Reference Values for Cervical Muscle Strength in Healthy Women Using a Hand-Held Dynamometer and the Association with Age and Anthropometric Variables

Knowledge of reference values for cervical muscle strength is a key tool for clinicians to use as a clinical reference measure and to establish goals during rehabilitation. The objective was to establish reference values for the maximal strength of cervical muscles in healthy women using a handheld dynamometer and verify the association of cervical muscle strength with age and anthropometric measurements. A hundred women were classified into four groups (n = 25) according to age: 18-29 years, 30-39 years, 40-49 years, and 50-60 years. Maximal muscle strength of the cervical spine was measured using a Lafayette® handheld dynamometer for flexion, extension, and bilateral lateral flexion. No differences in cervical muscle strength were observed among the groups (p > 0.05). However, the 18-29-year-old group took less time to reach the peak of force for flexion than the 50-60-year-old group. Moderate correlations were observed between cervical flexor strength and weight, body mass index, and neck circumference, and between cervical extensor strength and weight and body mass index (r = 0.43-0.55; p < 0.05). Reference values for cervical muscle strength in healthy women were established using a handheld dynamometer, and the association between muscle strength and anthropometric data was moderate.

A Novel Intrinsic Foot Muscle Strength Dynamometer Demonstrates Moderate-To-Excellent Reliability and Validity

Background

Intrinsic foot muscle (IFM) weakness can result in reduced foot function, making it crucial for clinicians to track IFM strength changes accurately. However, assessing IFM strength can be challenging for clinicians, as there is no clinically applicable direct measure of IFM strength that has been shown to be reliable and valid with the foot on the ground.

Purpose

The purpose was to investigate the intra-rater and inter-rater reliability of a novel, budget-friendly IFM dynamometer and determine its agreement with a handheld dynamometer (HHD). The researchers also examined correlations of foot morphology and activity level to IFM strength.

Study design

Descriptive Laboratory Study.

Methods

Two assessors measured IFM strength of 34 healthy volunteers (4 male, 30 female; age=21.14±2.57, height=164.66 ±7.62 cm, mass=64.45±11.93 kg) on two occasions 6.62±0.78 days apart with the novel dynamometer to assess intra- and inter-rater reliability. The HHD was used to measure IFM in the first session in order to assess validity.

Results

For the novel dynamometer, intra- and inter-rater reliability was moderate-to-excellent (ICC = 0.73 - 0.95), and the majority of the strength tests were within the 95% limits of agreement with the HHD. Wider foot morphology and a higher number of days walking over the prior seven days had small but significant correlations with IFM strength (dominant foot r = 0.34, non-dominant foot r = 0.39; r = -0.33, -0.39 respectively).

Conclusion

This novel IFM dynamometer is a budget-friendly ($75) tool that was shown to be reliable and valid in a healthy population.

Levels of evidence

Level 3©The Author(s).

[Effect of critical shoulder angle on deltoid muscle strength reduction in patients with rotator cuff tears]

Objective

To investigate the synergistic interaction between the deltoid muscle and the rotator cuff muscle group in patients with rotator cuff tears (RCT), as well as the impact of the critical shoulder angle (CSA) on deltoid muscle strength.

Methods

A retrospective analysis was conducted on clinical data from 42 RCT patients who met the selection criteria and were treated between March 2022 and March 2023. There were 13 males and 29 females, with an age range of 42-77 years (mean, 60.5 years). Preoperative visual analogue scale (VAS) score was 6.0±1.6. CSA measurements were obtained from standard anteroposterior X-ray films before operation, and patients were divided into two groups based on CSA measurements: CSA>35° group (group A) and CSA≤35° group (group B). Handheld dynamometry was used to measure the muscle strength of various muscle group in the shoulder (including the supraspinatus, infraspinatus, subscapularis, and anterior, middle, and posterior bundles of the deltoid). The muscle strength of the unaffected side was compared to the affected side, and muscle imbalance indices were calculated. Muscle imbalance indices between male and female patients, dominant and non-dominant sides, and groups A and B were compared. Pearson correlation analysis was used to examine the relationship between muscle imbalance indices and CSA as well as VAS scores.

