjects age 19–32 y.
Subjects performed shoulder-flexion and -abduction exercises using a Bodyblade Pro and dumbbells (5, 8, and 10 lb) while EMG recorded activity of the deltoid, pectoralis major, infraspinatus, serratus anterior, and erector spinae.
Main Outcome Measures:
Average peak muscle activity (% maximum voluntary isometric contraction) was separately measured for shoulder abduction and flexion in the range of 85° to 95°. Differences among exercise devices were separately analyzed for the flexed and abducted positions using 1-way repeated-measures ANOVA.
The Bodyblade Pro produced greater muscle activity than all the dumbbell trials. Differences were significant for all muscles measured (all P < .01) except for the erector spinae during shoulder flexion with a 10-lb dumbbell. EMG activity for the Bodyblade Pro exceeded 50% of the MVIC during both shoulder flexion and abduction. For the dumbbell conditions, only the 10-lb trials approached this effect.
Using a Bodyblade during shoulder exercises results in greater shoulder- and back-muscle recruitment than dumbbells. The Bodyblade Pro can activate multiple muscles in a single exercise and thereby minimize the need for multiple dumbbell exercises. The Bodyblade Pro is an effective device for shoulder- and back-muscle activation that warrants further use by clinicians interested in its use for rehabilitation.
Incorporating Kinetic-Chain Integration, Part 2: Functional Shoulder Rehabilitation
Darrin M. Smith
Column-editor : R. Barry Dale
Rotator-Cuff Muscle-Recruitment Strategies During Shoulder Rehabilitation Exercises
Kathleen A. Swanik, Kellie Huxel Bliven, and Charles Buz Swanik
There are contradictory data on optimal muscle-activation strategies for restoring shoulder stability. Further investigation of neuromuscular-control strategies for glenohumeral-joint stability will guide clinicians in decisions regarding appropriate rehabilitation exercises.
To determine whether subscapularis, infraspinatus, and teres minor (anteroposterior force couple) muscle activation differ between 4 shoulder exercises and describe coactivation ratios and individual muscle-recruitment characteristics of rotator-cuff muscles throughout each shoulder exercise.
healthy, physically active men, age 20.55 ± 2.0 y.
4 rehabilitation exercises: pitchback, PNF D2 pattern with tubing, push-up plus, and slide board.
Main Outcomes Measures:
Mean coactivation level, coactivation-ratio patterns, and level (area) of muscle-activation patterns of the subscapularis, infraspinatus, and teres minor throughout each exercise.
Coactivation levels varied throughout each exercise. Subscapularis activity was consistently higher than that of the infraspinatus and teres minor combined at the start of each exercise and in end ranges of motion. Individual muscle-recruitment levels in the subscapularis were also different between exercises.
Results provide descriptive data for determining normative coactivation-ratio values for muscle recruitment for the functional exercises studied. Differences in subscapularis activation suggest a reliance to resist anteriorly directed forces.
Limb Dominance Effects on Seated Single-Arm Shot-Put Limb Symmetry Indices Following Shoulder Rehabilitation
Bryan L. Riemann and George J. Davies
Context: Typically, most clinical return to activity guidelines recommend that an injured shoulder achieve a 90% to 100% functional performance test limb symmetry index (LSI); however, as previous research demonstrated a 103% to 111% dominant limb bias in seated single-arm shot-put test (SSASPT) performance, the typical criteria might not be appropriate for interpreting SSASPT LSI. Thus, the current objective was to evaluate SSASP LSI differences between dominant and nondominant involved shoulders and to determine how many patients met the suggested 90% to 100% LSI criteria, as well as the 103% for dominant (89% for nondominant) normative SSASPT threshold reported in the literature, at the time of discharge. Design: Cross-sectional. Methods: Patients with shoulder injury or surgery (n = 78) completed the SSASPT at the time of discharge from rehabilitation and were grouped according to whether the involved shoulder was the dominant (n = 42) or nondominant (n = 32) limb. LSI (involved/uninvolved × 100) was computed from the average of 3 SSASPT trial distances completed with each limb. Results: The LSI for the nondominant involved group (88.9% [12.4%]) was significantly less (confidence intervalDiff, −12.1% to −22.1%) than the dominant involved group (106.0% [9.3%]). While 95.2% of patients in the dominant involved group exhibited LSI > 90%, only 43.8% of patients in the nondominant involved group attained LSI > 90%. Across the entire cohort, the odds of a nondominant involved LSI being below the respective SSASPT normative range were 2.04 (95% confidence interval, 0.80–5.21) times higher than the odds of a dominant involved LSI being below the normative range. Conclusions: Patients with dominant limb involvement exhibited higher LSI than patients with nondominant limb involvement at discharge from rehabilitation. Particularly when the nondominant shoulder is involved, these results suggest that patients with shoulder injury and surgery may require longer rehabilitation to attain higher levels of upper-extremity function.
