Intraexaminer reliability of hand-held dynamometry in the upper extremity: a systematic review

Relationships among lateral medicine ball throw test performance, HIP and trunk muscle strength, and lower limb kinematics: A cross-sectional study

INTRODUCTION

The lateral medicine ball throw (LMBT) test is used to evaluate the throwing action, involving the entire kinetic chain and the principle of force transfer, with association between the strength of the lower limb and trunk muscles and the lower limb kinematics. The LMBT to investigate the association between lower limb kinematics and hip and trunk muscle strength.

EXPERIMENTAL

This was a cross-sectional study with 84 healthy and physically active young people. Determinations were made of the maximum isometric strengths of the hip abductor, lateral rotator, extensor, and flexor muscles, and the trunk lateral flexors and extensors. Kinematic analyses (2D) of the hip, knee, and ankle in the sagittal and frontal planes were performed during the countermovement phase of the LMBT, together with quantification of LMBT. Statistical analysis of the associations employed multiple linear regression, with α = 5%.

RESULTS

There were significant associations between the LMBT and the independent variables hip extensors strength, trunk flexors strength, valgus angle, and knee flexion angle and gender. The regression model presented adjusted R2 = 0.622.

CONCLUSIONS

LMBT was influenced by the trunk flexor and hip extensor muscle strengths, knee flexion kinematics, lower limb valgus in the countermovement phase, and gender.

Differences in biomechanical and metabolic factors between patients with frozen shoulder and asymptomatic individuals. A cross-sectional study

BACKGROUND

the pathogenesis of frozen shoulder (FS) is thought to be one of inflammation and fibrosis possibly influenced by hyperglycemia. Biomechanical changes of the shoulder joint in terms of muscle strength, scapular kinematics and proprioception might occur in FS.

OBJECTIVES

to compare muscle strength, scapular kinematics, proprioception, and blood glucose levels within patients with FS and to asymptomatic individuals.

DESIGN

cross-sectional study.

METHOD

Thirty-five patients with FS and 35 asymptomatic age and gender-matched individuals underwent physical assessment to determine muscle strength (abduction, external and internal rotation), scapular kinematics (both visually and with a plurimeter), proprioception (joint position sense), and blood glucose level.

RESULTS

Patients with FS showed a decrease in muscle strength in their affected shoulder compared to both the unaffected shoulder and asymptomatic individuals. Significant differences were found between the affected and unaffected shoulder in the FS group and between groups (FS versus controls) in scapular upward rotation (plurimeter) at 30° and 60° abduction. No difference in scapular kinematics (visual observation), proprioception, and blood glucose levels was found neither between shoulders in the FS group nor between groups.

CONCLUSION

A clinically relevant difference in muscle strength and increase in scapular upward rotation were found in the affected shoulder of patients with FS compared to their unaffected side and controls. However, no evidence of different levels of scapular kinematics (visual observation), proprioception, and blood glucose levels in the affected shoulder compared to the unaffected shoulder or controls is lacking.

Multimodal sensorimotor assessment of hand and forearm asymmetries: a reliability and correlational study

Background

Effective rehabilitation of upper limb musculoskeletal disorders requires multimodal assessment to guide clinicians' decision-making. Furthermore, a comprehensive assessment must include reliable tests. Nevertheless, the interrelationship among various upper limb tests remains unclear. This study aimed to evaluate the reliability of easily applicable upper extremity assessments, including absolute values and asymmetries of muscle mechanical properties, pressure pain threshold, active range of motion, maximal isometric strength, and manual dexterity. A secondary aim was to explore correlations between different assessment procedures to determine their interrelationship.

Methods

Thirty healthy subjects participated in two experimental sessions with 1 week between sessions. Measurements involved using a digital myotonometer, algometer, inclinometer, dynamometer, and the Nine-Hole Peg test. Intraclass correlation coefficients, standard error of the mean, and minimum detectable change were calculated as reliability indicators. Pearson's correlation was used to assess the interrelationship between tests.

Results

For the absolute values of the dominant and nondominant sides, reliability was 'good' to 'excellent' for muscle mechanical properties, pressure pain thresholds, active range of motion, maximal isometric strength, and manual dexterity. Similarly, the reliability for asymmetries ranged from 'moderate' to 'excellent' across the same parameters. Faster performance in the second session was consistently found for the Nine-Hole Peg test. No systematic inter-session errors were identified for the values of the asymmetries. No significant correlations were found between tests, indicating test independence.

Conclusion

These findings indicate that the sensorimotor battery of tests is reliable, while monitoring asymmetry changes may offer a more conservative approach to effectively tracking recovery of upper extremity injuries.

Test-retest reliability and concurrent validity of knee extensor strength measured by a novel device incorporated into a weight stack machine vs. handheld and isokinetic dynamometry

BACKGROUND

The current clinical gold standard for assessing isometric quadriceps muscle strength is an isokinetic dynamometer (IKD). However, in clinics without an IKD, clinicians default to using handheld dynamometers (HHD), which are less reliable and accurate than the IKD, particularly for large muscle groups. A novel device (ND) was developed that locks the weight stack of weight machines, and measures forces applied to the machine, turning this equipment into an isometric dynamometer. The objectives of this study were to characterize the test-retest reliability of the ND, determine the within-day and between-days inter-rater reliability and concurrent validity compared with that of the HHD, in healthy volunteers (HV) and individuals with knee osteoarthritis (OA) for measuring knee extensors isometric muscle force.

MATERIALS AND METHODS

29 healthy (age = 28.4 ± 7.4 years) and 15 knee OA (age = 37.6 ± 13.4 years) participants completed three maximum force isometric strength testing trials on dominant side knee extensor muscles on three devices (ND, HHD, and IKD) in two separate sessions by two raters. The maximum force (Fmax) produced, and the force-time series were recorded. Reliability and validity were assessed using Intraclass Correlation Coefficient (ICC), Bland-Altman Plots, Pearson's r, and cross-correlations.

RESULTS

The ND demonstrated excellent test-retest reliability (ICC2,3 = 0.97). The within-day (ICC2,3 = 0.88) and between-day inter-rater reliability (ICC2,3 = 0.87) was good for HHD. The ND showed excellent within-day (ICC2,3 = 0.93) and good between-day (ICC2,3 = 0.89) inter-rater reliability. The Bland-Altman analysis revealed HHD systematic bias and underestimation of force particularly with quadriceps force values exceeding 450 N. Mean differences were found in maximum force between HHD vs. IKD (MDabs = 58 N, p < .001) but not the HHD vs. ND (MDabs = 24 N, p = .267) or ND vs. IKD (MDabs = 34 N, p = .051). The concurrent validity of Fmax (r = 0.81) and force-time curve correlation (0.96 ± 0.05) were the highest between the ND and IKD.

CONCLUSIONS

The ND's test-retest reliability and concurrent validity make it a potential strength assessment tool with utility in physical therapy and fitness settings for large muscle groups such as the knee extensors.

Novel Posterior Shoulder Stretching With Rapid Eccentric Contraction and Static Stretching in Patients With Subacromial Pain Syndrome: A Randomized Trial

BACKGROUND

In subacromial pain syndrome (SPS), it is unknown whether posterior shoulder stretching exercises (PSSE) with rapid eccentric contraction, a muscle energy technique, improve clinical and ultrasonographic outcomes more than no stretching or static PSSE.

HYPOTHESIS

PSSE with rapid eccentric contraction is superior to no stretching and static PSSE in improving clinical and ultrasonographic outcomes in SPS.

STUDY DESIGN

Randomized controlled trial.

LEVEL OF EVIDENCE

Level 1.

METHODS

Seventy patients with SPS and glenohumeral internal rotation deficit were randomized into the modified cross-body stretching with rapid eccentric contraction group (EMCBS; n = 24), static MCBS group (SMCBS; n = 23), or control group (CG; n = 23). In addition to 4-week physical therapy, EMCBS received PSSE with rapid eccentric contraction, SMCBS static PSSE, and CG no PSSE. The primary outcome was internal rotation range of motion (ROM). Secondary outcomes were posterior shoulder tightness, external rotation ROM (ERROM), pain, modified Constant-Murley score, short form of the disabilities of the arm, shoulder, and hand questionnaire (QuickDASH), rotator cuff strength, acromiohumeral distance (AHD), supraspinatus tendon thickness, and supraspinatus tendon occupation ratio (STOR).

RESULTS

Shoulder mobility, pain, function and disability, strength, AHD, and STOR improved in all groups (P < 0.05).

CONCLUSION

In patients with SPS, PSSE with rapid eccentric contraction and static PSSE were superior to no stretching in improving clinical and ultrasonographic outcomes. Stretching with rapid eccentric contraction was not superior to static stretching, but improved ERROM compared with no stretching.

CLINICAL RELEVANCE

In SPS, both PSSE with rapid eccentric contraction and static PSSE included in physical therapy program are beneficial to improve posterior shoulder mobility and other clinical and ultrasonographic outcomes. In the case of ERROM deficiency, rapid eccentric contraction might be preferred.

The Shanghai Elbow Dysfunction Score: Psychometric Properties, Reliability and Validity Study of the Turkish Version

The Shanghai Elbow Dysfunction Score (SHEDS) is a self-reported assessment of post-traumatic elbow stiffness that measures elbow-related symptoms and elbow motion capacities. This study aimed to (1) translate and cross-culturally adapt the SHEDS into Turkish and (2) investigate the psychometric properties of the Turkish version in patients with post-traumatic elbow stiffness. The psychometric properties of the Turkish version of the SHEDS (SHEDS-T) were tested in 108 patients (72 male; mean age, 43.2 ± 11.2 years) with post-traumatic elbow stiffness. Cronbach's alpha was used to assess internal consistency. The intraclass correlation coefficients were used to estimate test-retest. Construct validity was analyzed with the Turkish version of the Disabilities Arm, Shoulder and Hand (DASH), the Mayo Elbow Performance Score (MEPS), and the Short Form-12 (PCS-12 and MCS-12). The SHEDS-T showed sufficient internal consistency (Cronbach's α coefficient = 0.83) and test-retest reliability (ICC = .96). The correlation coefficients between the SHEDS-T, the DASH, and the MEPS were .75 and .54, respectively (p < .001). There was a moderate correlation between the SHEDS-T and PCS-12 (r = .65, p = .01) and a weak positive correlation between the SHEDS and the MCS-12 (r = .40, p = .03). The SHEDS-T has sufficient reliability and validity to measure elbow-related symptoms and elbow motion capacities for Turkish-speaking individuals with post-traumatic elbow stiffness.