Results

Muscle strength in all muscle groups on the affected side was significantly lower than on the unaffected side ( P<0.05). The muscle imbalance indices for the supraspinatus, subscapularis, infraspinatus, and anterior, middle, and posterior bundles of the deltoid were 14.8%±24.4%, 5.9%±9.7%, 7.2% (0, 9.1%), 17.2% (5.9%, 26.9%), 8.3%±21.3%, and 10.2% (2.8%, 15.4%), respectively. The muscle imbalance indices of the anterior bundle of the deltoid, supraspinatus, and infraspinatus were significantly lower in male patients compared to female patients ( P<0.05); however, there was no significant difference in muscle imbalance indices among other muscle groups between male and female patients or between the dominant and non-dominant sides ( P>0.05). There was a positive correlation between the muscle imbalance indices of infraspinatus and VAS score ( P<0.05), and a positive correlation between CSA and the muscle imbalance indices of middle bundle of deltoid ( P<0.05). There was no correlation between the muscle imbalance indices of other muscle groups and VAS score or CSA ( P>0.05). Preoperative CSA ranged from 17.6° to 39.4°, with a mean of 31.1°. There were 9 cases in group A and 33 cases in group B. The muscle imbalance indices of the anterior bundle of the deltoid was significantly lower in group A compared to group B ( P<0.05), while there was no significant difference in muscle imbalance indices among other muscle groups between group A and group B ( P>0.05).

Conclusion

Patients with RCT have a phenomenon of deltoid muscle strength reduction, which is more pronounced in the population with a larger CSA.

Evaluating the Influence of Gravity on Shoulder Strength Measures Assessed via Handheld Dynamometry

CONTEXT

Handheld dynamometry is a feasible, reliable, and cost-effective method for assessing shoulder strength. One limitation to this tool is the lack of standardized testing protocols and specified shoulder strength test positions. Although it is recommended that strength tests be performed in a gravity-eliminated position, this may not always be a feasible or practical testing protocol. There is limited research on the influence of gravity on strength measures; to our knowledge, no study has compared handheld dynamometry shoulder strength assessments based on body position and gravity. Therefore, the purpose of this study was to compare shoulder flexion, extension, and abduction strength assessed via handheld dynamometry between a gravity-eliminated and a gravity-influenced test position.

DESIGN

This study was a comparison of shoulder strength based on test position. The test position was the independent variable, and the dependent variables were shoulder flexion, extension, and abduction strength.

METHODS

Supine (gravity-eliminated) and seated (gravity-influenced) strength measures were assessed in 20 healthy adults (19.4 [1.2] y) on the dominant arm. Paired t tests were used to determine differences between body positions for each test. Significance was accepted at P ≤ .05.

RESULTS

There were no differences between supine and seated flexion and extension measures. Absolute supine shoulder abduction scores (152.5 [58.4] N) were significantly higher than seated scores (139.9 [55.6] N).

CONCLUSIONS

Findings show that gravity should be considered when using handheld dynamometry scores as indicators of abductor shoulder strength and function.

Evaluating the strength of spinal and proximal girdle muscles in patients with axial spondyloarthritis: Correlation with activity, disability, and functionality

AIM

To compare the muscle strength of muscle groups in axial spondyloarthritis (axSpA) patients with the muscle powers of healthy volunteers and to examine the relationship of muscle strengths with disease activity, functionality, and disability.

METHOD

One hundred males (50 axSpA, 50 healthy) were included in the study. Bath Disease Activity Index (BASDAI), Functional Index (BASFI), and Health Assessment Questionnaire-Disability Index (HAQ-DI) scores were recorded. The maximum (max) and mean cervical flexion, extension, lateral flexion (CF, CE, CLF), truncal flexion, extension (TF, TE), root joint flexion, extension, abduction, internal and external rotation (SF, SE, SAB, SIR and SER for the shoulder; HF, HE, HAB, HIR and HER for the hip) muscle strengths of the patients in both groups were measured by a handheld dynamometer. Total muscle strength (CT, TT, ST, HT) was found according to the sum of the max and mean values for each region.

