Comparison of Rotational Strength in Shoulders with Anterior Instability and Normal Shoulders Using Isokinetic Testing

Context: Measuring isometric shoulder rotational strength is clinically important for evaluating motor disability in athletes with shoulder injuries. Recent evidence suggests that handheld dynamometry may provide a low-cost and portable method for the clinical assessment of isometric shoulder strength. Objective: To investigate the concurrent validity and the intrarater and interrater reliability of handheld dynamometry for measuring isometric shoulder rotational strength. Design: Cross-sectional study. Setting: Biomechanics laboratory. Participants: Thirty-nine young, healthy participants. Main Outcome Measures: The peak isometric strength of the internal rotators and external rotators, measured by handheld dynamometry (in newton) and isokinetic dynamometry (in newton meter). Interventions: Maximal isometric shoulder rotational strength was measured as participants lay supine with 90° shoulder abduction, neutral rotation, 90° elbow flexion, and forearm pronation. Measurements were performed independently by 2 different physiotherapists and in 3 different sessions to evaluate interrater and intrarater reliability. The data obtained by handheld dynamometry were compared with those obtained by isokinetic testing to evaluate concurrent validity. Results: The intraclass correlation coefficients for interrater reliability in measuring maximum isometric shoulder external and internal rotation strength were .914 (95% confidence interval [CI], .842–.954) and .842 (95% CI, .720–.914), respectively. The intrarater reliability values of the method for measuring maximal shoulder external and internal rotation strength were 0.865 (95% CI, 0.757–0.927) and 0.901 (95% CI, 0.820–0.947), respectively. The Pearson correlation coefficients between the handheld and isokinetic dynamometer measurements were .792 (95% CI, .575–.905) for external rotation strength and .664 (95% CI, .419–.839) for internal rotation strength. Conclusions: The handheld dynamometer showed good to excellent reliability and moderate to good validity in measuring maximum isometric shoulder rotational strength. Therefore, handheld dynamometry could be acceptable for health and sports professionals in field situations to evaluate maximum isometric shoulder rotational strength.

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Differences in strength and landing biomechanics between female jumpers and swimmers

Isokinetics and Exercise Science ◽

10.3233/ies-210149 ◽

2021 ◽

pp. 1-11

Author(s):

Mianfang Ruan ◽

Qiang Zhang ◽

Xin Zhang ◽

Jing Hu ◽

Xie Wu

Keyword(s):

Muscle Force ◽

Female Athletes ◽

Young Female ◽

Single Component ◽

Plyometric Training ◽

Isokinetic Testing ◽

Female College ◽

Landing Biomechanics ◽

Drop Landing ◽

Landing Mechanics

BACKGROUND: It remains unclear if plyometric training as a single component could improve landing mechanics that are potentially associated with lower risk of ACL injury in the long term OBJECTIVE: The purpose of this study was to investigate the influence of experience undertaking plyometrics on landing biomechanics in female athletes. METHODS: Non-jumpers with little experience in plyometric training (12 female college swimmers) and jumpers with five years of experience in plyometric training (12 female college long jumpers and high jumpers) were recruited to participate in two testing sessions: an isokinetic muscle force test for the dominant leg at 120∘/s and a 40-cm drop landing test. An independent t test was applied to detect any significant effects between cohorts for selected muscle force, kinematic, kinetic, and electromyography variables. RESULTS: While female jumpers exhibited greater quadriceps eccentric strength (P= 0.013) and hamstring concentric strength (P= 0.023) during isokinetic testing than female swimmers, no significant differences were observed in kinematics, kinetics, and muscle activities during both drop landing and drop jumping. CONCLUSIONS: The results suggest that the female jumpers did not present any training-induced modification in landing mechanics regarding reducing injury risks compared with the swimmers. The current study revealed that plyometric training as a single component may not guarantee the development of low-risk landing mechanics for young female athletes.

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Differences in Outcomes Between Anterior and Posterior Shoulder Instability After Arthroscopic Bankart Repair: A Systematic Review and Meta-analysis

Orthopaedic Journal of Sports Medicine ◽

10.1177/23259671211006437 ◽

2021 ◽

Vol 9 (5) ◽

pp. 232596712110064

Author(s):

Matthew L. Vopat ◽

Reed G. Coda ◽

Nick E. Giusti ◽

Jordan Baker ◽

Armin Tarakemeh ◽

...

