Hindawi BioMed Research International Volume 2021, Article ID 9945775, 13 pages https://doi.org/10.1155/2021/9945775 Research Article Progressive Resistance Exercises plus Manual Therapy Is Effective in Improving Isometric Strength in Overhead Athletes with Shoulder Impingement Syndrome: A Randomized Controlled Trial Saurabh Sharma ,1 Amer K. Ghrouz ,2,3 M. Ejaz Hussain ,1 Shalini Sharma ,4 Mosab Aldabbas ,1 and Sumbul Ansari 1 1 Centre for Physiotherapy and Rehabilitation Sciences, Jamia Millia Islamia, New Delhi, India 2 Department of Applied Medical Sciences, Faculty of Medicine and Health Sciences, An-Najah National University, Nablus, State of Palestine 3 Department of Medicine, Universitat Autònoma de Barcelona, Barcelona, Spain 4 Enrich Physio Clinics, Melbourne, Victoria, Australia Correspondence should be addressed to Amer K. Ghrouz; aghrouz@najah.edu Received 5 March 2021; Revised 9 June 2021; Accepted 21 June 2021; Published 1 July 2021 Academic Editor: Defne Kaya Copyright © 2021 Saurabh Sharma et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Reduction in isometric strength of the scapulohumeral muscles is a commonly seen impairment in overhead athletes afflicted with shoulder impingement syndrome (SIS). The purpose of this study was to compare the effects of two different treatment programs: progressive resistance exercises plus manual therapy (PRE plus MT) and motor control exercises (MCE), on isometric strength of upper trapezius (UT), middle trapezius (MTr), lower trapezius (LT), serratus anterior (SA), supraspinatus (Supr.), anterior deltoid (A.D), and latissimus dorsi (LD). 80 male university-level overhead athletes clinically diagnosed with SIS were randomly allocated into either of the two groups: PRE plus MT and MCE group. Athletes in the PRE plus MT group underwent graduated exercises with resistance elastic band, stretching exercises, and mobilization of the thoracic and shoulder joints. MCE group was submitted to motor control exercises in varied planar positions. Athletes in both groups underwent management 3 times a week for 8 weeks. Isometric strength of UT, MTr, LT, Supr, A.D, SA, and LD was measured at three-time points: baseline, 4th week, and 8th week. Relative to baseline, both interventions were found to be effective in increasing and optimizing the isometric strength of muscles (p < 0:05) except for supraspinatus in the MCE group (p > 0:05). However, athletes in PRE plus MT group presented a more pronounced increase in isometric strength than those in the MCE group. Between groups analysis found the largest isometric strength improvement in PRE plus MT group for A.D, followed by Supr. and UT muscles (p < 0:05; effect size: 0.39 to 0.40). The study concluded that compared to MCE, PRE plus MT provides greater improvement in the isometric strength of scapulohumeral muscles. 1. Introduction describes a condition where the subacromial structures are compressed between the humeral head and the coracoacro- Shoulder impingement syndrome (SIS) is a common muscu- mial arch causing a myriad of signs and symptoms [2]. loskeletal condition seen in overhead athletes, and it affects a The reduction in subacromial space can also occur due to large number of athletes at some point during their career mechanistic effects and improper scapular fixation resulting [1]. Overhead athlete is referred as to one who regularly uses in compromise of the subacromial space and its structures his arm above 90 degrees during play. SIS is a term that [3]. The most common clinical features include pain, limited 2 BioMed Research International range of motion, and decreased strength in the arm. Reduc- interview followed by an examination of the physiologic tion in isometric strength of shoulder external rotation and and accessory motion (roll, spin, and glide). The findings of abduction are the two most cardinal features of SIS. The the interview and examination are corroborated with each reduction in isometric strength could be firstly due to muscle other, and then, the therapist uses the findings as a treatment deconditioning following SIS onset and secondly related to tool [19]. The oscillatory technique of mobilization is used in deficits in motor control of the muscles [4, 5]. Lack of motor this concept for vertebral and peripheral joints to treat pain, control changes the muscle activation levels and decreases hypomobility, and increase capsular extensibility of mechan- the coordination between the glenohumeral and scapu- ical nature. Studies examining manual therapy techniques in lothoracic muscles during the overhead elevation motion, isolation have also reported that manual therapy is effective and eventually, it contributes to the reduction of isometric in relieving pain and hypomobility and improving the strength [5]. The muscles mainly affected by isometric strength of muscles [20, 21]. There have also been largely strength reduction are upper trapezius (UT), middle trape- inconclusive results of studies and systematic reviews on zius (MTr), lower trapezius (LT), serratus anterior (SA), the effects of the combination of resistance exercise and man- supraspinatus (Supr), anterior deltoid (AD), and latissimus ual therapy in patients with SIS. Some studies concluded that dorsi (LD) [5]. Isometric strength changes up to 33% and manual therapy should be used as an additive component of 29% in shoulder external rotation and shoulder abduction, resistance exercise, while authors in other studies could not respectively, have been reported in studies [6]. In compari- give a strong recommendation for use of a combination of son, the deficits in protraction and retraction have been resistance exercise and manual therapy [15, 22–25]. The