Effectiveness of specific scapular therapeutic exercises in patients with shoulder pain: a systematic review with meta-analysis

Background

Therapeutic exercise has been considered a useful tool to rehabilitate shoulder pain, namely through its influence on scapular dynamics. Accordingly, the effectiveness of scapular therapeutic exercise needs to be explored. The present study aims to evaluate the effectiveness of scapular therapeutic exercises in shoulder pain and to identify the most effective exercise type (focal or multijoint) and ways of delivering them (as dose and progression).

Methods

Search was conducted at EMBASE, Cochrane Library, MEDLINE via PubMed, Web of Science, PEDro (Physiotherapy Evidence Database), and trial registration databases. The meta-analysis considered randomized controlled/crossover trials that compared the effect of scapular exercises against other types of intervention in the shoulder pain, shoulder function, scapular motion, and/or muscular activity. The risk of bias was assessed through the PEDro scale.

Results

From the 8318 records identified, 8 (high to low risk of bias- scoring from 4 to 8 on the PEDro scale) were included. The overall data, before sensitivity analysis, indicated that the scapular therapeutic exercises are: a) more effective than comparators in improving shoulder function (standardized mean difference [SMD] = 0.52 [95% Cl: 0.05, 0.99], P = .03, I2 = 76%); and b) as effective as comparators in reducing shoulder pain (SMD = 0.32 [95% Cl: -0.09, 0.73], P = .13, I2 = 70%). Subgroup analysis revealed that scapular exercises are more effective in improving shoulder function when the program duration is equal to or higher than 6 weeks (SMD = 0.43 [95% Cl: 0.09, 0.76] P = .01, I2 = 21%) and/or when the maximum number of exercise repetitions per session is lower than 30 (SMD = 0.79 [95% Cl: 0.15, 1.42], P = .01, I2 = 77%). Only 1 study considered scapular motion as an outcome measure, revealing therapeutic exercise effectiveness to improve scapular range of motion.

Conclusions

Intervention programs involving scapular therapeutic exercises are effective in improving shoulder function, presenting benefits when performed for 6 or more weeks and/or when used up to a maximum of 30 repetitions per exercise, per session.

Kinematic and electromyography characteristics of performing butterfly stroke with different swimming speeds in flow environment

Objective

To investigate effect of flow speeds on the upper limb muscular activity of butterfly swimmers training in a flow environment. A comparison of kinematic characteristics and muscular activity of upper limbs were made when the swimmers training with different flow speeds in a swimming flume. The purpose was to provide a basis for scientifically formulating special swimming training advice for athletes' training in flow environment.

Methods

Ten youth female butterfly swimmers participated in the study with the speed of 70%, 80%, and 90% level of their max speeds. A stroke cycle was divided into four phases (entry, pull, push, and recovery). The kinematic parameters of upper limbs (stroke rate, stroke length, duration of each phase in a stroke cycle) and muscular activity (onset timing, integrated electromyography (iEMG), contribution ratio) of four muscles (Biceps brachii (BB), Triceps brachii (TB), Pectoralis major (PM), and Latissimus dorsi (LD)) were collected and analyzed in different stroke phases.

Results

There was no significant difference between stroke rate and stroke length with different flow speeds. There were significant differences among the duration of the four stroke phases. The entry phase had the longest duration, the pull phase had the shortest duration, the push phase was longer than the recovery phase, and the recovery phase was shorter than the entry phase. The BB and PM were activated significantly earlier at 90% of target speed than at 80% of target speed, while the TB was activated significantly later than other two speeds. The muscular contribution ratio of the PM was highest in the pull phase and lowest in the pushing phase. The muscular contribution ratio of the BB was significantly lower in the pushing phase than in other three stroke phases. The muscular contribution of the TB was significantly higher in the recovery phase than in other three stroke phases. The muscular contribution ratio of the LD was highest in the pushing phase, and it was significantly higher in pushing phase and recovery phase than in pull phase.

Conclusions

(1) When butterfly athletes training with 70%, 80% and 90% of their max speed in a flow environment, it didn't make significant differences between the kinematic or muscle activation characteristics of the upper limbs movement except the muscle onset timing. (2) Stroke phase was the main factor of the duration and the muscle contribution ratio during butterfly arm stroke for young athletes.