Rehabilitation of the painful shoulder

Managing the painful shoulder in overhead athletes can be difficult because of a lack of time-loss injuries in overhead sports and focusing primarily on either pathoanatomic causes or movement impairments. Although managing the painful shoulder can be challenging, the combination of identifying pathoanatomic causes with movement impairments can provide a more focused rehabilitation approach directed at the causes of shoulder pain. Understanding the potential influence of scapular positioning as well as mobility and/or strength impairments on shoulder pain can help clinicians develop more directed rehabilitation programs. Furthermore, sports-specific methods such as long toss or the use of weighted balls for achieving physiological or performance-based gains have limited empirical evidence regarding their clinical and performance-based benefits, which may impede the rehabilitation process. Applying a comprehensive evaluation approach prior to and throughout the treatment process can assist clinicians with selecting the most appropriate treatment based on patient need. Reconsidering traditional treatments based on existing evidence may help refine the treatment process for overhead athletes with shoulder pain.

Are luggage scales a viable alternative to hand-held dynamometers for the measurement of shoulder scaption strength?

Background

The accurate and reliable measurement of muscle strength is a valuable tool in most medical practices. The use of dynamometers allows for objective muscle strength assessment. Even so, dynamometry has its limitations due to increased cost and inconvenience in the clinic. Isokinetic dynamometers, the gold standard, are typically very large and expensive. However, smaller hand-held dynamometers are a cheaper and more efficient alternative. Hand-held dynamometers have been shown to demonstrate comparable reliability to the more expensive isokinetic dynamometers, despite their reduced cost and ease of use. Even though hand-held dynamometers are cheaper and more convenient to use in the clinical setting, their price tag is still burdensome for most medical practices, commonly costing $1000 or more. The aim of this study is to assess the reliability of luggage scales vs. dynamometers for measuring shoulder scaption strength.

Methods

One hand-held dynamometer was compared to two luggage scales using a set-up intended to mimic clinical testing. The set-up consisted of each device being tethered to the floor with the opposite end tied to a length of paracord that had been placed through a shoulder-height pulley and fastened to a flat plate used to hold the weight. In total, ten trials were completed, where a 2.3 kg (5 lb), 4.5 kg (10 lb), and 11.3 kg (25 lb). weight was measured by each device. Analysis of variance was used to compare the numerical data for the three groups.

Results

Our results indicate that there were no significant differences in the force measurements between each device (P = .99). The average force measurements between the three dynamometers were: 2.3 kg trial: 2.3 kg, 2.4 kg, and 2.2 kg; 4.5 kg trial: 4.5 kg, 4.6 kg, and 4.5 kg ; and 11.3 kg trial: 11.4 kg, 11.3 kg, and 11.4 kg. for the digital dynamometer, digital luggage scale, and the analog luggage scale, respectively. Subgroup analysis showed there was also no difference in force measurements between the 3 devices for the 2.3 kg, 4.5 kg, and 11.3 kg. trials (P = .14, P = .49, and P = .40, respectively).

Conclusion

Our data demonstrates that two inexpensive luggage scales showed no statistically significant differences in measurements compared to an expensive hand-held dynamometer. Utilization of luggage scales to measure shoulder scaption strength should yield similar results to handheld dynamometers. This may be an alternative, objective measure of manual muscle strength that is both efficient and economical.

Isometric Shoulder Testing Using a Forcemeter Is a Reliable Method of Strength Evaluation

Isometric strength testing using a digital dynamometer is reliable for muscle function evaluation. It allows us to objectify manual strength assessment measurement. We tested intra- and inter-observer reliability of a user-friendly efficient digital dynamometer-the Forcemeter-equipped with a computer program to monitor the measurements and to store the data. Abduction, forward flexion, and external and internal rotation of both shoulders were tested three times in 20 healthy volunteers with no record of shoulder trauma. Isometric contracture was recorded in newtons. The first and the third test were carried out by Examiner A (intra-rater reliability); the second test, by Examiner B (inter-rater reliability). Good reliability was shown for intra-class correlation coefficient (ICC) values which mean moderate to high correlations (r = 0.66-0.93) for both examiners. Moderate to high correlations (r = 0.72-0.91) were found for comparisons between the results obtained by Examiner A.

Rehabilitation of Annular Pulley Injuries of the Fingers in Climbers: A Clinical Commentary

ABSTRACT

The annular pulley ligaments of the fingers are one of the most injured anatomical structures in those who participate in climbing. Despite this, there is a paucity of guidance clearly describing the rehabilitation and physical preparation parameters to return to sport following such injuries. The foundation of effective rehabilitation is the judicious application of progressive loading to increase the morphological and material properties of the damaged tissues. We maintain the optimal management of the climbing athlete after a traumatic annular flexor pulley system rupture should be grounded in the principles of strength and conditioning.

Intra- and interrater reliability of belt-stabilized hand-held dynamometer in scapular protraction strength tests in individuals with shoulder pain

PURPOSE

Scapular protraction strength can be evaluated using a hand-held dynamometer (HHD). However, it is necessary to measure the reliability of HHD in individuals with shoulder pain and to minimize the limitations related to the evaluator and the low methodological quality cited in previous studies. This study assessed, with methodological enhancement, the intra- and interrater reliability of belt-stabilized HHD in the assessment of scapular protraction strength in individuals with shoulder pain.

METHOD

Fifty individuals with unilateral symptoms of subacromial pain syndrome (20 men, aged 40.5 ± 15.3 years) were evaluated in two sessions using the belt-stabilized HHD for maximum isometric strength of scapular protraction with the individual in the sitting and supine positions. Reliability values were obtained using the intraclass correlation coefficient with the standard error of measurement (SEM and %SEM) and the minimal detectable change (MDC).

RESULTS

The intra- and interrater HHD reliability were excellent for all measurements ranging from 0.88 to 0.96 (SEM = 2.0-4.0 kg; %SEM 12 to 17; MDC = 6-11 kg).

CONCLUSION

Belt-stabilized HHD is reliable for the assessment of scapular protraction strength in individuals with subacromial pain syndrome in both the sitting and supine positions.

Assessment of Physical Tests in 6-11 Years Old Children: Findings from the Play Lifestyle and Activity in Youth (PLAY) Study

The purpose was to evaluate selected physical tests in children and to compare the outcomes by sex. A cross-sectional study design was used to evaluate children 6-11 years who completed five physical tests: hand grip, vertical jump, sit and reach, Y-balance, and obstacle course (time and score). The outcome measures including test results were descriptively examined and compared by sex. The study participants consisted of 133 children (62 males and 71 females, with a median age of 7.8 years). Girls showed superior sit and reach performance (p = 0.002) compared with boys. Boys demonstrated better Y-balance scores (p = 0.007) and faster obstacle time (p = 0.042) than girls. Sex comparison within three age groups (6-<8 years, 8-<10 years, and 10-<12 years) showed that girls performed better on the sit and reach compared with boys in the in 6-<8 years (p = 0.009). Boys demonstrated higher Y-balance scores (p = 0.017) and faster obstacle time (p = 0.007) compared with girls in the 8-<10-year age group. These data will serve to guide future efforts to evaluate normative measures of physical literacy and guide targeted training interventions to promote sustained physical activity in children with deficits relative to their age and sex norms.

Test-Retest Reliability and Minimum Difference Values of a Novel and Portable Upright Row Strength Assessment in Probation Officers

Upper body (UB) strength is important for occupational tasks and injury prevention in law enforcement officers (LEOs). Portable, reliable, and cost-effective assessments are needed to examine UB strength among LEOs in field settings. The purpose of this study was to examine the test-retest reliability and minimum difference (MD) values of a novel and portable isometric upright row assessment in probation officers. Thirty certified probation officers (18 women; age = 38.9 ± 9.0 years, body mass = 98.8 ± 27.1 kg, stature = 171.4 ± 14.0 cm) volunteered for this investigation. Testing occurred on-site across two sessions (2-5 days apart). Participants stood upon an aluminum plate with a chain attached to a handle and dynamometer. They grasped the handle with a pronated grip, two cm below the umbilicus, and performed three isometric maximal voluntary contractions. Intraclass correlation coefficient (ICC2,1), standard error of the measurement (SEM), and MD values were calculated. Results indicated no significant systematic error (p = 0.080) across sessions. The ICC2,1, SEM, and MD values for UB strength were 0.984, 27.20 N (4.1% of the mean), and 75.38 N (11.3% of the mean), respectively. These data suggest this isometric upright row assessment is a reliable, portable, and cost-effective measure of UB strength to assess and monitor LEOs in field settings.

Shoulder Proprioception Following Reverse Total Shoulder Arthroplasty for Unreconstructable Upper Third Fractures of the Humerus: 2-Year Outcomes

Background

Proximal humerus fractures may be comminuted in the elderly or after injury with high-energy mechanisms. Reverse total shoulder arthroplasty that may affect shoulder proprioception (rTSA) has also begun to play a part in treating acute proximal humeral fractures. In this study, the authors aimed to evaluate joint position sense (JPS) after rTSA.