reported to be 8% and 18%, respectively [6]. The isometric main reason for not being able to draw strong recommenda- strength improvement could be considered as a prognostic tions is that most of the trials to date have included heteroge- marker in SIS as it is markedly reduced in most cases. There neous samples, poor exercise prescription in terms of is a paucity of evidence due to a limited number of studies frequency, time, type, and intensity and usually studied the that have examined isometric strength improvement as their effects of resistance exercise and manual therapy in isolation. primary outcome. Regarding the abovementioned isometric strength impair- SIS contributes 27% of the total shoulder injury burden in ment, PRE, MT, and MCE seem to scientifically form an overhead athletes [7]. The prevalence of shoulder injuries is essential and integral component of the treatment regime of high in athletes because of repetitive overhead use and inad- athletes diagnosed with SIS. As per recommendations in ear- equate conditioning in the early phase of the season [7]. Due lier research, in this study, PRE was combined with MT so to multiple etiological and pathomechanical pathways of SIS, that restored mobility of the joint is retained with the help a wide range of treatment strategies has been proposed for of exercises [26]. Because of evidence obtained from the liter- the management of SIS with each strategy aiming to target ature review, the hypothesis that can be derived from find- a particular mechanical pathway [8, 9]. Isometric strength ings is that altered isometric strength of the scapulothoracic improvement can occur by two mechanisms. First is the neu- muscles affects the shoulder girdle movements and plays a romuscular adaptations resulting from increased motor unit major role in the sustenance of the SIS. Therefore, an recruitment to hyperplasia of muscle fibres occurring due to improvement in the isometric strength possibly could help exercise therapy [10]. Second is the reduction in alpha motor in mitigating the symptoms in overhead athletes suffering neuron inhibition due to manual therapy by reducing pain from SIS. level and hypomobility in the spinal and related joints. However, to the best of our knowledge, there is a dearth Both progressive resistance exercises (PRE) and motor of studies that have investigated the effectiveness of PRE plus control exercises (MCE) are the most frequently and com- MT and MCE; therefore, it seems rationale and imperative to monly used conservative techniques. In the systematic study these intervention programs in overhead athletes reviews of clinical trials, it was reported that PRE had a pos- affected by SIS. The present study was aimed to compare itive impact on the outcomes of SIS (pain, strength, range of the effects of two different treatment interventions: PRE plus motion, and function) [11, 12]. A few studies and systematic MT versus MCE on isometric strength of scapulothoracic reviews have concluded that exercise therapy is equivalent or muscles (UT, MTr, LT, SA, Supr, AD, and LD) in overhead even better than surgical procedures as similar outcomes can athletes with SIS. We hypothesized that both treatment inter- be achieved by exercise therapy alone [13, 14]. Both PRE and ventions (PRE plus MT and MCE) will result in improve- MCE have been shown promising results in the management ment of isometric strength of shoulder and scapular muscles. of SIS [15–17]. PRE exercises work on the principle of pro- ducing physiologic adaptations by activating a greater num- 2. Material and Methods ber of satellite cells [4]. In contrast, the MCE changes the altered muscle activation levels and corrects the control and 2.1. Participants. Athletes were recruited in the study as per coordination of the glenohumeral and scapulothoracic joint the following criteria: (i) 17-35 years of age; (ii) male over- during the overhead elevation motion [5]. Maitland mobili- head athletes playing competitive sports like volleyball, ten- zation is one of the widely used manual therapy (MT) tech- nis, baseball, cricket, swimming, badminton, and basketball niques for the management of musculoskeletal dysfunctions for at least 6 hours a week; (iii) shoulder impingement symp- [18]. Maitland’s concept of mobilization is an evolved system toms duration of ≥1 month; (iv) pain rating on visual analog of assessment, clinical reasoning, and hypothesis framing scale (VAS) of less than or equal to 7/10 (during elevation and treatment. The assessment includes a detailed patient activity); (v) athletes agreeing to participate for the entire BioMed Research International 3 duration of treatment; and (vi) athletes were recruited on 2.6. Measurements fulfilling a minimum of 2 out of 5 diagnostic criteria for SIS. The following diagnostic criteria were used for clini- 2.6.1. Isometric Strength Measurement. For the evaluation of cally diagnosing SIS criteria but not based on the last isometric strength of muscles, the Lafayette® handheld dyna- two criteria alone [27]: (a) Positive Neer’s sign, (b) Posi- mometer (HHD) Model-01165 (Lafayette Instrument Com- tive Hawkins sign, (c) Positive Jobe’s sign, (d) Positive pany, Lafayette IN, USA, 2013) system was utilized. It is a Apprehension test, and (e) Positive relocation test. Subjects microprocessor-controlled handheld instrument for the were excluded when they have any of the following: prior quantitative assessment of isometric muscle strength. The shoulder dislocation in the same or opposite shoulder, ath- measurement range of the instrument is up to 1335 N. Iso- letes with bilateral shoulder pain, acromioclavicular (AC) metric muscle strength is the ability of the subject to hold a