RESULTS

All muscle strengths were lower in the axSpA group compared to the healthy volunteers. The symptom duration was found to have a weak-moderate negative correlation with CT, TT, ST, HT and all individual muscle strengths except for the TE, CF, HIR, and HER. BASDAI and HAQ-DI had weak-moderate negative correlations with HIR and HER. BASFI had a weak-moderate negative correlation with cervical measurements, TE, TF, SF, SER, SIR, and hip measurements.

CONCLUSION

All muscle strengths were lower in patients compared to healthy volunteers. Strengthening specific muscle groups for the desired goal can be a reasonable strategy. The study is prospectively registered and available at www.clinicaltrials.gov (NCT04435860).

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.

MEASURES OF HIP MUSCLE STRENGTH AND RATE OF FORCE DEVELOPMENT USING A FIXATED HANDHELD DYNAMOMETER: INTRA-TESTER INTRA-DAY RELIABILITY OF A CLINICAL SET-UP

BACKGROUND

Evaluation of hip muscle function is considered an important part of the examination and treatment of physically active subjects with hip and groin pain. However, methods to reliably measure explosive hip muscle strength are lacking.

HYPOTHESIS/PURPOSE

The purpose was to investigate the reliability of a clinically available set-up using a fixated handheld dynamometer to test isometric peak force and rate of force development of the hip abductors, adductors, flexors, and extensors.

METHODS

Seventeen subjects (males: 9, females: 8, mean aged 25.4 (+/- 4.2) y, with mean body mass of 73.9 (+/- 15.2) kg, and mean height 174.2 (+/- 12.4) cm) were included. One experienced tester performed all measures in a randomized order. Three trials of isometric peak force and early- (0-100 ms) and late-phase (0-200 ms) rate of force development for the hip abductors, adductors, flexors, and extensors were obtained using a fixated handheld dynamometer. The trial with the highest value for each measure was used for analysis. Test-retest sessions were separated by 30 minutes of rest.

RESULTS

No systematic between-session bias were observed for any of the measures. The relative intra-tester reliability (ICC_2,1) for peak force, 0-100 ms rate of force development, and 0-200 ms rate of force development ranged from 0.93-0.96, 0.82-0.93, and 0.85-0.92, respectively, corresponding to good reliability for all force measures.

CONCLUSION

The present study shows that assessment of isometric hip muscle peak force, including early- (0-100 ms) and late-phase (0-200 ms) rate of force development using a fixated handheld dynamometer have good intra-tester reliability for testing of the hip adductors, abductors, flexors and extensors. Thus, in clinical research settings where an isokinetic dynamometer may not always be readily accessible, the present test procedure can be used as a feasible alternative to reliably provide objective of hip muscle function relevant for rehabilitation of patients with hip and groin pain.

LEVEL OF EVIDENCE

Level 3, Reliability study.

The Takei Handheld Dynamometer: An Effective Clinical Outcome Measure Tool for Hand and Wrist Function in Boxing

BACKGROUND

The aim of this article was to explore retrospectively the Takei dynamometer as a valid and reliable outcome measure tool for hand and wrist pathology in the Great Britain amateur boxing squad between 2010 and 2014.

METHODS

Longitudinal retrospective injury surveillance of the Great Britain boxing squad was performed from 2010 to 2014. The location, region affected, description, and duration of each injury were recorded by the team doctor and team physiotherapists. For each significant injury, we recorded hand grip scores using the Takei handheld dynamometer and compared the scores with baseline measures.

RESULTS

At the hand, fractures and dislocations were highly detected with an average difference of 40.2% ( P < .05) when comparing postinjury to baseline measures. At the wrist, carpometacarpal and carpal joint injuries were highly detected with an average difference of 32.6% ( P < .05). Other injuries provided varied results. In the absence of pathology, up to 15% difference between left and right scores can be considered normal with a predominance observed below 10%. A difference of 20% can be indicative of a form of pathology, although pathologies can also be present with lower difference or no apparent changes. A difference of >20% should be highly considered for significant pathology.