Keyword(s):

Systematic Review ◽

Shoulder Instability ◽

Anterior Shoulder Instability ◽

Posterior Shoulder Instability ◽

Anterior Instability ◽

Posterior Instability ◽

Female Patients ◽

Posterior Shoulder ◽

Male Patients ◽

Postoperative Instability

Background: The glenohumeral joint is one of the most frequently dislocated joints in the body, particularly in young, active adults. Purpose: To conduct a systematic review and meta-analysis to evaluate and compare outcomes between anterior versus posterior shoulder instability. Study Design: Systematic review; Level of evidence, 4. Methods: A systematic review was performed using the PubMed, Cochrane Library, and MEDLINE databases (from inception to September 2019) according to PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines. Studies were included if they were published in the English language, contained outcomes after anterior or posterior shoulder instability, had at least 1 year of follow-up, and included arthroscopic soft tissue labral repair of either anterior or posterior instability. Outcomes including return-to-sport (RTS) rate, postoperative instability rate, and pre- and postoperative American Shoulder and Elbow Surgeons (ASES) scores were recorded and analyzed. Results: Overall, 39 studies were included (2077 patients; 1716 male patients and 361 female patients). Patients with anterior instability had a mean age of 23.45 ± 5.40 years (range, 11-72 years), while patients with posterior instability had a mean age of 23.08 ± 8.41 years (range, 13-61 years). The percentage of male patients with anterior instability was significantly higher than that of female patients (odds ratio [OR], 1.36; 95% CI, 1.04-1.77; P = .021). Compared with patients with posterior instability, those with anterior instability were significantly more likely to RTS (OR, 2.31; 95% CI, 1.76-3.04; P < .001), and they were significantly more likely to have postoperative instability (OR, 1.53; 95% CI, 1.07-2.23; P = .018). Patients with anterior instability also had significantly higher ASES scores than those with posterior instability (difference in means, 6.74; 95% CI, 4.71-8.77; P < .001). There were no significant differences found in postoperative complications between the anterior group (11 complications; 1.8%) and the posterior group (3 complications; 1.6%) (OR, 1.12; 95% CI, 0.29-6.30; P = .999). Conclusion: Patients with anterior shoulder instability had higher RTS rates but were more likely to have postoperative instability compared with posterior instability patients. Overall, male patients were significantly more likely to have anterior shoulder instability, while female patients were significantly more likely to have posterior shoulder instability.

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Discipline and Sex Differences in Angle-specific Isokinetic Analysis in Elite Skiers

International Journal of Sports Medicine ◽

10.1055/a-0850-0016 ◽

2019 ◽

Vol 40 (05) ◽

pp. 317-330 ◽

Cited By ~ 2

Author(s):

Marine Alhammoud ◽

Baptiste Morel ◽

Clint Hansen ◽

Mathew Wilson ◽

Regis Mecca ◽

...

Keyword(s):

Statistical Parametric Mapping ◽

Knee Extension ◽

Current Data ◽

Screening Methods ◽

Full Extension ◽

Isokinetic Testing ◽

Parametric Mapping ◽

National Team ◽

Alpine Skiers ◽

The Impact

AbstractStandard outcomes of traditional isokinetic testing do not detect differences between various muscle mechanical properties. This study i) explored a novel analysis throughout the range of motion based on statistical parametric mapping and ii) examined the impact of sex and discipline on hamstrings/quadriceps torque in elite alpine skiers. Twenty-eight national team skiers (14 females, 14 males; 14 technical, 14 speed) undertook an isokinetic evaluation of the knee flexors/extensors (range 30–90°, 0° representing full extension). There was no effect of sex (p=0.864, d=0.03) and discipline (p=0.360, d=0.17) on maximal hamstrings-to-quadriceps ratio and no effect of discipline on maximal torque (p>0.156, d≤0.25). Hamstrings torque and hamstrings-to-quadriceps ratio were lower in females than males toward knee extension only (p<0.05). Quadriceps torque was greater after 72° of knee flexion in technicians than downhill skiers (p<0.05). The current data showed that statistical parametric mapping analysis identified angle-specific differences that could not be evidenced when analyzing only maximal torques and reconstructed ratios. This may enhance screening methods to identify pathologic knee function or monitor rehabilitation programs, and inform sex- and discipline-specific training in alpine skiing.