joint pathology, cervical spine radiculopathy, athletes cur- sustained contraction against an unyielding resistance for a rently on medicines like NSAIDs, prior shoulder surgery specified duration of time. In isometric contraction, there is on the symptomatic side, or positive drop arm test for no movement of the joint but due to contraction; tension is full-thickness rotator cuff tear. generated in the muscle. The isometric strength was assessed by applying counter force with the HHD, opposite to the ath- 2.2. Study Design. The present study was a randomized con- lete’s direction of the force. HHD is a reliable instrument for trolled trial with a two-arm parallel repeated measure design measuring muscle strength [29]. The athlete was required to and was conducted at the physiotherapy clinic of the univer- perform maximal contraction of the muscle while the exam- sity (Jamia Millia Islamia-A Central University). iner applied counter-force to achieve isometric contraction. A familiarization session was done before actual testing. 2.3. Ethical Consideration. All procedures performed in the The athlete performed three trials (maximal strength) such study were in accordance with the ethical standards of the that the average of the maximal strength recordings was used institutional/or national research committee (Institutional for analysis (sum of maximal strength trials/no. of repeti- Ethics Committee, Jamia Millia Islamia (vide no tions). One minute of rest was provided between each trial. 07/04/JMI/IEC) and with the 1964 Helsinki declaration and The maximal isometric strength was recorded by the device its late amendments or comparable ethical standards. The during the test in Newton. The isometric measurement was trial was registered at the central trial registry vide no. measured for UT, MTr, LT, SA, Supr, AD, and LD. The iso- CTRI/2018/05/013892. metric strength was measured by utilizing the following posi- tioning as mentioned in Table 1 [29]. 2.4. Sample Size. The sample size for the study was deter- mined by the use of the statistical program G ∗ power Soft- 2.7. Interventions. Athletes were randomly assigned to one of ware (version 3.1.9.4; Henrich-Heine-Universitat the two intervention groups: PRE plus MT group and MCE Dusseldorf, Germany) [28]. The calculations were based on group for 8 weeks protocol. The intervention in both groups the assumption of finding a 30 percent difference in primary was performed by a physiotherapist having clinical experi- outcome measure, i.e., isometric strength of internal rotator, ence of 10+ years after postgraduate education and also hav- at an alpha level of 0.05, Cohen d = 0:60 effect size and ing add-on requisite manual therapy certifications. The pre- power ð1 − βÞ of 0:80 [15]. This generated a sample size of and postassessment were performed by the different asses- 34 subjects in each group. After accounting for a dropout of sors (physiotherapist) who were blinded to group allocation 15%, a total of 78 subjects were found to be necessary to find and treatment protocols. meaningful differences between groups. 2.7.1. Progressive Resistance Exercises plus Manual Therapy 2.5. Procedures. The recruitment was done through the (PRE plus MT) Group. Athletes in the PRE plus MT group screening process of athletes with shoulder pain who came underwent an amalgamated protocol of resistance exercise to the clinic after reading flyers posted online on the uni- and manual therapy [24, 30]. The protocol aimed to versity website. The athletes were physically examined as strengthen shoulder and scapular muscles, regain range of per the eligibility criteria, and those who agreed to partic- motion (ROM) of the shoulder quadrant joints, and stretch ipate were recruited for the study. The athletes were ran- the shortened muscles. The total protocol duration was of 8 domly allocated to one of the two groups: PRE plus MT weeks. The strengthening component of the protocol was to group and MCE group, by using a computerized random be performed 3 times a week, while the ROM exercises were number generator. The total duration of the study was 8 to be done on daily basis for 10 repetitions (reps). Stretching weeks. The baseline measurement of isometric strength exercise also comprised an important component of the pro- of muscles (UT, MTr, LT, SA, Supr, AD, and LD) was tocol, and 5 repetitions daily withhold of 30 seconds for each recorded on the day of the recruitment. The entire process repetition were performed by the athletes. The program of examination and recording baseline measurements took began with ROM exercises that included shoulder retraction around 30 minutes on average. The recordings in the (athletes actively performed shoulder external rotation by study were taken at three-time points, i.e., baseline, 4th keeping elbow in a flexed position), pendulum exercise (ath- week of intervention, and 8th week of intervention for iso- letes performed swinging movement of shoulder joint in a metric strength of the muscles. The study protocol is given clockwise and counter-clockwise direction for one minute in Figure 1. each), an active training of scapula muscles (athletes 4 BioMed Research International Enrollment Assessed for eligibility Excluded (n = 12) (i) Not meeting inclusion criteria (n = 5) (i) Declined to participate (n = 7) Randomized (n = 88) Allocation Baseline assessment Group PRE plus MT Group MCE Received combined progressive resistance Received motor control exercises exercises and manual therapy Allocated to intervention (n = 44) (i) Allocated to intervention (n = 44) Follow-up (4 weeks) Second assessment Discontinued intervention (n = 4) Discontinued intervention (n = 4) Follow up (8 weeks) and Analysis