CONCLUSIONS

The Takei dynamometer is a valid and reliable outcome measure tool for hand and wrist pathologies in boxing. Our study highlights the importance of appropriate clinical tools to guide injury management in this sport.

Functional Outcomes After Double-Row Versus Single-Row Rotator Cuff Repair: A Prospective Randomized Trial

Background:

The functional benefits of double-row (DR) versus single-row (SR) rotator cuff repair are not clearly established.

Purpose:

To examine the effect of DR versus SR rotator cuff repair on functional outcomes and strength recovery in patients with full-thickness tears.

Study Design:

Randomized controlled trial; Level of evidence, 2.

Methods:

Forty-nine patients were randomized to DR or SR repairs; 36 patients (13 women, 23 men; mean age, 62 ± 7 years; 20 SR, 16 DR) were assessed at a mean 2.2 ± 1.6 years after surgery (range, 1-7 years; tear size: 17 medium, 13 large, 9 massive). The following data were recorded prior to surgery and at follow-up: Penn shoulder score, American Shoulder and Elbow Surgeons (ASES), and Simple Shoulder Test (SST) results; range of motion (ROM) for shoulder flexion, external rotation (ER) at 0° and 90° of abduction, and internal rotation (IR) at 90° of abduction; and shoulder strength (Lafayette manual muscle tester) in empty- and full-can tests, abduction, and ER at 0° of abduction. Treatment (SR vs DR) × time (pre- vs postoperative) mixed-model analysis of variance was used to assess the effect of rotator cuff repair.

Results:

Rotator cuff repair markedly improved Penn, ASES, and SST scores (P < .001), with similar improvement between SR and DR repairs (treatment × time, P = .38-.10) and excellent scores at follow-up (DR vs SR: Penn, 91 ± 11 vs 92 ± 11 [P = .73]; ASES, 87 ± 12 vs 92 ± 12 [P = .21]; SST, 11.4 ± 1.0 vs 11.3 ± 1.0 [P = .76]). Patients with DR repairs lost ER ROM at 0° of abduction (preoperative to final follow-up, 7° ± 10° loss [P = .013]). ER ROM did not significantly change with SR repair (5° ± 14° gain, P = .16; treatment by time, P = .008). This effect was not apparent for ER ROM at 90° of abduction (treatment × time, P = .26). IR ROM improved from preoperative to final follow-up (P < .01; SR, 17° ± 27°; DR, 7° ± 21°; treatment × time, P = .23). Rotator cuff repair markedly improved strength in empty-can (54%), full-can (66%), abduction (47%), and ER (54%) strength (all P < .001), with no difference between SR and DR repairs (P = .23-.75). All clinical tests with the exception of the lift-off test were normalized at follow-up (P < .05).

Conclusion:

Outcomes were not different between SR or DR repair, with generally excellent outcomes for both groups. Rotator cuff repair and subsequent rehabilitation markedly improved shoulder strength.

Performance Demands in Softball Pitching: A Comprehensive Muscle Fatigue Study

BACKGROUND

Monitoring pitch count is standard practice in minor league baseball but not in softball because of the perception that fast-pitch softball pitching is a less stressful motion.

PURPOSE

To examine muscle fatigue after fast-pitch softball performances to provide an assessment of performance demand.

STUDY DESIGN

Descriptive laboratory study.

METHODS

Bilateral strength measurements (handheld dynamometer) were made on 19 female softball pitchers (mean age [±SD], 15.2 ± 1.2 years) before and after pitching a game (mean number of pitches, 99 ± 21; mean innings pitched, 5 ± 1). A total of 20 tests were performed on the dominant and nondominant sides: forearm (grip, wrist flexion/extension, pronation/supination, elbow flexion/extension), shoulder (flexion, abduction/adduction, external/internal rotation, empty can test), scapula (middle/lower trapezius, rhomboid), and hip (hip flexion/extension, abduction/adduction). Fatigue (percentage strength loss) was categorized based on bilateral versus unilateral presentation using paired t tests: bilateral symmetric (significant on dominant and nondominant and not different between sides), bilateral asymmetric (significant on dominant and nondominant but significantly greater on dominant), unilateral asymmetric (significant on dominant only and significantly greater than nondominant), or unilateral equivocal (significant on dominant only but not different from nondominant).