Methods

Humac Norm II isokinetic device was used to evaluate the joint position sense. A joint angle was determined and the ability of the patient to create the same value of the angle by the active movement was evaluated. The difference between the pre-determined angle and the patient's measured angle was recorded. For proprioceptive sense, the initial position was 0° and the determination position was 30°, 60°, and 90° for flexion and abduction, and 15° and 30° for internal rotation and external rotation.

Results

While both the mean Constant and ADLEIR scores did not differ between non-operated and operated sides, the mean proprioception differences in all flexion (30°, 60°, and 90°), abduction (30°, 60°, and 90°), internal rotation (15° and 30°), and external rotation (15° and 30°) were significantly higher in the operated side than that in non-operated side (p < 0.01 for each pairwise comparison).

Conclusion

Reverse total shoulder arthroplasty (rTSA) treatment, which has increasingly become a surgical option in un-reconstructable proximal humeral fractures has significant adverse effects on proprioception on the operated side and may pose a risk for long-term instability, premature loosening, and prosthesis mechanical complications, in this context, well-designed prospective controlled studies are required.

Reliability and Validity of Scoliosis Measurements Obtained with Surface Topography Techniques: A Systematic Review

BACKGROUND

Surface topography (ST) is one of the methods in scoliosis assessment. This study aimed to systematically review the reliability and validity of the ST measurements for assessing scoliosis.

METHODS

A literature search of four databases was performed and is reported following PRISMA guidelines. The methodological quality was evaluated using Brink and Louw appraisal tool and data extraction was performed. The results were analyzed and synthesized qualitatively using the level of evidence method.

RESULTS

Eighteen studies were included and analyzed. Four were evaluated for reliability, six for validity, and eight for reliability and validity. The methodological quality of fourteen studies was high. Good to excellent intra-investigator reliability was shown on asymmetry, sagittal, horizontal, and most frontal ST measurements (evidence level: strong). Asymmetry and most frontal, sagittal, horizontal ST measurements showed good to excellent inter-investigator reliability (evidence level: moderate). When comparing corresponding ST and radiological measurements, good to strong validity was shown on most frontal, sagittal, and asymmetry measurements (evidence level: strong). Formetric measurements had good intra-investigator reliability and validity (evidence level: strong).

CONCLUSIONS

Most asymmetry, sagittal, and frontal ST measurements showed satisfactory reliability and validity. Horizontal ST measurements showed good reliability and poor validity. The ST technique may have great potential in assessing scoliosis, especially in reducing radiation exposure and performing cosmetic assessments.

The Intra- and Inter-Rater Reliability of a Variety of Testing Methods to Measure Shoulder Range of Motion, Hand-behind-Back and External Rotation Strength in Healthy Participants

This study determined the intra- and inter-rater reliability of various shoulder testing methods to measure flexion range of motion (ROM), hand-behind-back (HBB), and external rotation (ER) strength. Twenty-four healthy adults (mean age of 31.2 and standard deviation (SD) of 10.9 years) without shoulder or neck pathology were assessed by two examiners using standardised testing protocols to measure shoulder flexion with still photography, HBB with tape measure, and isometric ER strength in two abduction positions with a hand-held dynamometer (HHD) and novel stabilisation device. Intraclass correlation coefficient (ICC) established relative reliability. Standard error of measurement (SEM) and minimum detectable change (MDC) established absolute reliability. Differences between raters were visualised with Bland-Altman plots. A paired t-test assessed for differences between dominant and non-dominant sides. Still photography demonstrated good intra- and inter-rater reliability (ICCs 0.75-0.86). HBB with tape measure demonstrated excellent inter- and intra-rater reliability (ICCs 0.94-0.98). Isometric ER strength with HHD and a stabilisation device demonstrated excellent intra-rater and inter-rater reliability in 30° and 45° abduction (ICCs 0.96-0.98). HBB and isometric ER at 45° abduction differed significantly between dominant and non-dominant sides. Standardised shoulder ROM and strength tests provide good to excellent reliability. HBB with tape measure and isometric strength testing with HHD stabilisation are clinically acceptable.

The Impact of Piano Styles on Muscle Force in Pianist Students

The study of the consequences of different sonata styles (baroque, classical and romantic piano repertoire) on pianists’ upper limbs represents a research topic for both the musical and medical fields. Twenty piano students were examined using a MicroFet2 dynamometer after playing three sonatas (Scarlatti K. 1 Sonata as a representative of the baroque style, Haydn Sonata no. 60 for the classical style and Chopin second Sonata for the romantic style). The phase sequence was randomised for each subject: firstly, continuous interpretation of 10 bars of a sonata was conducted 10 times, with the metronome tempo set by the investigator; secondly, the subject interpreted 10 bars of a different sonata continuously, standardised by tempo, which was carried out 10 times; finally, the continuous interpretation of 10 bars of the remaining third sonata, standardised by tempo, was carried out 10 times. After each performance of the 10 bars, the elbow extensor’s isometric muscle force was measured. Significant differences were found between the elbow extensor’s isometric muscle force assessed after playing Scarlatti’s sonata and Haydn’s sonata (p = 0.005 for left arm, p = 0.03 for right arm), between Scarlatti’s sonata and Chopin’s sonata (p < 0.0001 for both left and right arms) and between Haydn’s sonata and Chopin’s sonata (p = 0.01 for left arm, p < 0.0001 for right arm). In healthy piano students, the dynamometric assessment of elbow extensors’ isometric muscle force after playing three different sonatas (baroque, classical and romantic) showed that the lowest values were recorded after playing the baroque style. Our results showed bilateral symmetry in the elbow extensor’s isometric muscle force for all three piano styles. The testing of arm muscles, besides that of the fingers, should be considered as a regular evaluation for future professional pianists with regard to the prevention of musculoskeletal complaints.

Isometric strength of upper limb muscles in youth using hand-held and hand-grip dynamometry

The present study aimed to determine the isometric strength profile of the upper limb muscles of children and adolescents between 7–15 years of age. Furthermore, to (a) identify the age at which differences in strength are observed between sexes; to (b) determine the age range at which significant progression of strength could be observed; and (c) identify the role of each muscle on the total upper limb strength. Cross-sectional study that evaluated the isometric strength of nine muscle groups of the upper limb of 243 Chilean children, split into 9 age groups, separated by 1-year intervals. For this, hand-held dynamometry and hand-grip dynamometry were used. A two-factor analysis of variance for the maximum isometric strength and a stepwise multiple linear regression analysis were performed. From 11 years of age, wrist flexors were the first muscle group that revealed a significant difference in isometric strength in favor of boys (P=0.0143). In boys, the narrowest and earliest age range in the progression of isometric strength was 10 to 12 years for wrist flexors (P=0.0392). Shoulder flexors was the main factor that explained the performance of the total upper limb strength (R²=0.742; P<0.001). The most progressive isometric strength development occurred from age 10 years in the ventral and distal muscles of the upper limb; and from this age the boys begin to present a greater isometric strength than girls. In addition, the isometric strength of shoulder flexors explained the higher total upper limb strength performance.

Reliability and Validity of the ActivForce Digital Dynamometer in Assessing Shoulder Muscle Force across Different User Experience Levels

Background

Currently available hand-held dynamometers (HHD) offer a more objective and reliable assessment of muscle force production as compared to a manual muscle test (MMT). Yet, their clinical utility is limited due to high cost. The ActivForce (AF) digital dynamometer is a new low-cost HHD with unknown psychometric properties, and its utilization may benefit clinical practice.

Hypothesis/Purpose

This study aimed to determine the AF intra- and inter-tester reliabilities, standard error of measurement (SEM), minimal detectable change (MDC), and criterion validity for assessing shoulder isometric force as compared to the microFET2 (MF2) across testers with different experiences.

Design

Descriptive observational study.

Methods

A convenience sample of 29 healthy adults were assessed twice by each of three testers (two experienced clinicians and a novice PT student) on shoulder external rotation (ER), internal rotation (IR), and forward elevation (FE) using both the AF and MF2 devices. Tester, HHD, and shoulder motion assignment orders were randomized. All testing was performed in a standardized seated position. ER and IR were tested with the shoulder fully adducted. FE was tested at 45° at the scapular plane. All testing and rest periods between testers and tested motions were standardized and monitored via a stopwatch.

Results

Both devices had high intra- [ ER (.95-.98), IR (.97 - .99), FE (.96 - .99)] and inter-tester [ ER (.85-.96), IR (.95 - .97), FE (.88 - .95)] intraclass correlation coefficient (ICC) with comparable intra- (1.68-1.80) and inter-tester (2.36-2.98) SEM, and intra- (4.64-4.97) and inter-tester (6.50-8.24) MDC values across all motions. Tester experience did not affect these values. High (.89-.93) statistically significant Pearson correlations were found between HHDs for all shoulder motions.

Conclusion

Both the AF and MF2 HHDs were found to have high reliability levels across all shoulder motions regardless of tester clinical experience. The AF was also found to be valid for measuring shoulder isometric force production compared to the criterion standard device, the MF2. Its low-cost and electronic accessibility features may promote better compliance for clinicians using dynamometry to objectively assess and store muscle force data in a cost-effective manner.

Level of Evidence

3.

The internal rotation and shift-test for the detection of superior lesions of the rotator cuff: reliability and clinical performance

Background

Using reliable and valid clinical tests are essential for proper diagnosis and clinical outcomes among injuries involving the rotator cuff. The addition of a new clinical examination test could improve the clinical diagnosis and informative value of the sensitivity and specificity of pathology. This study of diagnostic accuracy evaluated the use of a new rotator cuff test, called the internal rotation and shift-test (IRO/shift-test), to determine its reliability and clinical performance (sensitivity, specificity, positive (PPV)/negative predictive value (NPV)). Clinical diagnostic outcomes were confirmed with radiological findings (MRI).