Third assessment Analysed (n = 40) Analysed (n = 40) (i) Excluded from analysis (n = nil) (i) Excluded from analysis (n = nil) Figure 1: Details of the study protocol. Table 1: Positioning of athletes for isometric strength measurement of muscles. Muscle Procedure With the subject in high sitting, the dynamometer was pushed down over the suprascapular fossa and the subject was told to UT perform shoulder elevation After placing the dynamometer on the mid-way point of the spine of the scapula and acromion, the dynamometer was pushed MTr. laterally while the subject was asked to keep the arm in an abducted externally rotated position while the subject lay prone. After placing the dynamometer on the mid-point of the acromion and medial root spine of the scapula, the dynamometer was LT pushed in superolateral direction while the subject was prone with arm in 140° of flexion. The subject was in high sitting and the shoulder is put in 30 degrees of abduction and in 90 degrees of flexion and counterforce was Supr. given just proximal to the elbow. After placing the dynamometer on the forearm ulnar border while the shoulder and elbow were flexed to 90°, the subjects were S.A asked to lift the point of the elbow towards the ceiling for which the counterforce was applied. After placing the dynamometer just proximal to the elbow, the subject in high sitting was asked to counter the downward force A.D. applied by the examiner while the shoulder was in 90° of flexion. After placing the dynamometer on the posterior aspect of the elbow, the subject in the seated position was asked to counter the L.D anterior direction while the shoulder was in 30° extension and 90°elbow flexion. Abbreviation: UT: upper trapezius; MTr.: middle trapezius; LT: lower trapezius; SA: serratus anterior; Supr: supraspinatus; A.D: anterior deltoid; LD: latissimus dorsi. performed scapular pullbacks while keeping the arms by the their forearms and hand on the wall, stood at an arms dis- side), active-assisted exercises with the cane (athletes per- tance and then the athlete leaned forward) and posterior formed medial and lateral rotations, flexion, and diagonal shoulder capsule (athletes stood against the wall and while elevation by holding a cane with both hands and applied anchoring the affected side scapula brought the affected force primarily from the normal side), and posture exercises shoulder into cross-body adduction in such a manner that (athletes were taught to self-correct their abnormal hiking of stretch was felt in the back of the shoulder). shoulder while performing active shoulder elevation in front Maitland manual therapy grades (nonthrust) I to IV were of a mirror). Participants were also educated to perform used for treatment. A total of 12 MT sessions were adminis- stretching of the anterior shoulder (athletes while placing tered over a period of 8 weeks [19, 31]. The athlete was in the BioMed Research International 5 prone position and the physiotherapist performed the tho- From the 5th to 8th week of the therapeutic program, racic PA (posteroanterior) glides by keeping the elbow phase 3 progressive resistance exercises (PRE) were per- straight and used the pisiform bone to apply the PA glide formed. With the addition of two new exercises, other exer- on the thoracic spinous process. To apply precise mobiliza- cises remained the same as in phase 2. The exercises tion, the physiotherapist hooked the fifth finger of the above comprised of chair press (athlete while in sitting position hand with the index finger of the bottom hand. Glenohum- tried to lift the buttocks off the chair) and “protraction plank” eral posterior and inferior glide mobilizations were per- (athlete while in prone plank posture with the thoracic spine formed by placing the athlete in a supine position with a in an extended position (slouched) pushed downward towel under the scapula. The physiotherapist placed one through the forearm producing upper trunk spinal flexion hand over the humeral head (for posterior glide) and lateral position and after that slowly returned to starting position). to the acromion (for inferior glide), while the other hand sup- The progression was made by increasing the repetition count ported the elbow and then a glide in posterior and inferior at the end of the 8th week [4] (Table 2). direction was applied to the humeral head in different ele- vated positions of below and above 90 degrees. The stability 2.7.2. Motor Control Exercise (MCE) Group. The motor con- of the shoulder complex was improved by performing trol exercises mainly composed the MCE group. Athletes in strengthening exercises. The duration of phase 1 progres- the MCE group were submitted to a group of six free exer- sive resistance exercises (PRE) lasted up to two weeks cises for the upper quadrant region. The range of exercises from the inception of the exercises. The exercises were consisted of shoulder abduction in the frontal plane (athlete performed with an elastic resistance band by moving in while in the standing position, raised the arms in the frontal the opposite direction of band fixation (held by the exam- plane to perform sideways elevation), shoulder retraction iner). The resistance exercises comprised of shoulder lat- (athlete brought the two shoulder blades together during eral rotation and medial rotation in a neutral position, standing position by laterally rotating the arms and held scapular retraction (athlete held the resistance band with for five seconds), neck retraction (athlete drew his neck in both hands and then pulled it outwards followed by slow backward position as if trying to touch chin to the throat), release while keeping the elbow inflexed position), and shoulder