RESULTS

Bilateral symmetric fatigue was evident for all hip (dominant, 19.3%; nondominant, 15.2%) and scapular tests (dominant, 19.2%; nondominant, 19.3%). In general, shoulder tests exhibited bilateral asymmetric fatigue (dominant, 16.9%; nondominant, 11.6%). Forearm tests were more variable, with bilateral symmetric fatigue in the elbow flexors (dominant, 22.5%; nondominant, 19.2%), and wrist flexors (dominant, 21.6%; nondominant, 19.0%), bilateral asymmetric fatigue in the supinators (dominant, 21.8%; nondominant, 15.5%), unilateral asymmetric fatigue in the elbow extensors (dominant, 22.1%; nondominant, 11.3%), and unilateral equivocal fatigue in the pronators (dominant, 18.8%; nondominant, 15.2%) and grip (dominant, 11.4%; nondominant, 6.6%). The mean (±SD) pitch velocity was 49 ± 4 mph, with a small loss of velocity from the first to last inning pitched (3.4% ± 5.0%, P < .01).

CONCLUSION

Fast-pitch softball pitching resulted in profound bilateral fatigue in the hip and scapular muscles, with more selective fatigue in the shoulder and arm muscles.

CLINICAL RELEVANCE

These findings emphasize the importance of strength in the proximal musculature to provide a stable platform for the arm to propel the ball.

Comparison of isometric ankle strength between females with and without patellofemoral pain syndrome

INTRODUCTION

Proximal and distal influences on the knee may be related as etiological factors of patellofemoral pain syndrome (PFPS). The distal factors include subtalar excessive pronation as well as medial tibia rotation, but no study has investigated whether ankle weakness could lead to alterations that influence the patellofemoral joint. Thus, the purpose of this study was to compare the ankle dorsiflexor and invertor muscles strength, as well as rearfoot eversion and the Navicular Drop Test (NDT) in females with PFPS to a control group of females of similar demographics without PFPS.

METHODS

Forty females, between 20 and 40 years of age (control group: n=20; PFPS group: n=20) participated. Rearfoot eversion range of motion and the NDT were assessed for both groups. The Numeric Pain Rating Scale and the Anterior Knee Pain Scale were used to evaluate the level of pain and the functional capacity of the knee during activities, respectively. Isometric ankle dorsiflexor and invertor strength was measured using a handheld dynamometer as the dependent variable.

RESULTS

The isometric strength of the dorsiflexor and invertor muscle groups in females with PFPS was not statistically different (P>0.05) than that of the control group. There was no statistically significant difference between groups for rearfoot eversion and NDT (p>0.05).

DISCUSSION/CONCLUSION

These results suggest that there is no difference between isometric ankle dorsiflexion and inversion strength, the NDT, and rearfoot eversion range of motion in females with and without PFPS.

LEVEL OF EVIDENCE

3-b.

Reliability of measurements of hip abduction strength obtained with a hand-held dynamometer

This study aimed to evaluate intrarater and interrater reliability when measuring hip abductor strength in the supine position using a hand-held dynamometer (HHD) (Study 1), and to elucidate the relationships between measured values and examiners' physical characteristics (Study 2). Three healthy examiners (1 female, 24 y.o. and 2 males 23 and 27 y.o) and 12 subjects (6 females, 24.5 ± 2.8 years and 6 males, 27.7 ± 3.5 years) participated in Study 1, and 20 healthy examiners (7 females, 22.3 ± 1.3 years and 13 males, 29.4 ± 8.2 years) and 2 subjects (1 female, 24 y.o. and 1 male 27 y.o) participated in Study 2. All healthy examiners were hospital employees. Hip abductor strength was measured by HHD with hand fixation and with belt fixation, and examiner age, sex, height, weight, BMI, and dominant hand grip strength were evaluated. The intraclass correlation coefficient (ICC) (1,1), a measure of intrarater reliability, was 0.89-0.95 with hand fixation and 0.96-0.97 with belt fixation. ICC (2,1), a measure of interrater reliability, was 0.76-0.79 and 0.90-0.93, respectively. In subjects with high muscle strength (the examiner's hand was moved), the examiner's dominant hand grip strength affected muscle strength values with hand fixation (standardized partial regression coefficient = 0.78, determination coefficient R(2 )= 0.61, p < 0.01). In subjects with low muscle strength (the examiner's hand was not moved), no variables had effect. When the muscle strength of the subject is weak, both methods can be used. When the muscle strength of the subject is strong, it is necessary to adjust the value obtained by the examiner's dominant hand grip strength in the hand fixation method.