Methods

100 patients from a specialized shoulder unit participated (64 male, 36 female, mean age: 55 ± 13.5 years). A single-blinded (no knowledge of prior clinical or technical diagnostics) study design was used with two experienced physicians performing the IRO/shift-test. For clinical performance, all clinical testing was compared with MRI.

Results

The intra-rater (ICC = 0.73, 95% CI: 60-82) and inter-rater (ICC = 0.89, 95% CI: 81-94) coefficients for the IRO/shift-test showed good-to-excellent reliability. 75% of the patients showed a positive IRO/shift-test, while 65% had a radiologically diagnosed superior rotator cuff tear. 60% of these patients had both a positive IRO/shift-test and objective rotator cuff tear via MRI. The sensitivity of the IRO/shift-test to detect superior rotator cuff lesions based on MRI diagnosis was calculated at 92% (95% CI: 86-99%), while specificity was 67% (95% CI: 50-84%). Predictive values were also found to be high with 86% PPV (95% CI: 78-94%) and 80% NPV (95% CI: 64-96%).

Conclusion

Our results demonstrate that the IRO/shift-test is a reliable and valid tool for assessing superior rotator cuff pathology. With good-to-excellent intrarater and inter-rater reliability and strong sensitivity and specificity this test should be considered a valuable addition to clinicians' cadre of clinical evaluation tools.

Differences in Health-Related Physical Fitness and Academic School Performance in Male Middle-School Students in Qatar: A Preliminary Study

This study examined the differences in the level of physical fitness and academic performance among male middle-school children based on different body status categories. A total of 69 male children [age: 12.4 ± 0.7 years; body mass: 58.5 ± 7.2 kg; height: 1.62 ± 0.09 m; and body mass index (BMI): 22.4 ± 3.3 kg/m²] participated and were divided into BMI age-adjusted groups (i.e., lowest, middle, and highest BMI). Height, mass, BMI, stork test of static balance, 10 and 15 m sprint as an indicator for speed, hand-grip strength test, agility T-half test, medicine ball throw (MBT), and the Yo-Yo Intermittent Recovery Test level 1 (Yo-Yo IR1) were assessed. School records were retrieved for grade point averages (GPA) of mathematics, science, and Arabic. We found significant group differences regarding anthropometric (height: ηp2 = 0.24, mass: ηp2 = 0.33, and BMI: ηp2 = 0.66), physical (sprint 10 m: ηp2 = 0.26), and academic (mathematics: ηp2 = 0.19 and science: ηp2 = 0.15) performance parameters. The largest difference (p < 0.001) was observed between the lowest and highest group for the 10 m sprint. All pairwise differences were between the lowest and highest BMI group or the lowest and middle BMI group. No relevant (r > 0.5) correlation between parameters of different dimensions (e.g., anthropometric vs. physical performance parameters) was found. In conclusion, the highest BMI group exhibited similar physical and academic performances than the lowest group. Thus, these data emphasize the importance and appropriateness to engage young Qatari schoolchildren in physical activity as it associates with superior academic performance.

Function, strength, and muscle activation of the shoulder complex in Crossfit practitioners with and without pain: a cross-sectional observational study

BACKGROUND

The shoulder joint is the most commonly injured joint in CrossFit practitioners, because of the high intensity and loads associated with this sport. Despite the large number of clinical cases, there is a shortage of studies that investigate influence of biomechanical aspects of upper limbs' injuries on CrossFit practitioners. This study hypothesized that there would be a difference in function, strength, and muscle activation between Crossfit practitioners with and without shoulder pain.

METHODS

We divided 79 Crossfit practitioners into two groups according to whether they reported pain (n = 29) or no pain (n = 50) in the shoulder during Crossfit training. Muscle function, strength, and activation were assessed using the Disability Arm, Shoulder and Hand function questionnaire, Upper Quarter Y Balance Test and Closed Kinetic Chain Upper Extremity Stability Test shoulder tests, isometric muscle strength assessment by manual dynamometry and muscle activation by surface electromyography and pain report.

RESULTS

The function based on questionnaire was associated with pain (p = 0.004). We observed a statistically significant difference between the two groups only in the surface electromyography activity of the lower trapezius, and in the variables of shoulder pain and function (p = 0.038).

CONCLUSION

Crossfit practitioners with shoulder pain occurring during training showed good function and stability of the shoulder joint, but there was a reduction in the activation of stabilizing muscles, especially the lower trapezius. Trial registration Registro Brasileiro de Ensaios Clinico (Brasilian National Registry) with the ID: RBR-2gycyv.

The Validity and Reliability of Two Commercially Available Load Sensors for Clinical Strength Assessment

Objective: Handheld dynamometers are common tools for assessing/monitoring muscular strength and endurance. Health/fitness Bluetooth load sensors may provide a cost-effective alternative; however, research is needed to evaluate the validity and reliability of such devices. This study assessed the validity and reliability of two commercially available Bluetooth load sensors (Activ5 by Activbody and Progressor by Tindeq). Methods: Four tests were conducted on each device: stepped loading, stress relaxation, simulated exercise, and hysteresis. Each test type was repeated three times using the Instron ElectroPuls mechanical testing device (a gold-standard system). Test–retest reliability was assessed through intraclass correlations. Agreement with the gold standard was assessed with Pearson’s correlation, interclass correlation, and Lin’s concordance correlation. Results: The Activ5 and Progressor had excellent test–retest reliability across all four tests (ICC(3,1) ≥ 0.999, all p ≤ 0.001). Agreement with the gold standard was excellent for both the Activ5 (ρ ≥ 0.998, ICC(3,1) ≥ 0.971, ρ_c ≥ 0.971, all p’s ≤ 0.001) and Progressor (ρ ≥ 0.999, ICC(3,1) ≥ 0.999, ρ_c ≥ 0.999, all p’s ≤ 0.001). Measurement error increased for both devices as applied load increased. Conclusion: Excellent test–retest reliability was found, suggesting that both devices can be used in a clinical setting to measure patient progress over time; however, the Activ5 consistently had poorer agreement with the gold standard (particularly at higher loads).

Reliability and validity of hand-held dynamometry for assessing lower limb muscle strength

BACKGROUND: Hand-held dynamometry (HHD) is used to assess muscle strength in various patient populations, but many variations in protocols exist. OBJECTIVE: First, to systematically develop a protocol of HHD for all lower limb muscle groups and evaluate intra-rater reliability; second, to validate HHD with fixed dynamometry for the knee flexor and extensor muscles. METHODS: Thirty healthy young adults (women: men – 15:15) participated in two testing sessions. HHD of 12 lower limb muscle groups was performed in both sessions, while fixed dynamometry of knee muscle groups was performed only in the second session. RESULTS: The intra-rater reliability of HHD was good for five muscle groups and excellent for seven muscle groups (ICC3, k= 0.80–0.96). The criterion validity of HHD ranged from very good to excellent for the knee flexors (r= 0.77–0.89) and from good to very good for the knee extensors (r= 0.65–0.78). However, peak moment values for the knee extensor muscles were underestimated by 32% (p< 0.001). CONCLUSIONS: The proposed HHD protocol provides reliable and valid measurements of lower limb muscle isometric strength in healthy adults, which may also be used to test patients with mild muscle strength deficits. However, possible underestimation of absolute strength must be considered when interpreting the results of knee extensors or other large muscles.

Establishing Reference Values for Isometric Knee Extension and Flexion Strength

Single-joint isometric and isokinetic knee strength assessment plays an important role in strength and conditioning, physical therapy, and rehabilitation. The literature, however, lacks absolute reference values. We systematically reviewed the available studies that assessed isometric knee strength. Two scientific databases (PubMed and PEDro) were searched for the papers that are published from the inception of the field to the end of 2019. We included studies that involved participants of both genders and different age groups, regardless of the study design, that involved isometric knee extension and/or flexion measurement. The extracted data were converted to body-mass-normalized values. Moreover, the data were grouped according to the knee angle condition (extended, mid-range, and flexed). A meta-analysis was performed on 13,893 participants from 411 studies. In adult healthy males, the pooled 95% confidence intervals (CI) for knee extension were 1.34–2.23Nm/kg for extended knee angle, 2.92–3.45Nm/kg for mid-range knee angle, and 2.50–3.06Nm/kg for flexed knee angle, while the CIs for flexion were 0.85–1.20, 1.15–1.62, and 0.96–1.54Nm/kg, respectively. Adult females consistently showed lower strength than adult male subgroups (e.g., the CIs for knee extension were 1.01–1.50, 2.08–2.74, and 2.04–2.71Nm/kg for extended, mid-range, and flexed knee angle condition). Older adults consistently showed lower values than adults (e.g., pooled CIs for mid-range knee angle were 1.74–2.16Nm/kg (male) and 1.40–1.64Nm/kg (female) for extension, and 0.69–0.89Nm/kg (male) and 0.46–0.81Nm/kg (female) for flexion). Reliable normative for athletes could not be calculated due to limited number of studies for individual sports.

Absolute Reliability and Concurrent Validity of Hand-Held Dynamometry in Shoulder Rotator Strength Assessment: Systematic Review and Meta-Analysis

The purpose of this study is to establish the absolute reliability between hand-held dynamometers (HHDs) and concurrent validity between HHDs and isokinetic dynamometers (IDs) in shoulder rotator strength assessment. The Medline, CINAHL, and Central databases were searched for relevant studies up to July 2020. Absolute reliability was determined by test–retest studies presenting standard error of measurement (SEM%) and/or minimal detectable change (MDC%) expressed as percentage of the mean. Studies considering intra-class correlation coefficient (ICC) between IDs and HHDs were considered for concurrent validity. The risk of bias and the methodological quality were evaluated according to COnsensus-based Standards for the selection of health Measurement INstruments (COSMIN). Thirteen studies were included in the meta-analysis. Shoulder internal rotator strength assessment MDC% was 0.78%, 95% confidence interval (CI) −5.21 to 3.66, while shoulder external rotators MDC% was 3.29%, CI −2.69 to 9.27. ICC between devices was 0.94, CI (0.91 to 0.96) for shoulder internal rotators and 0.92, IC (0.88 to 0.97) for shoulder external rotators. Very high correlation was found for shoulder rotator torque assessment between HHDs and IDs. The COSMIN checklist classified the selected studies as adequate and inadequate.