Effects of ground and load on upper trapezius, biceps brachii muscle and hand forces in one- and two-wheeled wheelbarrow pushing

This study examines the effects of ground surface, load, one- and two-wheeled wheelbarrow on muscular activities, hand force, and subject-perceived exertions while pushing a wheelbarrow in a straight line on a horizontal surface. The experimental results show that wheelbarrow load significantly affected muscular activities, hand force, and subject-perceived exertion. Additionally, different ground surfaces and wheelbarrow types also affected the muscular activities of the dominant hand; grass generated the highest muscle load and asphalt pavement generated the smallest muscle load. The user has to apply 57% and 23% more force in the vertical and horizontal direction while pushing one-vs. two-wheeled wheelbarrow. Muscular activity increased significantly in the dominant hand with the one-wheeled wheelbarrow compared with the two-wheeled wheelbarrow, suggesting that, in terms of muscle loads, the two-wheeled wheelbarrow is better than the one-wheeled wheelbarrow.

The latissimus dorsi tendon functions as an external rotator after arthroscopic-assisted transfer for massive irreparable posterosuperior rotator cuff tears

PURPOSE

Latissimus dorsi tendon transfer is a surgical option for the treatment of massive irreparable posterosuperior rotator cuff tear. Whether a favourable clinical outcome is due to the latissimus dorsi muscle contraction rather than the passive tenodesis effect remains to be confirmed. The purpose of the current case-control study was to evaluate the shoulder kinematics and latissimus dorsi activation after latissimus dorsi tendon transfer.

METHODS

Eighteen patients suffering from irreparable rotator cuff tear that underwent latissimus dorsi tendon transfer and 18 healthy individuals were examined using a 3D kinematic tracking system and electromyography. Active maximal flexion-extension and abduction-adduction of the humerus were measured for the operated and the contralateral shoulder of the patients and the shoulder of healthy individuals to evaluate the range of motion (ROM) and scapulohumeral rhythm. Electromyographic comparison of isometric contraction between the latissimus dorsi of the operated and contralateral shoulder was carried out.

RESULTS

After arthroscopic-assisted latissimus dorsi tendon transfer, patients showed comparable flexion and abduction ROM to their asymptomatic contralateral shoulders and to the shoulders of healthy individuals. Significantly higher scapular ROM values were found between the latissimus dorsi tendon transfer side and the shoulders of healthy individuals. While performing external rotation with 0° shoulder abduction, a greater percentage of the electromyographic peak value (p = 0.047) and a higher latissimus dorsi internal/external rotation ratio (p = 0.004) were noted for the transferred muscle in comparison to the contralateral shoulder.

CONCLUSION

Although the arthroscopic-assisted latissimus dorsi tendon transfer failed to normalize scapulothoracic joint movements of patients, a functional latissimus flap and a shoulder ROM similar to the contralateral side or the shoulder of healthy individuals can be expected after this procedure in patients with massive irreparable posterosuperior rotator cuff tear.

LEVEL OF EVIDENCE

III.

Normalising surface EMG of ten upper-extremity muscles in handcycling: Manual resistance vs. sport-specific MVICs

Muscular activity in terms of surface electromyography (sEMG) is usually normalised to maximal voluntary isometric contractions (MVICs). This study aims to compare two different MVIC-modes in handcycling and examine the effect of moving average window-size. Twelve able-bodied male competitive triathletes performed ten MVICs against manual resistance and four sport-specific trials against fixed cranks. sEMG of ten muscles [M. trapezius (TD); M. pectoralis major (PM); M. deltoideus, Pars clavicularis (DA); M. deltoideus, Pars spinalis (DP); M. biceps brachii (BB); M. triceps brachii (TB); forearm flexors (FC); forearm extensors (EC); M. latissimus dorsi (LD) and M. rectus abdominis (RA)] was recorded and filtered using moving average window-sizes of 150, 200, 250 and 300 ms. Sport-specific MVICs were higher compared to manual resistance for TB, DA, DP and LD, whereas FC, TD, BB and RA demonstrated lower values. PM and EC demonstrated no significant difference between MVIC-modes. Moving average window-size had no effect on MVIC outcomes. MVIC-mode should be taken into account when normalised sEMG data are illustrated in handcycling. Sport-specific MVICs seem to be suitable for some muscles (TB, DA, DP and LD), but should be augmented by MVICs against manual/mechanical resistance for FC, TD, BB and RA.

Lower limb muscular activity during walking at different speeds: Over-ground versus treadmill walking: A voluntary response evaluation

OBJECTIVE

To evaluate the overall lower limb muscular activity pattern during treadmill walking compared to over-ground walking.