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A Rare Complication of Tuberculous Meningitis Pediatric Anterior Glenohumeral Instability

Case Reports in Orthopedics ◽

10.1155/2012/385782 ◽

2012 ◽

Vol 2012 ◽

pp. 1-4 ◽

Cited By ~ 1

Author(s):

Kerem Bilsel ◽

Mehmet Erdil ◽

Mehmet Elmadag ◽

Hasan H. Ceylan ◽

Derya Celik ◽

...

Keyword(s):

Central Nervous System ◽

Tuberculous Meningitis ◽

Shoulder Instability ◽

Rare Complication ◽

Central Nervous System Infection ◽

Arthroscopic Stabilization ◽

Anterior Instability ◽

Glenohumeral Instability ◽

Rehabilitation Protocols ◽

Anterior Glenohumeral Instability

Dislocation and instability of the shoulder joint are rare occurrences in childhood. Traumatic, infectious, congenital, and neuromuscular causes of pediatric recurrent shoulder dislocations are reported before. Central nervous system infection in infancy may be a reason for shoulder instability during childhood. This situation, which causes a disability for children, can be treated successfully with arthroscopic stabilization of the shoulder and postoperative effective rehabilitation protocols. Tuberculous meningitis may be a reason for neuromuscular shoulder instability. We describe a 12-year-old child with a recurrent anterior instability of the shoulder, which developed after tuberculous meningitis at 18 months of age. We applied arthroscopic treatment and stabilized the joint.

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Validity of Isokinetic and Isometric Testing modalities for Assessing Short-term Resistance Exercise Strength Gains

Journal of Sport Rehabilitation ◽

10.1123/jsr.1.4.275 ◽

1992 ◽

Vol 1 (4) ◽

pp. 275-283 ◽

Cited By ~ 5

Author(s):

Andrew C. Fry ◽

Dawn R. Powell ◽

William J. Kraemer

Keyword(s):

Resistance Exercise ◽

Human Performance ◽

Peak Torque ◽

Quadriceps Strength ◽

Short Term ◽

Isokinetic Testing ◽

Leg Extension ◽

Leg Flexion ◽

Isokinetic Torque ◽

Torque Values

Although it is generally accepted that human performance must be assessed in a manner specific to the training, previous studies have violated this principle. In order to determine the validity of evaluating short-term resistance training programs with isometric and isokinetic measures, 23 recreationally active males participated in an 8-week training program. Subjects were randomly divided into barbell squat, hip sled, leg extension, and control groups. Pre- and posttesting of quadriceps strength was performed with a Cybex isokinetic dynamometer. Six angle-specific torques (N.m) were determined at 0 rad-s-1 and 1.05 rad-s-1. Ten RM training loads increased significantly for all groups that trained. Isometric torque values differed significantly from isokinetic torque values at 30, 60, 75, and 90° of leg flexion for all groups. No significant torque increases from pre- to posttest were observed for any group at any limb angle for either isometric or isokinetic testing, or for isokinetic peak torque. This indicates that strength increases during short-term dynamic external resistance exercise are not adequately assessed with either isometric or isokinetic evaluations.

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The anterior labroligamentous periosteal sleeve avulsion lesion: A cause of anterior instability of the shoulder

Arthroscopy The Journal of Arthroscopic and Related Surgery ◽

10.1016/s0749-8063(05)80338-x ◽

1993 ◽

Vol 9 (1) ◽

pp. 17-21 ◽

Cited By ~ 248

Author(s):

Thomas J. Neviaser

Keyword(s):

Anterior Instability

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Recurrent Anterior Instability Manifesting as Luxatio Erecta Humeri

JBJS Case Connector ◽

10.2106/jbjs.cc.m.00048 ◽

2013 ◽

Vol 3 (4) ◽

pp. e106 ◽

Cited By ~ 1

Author(s):

Chee Ching Chan ◽

V-Liem Soon ◽

Christopher Michael Robinson

Keyword(s):