Intra- and Inter-Rater Reliability of Strength Measurements Using a Pull Hand-Held Dynamometer Fixed to the Examiner's Body and Comparison with Push Dynamometry

Hand held dynamometers (HHDs) are the most used method to measure strength in clinical sitting. There are two methods to realize the assessment: pull and push. The purpose of the present study was to evaluate the intra- and inter-rater reliability of a new measurement modality for pull HHD and to compare the inter-rater reliability and agreement of the measurements. Forty healthy subjects were evaluated by two assessors with different body composition and manual strength. Fifteen isometric tests were performed in two sessions with a one-week interval between them. Reliability was examined using the intra-class correlation (ICC) and the standard error of measurement (SEM). Agreement between raters was examined using paired t-tests. Intra- and inter-rater reliability for the tests performed with the pull HHD showed excellent values, with ICCs ranging from 0.991 to 0.998. For tests with values higher than 200 N, push HHD showed greater differences between raters than pull HHD. Pull HHD attached to the examiner’s body is a method with excellent reliability to measure isometric strength and showed better agreement between examiners, especially for those tests that showed high levels of strength. Pull HHD is a new alternative to perform isometric tests with less rater dependence.

Validity and reliability of the DiCI for the measurement of shoulder flexion and abduction strength in asymptomatic and symptomatic subjects

Background

A higher risk of shoulder injury in the athletic and non-athletic population is frequently associated with strength deficits. Therefore, shoulder strength assessment can be clinically useful to identify and to quantify the magnitude of strength deficit. Thus, the aim of this study was to evaluate the validity and reliability of a DiCI (a new hand-held dynamometer) for the measurement of shoulder flexion and abduction strength in asymptomatic and symptomatic subjects.

Methods

Forty-three recreational athletes (29 males and 14 females; age: 22.1 ± 0.47 years; body mass: 68.7 ± 13.1 kg; height = 173.3 ± 9.7 cm) and 40 symptomatic subjects (28 males and 12 females; age: 49.9 ± 8.1 years; body mass: 70.6 ± 14.3 kg; height = 171.7 ± 9.0 cm) completed shoulder flexion and abduction strength tests in two identical sessions one-week apart. Both types of movement were evaluated at 45º and 90º.

Results

Relative reliability analysis showed excellent intra-class correlation coefficients (ICC) for all evaluated movements (ICC range = 0.90 to 0.99). Absolute reliability analysis showed a standard error of measurement (SEM) ranging from 1.36% to 2.25%, and minimal detectable change (MDC) ranging from 3.93% to 6.25%. In conclusion, the DiCI is a valid and reliable device for assessing shoulder strength both in recreational athletes and in subjects with restricted mobility and loss of strength.

Shoulder Strength and Closed Kinetic Chain Upper Extremity Stability Test Performance in Division III Collegiate Baseball and Softball Players

BACKGROUND

Shoulder strength measured with a handheld dynamometer (HHD) and the Closed Kinetic Chain Upper Extremity Stability Test (CKCUEST) are clinical tools that have been used to measure athlete's performance and track their progress.

PURPOSE

The specific aims of this study were to describe baseball (BB) and softball (SB) players isometric strength measures and their performance on the CKCUEST; examine the relationships between strength and the CKCUEST; compare isometric strength measures of the throwing and non-throwing arms; and compare the strength and the CKCUEST measures between BB and SB players.

STUDY DESIGN

Observational cohort study.

METHODS

Participants included 50 DIII BB and 24 DIII SB players. Shoulder strength for the internal and external rotators were measured using a HHD and the CKCUEST was performed. The CKCUEST score and power were calculated. Descriptive statistics and paired t-tests were used to compare throwing and non-throwing shoulder strength. Independent t-test was used to compare BB and SB players shoulder strength and the CKCUEST measures.

RESULTS

The BB players demonstrated significant strength differences between the throwing and non-throwing shoulders and the internal rotators were significantly stronger than the external rotators (p < 0.05), while the strength ratio of the internal and external rotators was not different between arms (p=0.87). The SB players demonstrated no significant strength differences between the throwing and non-throwing shoulders for the internal and external rotators or the strength ratio of the rotators (p > 0.05). There were no significant differences between the strength of the internal and external rotators of the non-throwing shoulder (p=0.075) or the throwing shoulder (p=0.096). The BB players throwing and non-throwing shoulders produced significantly more internal and external force than the SB players (p < 0.001), however, the internal/external rotators strength ratio were similar (p=0.32, p=0.30). The CKCUEST power had inverse and significant correlations (p=0.006, p=0.003) with SB players internal and external rotators, respectively. The CKCUEST power was significantly different between BB and SB players (p < 0.001).

CONCLUSION

This study presented shoulder rotator strength and CKCUEST reference values for DIII BB and SB players. BB players demonstrated more strength but overall, less symmetry compared to SB players. CKCUEST power may be considered for the evaluation of athletes.

LEVEL OF EVIDENCE

Level III.

Relationship between upper limb physical performance tests and muscle strength of scapular, shoulder and spine stabilizers: A cross-sectional study

INTRODUCTION

Performance tests of the upper limb have been frequently used in the evaluation of individuals to identify risk of injury and to determine improvement in physical performance. Understanding the variables related to the performance of the tests is important for better applicability and interpretation of test results. The aim of this cross-sectional study was to investige the correlation between isometric strength of scapular, shoulder and spine muscles with physical performance test of upper limb in men and women.

EXPERIMENTAL

Forty-nine healthy and physically conditioned individuals, men (n = 24) (22,7 ± 3,2 years; 74,6 ± 8,1 Kg; 176,7 ± 7,1 cm) women (n = 25) (23 ± 2,7 years; 61,5 ± 9,1 Kg; 163,2 ± 5,6 cm), were evaluated for shoulder abductor isometric strength (S-ABD); Middle (MT) and lower (LT) trapezium; lateral shoulder rotators (S-LR); flexors (T-FLEX), lateral incliners (T-INCL), and trunk extenders (T-EXT). Evaluation of upper limb physical performance was carried out by Upper Quarter Y Balance test (YBT-UQ) and Chain upper extremity stability test (CKC-UEST). Pearson's test (r values) p ≤ 0.05 was used to analyze the correlation.

RESULTS

The results reveal strong correlations between S-ABD and CKC-UEST in male group; and strong correlations in female group between S-ABD strength with CKC-UEST; and S-LR with all YBT-UQ directions and score and between T-EXT strength with CKC-UEST.

CONCLUSION

Therefore, strength of shoulder and spine stabilizers influences performance in upper limb tests, but with different correlations as to sex. To improve test performance, it may be important to increase the strength of the shoulder and spine muscles.

Hand-held dynamometry for assessment of muscle strength in patients with inflammatory myopathies

OBJECTIVES

Muscle weakness in idiopathic inflammatory myopathies (IIMs) is conventionally assessed using manual muscle testing (MMT). However, more objective tools must be developed to accurately and reliably quantify muscle strength in myositis patients. Hand-held dynamometry (HHD) is a quantitative, portable device with reported reliability in neuromuscular disorders. Our aim was to assess the reliability, validity and responsiveness of HHD in myositis.

METHODS

Myositis patients [DM, necrotizing myopathy (NM), PM and anti-synthetase syndrome] evaluated at the University of Pittsburgh myositis centre were prospectively enrolled. Each patient was assessed at 0, 3 and 6 months for validated outcome measures of myositis disease activity and physical function. At each visit, muscle strength was assessed using both MMT and HHD (Micro FET2, Hoggan Health Industries, Draper, UT, USA). The reliability, validity and responsiveness of the HHD was assessed using standard statistical methods.

RESULTS

Fifty IIM patients (60% female; mean age 51.6 years; 6 PM, 9 NM, 24 DM and 11 anti-synthetase syndrome) were enrolled. HHD showed strong test-retest intrarater reliability (r = 0.96) and interrater reliability (r = 0.98). HHD correlated significantly with the MMT score (r = 0.48, P = 0.0006) and myositis disease activity and functional measures. Longitudinal analysis showed a significant and strong association between the HHD and MMT as well as 2016 ACR/EULAR myositis response criteria (r = 0.8, P < 0.0001) demonstrating responsiveness. The mean effect size and standardized response mean of HHD was large: 0.95 and 1.03, respectively. MMT had a high ceiling effect compared with HHD.

CONCLUSION

HHD demonstrated strong reliability, construct validity and responsiveness in myositis patients. External validation studies are required to confirm these findings.

Differences in Fitness and Academic Attainment between Obese, and Non Obese School-Age Adolescent Handball Players: An Explorative, Cross-Sectional Study

This study investigated differences in physical fitness and academic attainment in obese and non-obese adolescent handball players. A total of 31 males (age: 15.5 ± 1.2 years; body mass: 77.8 ± 17.7 kg; height: 1.71 ± 0.10 m; body mass index (BMI): 26.8 ± 6.9 kg/m2; body fat: 26.4 ± 6.34%) from the Qatar handball first division participated and were divided into two body fat percentage (%BF) groups (i.e., obese or non-obese). Anthropometrics (height, mass, BMI, and %BF) and physical performance testing ability (T-half test for change-of-direction (COD); squat jump (SJ), countermovement jump (CMJ), and 10 and 15 m sprints; medicine ball throw (MBT), and aerobic capacity (Yo-Yo Intermittent Recovery Test level 1 (Yo-Yo IR1)) were determined. Academic attainment was determined through grade point averages (GPA). Non-obese participants had superior performances in mathematics (p < 0.001) and science (p = 0.013), agility T-half test (p = 0.001), CMJ (p < 0.001), and 15 m sprint (p = 0.019). Correlations were found between T-half test and mathematics (r = 0.500) and science (r = 0.484). To conclude, obese school-age handball players have poorer fitness and academic performances than normal body weight adolescents.