METHODOLOGY

The study was conducted on 25 healthy young females. Surface electromyography was recorded from gastrocnemius, hamstrings, vasti and gluteus medius muscles during walking over-ground and treadmill at 3 different speeds (comfortable, slow and fast). The pattern of muscle activity was compared between two walking conditions at different speeds by the voluntary response index method. Voluntary response index is composed of two numeric values: magnitude which represents the strength of overall muscular activity, and similarity index which represents the resemblance of overall muscle activity.

RESULTS

The main effect of walking conditions and speed as well as their interaction effect (P < 0.001) on magnitude of muscle activity were significant but not for similarity index.

CONCLUSIONS

The pattern of muscular activity during walking on treadmill and over-ground was similar but walking on treadmill induced higher muscular activity in the lower limb musculature.

Comparing electro- and mechano-myographic muscle activation patterns in self-paced pediatric gait

Electromyography (EMG) is the standard modality for measuring muscle activity. However, the convenience and availability of low-cost accelerometer-based wearables makes mechanomyography (MMG) an increasingly attractive alternative modality for clinical applications. Literature to date has demonstrated a strong association between EMG and MMG temporal alignment in isometric and isokinetic contractions. However, the EMG-MMG relationship has not been studied in gait. In this study, the concurrence of EMG- and MMG-detected contractions in the tibialis anterior, lateral gastrocnemius, vastus lateralis, and biceps femoris muscles were investigated in children during self-paced gait. Furthermore, the distribution of signal power over the gait cycle was statistically compared between EMG-MMG modalities. With EMG as the reference, muscular contractions were detected based on MMG with balanced accuracies between 88 and 94% for all muscles except the gastrocnemius. MMG signal power differed from that of EMG during certain phases of the gait cycle in all muscles except the biceps femoris. These timing and power distribution differences between the two modalities may in part be related to muscle fascicle length changes that are unique to muscle motion during gait. Our findings suggest that the relationship between EMG and MMG appears to be more complex during gait than in isometric and isokinetic contractions.

Moderate anxiety modifies the electromyographic activity of a forearm muscle during a time-reaction task in women

Arousal anxiety has a great impact on reaction time, physiological parameters and motor performance. Numerous studies have focused on the influence of anxiety on muscular activity during simple non ecologic task. We investigate the impact of a moderate state-anxiety (arousal stressor) on the specific component of a complex multi-joint ecologic movement during a reaction time task of auditory stimulus-response. Our objective is to know if central and peripheral voluntary motor processes were modulated in the same way by an arousal stressor. Eighteen women volunteers performed simple reaction time tasks of auditory stimulus-response. Video-recorded Stroop test with interferences was used to induced moderate state-anxiety. Electromyographic activity of the wrist extensor was recorded in order to analyse the two components of the reaction time: the premotor and motor time. In anxiogenic condition, an acceleration and an increase of muscular activity of the reaction time was obtained. This increase was due to a stronger muscle activity during the premotor time in the anxiogenic condition. Arousal anxiety has a different impact on central and peripheral voluntary motor processes. The modifications observed could be related to an increase in arousal related to a higher anxiety in order to prepare the body to act.

Exposure-response relationships for work-related neck and shoulder musculoskeletal disorders--Analyses of pooled uniform data sets

There is a lack of quantitative data regarding exposure-response relationships between occupational risk factors and musculoskeletal disorders in the neck and shoulders. We explored such relationships in pooled data from a series of our cross-sectional studies. We recorded the prevalence of complaints/discomfort (Nordic Questionnaire) and diagnoses (physical examination) in 33 groups (24 female and 9 male) within which the workers had similar work tasks (3141 workers, of which 817 were males). In representative sub-groups, we recorded postures and velocities of the head (N = 299) and right upper arm (inclinometry; N = 306), right wrist postures and velocities (electrogoniometry; N = 499), and muscular activity (electromyography) in the right trapezius muscle (N = 431) and forearm extensors (N = 206). We also assessed the psychosocial work environment (Job Content Questionnaire). Uni- and multivariate linear meta-regression analysis revealed several statistically significant group-wise associations. Neck disorders were associated with head inclination, upper arm elevation, muscle activity of the trapezius and forearm extensors and wrist posture and angular velocity. Right-side shoulder disorders were associated with head and upper arm velocity, activity in the trapezius and forearm extensor muscles and wrist posture and angular velocity. The psychosocial work environment (low job control, job strain and isostrain) was also associated with disorders. Women exhibited a higher prevalence of neck and shoulder complaints and tension neck syndrome than men, when adjusting for postures, velocities, muscular activity or psychosocial exposure. In conclusion, the analyses established quantitative exposure-response relationships between neck and shoulder disorders and objective measures of the physical workload on the arm. Such information can be used for risk assessment in different occupations/work tasks, to establish quantitative exposure limits, and for the evaluation of preventive measures.