Intrarater reliability of assessing strength of the shoulder and scapular muscles

CONTEXT

Handheld dynamometry (HHD) is considered an objective method of measuring strength, but the reliability of the procedure can be compromised by inadequate tester strength and insufficient stabilization of the dynamometer especially, for the scapular muscles.

OBJECTIVE

Primarily, to determine the intrarater reliability of HHD when testing shoulder and scapular muscle strength, and secondarily, to report reliability when corrected for body-mass index (BMI).

DESIGN

Technical report.

SETTING

University physiotherapy department.

PARTICIPANTS

57 adults (17 men, 40 women; mean age = 35.05 ± 13.5 y), both healthy individuals and patients with shoulder impingement.

INTERVENTION

HHD.

MAIN OUTCOME VARIABLES

Muscle strength of the upper, middle, and lower trapezius; anterior deltoid; serratus anterior; supraspinatus; and latissimus dorsi determined by HHD. Each muscle was assessed 3 times, and the mean value was calculated. The subjects were divided into 3 groups according to BMI. Group 1: BMI ≤ 20 kg/m(2) (n = 22); Group 2: BMI ≤ 24.9 kg/m(2) (n = 54); and Group 3: BMI ≤ 29.9 kg/m(2) (n = 38).

RESULTS

Correlations were calculated for each pair of strength scores. Intraclass correlation coefficients (ICCs) ranged from .77 to .99 in healthy subjects and from .75 to .99 in patients, for all muscle groups except the upper trapezius (P < .05). Reliability values ranged from good to high in healthy subjects but were less consistent for the upper trapezius (ICC .45-.65). The relationship with BMI and muscle strength illustrates that as BMI increases, there is a decrease in reliability values of the lower trapezius (ICC = .35-.65).

CONCLUSION

The study demonstrates that evaluating the strength of scapular and shoulder muscles using HHD presents reliable results for both patients with impingement syndrome and healthy subjects. Reliability values were compressed when testing the trapezius in subjects with higher BMI. This is likely a result of the examiner's difficulty in overcoming the patients with this maneuver.

Hip strength assessment using handheld dynamometry is subject to intertester bias when testers are of different sex and strength

Handheld dynamometry (HHD) is a promising tool for obtaining reliable hip strength measurements in the clinical setting, but intertester reliability has been questioned, especially in situations where testers exhibit differences in upper-extremity muscle strength (male vs female). The purpose of this study was to examine the intertester reliability concerning strength assessments of hip abduction, adduction, external and internal rotation, flexion and extension using HHD, and to test whether systematic differences in test values exist between testers of different upper-extremity strength. Fifty healthy individuals (29 women), aged 25 ± 5 years were included. Two physiotherapist students (one female, one male) of different upper-extremity strength performed the measurements. The tester order and strength test order were randomized. Intraclass correlation coefficients were used to quantify reliability, and ranged from 0.82 to 0.91 for the six strength test. The female tester systematically measured lower strength values for all isometric strength tests (P < 0.05). In hip strength assessments using HHD, systematic bias exists between testers of different sex, which is likely explained by differences in upper-extremity strength. Hence, to improve intertester reliability, the dynamometer likely needs external fixation, as this will eliminate the influence of differences in upper-extremity strength between testers.