Influence of Baseball Training Load on Clinical Reach Tests and Grip Strength in Collegiate Baseball Players

CONTEXT

A baseball-specific training load may influence strength or glenohumeral range of motion, which are related to baseball injuries. Glenohumeral reach tests and grip strength are clinical assessments of shoulder range of motion and upper extremity strength, respectively.

OBJECTIVE

To examine changes in glenohumeral reach test performance and grip strength between dominant and nondominant limbs and high, moderate, and low baseball-specific training-load groups.

DESIGN

Repeated-measures study.

SETTING

University laboratory and satellite clinic.

PATIENTS OR OTHER PARTICIPANTS

Collegiate baseball athletes (n = 18, age = 20.1 ± 1.3 years, height = 185.0 ± 6.5 cm, mass = 90.9 ± 10.2 kg).

MAIN OUTCOME MEASURE(S)

Participants performed overhead reach tests (OHRTs), behind-the-back reach tests (BBRTs), and grip strength assessments using the dominant and nondominant limbs every 4 weeks for 16 weeks. Percentage change scores were calculated between testing times. After each training session, participants provided their duration of baseball activity, throw count, and body-specific and arm-specific ratings of perceived exertion. We classified them in the high, moderate, or low training-load group based on each training-load variable: body-specific acute:chronic workload ratio (ACWR), arm-specific ACWR, body-specific cumulative load, and arm-specific cumulative load. Mixed models were used to compare training-load groups and limbs.

RESULTS

The arm-specific ACWR group demonstrated as main effect for OHRT (F = 7.70, P = .001), BBRT (F = 4.01, P = .029), and grip strength (F = 8.89, P < .001). For the OHRT, the moderate training-load group demonstrated a 10.8% greater increase than the high group (P = .004) and a 13.2% greater increase than the low group (P < .001). For the BBRT, the low training-load group had a 10.1% greater increase than the moderate group (P = .011). For grip strength, the low training-load group demonstrated a 12.1% greater increase than the high group (P = .006) and a 17.7% greater increase than the moderate group (P < .001).

CONCLUSIONS

Arm-specific ACWR was related to changes in clinical assessments of range of motion and strength. Clinicians may use arm-specific ACWR to indicate when a baseball athlete's physical health is changing.

The Associations Between Physical Performance and Anthropometric Characteristics in Obese and Non-obese Schoolchild Handball Players

This study investigated the relationship of body fat and fitness measures in schoolchild handball players. Twenty-eight young male handball players from handball first youth league volunteered for the present investigation (age: 10.9 ± 0.72 years; body mass: 54.8 ± 22.9 kg; height: 1.48 ± 0.10 m; body fat: 27.6 ± 9.23%). Measures included the Yo-Yo Intermittent Recovery Test level 1 (Yo-Yo IR1), jumping ability [squat and counter-movement jumps (SJ, CMJ)], and sprint tests (10 m, 15 m). Anthropometry was assessed by body mass, body mass index (BMI), and fat percentage (%BF). The power of the upper limb was measured as the total distance thrown overhead using a 2 kg medicine ball. Intrarater reliability for all parameters showed a coefficient of variation (CV) below 10% and an intraclass correlation coefficient (ICC) above 0.75. All ICC were excellent (ICC ≥ 0.96). Reliability as shown by the CV differed between 1.0 (sprint 15 m) and 5.6 (sprint 10 m). With the exception of medicine ball throw, we found significant differences between non-obese and obese in all performance parameters. The differences ranged from η _p ² = 0.47 (sprint 10 m) to η _p ² = 0.09 (medicine ball throw). The two-step-linear regression analysis using the predictors body height and body weight (step 1) and body fat (step 2) showed a marked increase of explained variance by adding body fat. The largest r² changes were calculated for sprint 10 m (0.54), CMJ (0.49), and sprint 15 m (0.42). The lowest influence of the predictors was observed for medicine ball throw (step 1: r ² = 0.03, step 2: r ² = 0.07). With the exception of sprint parameters (β-coefficient sprint 10 m: -0.74; β-coefficient sprint 20: -0.66), a decrease of %BF leads to a higher performance in all parameters. %BF in youth handball players should be an important concern for practitioners working in this team sport in contrast to the frequently used BMI. It seems sensible and appropriate to engage very young children in physical activities such as team handball in order to improve their physical fitness. Decrease in% body fat could be considered both as a training and nutritional target to enhance and optimize sport performance-related outcomes.

Measurement properties of handheld dynamometry for assessment of shoulder muscle strength: A systematic review

Like any assessment tool, handheld dynamometry (HHD) must be valid and reliable in order to be meaningful in clinical practice and research. To summarize the evidence of measurement properties of HHD for the assessment of shoulder muscle strength. Cochrane Central Register of Controlled Trials (CENTRAL), PubMed, EMBASE, and PEDro were searched up to February 2020. Inclusion criteria were studies (a) evaluating HHD used on the glenohumeral joint, (b) evaluating measurement properties, and (c) included individuals ≥ 18 years old with or without shoulder symptoms. Exclusion criteria were studies (a) including patients with neurologic, neuromuscular, systemic diseases, or critical illness or bed-side patients and (b) that did not report the results separately for each movement. In total, 28 studies with 963 participants were included. The reliability results showed that 98% of the intraclass correlation coefficient (ICC) values were ≥0.70. The measurement error showed that the minimal detectable change in percent varied from 0% to 51.0%. The quality of evidence was high or moderate for the majority of movements and type of reliability examined. Based on the evidence of low or very low quality of evidence, the convergent validity and discriminative validity of HHD were either sufficient, indeterminate, or insufficient. The reliability of HHD was overall sufficient, and HHD can be used to distinguish between individuals on the group level. The measurement error was not sufficient, and evaluation of treatment effect on the individual level should be interpreted with caution.

COMPARISON OF METHODS FOR EVALUATING UPPER LIMB STRENGTH BY HAND-HELD DYNAMOMETRY

ABSTRACT Introduction The upper limbs are segments of the human body responsible for primary activities of daily life, and the muscles are essential structures for performing these activities. There have been few studies on intra- and inter-examiner reliability of the hand-held dynamometer (HHD) in healthy subjects, and none have been published that compare dynamometric evaluation methods in the main muscles in this segment. Objective Evaluate intra-examiner and inter-examiner assessment reliability of the hand-held dynamometry of upper limb muscles in healthy individuals, as well as comparing the assessment reliability between fixed and non-fixed methods. Methods Healthy subjects aged over 18 years were recruited for the study. The isometric contraction for ten muscle groups of the dominant upper limb was tested. For the fixed method, we used a system of suction cups, connected to the HHD by an inelastic belt. For the non-fixed method, the examiner supported the device by hand. The isometric contraction was sustained for three seconds. Each measurement was repeated three times, considering the highest value obtained. The reliability was calculated using the intraclass correlation coefficient (ICC). The dispersion between measurements was expressed by a Bland-Altman plot. Results The sample consisted of 25 volunteers, all right-handed. The intra-examiner ICC was 0.89-0.99 for the non-fixed method, and 0.43 to 0.85 for the fixed method. Inter-examiner reliability showed equivalent behavior. This study showed that evaluation of upper limb muscle strength using an isometric dynamometer has excellent intra-examiner and inter-examiner reliability. The supine position was chosen due to the need to propose a feasible protocol for clinical practice that could be replicated for the majority of publics and in different environments. The non-fixed method showed better reliability overall, demonstrating the feasibility of this tool without the need for adaptations, additional devices, or increased operating costs for this evaluation. Conclusion Comparison between the fixed and non-fixed HHD methods demonstrated superiority of the non-fixed method in terms of reliability. Level of evidence II; Investigation of a diagnostic exam - Development of diagnostic criteria with consecutive patients.

Rotator cuff unloading versus loading exercise program in the conservative treatment of patients with rotator cuff tear: protocol of a randomised controlled trial

INTRODUCTION

Atraumatic and degenerative rotator cuff tears are common in individuals over 55 years of age. This condition can have a high impact on social life and is associated with chronic pain, weakness and dysfunction of the upper limb. There is evidence that conservative approaches should be the first treatment option. Conservative treatment usually addresses a variety of therapeutic behaviours without providing scientific arguments for the choice and progression of exercises.

OBJECTIVE

To compare the effects of two different exercise programmes based on the load of the rotator cuff on a population with shoulder pain and rotator cuff tears.

METHODS AND ANALYSIS

This is a controlled, randomised, blinded clinical trial. Seventy-eight individuals with shoulder pain and presence of atraumatic and degenerative rotator cuff tear will participate and will be randomly distributed between two groups. The primary outcome will be quality of life (The Western Ontario Rotator Cuff Index), and secondary outcomes will include pain, function (Disabilities of the Arm, Shoulder and Hand), fear avoidance beliefs (Fear Avoidance Beliefs Questionnaire-Brazil), kinesiophobia (Tampa Scale), Pain Catastrophizing Scale, muscle strength of abductors, external and internal rotators of the shoulder, range of motion of arm elevation and patient satisfaction. The treatment will be performed for 12 weeks (2 x/week) acording to the selected group (Rotator Cuff Unloading x Rotator Cuff Loading Exercise Programme).

ETHICS AND DISSEMINATION

The study protocol was approved by the Institutional Review Board. The findings of the trial will be disseminated through peer-reviewed journals and scientific conferences.

TRIAL REGISTRATION NUMBER

NCT03962231.