Analysis of scapular kinematics during active and passive arm elevation

[Purpose] Early postoperative passive motion exercise after arthroscopic rotator cuff repair remains controversial. To better understand this issue, this study was aimed at evaluating scapular kinematics and muscle activities during passive arm elevation in healthy subjects. [Subjects and Methods] The dominant shoulders of 27 healthy subjects were examined. Electromagnetic sensors attached to the scapula, thorax, and humerus were used to determine three-dimensional scapular kinematics during active arm elevation with or without external loads and passive arm elevation. Simultaneously, the activities of seven shoulder muscles were recorded with surface and intramuscular fine-wire electrodes. [Results] Compared with active arm elevation, passive elevation between 30° and 100° significantly decreased the scapular upward rotation and increased the glenohumeral elevation angle. However, no significant differences in scapular posterior tilt and external rotation were observed between active and passive arm elevation, and scapular plane kinematics were not affected by muscle activity. [Conclusion] Unlike active motion with or without an external load, passive arm elevation significantly decreased the scapular upward rotation and significantly increased the mid-range glenohumeral elevation. These data, which suggest that passive arm elevation should be avoided during the early postoperative period, may expand the understanding of rehabilitation after arthroscopic rotator cuff repair.

Changes in urinary amino acids excretion in relationship with muscle activity markers over a professional cycling stage race: in search of fatigue markers

The aim of this study was to identify the relationship between metabolic effort, muscular damage/activity indices, and urinary amino acids profile over the course of a strenuous prolonged endurance activity, as a cycling stage race is, in order to identify possible fatigue markers. Nine professional cyclists belonging to a single team, competing in the Giro d'Italia cycling stage race, were anthropometrically characterized and sampled for blood and urine the day before the race started, and on days 12 and 23 of the race. Diet was kept the same over the race, and power output and energy expenditure were recorded. Sera were assayed for muscle markers (lactate dehydrogenase, aspartate aminotransferase, and creatine kinase activities, and blood urea nitrogen), and creatinine, all corrected for plasma volume changes. Urines were profiled for amino acid concentrations, normalized on creatinine excretion. Renal function, in terms of glomerular filtration rate, was monitored by MDRD equation corrected on body surface area. Creatine kinase activity and blood urea were increased during the race as did serum creatinine while kidney function remained stable. Among the amino acids, taurine, glycine, cysteine, leucine, carnosine, 1-methyl histidine, and 3-methyl histidine showed a net decreased, while homocysteine was increased. Taurine and the dipeptide carnosine (β-alanyl-L-histidine) were significantly correlated with the muscle activity markers and the indices of effort. In conclusion, the metabolic profile is modified strikingly due to the effort. Urinary taurine and carnosine seem useful tools to evaluate the muscle damage and possibly the fatigue status on a long-term basis.

Assessment of masticatory muscle activity and occlusion time in patients with advanced tooth wear

OBJECTIVE

Tooth wear is a basic physiological adjustment mechanism in the masticatory system. Unfortunately, it is not clear what the relationship is between the activity of the masticatory muscles and the tooth hard tissue loss (mainly enamel) in patients with advanced tooth wear. The aims of this study were (1) to compare the occlusion times and (2) to compare the EMG activity in maximal voluntary clench of the masseter and anterior temporalis muscles of patients with advanced tooth wear to the same activity of healthy volunteers.

DESIGN

50 (16F, 34M) patients and 30 (12F, 18M) age matched controls were clinically examined to assess the degree of wear (TWI). Each subject underwent electromyographic analysis (bilateral anterior temporalis, superficial masseter, anterior digastric and sternocleidomastoid muscles) and digital occlusal analysis.

RESULTS

Mean values of the electrical potentials of the mandible elevating muscles during clench were higher in the study group compared to the controls. A negative correlation was found between the temporalis and masseter muscle activities during clench and the mean value of TWI (r=-0.383, p=0.009; r=-0.447, p=0.002). Occlusion time was longer in the study group compared to controls (p<0.05).

CONCLUSIONS

Mandibular adductors demonstrated lower muscular activities during clenching in the tooth wear patients; however, the cause of this finding is not certain. Prolongation of occlusion time may exacerbate occlusal surfaces wear or excessive wear may prolong occlusion time.