shrugging (athlete while in the standing position, resisted scapular protraction (bodyweight secured band elevated both the shoulder and brought them closer to the was pushed towards the ceiling such that the shoulder ear for a duration of five seconds), stretching of upper trape- blades were lifted off the table), while the elbow was kept zius (athlete while in the chair sitting position, pulled one of extended, scapular retraction with chin tuck-in. the shoulders back by holding onto the chair while the other The progression pattern of the resistance exercise regime hand grasped the head region and pulled the neck in the in phase 1 comprised graduating the repetition counts from opposite direction toward the armpit and held it for a dura- starting 2 sets of 10 reps to 3 sets of 10 reps. The starting tion of 20 seconds), and pectoralis major (athlete was in resistance of the elastic resistance band (colour code) was lying position, the arm was raised to 125°for duration of 20 selected on the criteria of repetition maximum, i.e., resistance seconds and then gradually go down towards the floor) band that permitted an athlete to complete 8 to12 repetitions [13] (Table 3). per set to the point of fatigue [32]. On every 4th day of this phase, progression was made by changing the colour of the resistance band (different colours denote varying resistance) 2.8. Analysis. Data analysis was conducted with the SPSS [4] [Table 2]. software (version 21.0, SPSS Inc., Chicago, IL). The statistical The duration of phase 2 progressive resistance exercises analysis was framed to analyze the within-subject and (PRE) was also 2 weeks. The exercises were performed with between-subject effects over all the time points. The data is the elastic resistance band by moving in the opposite direc- presented as mean ± SD, and the normality of the data was tion (followed by slow descent) of band fixation (held by assessed with the Shapiro Wilk test. The baseline demo- the examiner), namely, shoulder elevation and flexion up to graphic and descriptive characteristics of the two interven- 90°, shoulder lateral and internal rotation in shoulder tion groups were assessed through an independent sample t abducted and elbow flexed position of 45°-90°, shoulder -test. Mean change in isometric strength of muscles was also resisted extension from 45° flexed position, quadruped calculated between baseline to midtreatment (4th week) and push-up plus “camel” (athlete was in all four positions and baseline to 8 weeks of treatment. Split-plot repeated measure then upper trunk slouching was performed by pushing ANOVA (2x 3 models) was conducted to find the effect of downwards followed by gradually release), and scapular “T” time, group, and time × group effect on the isometric muscle and “Y” exercise (athlete was in prone lying with the shoulder strength (UT, MTr., LT, SA, A.D, Supr., and LD). Mauchly’s in abducted and thumbs turned up position, following this test was used as a reference, and Green-Geisser correction athlete raised the arms towards the ceiling and/or raised diag- was applied if sphericity was violated. Effect size (ES) was onally up, while contracting scapula together towards spine). used as an indicator of the treatment effect, which was At the end of the 4th week of progression of the resistance, the defined as small (0.20), moderate (0.50), and large (0.80) program consisted of an increase in the repetition counts [33]. Percentage change was calculated from baseline to the from the initial 2 sets of 10 repetitions to 3 sets of 10 repeti- 8th week by using the formula: pre − post/pre ∗ 100 [34]. tions. The progression of the band was done every week in For the present study, the level of significance was considered this phase (Table 2). as p < 0:05. 6 BioMed Research International Table 2: Detailed description of the intervention in the PRE plus MT group. Progression (repetition and sets) First 4 weeks Next 4 weeks Phase 1 Range of motion exercises 10 × 1 (daily) 10 × 1 (daily) Stretching(7 days a week) 5 times ×30-sec hold 5 times ×30-sec hold Manual therapy Thoracic PA glides in prone 6 sessions 6 sessions Post. and inf. glide GH joint. Strengthening exercises PRE shoulder IR and ER(NP) 1st: 10 reps × 2 sets PRE shoulder extension 2nd: 10 reps × 3 sets na PRE scap. retr and protraction(supine) (grade-up resistance band to red to green Scapular retraction with tuck-in chin to blue) Phase 2 Shoulder elevation and flexion (up to 90°) and resisted extension 3rd week 10 reps × 2 sets 2 − 3 sets × 10 reps (progressing from Shoulder ER and IR [45°-90°] 4th week 10 reps × 3sets (grade up from green to blue) Quadruped push-up plus “camel” yellow to red) Scapular “T” and “Y” exercise Phase 3 (In addition to phase 2 exercises) Chair press na 5th to 8th week - 2 -3sets x 10 reps Protraction-plank Abbreviation: PA: posteroanterior; reps: repetitions; PRE: progressive resistance exercise; na: not applicable; Post: posterior; Inf: inferior; NP: neutral position; scap: scapula; retr: retraction. Table 3: Detailed description of the intervention in the MCE group. Progression (repetition and sets) First 4 weeks Next 4 weeks Phase 1 Range of motion exercises Frontal pl. abd. 20 times × daily 20 times × daily Neck retr. 20 times × daily 20 times × daily Stretching exercise UT 6 times × 20-sec hold 6 times × 20-sec hold Phase 2 Range of motion exercises Shoulder shrugging 20 times × daily 20 times × daily Shoulder retr. 20 times × daily 20 times × daily Stretching exercise Pec. major 6 times × 20-sec hold 6 times × 20-sec hold Abbreviations: MCE: motor control exercise; pl.: plane; abd: abduction; retr: retraction; UT: upper trapezius; Pec. major: pectoralis major. 