Reliability and validity of a return to sports testing battery for the shoulder

OBJECTIVE

To determine the validity, intra- and inter-rater, and absolute reliability of a return to sport testing battery for the shoulder in a healthy cohort.

DESIGN

Cross-sectional design. All participants completed a battery of strength (isokinetic, isometric, and repetition to failure) and functional assessments on two occasions. Concurrent validity to isokinetic testing was assessed, and intra-rater, inter-rater, and absolute reliability were established for all assessments.

SETTING

Controlled clinical environment.

PARTICIPANTS

Thirty healthy adults active in recreational sports participated, mean age 24.0 ± 1.6 years; MAIN OUTCOME MEASURES: Correlations (Pearson's r), reliability (Intraclass Correlation Coefficient), Standard error of the measurement, Minimal detectable change.

RESULTS

Correlations to isokinetic assessments at 60° & 180°/second were moderate to strong for isometric (r: 0.68-0.80) and functional testing (r: 0.55-0.83) and weak for repetition to failure testing (r: 0.37-0.74). All isokinetic (ICC: 0.88-0.94), isometric (ICC: 0.83-0.94), and functional assessments (ICC: 0.80-0.92) had good to excellent intra-rater reliability, while repetition to failure testing had poor to moderate reliability (ICC: 0.48-0.57). The inter-rater reliability of the isometric assessments was moderate to excellent (ICC: 0.71-0.92) across movements. Expressed as a percentage of the mean, the standard error of the measurement ranged from 7% to 25% and the minimal detectable change ranged from 20% to 69% across all assessment methods.

CONCLUSION

The isokinetic, isometric, and functional assessments used in this return to sports testing battery demonstrates acceptable validity and reliability. Further refinement to the methods used to assess muscular endurance is needed to improve reliability. This study offers clinicians information that can be utilized in clinical decision-making as it relates the testing battery's psychometric properties.

Shoulder muscle force and electromyography activity during make versus break tests

BACKGROUND

Shoulder muscle force is commonly assessed during clinical examination using both an isometric "make" test against a fixed resistance or a "break" test where the examiner exerts enough force to break the isometric contraction. The purpose of this study was to explain the difference in force produced during these two forms of testing.

METHODS

Data were collected on 25 subjects. Both shoulder external rotation and elevation force were measured over three trials, isometrically, for approximately 3 s, after which the examiner exerted enough force to move the arm. Surface EMG was recorded for the infraspinatus for external rotation and middle deltoid for elevation. Peak isometric and break forces, and normalized, averaged EMG data at peak isometric and break forces were compared with paired t-tests.

FINDINGS

External rotation peak break force was 46.9% (SD33.6, range - 3% to 108.6%) greater than isometric force (p < 0.01). EMG for the infraspinatus was 17.0% (20.8) greater at break (p < 0.01). For elevation, peak break force was 63% (73.1, range - 3.5 to 238.16%) greater than isometric force (p < 0.01). EMG for the middle deltoid was 11.1% (30.8) greater during peak break force (not significant).

INTERPRETATIONS

There is a difference in both force and muscle activity between "make" and "break" tests. Clinicians should use a consistent method when measuring force and a break test will provide the maximum force. The cause of greater force produced during a break test is likely attributable to the brief eccentric contraction rather than greater recruitment. Future analysis will include examining the differences in make and break forces based on activity levels.

Body Fat Is a Predictor of Physical Fitness in Obese Adolescent Handball Athletes

We examined the relationships between body fat (BF) and field measures of physical fitness in adolescent handball players. Twenty nine players (age: 16.6 ± 1.72 years; body mass: 79.8 ± 17.0 kg; height: 1.70 ± 0.12 m; body fat: 27.7 ± 8.67%) from Qatar handball first league performed a series of anthropometric and fitness tests related to their performance in sprinting (i.e., 15 m and 30 m sprint), jumping (i.e., countermovement and squat jumps), throwing (i.e., 3 kg medicine ball seated front throw) and running (i.e., agility T-Half and Yo-Yo intermittent recovery level 1 tests). Significant differences between obese and non-obese groups, classified based on age-stratified %BF norms, were found, with the largest difference being attributed to aerobic performance on the Yo-Yo test. Results indicated no significant relationships between anthropometric variables and sprinting or jumping abilities. %BF predicted a significant 8–15% portion in running performances of agility and aerobic capacity, while the latter were mainly explained by body height and mass. %BF was the only and strongest predictor of throwing performance, being an important determinant of performance in handball. Optimizing %BF should be considered as a training and nutrition goal in order to improve sport performance.

Shoulder complaints more likely in volleyball players with a thickened bursa or supraspinatus tendon neovessels

Shoulder problems are common in volleyball and greatly impede both training and player performance. Subacromial bursa (SAB) thickening and tendon neovascularity have shown relevance in other populations, but their relationship with the development of shoulder complaints has not been investigated in volleyball players or overhead-throwing athletes. The study aim was to examine the role of SAB thickness, neovascularization of the supraspinatus tendon, shoulder strength, range of motion (ROM), player position, and age in the development of shoulder complaints in professional volleyball players. Players underwent preseason baseline testing (n = 86) and reported shoulder complaints during the subsequent 12-week period. Generalized estimating equations were used to model for probabilities of complaints after adjusting for player position, SAB side-to-side difference, neovessel presence, shoulder external rotation (ER) ROM, and age. Outside hitters and opposites were 12.2-fold more likely to develop complaints, and greater shoulder ER ROM increased risk by 8% for each additional degree. A side-to-side difference in SAB thickness ≥0.3 mm in the dominant compared with the non-dominant arm was associated with a 10.2-fold increased risk. Those with neovessels were 6.5 times more likely to develop complaints. Players without neovessels and with normal SAB thickness were very unlikely to develop complaints. This stark contrast to players with neovessels or increased SAB thickness, where nearly half of the players developed complaints, is of interest. Players with current complaints at baseline presented with greater IR:ER strength ratios; however, neither strength nor IR ROM at baseline was associated with an increased risk of developing complaints.

The reliability and validity of novel clinical strength measures of the upper body in older adults

Introduction

Research investigating psychometric properties of multi-joint upper body strength assessment tools for older adults is limited. This study aimed to assess the test–retest reliability and concurrent validity of novel clinical strength measures assessing functional concentric and eccentric pushing activities compared to other more traditional upper limb strength measures.

Methods

Seventeen participants (6 males and 11 females; 71 ± 10 years) were tested two days apart, performing three maximal repetitions of the novel measurements: vertical push-off test and dynamometer-controlled concentric and eccentric single-arm press. Three maximal repetitions of hand-grip dynamometry and isometric hand-held dynamometry for shoulder flexion, shoulder abduction and elbow extension were also collected.

Results

For all measures, strong test–retest reliability was shown (all ICC > 0.90, p < 0.001), root-mean-squared coefficient of variation percentage: 5–13.6%; standard error of mean: 0.17–1.15 Kg; and minimal detectable change (90%): 2.1–9.9. There were good to high significant correlations between the novel and traditional strength measures (all r > 0.8, p < 0.001).

Discussion

The push-off test and dynamometer-controlled concentric and eccentric single-arm press are reliable and valid strength measures feasible for testing multi-joint functional upper limb strength assessment in older adults. Higher precision error compared to traditional uni-planar measures warrants caution when completing comparative clinical assessments over time.

Assessing Stiffness, Joint Torque and ROM for Paretic and Non-Paretic Lower Limbs during the Subacute Phase of Stroke Using Lokomat Tools

The efficacy of Lokomat on motor recovery in stroke patients is well known. However, few studies have examined Lokomat tools to assess stiffness, joint torque and range of motion (ROM) during the subacute phase of stroke. The purpose of this retrospective observational study is to assess the changes of joint torque, ROM and stiffness that were estimated with Lokomat tools, namely L-FORCE (lower limb-force), L-ROM (lower limb-range of motion)and L-STIFF (lower limb-stiff), for paretic and non-paretic lower limbs in the subacute phase of stroke, assuming that the tools were able to measure these changes. The data come from 10 subjects in the subacute phase who had their first ever-stroke and followed a treatment that included Lokomat. The measurements came from basal assessments (T0) and one-month follow-up (T1). The measures were compared between paretic and non-paretic legs, and between T0 and T1. Significant differences in stiffness, joint torque and ROM were obtained between the paretic and non-paretic limbs at both T0 and T1. A non-significant trend was obtained for reduced stiffness and increased torque and ROM between T0 and T1 of the paretic limbs. The Lokomat tools were able to measure the changes between paretic and non-paretic legs and the small changes between T0 and T1 measurements.

Shoulder proprioception following reverse total shoulder arthroplasty

Joint replacement affects the proprioception, as shown in knees, elbows, and shoulder studies.

AIM

The aim was to evaluate shoulder joint position sense (JPS) following reverse total shoulder arthroplasty (rTSA) for patients with cuff arthropathy.

METHODS

Twenty-nine patients that underwent unilateral rTSA (19 females, 10 males) and 31 healthy volunteers evaluated for JPS of shoulder using a dedicated high accuracy electronic goniometer. Error of active reproduction of joint position (EARJP) was assessed at the following reference positions: 30°, 60°, 90°, and 120° for forward flexion and abduction and 15°, 30°, and 45° for internal and external rotation in rTSA, contralateral non-operated, and control shoulders.