Anterior Instability ◽

Luxatio Erecta

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Reproducibility of velocity-dependent power: before and after lengthening contractions

Applied Physiology Nutrition and Metabolism ◽

10.1139/h11-068 ◽

2011 ◽

Vol 36 (5) ◽

pp. 626-633 ◽

Cited By ~ 17

Author(s):

Geoffrey A. Power ◽

Brian H. Dalton ◽

Charles L. Rice ◽

Anthony A. Vandervoort

Keyword(s):

Peak Power ◽

High Reliability ◽

Similar Amount ◽

Shortening Velocity ◽

Lengthening Contractions ◽

Isokinetic Testing ◽

Typical Error ◽

Before And After ◽

Absolute Reliability ◽

Ankle Dorsiflexors

The determination of power using isokinetic testing has been shown to be highly reliable. However, isotonic and isokinetic testing involve specific mechanical constraints that likely necessitate different neuromuscular strategies. Therefore, the purpose here was to establish test–retest intrarater reliability (separated by 7 days) of loaded maximal shortening velocity and velocity-dependent power of the ankle dorsiflexors using the isotonic mode of the Biodex dynamometer (i) at baseline and (ii) throughout recovery following 150 high-intensity lengthening contractions. Intraclass correlation coefficients (ICC)2,1 with 95% CIs were used to determine relative reliability, whereas absolute reliability included typical error (TEM) and typical error expressed as a coefficient of variation (TEMCV). Twenty-four young men and women volunteered for the study. Maximal shortening velocity and power were determined with a fixed resistance set at 20% of maximal voluntary isometric contraction across 2 testing sessions separated by 7 days. ICCs were 0.93 and 0.98 for maximal shortening velocity and peak power, respectively. Following the lengthening contractions, ICCs indicated high reliability for maximal shortening velocity and peak power, 0.86 and 0.94, respectively, suggesting that a similar amount of fatigue was incurred on both days. Measures of absolute reliability for maximal shortening velocity and peak power also yielded high reliability. The isotonic mode is highly reliable when testing velocity-dependent power of the ankle dorsiflexors at baseline and following fatiguing lengthening contractions. The high reliability of this measure is encouraging and suggests that the isotonic mode can be used in various settings to track group changes before and after training and following fatigue and lengthening contractions.

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Stability Outcomes following Computer-Assisted ACL Reconstruction

Minimally Invasive Surgery ◽

10.1155/2015/638635 ◽

2015 ◽

Vol 2015 ◽

pp. 1-7

Author(s):

Melissa A. Christino ◽

Bryan G. Vopat ◽

Alexander Mayer ◽

Andrew P. Matson ◽

Steven E. Reinert ◽

...

Keyword(s):

Internal Rotation ◽

Acl Reconstruction ◽

External Rotation ◽

Patient Characteristics ◽

Computer Assisted ◽

Single Bundle ◽

Anterior Instability ◽

Knee Stability ◽

Anterior Translation ◽

Stability Measurements

Purpose. The purpose of this study was to determine whether intraoperative prereconstruction stability measurements and/or patient characteristics were associated with final knee stability after computer-assisted ACL reconstruction.Methods. This was a retrospective review of all patients who underwent computer-assisted single-bundle ACL reconstruction by a single surgeon. Prereconstruction intraoperative stability measurements were correlated with patient characteristics and postreconstruction stability measurements. 143 patients were included (87 male and 56 female). Average age was 29.8 years (SD ± 11.8).Results. Females were found to have significantly more pre- and postreconstruction internal rotation than males (P< 0.001 andP= 0.001, resp.). Patients with additional intra-articular injuries demonstrated more prereconstruction anterior instability than patients with isolated ACL tears (P< 0.001). After reconstruction, these patients also had higher residual anterior translation (P= 0.01). Among all patients with ACL reconstructions, the percent of correction of anterior translation was found to be significantly higher than the percent of correction for internal or external rotation (P< 0.001).Conclusion. Anterior translation was corrected the most using a single-bundle ACL reconstruction. Females had higher pre- and postoperative internal rotation. Patients with additional injuries had greater original anterior translation and less operative correction of anterior translation compared to patients with isolated ACL tears.

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