3. Results come of the muscles in the two groups were not found to be significant at the baseline level (p < 0:05) (Table 4). The mean A total of 88 overhead athletes with SIS were recruited for the changes in the isometric strength measured from baseline to study. There was a dropout of four athletes from each group the 4th week of intervention were found significant (p < 0:05) during the intervention. A total of eighty athletes (PRE plus for all muscles in both the groups except for supraspinatus MT group mean age: 21:30 ± 2:10 years, MCE group mean muscle in the MCE group (Table 5, Figure 2). This statisti- age: 21:80 ± 2:80 years) clinically diagnosed with SIS agreed cally significant improvement of isometric strength was to participate and completed the study. The demographic found for all the muscles in both groups when recordings and descriptive measurements of the isometric strength out- were again done postintervention at the end of the 8th BioMed Research International 7 Table 4: Comparison of the demographic characteristics and outcome measures between groups at baseline. PRE plus MT group (n = 40) MCE group (n = 40) Characteristics p Mean ± SD Mean ± SD Age (years) 21:30 ± 2:10 21:80 ± 2:80 0.93 Height (cm) 178 ± 2:50 177 ± 2:30 0.76 Weight (kg) 72:3 ± 1:20 71:2 ± 1:30 0.66 2 Body mass index (BMI) (kg/m ) 22:80 ± 0:68 22:57 ± 0:72 0.40 Symptom duration (months) 5:50 ± 2:20 4:42 ± 1:88 0.32 VAS level (E.A) 6:52 ± 0:35 6:14 ± 0:18 0.72 Years of playing 4:50 ± 1:50 4:30 ± 1:30 0.42 UT Str. (N) 234:02 ± 19:15 233:55 ± 21:13 0.98 MTr. Str. (N) 189:84 ± 22:65 190:76 ± 22:59 0.86 LT Str. (N) 197:64 ± 18:64 189:01 ± 20:36 0.16 SA Str. (N) 117:91 ± 10:07 121:10 ± 11:02 0.55 Supr. Str. (N) 143:91 ± 16:74 142:08 ± 21:11 0.41 A.D. Str. (N) 212:48 ± 13:05 212:03 ± 12:43 0.44 LD Str. (N) 119:74 ± 12:86 121:88 ± 9:70 0.08 Abbreviations: BMI: body mass index; PRE plus MT group: progressive resistance exercises plus manual therapy group; MCE group: motor control exercise group; UT: upper trapezius; MTr.: middle trapezius; LT: lower trapezius; SA: serratus anterior; Supr: supraspinatus; AD: anterior deltoid; LD: latissimus dorsi; Str: strength; VAS: visual analogue scale; E.A: elevation activity; p: level of significance set at <0.05; ∗ level of significance p < 0:05; N: newtons. Table 5: Mean change ± SD of outcome measure of both group and summary of mixed model ANOVA. M.D. (G) T G G∗T Variables Time (wk) PRE plus MT (n:40) MCE (n:40) p E.S p E.S p E.S 4 th 23:35 ± 21:21∗ 0:82 ± 1:27∗ UT Str. 0.008∗ 0.65 0.004∗ 0.39 0.007∗ 0.62 8th 36:26 ± 26:97∗ 2:02 ± 1:84∗ 4th −20:57 ± 14:66∗ −0:34 ± 1:65∗ MT Str. ∗ 0.007∗ 0.80 0.009∗ 0.16 0.006∗ 0.77 8 th −40:78 ± 13:29 −1:95 ± 2:02∗ 4th −25:02 ± 23:34∗ −0:94 ± 1:43∗ LT Str. 0.009∗ 0.48 0.005∗ 0.38 0.008∗ 0.45 8th −45:39 ± 29:71∗ −1:38 ± 3:10∗ 4th −14:02 ± 7:96∗ −0:54 ± 0:54∗ SA Str. 0:002∗ 0.93 0:006∗ 0.36 0.002∗ 0.91 8th −49:27 ± 9:29∗ −2:52 ± 1:47∗ 4th −31:77 ± 11:96∗ −0:88 ± 1:47∗∗ Supr. Str. 0.005∗ 0.85 0.004∗ 0.39 0.004∗ 0.84 8th −55:32 ± 14:10∗ −0:61 ± 5:07∗∗ 4th 21:03 ± 7:96∗ 1:33 ± 1:02∗ A.D Str. 0.003∗ 0.90 0.003∗ 0.40 0.003∗ 0.88 8th 47:03 ± 10:58∗ 2:24 ± 1:43∗ 4th −14:27 ± 9:51∗ −0:38 ± 0:91∗ LD Str. 0.002∗ 0.93 0.007∗ 0.33 0.002∗ 0.92 8th −44:57 ± 7:59∗ −1:53 ± 1:26∗ Abbreviation: PRE plus MT group: progressive resistance exercise plus manual therapy group; MCE group: motor control exercise group; n: number of athletes; UT: upper trapezius; MTr: middle trapezius; LT: lower trapezius; SA: serratus anterior; Supr: supraspinatus; A.D: anterior deltoid; LD: latissimus dorsi; time (wk): measurement at 4th and 8th week; M.D (G).: mean change groups; E.S: effect size: time effects; G: group effects; G ∗ T: group × time interactions; Str: strength; ∗ : significant at p < 0:05; ∗∗ : nonsignificant at p > 0:05. (p < 0:05). MCE group did not show improvement in supras- The percentage change in PRE plus MT and MCE group pinatus isometric (p < 0:05) (Table 5, Figure 2). The mean was statistically significant (p < 0:05) and in the range of change comparison of groups before and after treatments 21.48 to 41.78% and was 0.42 to 2.08%, respectively. Only revealed that both groups presented an increase in isometric supraspinatus muscle in the MCE group did not have signif- strength. However, the PRE plus MT group presented a sig- icant change (p < 0:05). There was statistically significant nificantly higher increase as per the effect size value in iso- main effect of time on isomeric strength UT: (p = 0:008), ES metric strength of muscles than those in the MCE group. = 0:65; MTr: (p = 0:007), ES = 0:80; LT: (p = 0:009), ES = 8 BioMed Research International ⁎ 300 ⁎ ⁎ ⁎ ⁎ 300 ⁎ ⁎ ⁎ 200 Newton 200 Newton 100 100 0 0 MCE PRE+MT MCE PRE+MT MCE PRE+MT MCE PRE+MT MCE PRE+MT PRE+MT MCE UT MTr Baseline Baseline 4th week 4th week 8th week 8th week (a) (b) ⁎ ⁎ ⁎ 200 ⁎ ⁎ 300 ⁎ ⁎ ⁎ 150 200 Newton Newton 100 100 50 0 0 PRE+MT MCE PRE+MT MCE PRE+MT MCE PRE+MT MCE PRE+MT MCE PRE+MT MCE LT SA Baseline Baseline 4th week 4th week 8th week 8th week (c) (d) ⁎ ⁎ 250 ⁎ 250 ⁎ ⁎ 200 200 Newton Newton 150 150 100 100 50 50 0 0 PRE+MT MCE PRE+MT MCE PRE+MT MCE PRE+MT MCE PRE+MT MCE PRE+MT MCE Supr Ant delt Baseline Baseline 4th week 4th week 8th week 8th week (e) (f) Figure 2: Continued. BioMed Research International 9 ⁎ 200 ⁎ ⁎ ⁎ 150 Newton 100 50 0 PRE+MT MCE PRE+MT MCE PRE+MT MCE LD Baseline 4th week 8th week (g) Figure 2: (a) UT isometric strength for the PRE plus MT and MCE group at baseline, 4th and 8th week. Data are presented as mean ± SD. ∗ Significant difference for p < 0:05. (b) MTr isometric strength for the PRE plus MT and MCE group at baseline, 4th and 8th week. Data are presented as mean ± SD. ∗ Significant difference for p < 0:05. (c) LT isometric strength for the PRE plus MT and MCE group at baseline, 4th and 8th week. Data are presented as mean ± SD. ∗ Significant difference for p < 0:05. (d) SA isometric strength for the PRE plus MT and MCE group at baseline, 4th and 8th week. Data are presented as mean ± SD. ∗ Significant difference for p < 0:05. (e) Supr. Isometric strength for the PRE plus MT and MCE group at baseline, 4th and 8th week. Data are presented as mean ± SD. ∗ Significant difference p < 0:05. (f) Ant Delt. Isometric strength for the PRE plus MT and MCE group at baseline, 4th and 8th week. Data are presented as mean ± SD . ∗ Significant difference for p < 0:05. (g) LD isometric strength for the PRE plus MT and MCE group at baseline, 4th and 8th week. Data are presented as mean ± SD. ∗ Significant difference for p < 0:05. 