RESULTS

Results of EPRJP for rTSA, contralateral, and control (respectively) are as follows:Forward flexion: 30° = (8.0 ± 5.7, 9.8 ± 6.1, and 4.9 ± 3.0), 60° = (5.0 ± 2.8, 5.9 ± 2.7, and 5.1 ± 3.2), 90° = (3.1 ± 1.6, 5.5 ± 2.6, and 3.2 ± 1.4), and 120° = (3.4 ± 2.1, 5.6 ± 4.0, and 3.5 ± 1.7)Abduction: 30° = (5.2 ± 2.5, 9.1 ± 6.1, and 4.6 ± 2.3), 60° = (5.2 ± 3.6, 6.6 ± 4.1, and 5.3 ± 3.1), 90° = (3.8 ± 2.0; 7.4 ± 5.5, and 4.1 ± 1.9), and 120° = (5.3 ± 2.9, 7.7 ± 5.3, and 4.2 ± 1.9)Internal rotation: 15° = (4.3 ± 3.1, 6.2 ± 4.4, and 2.8 ± 1.2), 30° = (3.2 ± 1.9, 4.5 ± 2.3, and 3.3 ± 1.4), and 45° = (3.5 ± 2.0, 4.1 ± 1.8, and 2.8 ± 1.0)External rotation: 15° = (3.0 ± 1.7, 4.2 ± 2.2, and 3.6 ± 1.4) and 30° = (3.1 ± 1.5, 3.8 ± 2.6, and 3.4 ± 1.6)The results showed significantly better JPS (lower EPRJP) in shoulders following rTSA and normal control shoulders comparing with the patient's contralateral shoulder. The explanation can be that rTSA improves joint kinematics and stability, which allows better muscular performance and proprioception feedback.

CONCLUSION

Shoulders following rTSA show JPS superior to non-operated contralateral shoulders and comparable with healthy population shoulders. It seems that rTSA restores shoulder proprioception.

Measurement Properties of Isokinetic Dynamometry for Assessment of Shoulder Muscle Strength: A Systematic Review

OBJECTIVE

To investigate the evidence of measurement properties of isokinetic dynamometry (ID) for assessment of shoulder muscle strength in healthy individuals and patients with nonneurologic shoulder pathology.

DATA SOURCES

Cochrane Central Register of Controlled Trials, PubMed, EMBASE, and Physiotherapy Evidence Database were searched up to February 2020 without restrictions. Reference lists and citations were hand-searched.

STUDY SELECTION

Two review authors independently included studies that met the following criteria: (1) evaluated measurement properties of ID when used on the glenohumeral joint and (2) included individuals 18 years and older. Studies including patients with neurologic, neuromuscular, or systemic diseases or critical illness were excluded.

DATA EXTRACTION

The quality assessment and data synthesis were performed according to the COnsensus-based Standards for the selection of health Measurement INstruments methodology.

DATA SYNTHESIS

Twenty-one studies with a total of 597 participants were included. The results were combined separately for isometric, concentric, and eccentric test mode; for the velocities 30°/s-60°/s, 90°/s, 120°/s, and 240°/s; for the seated, supine, and standing position; and for internal rotation (IR), external rotation (ER), and the ER/IR ratio. The reliability of ID was overall sufficient with the majority of intraclass correlation coefficients ≥0.70. The quality of evidence was moderate or low for 20 of 30 strata examined. The measurement error results were rated as insufficient for all strata. The SEM ranged from 4%-28%. The quality of evidence varied depending of strata examined.

CONCLUSIONS

The reliability of ID for measurement of shoulder strength was overall sufficient for all positions, velocities, and modes of strength. The measurement error was not sufficient. Because most studies used the seated position, the velocities 30°/s-60°/s or 120°/s, and the concentric test mode, the quality of evidence was highest for these conditions.

Reliability and Validity of a Novel Wearable Device for Measuring Elbow Strength

Muscle strength is an important clinical outcome in rehabilitation and sport medicine, but options are limited to expensive but accurate isokinetic dynamometry (IKD) or inexpensive but less accurate hand-held dynamometers (HHD). A wearable, self-stabilizing, limb strength measurement device (LSMD) was developed to fill the current gap in portable strength measurement devices. The purpose of this study was to evaluate the reliability and validity of the LSMD in healthy adults. Twenty healthy adults were recruited to attend two strength testing sessions where elbow flexor and extensor strength was measured with the LSMD, with HHD and with IKD in random order, by two raters. Outcomes were intra-rater repeatability, inter-rater reproducibility and inter-session reproducibility using intra-class correlation coefficients (ICC). Limits of agreement and weighted least products regression were used to test the validity of the LSMD relative to the criterion standard (IKD), and calibration formulas derived to improve measurement fidelity. ICC values for the LSMD were >0.90 for all measures of reliability and for both muscle groups, but over-predicted extensor strength and under-predicted flexor strength. Validity was established by transforming the data with the criterion standard-based calibration. These data indicate that the LSMD is reliable and conditionally valid for quantifying strength of elbow flexors and extensors in a healthy adult population.

Validity and Reliability of Hand-Held Dynamometry for Abdominal Flexion Muscular Assessment

CONTEXT

Abdominal musculature underpins core stability, which can allow for optimal performance in many activities of daily living (eg, walking and rising from a chair). Therefore, assessment of the abdominal muscles poses as an important consideration for clinicians in order to identify people at risk of injury or functional decline.

OBJECTIVE

This study aimed to build on the limited amount of knowledge surrounding abdominal muscle strength assessments by investigating the validity and reliability of hand-held dynamometry (HHD) for the assessment of isometric abdominal flexion strength.

STUDY DESIGN AND PARTICIPANTS

Comparative analysis for validity and test-retest reliability was employed on a cohort of apparently healthy individuals. HHD was compared with the criterion, isokinetic dynamometry, through an isometric contraction of trunk flexion on both instruments. Hand-held dynamometry assessments only were performed on a subsequent day for reliability analysis. The peak values for all assessments were recorded.

RESULTS

A total of 35 participants were recruited from the University of South Australia and the general public. Comparative analysis between the HHD and isokinetic dynamometer showed good agreement (intraclass correlation coefficients = .82), with the Bland-Altman plots confirming no proportional bias. Reliability analysis for the HHD reported good consistency (intraclass correlation coefficients = .87).

CONCLUSION

HHD together with the participant setup (supine, trunk flexed, and supported at 25° with the legs horizontal and remaining unfixed) is a valid and reliable tool to assess isometric abdominal flexion strength.

The Self-Assessment Corner for Shoulder Strength: Reliability, Validity, and Correlations With Upper Extremity Physical Performance Tests

CONTEXT

Rotator cuff weakness and rotation ratio imbalances are possible risk factors for shoulder injury among overhead athletes. In consensus statements, organizations have highlighted the importance of a screening examination to identify athletes at risk of injury. The screening should be portable and designed to be feasible in many different environments and contexts.

OBJECTIVE

To evaluate the reliability and validity of the Self-Assessment Corner (SAC) for self-assessing shoulder isometric rotational strength and examining whether performance on 2 physical performance tests was correlated with isometric shoulder rotational strength using the SAC in handball players.

DESIGN

Cross-sectional study.

SETTING

Sport setting.

PATIENTS OR OTHER PARTICIPANTS

A first sample of 42 participants (18 men, 24 women) was recruited to determine the reliability and validity of the SAC. In a second sample of 34 handball players (18 men, 16 women), we examined correlations between physical performance tests and the SAC.

MAIN OUTCOME MEASURE(S)

The SAC was used to measure isometric rotational strength with the upper extremity at 90° of abduction in the frontal plane and 90° of external rotation and the elbow flexed to 90° with neutral rotation of the forearm. The SAC findings were compared with those from manual testing. Results from the seated medicine ball throw (SMBT) and closed kinetic chain upper extremity stability test (CKCUEST) were used to establish relationships with the SAC. We calculated intraclass correlation coefficients to determine relative reliability and used standard error of measurement and minimal detectable change to quantify absolute reliability. Relationships among the different strength-testing procedures and with the physical performance tests were determined using the Pearson product moment correlation coefficient (r) or Spearman rank correlation coefficient (r_s).

RESULTS

We observed good to excellent reliability (intraclass correlation coefficient [2,k] range = 0.89 to 0.92). The standard error of measurement varied from 3.45 to 3.48 N. The minimal detectable change with 95% confidence intervals ranged from 8.06 to 8.13 N. Strong correlations were present among strength procedures (r = 0.824, r_s range = 0.754-0.816). We observed moderate to strong correlations between the CKCUEST findings and rotational strength (r range = 0.570-0.767). Moderate correlations were found between rotational strength and SMBT (r range = 0.573-0.626).

CONCLUSIONS

The SAC is a clinically applicable and standardized protocol for self-assessing rotational strength in young healthy adults without pathologic conditions. Performance on the SMBT and CKCUEST may be valuable as a screening tool to further assess shoulder strength.

The Effects of Circuit Strength Training on the Development of Physical Fitness and Performance-Related Variables in Handball Players

The purpose of this study was to determine the effects of 12 weeks of circuit training on physical fitness in handball players. Subjects were randomly divided into a circuit strength training group (CT, n = 10) and a control group (CG, n = 9). Training sessions and matches were performed together, but during the 12-week intervention, the experimental group replaced part of the regular regimen with circuit strength training. Measures assessed in both groups before and after the intervention included: the agility T-half Test, the Yo-Yo intermittent recovery test, squat and counter-movement jumps, 15 m and 30 m sprints, and strength tests for the bench press, pull over, and the half squat. The upper limb bench press and pull-over tests along with the lower limb back half squat were performed using a 1-repetition maximum protocol. Based on the intraclass correlation coefficient and excluding the agility T-test (ICC = 0.72), we found excellent relative reliability for all variables (intraclass correlation coefficient range: 0.85-0.96, SEM range: 0.03-3.00). For absolute reliability or coefficients of variation, 71% (5/7) of the variables were excellent (CV < 5%). The circuit strength training group showed significant interaction effects and relevant effect sizes for the 12-week training period (8/9, 89%), and the mean effect size for the CT was markedly higher (d = 1.3, range: 0.41 - 2.76) than in the CG (d = - 1.0, range: -0.73 - 0.29). The largest improvements were in the Yo-Yo test (d = 2.76) and the squat jump (d = 2.05). These results show that a 12-week circuit strength training program is an effective method to increase handball-related performance characteristics.