Relationship between Maximum Strength and Relative Endurance for the Empty-Can Exercise
Martha Walker, Donald Sussman, Michael Tamburello, Bonnie VanLunen, Elizabeth Dowling, and Beth Ernst Jamali
A strength-endurance diagram predicts that a person should be able to perform 30 repetitions of an exercise if the resistance level is 60% of 1-repetition maximum (1RM).
To compare the number of repetitions predicted by the diagram with recorded repetitions of a shoulder exercise.
Single-group comparison with a standard.
34 healthy adults (20 women, 14 men) with a mean age of 29 years (range 20–49).
Main Outcome Measures:
The number of repetitions that subjects could perform in good form of a shoulder exercise with resistance of 60% 1RM.
The mean number of repetitions was 21 (± 3, range 15–28), which was significantly different than the 30 repetitions that the diagram predicted.
The strength-endurance diagram did not accurately predict the number of repetitions of a shoulder exercise that subjects could perform.
Scapula Muscle Activations During Overhead Throwing Holds
Gretchen Oliver, Lisa Henning, and Hillary Plummer
The purpose of this study was to examine activations of selected scapular stabilizing musculature while performing an overhead throw with a hold (not releasing the ball) in two different throwing positions—standing with a crow hop and kneeling on the ipsilateral knee. Surface electromyography was used to examine activations of throwing side lower trapezius (LT), middle trapezius (MT), serratus anterior (SA), and upper trapezius (UT). Muscle activations were recorded while performing the overhead throw with holds while in two throwing positions. MANOVA results revealed no significant differences between the two throwing conditions and muscle activations of LT, MT, SA, and UT: F(8,124) = .804, p = .600; Wilks’s Λ = .904, partial η2 = .049. Although no significant differences were observed in the scapular stabilizers between the two conditions, moderate (21–50% MVIC) to high (> 50% MVIC) activations of each muscle were present, indicating that nonrelease throws may be beneficial for scapular stabilization in throwers.
The Effect of Muscle Fatigue on Muscle Force-Couple Activation of the Shoulder
Timothy J. Henry, Scott M. Lephart, Jorge Giraldo, David Stone, and Freddie H. Fu
Muscle fatigue is an important concept in regard to the muscle function of the shoulder joint. Its effect on the muscle force couples of the glenohumeral joint has not been fully identified.
To examine the effects of muscle fatigue on muscle force-couple activation in the normal shoulder.
Ten male subjects, age 18–30 years, with no previous history of shoulder problems.
Main Outcome Measures:
EMG (area) values were assessed for the anterior and middle deltoid, subscapularis, and infraspinatus muscles during 4 dynamic stabilizing exercises before and after muscle fatigue. The exercises examined were a push-up, horizontal abduction, segmental stabilization, and rotational movement on a slide board.
No significant differences were observed for any of the muscles tested.
The results of our study indicate that force-couple coactivation of the glenohumeral joint is not significantly altered after muscle fatigue.