0:48; SA: ðp = 0:002ÞES = 0:93; Supr: (p = 0:005), ES = 0:85; for isometric strength of SA and LD muscle. Results also A, D: (p = 0:003), ES = 0:90; L.D: ðp = 0:002Þ, ES = 0:93 showed that there was a significant small increase or optimi- (Table 5). zation in isometric strength for A.D and UT, Supr. muscle for There were statistically significant group effects on iso- group effects. The interaction effects (group × time) were metric strength UT: (p = 0:004), ES = 0:39; MTr: (p = 0:009 largest for LD and SA muscles, respectively. In terms of effect ), ES = 0:16; LT: (p = 0:005), ES = 0:38; SA: (p = 0:006), ES size interpretation, the changes were large for time and inter- = 0:36; Supr.: (p = 0:004), ES = 0:39; A.D: (p = 0:003), ES = action effects, while for group effects, it was small [33]. The 0:40; LD: (p = 0:007), ES = 0:33 (Table 5). MCE group showed significant improvement in all examined There were statistically significant interaction effects muscles except for Supr. at both time points. The results (time × group) on isometric strength UT: (p = 0:007), ES = demonstrated that both interventions were effective in 0:62; MTr: (p = 0:006), ES = 0:77; LT MA: (p = 0:008), ES = improving and optimizing isometric strength; nevertheless, 0:45; SA: (p = 0:002), ES = 0:91, Supr.: (p = 0:004), ES = 0:84 athletes who underwent combined PRE plus MT presented ; A. D: (p = 0:003), ES = 0:88; LD: (p = 0:002), ES = 0:92 a more pronounced increase or optimization of isometric (Table 5). strength. The increase in isometric strength from the present study 4. Discussion is in line with other research findings involving therapeutic exercises [15, 35]. The abovementioned results are in syn- In this study, we compared the effect of two different proto- chrony with the study performed to evaluate isometric cols on the quantum of isometric improvement in overhead strength changes in shoulder impingement syndrome after athletes with SIS. This study has tried to fill in the void due two different exercise interventions in female subjects with to the dearth of evidence in the area of athletic injuries. The shoulder impingement syndrome [35]. The isometric primary findings of this study indicate that the largest strength in this study was measured by the isokinetic dyna- improvement in terms of isometric strength for between- mometer. The percentage change for the isometric strength groups analysis (descending order) occurred in AD, Supr, for MT, LT, SA, and Supraspinatus was 53.01, 50.74%, and UT muscles in the PRE plus MT group. The isometric 36.45%, and 58.01% (p < 0:001), respectively, for the experi- strength of A.D and UT decreased while that of Supr. mental group. On the contrary, the percentage change was increased as noted in the between-group analysis. Although found nonsignificant in the control group (p > 0:05) [35]. lesser, the MCE group also reported significant improvement In another study, the composite isometric strength measure- for all muscles except for Supr. For the within-group effects, ment was reported to have improved by 19.24% in the man- the highest improvement was found for Supr and SA muscles ual therapy plus exercise group and by 6.55% in the exercise in the PRE plus MT group. therapy group [15]. The percentage changes in the current The results of the study demonstrated that both groups study are also on similar lines (increasing trend) to the above- showed significant large improvement with respect to time mentioned studies for isometric strength of UT, MTr., LT, 10 BioMed Research International SA, supraspinatus, A.D, and LD (24.05%, -21.48%, -22.96%, between UT and SA. In continuation, when the subject takes -41.78%, -33.43%, 22.13%, and -37.22%, respectively). The the arms overhead, at that time, the two force couples of slightly higher isometric strength values in the abovemen- UT/LT and UT/SA are physiologically active. However, due tioned study could have been due to proper stabilization to SIS, this force couple is again disrupted, and LT and SA and support provided by the isokinetic device [35]. Although are inhibited and UT becomes overactive [40, 41]. The proto- significant, the percentage change was much lesser in the col used in this study might normalize these force couple by MCE group in the present study. Concerning the other study, first inhibiting the overtly active UT activity and then the gains might have been lesser than our study possibly due strengthening the other scapular muscles like LT and SA to the heterogeneous population (age group) and shorter [42, 43]. The stretching exercise component of the protocol duration of the intervention (3 weeks) [15]. In another study, alters the muscle spindle (Ia and II afferents) and perhaps which evaluated the effectiveness of conservative therapy ver- the Golgi tendon organ (Ib afferents) output to the central sus motor control and strengthening exercises, a total of 35 nervous system. Such an altered afferent drive is supposed subjects were subjected to 4 weeks (3 sessions per week) of to downregulate the activity of the α-motor neurons and treatment in both groups. The authors reported that there reduce the overactivity of the muscles [43]. Secondly, due to was a significant improvement in the external and internal the chronicity of SIS, there is an insidious decrease in rotator rotator strength in the motor control and strengthening cuff muscle activity and functioning. This usually starts with groups [36]. The combination of progressive resistance exer- the supraspinatus muscle, and if the dysfunction is not cise and manual therapy is a promising field of research in addressed effectively, the other remaining rotator cuff mus- SIS rehabilitation. A study that compared the effects of exer- cles also shut down, and there is a reduction in abduction cise therapy with and without manual therapy found that force. Rotator cuff muscles are also called the core muscles fifty-two subjects of SIS submitted to six sessions in the of the shoulder joint; in the presence of weak core muscles, experimental group (exercise and manual therapy) had sig- the superficially placed global muscles like anterior deltoid nificantly higher isometric muscle strength after an interven- start overworking. tion of 3 weeks [15]. In continuation, thirty-three subjects Reverse scapulohumeral rhythm is one of the results of with SIS were submitted to similar intervention for 6 weeks, this muscular dysfunction. In the present study, there was a similar improvement was observed in the strength and the reduction in the overactivity of the anterior deltoid and an function measures outcomes [24]. increase in activity of the supraspinatus muscle strength In contrast, few studies have reported contrary findings which suggests that this protocol of combined PRE plus than that of the present study. In one of the studies, forty- MT has the potential to correct this imbalance [42]. Thirdly, six patients were randomly divided into two groups, i.e., exer- one of the prime findings in SIS is a large reduction in exter- cise plus manual therapy and exercise therapy alone; both the nal rotation force, and it is also a vital prognostic marker. The groups received 4 weeks of intervention and concluded that usual postural phenotype of the scapular position reported the addition of manual therapy to an exercise protocol did and seen in SIS is excessive anterior tipping, internal rotation, not enhance muscle strength of individuals having SIS [37]. and scapular abduction. Due to this posture, the patients with Minor to inconclusive evidence on strength improvement SIS have rounded and stooped shoulders that further increase has been concluded by few meta-analytic studies for inte- the probability of impingent during overhead activities [9, grated exercise and manual therapy programs [22, 23, 38]. 44]. Glenohumeral external rotation of the shoulder requires Mainly, these reviews have concluded that most of the studies a stable preposition and kinematics of scapular retraction, to date lack strong methodology, homogenous group, and adduction, and scapular external rotation [41, 45]. The com- amalgamated protocol for effective management. bination of PRE plus MT in the present study increased the The present study was a randomized controlled trial with isometric muscle strength of MT, LT, and LD that might nor- a homogenous sample having SIS dysfunction and the proto- malize the kinematics of scapula and muscle length-tension col is a broad spectrum, based on best available evidence and relationship for optimal shoulder external rotation force encompasses progressive resistance exercise along with generation. stretching exercises, manual therapy which covers up for The strength of the study lies with the fact that the the lacunae of previous researches and future recommenda- present study is amongst the few studies that have exam- tions of meta-analysis. There are three plausible reasons for ined the combined effects of PRE plus MT and compared the results obtained in the present study. it with another effective treatment protocol of MCE in Firstly, the combined exercise therapy and manual ther- overhead athletes with SIS. Secondly, the protocol which apy protocol increased the activity of the scapular muscles has been adopted is an amalgamated protocol from best by initially inhibiting the overactive muscles like Ant. Deltoid practice patterns reported by authors in research and no and UT as reported in literature [39]. These two overactive adverse effects were reported. Thirdly, the manual therapy muscles are known to disturb the functioning of force cou- techniques used in the study was performed by practi- ples around the shoulder complex. The UT and SA force cou- tioner having requisite experience after postgraduate ple during the 0° to 30° of movement is impaired in SIS. As education. per the Janda approach, due to pain, all periscapular muscles undergo inhibition of their activity except the antigravity 4.1. Limitations. In the present study, only male overhead muscle like the upper trapezius [40]. This leads to overactiv- athletes were recruited, which could have a bearing on the ity of the upper trapezius, and it disturbs the strength ratio generalization of the results of the study for all overhead BioMed Research International 11 athletes. Secondly, there was no follow-up with the athletes References after the intervention. The compliance of the athletes with the treatment proto- [1] M. A. Mohseni-Bandpei, R. Keshavarz, H. Minoonejhad, cols in both groups was good. There were no adverse effects H. Mohsenifar, and H. 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