scholarly journals Geometric Morphology of the Coracoacromial Ligament: A Cadaveric Study

2019 ◽  
Vol 2019 ◽  
pp. 1-8
Author(s):  
Mehmet Demir ◽  
Bülent Güneri
Keyword(s):  
Statistical Analysis ◽  
Shoulder Pain ◽  
Humeral Head ◽  
Common Knowledge ◽  
Coracoid Process ◽  
Coracoacromial Ligament ◽  
Death Time ◽  
The Mean ◽  
Geometric Morphology ◽  
Digital Caliper

The coracoacromial ligament (CAL), which restrains superior displacement of humeral head, connects the acromion and coracoid process. Due to the ligament’s variations and its role in shoulder pain, CAL was investigated in this study. Sixty shoulders of 34 cadavers, from persons aged 61-98 (80.95 ± 8.81) years at death time, were dissected. The lengths of lateral (LBL) and medial borders (MBL), widths of acromial (AIW) and coracoid insertions (CIW), and thicknesses of lateral (LSTAI) and medial (MSTAI) sides of acromial insertions were measured by digital caliper. The data were subjected to statistical analysis. 24 (40%) V-shaped, 12 (20%) broad-banded, 9 (15%) quadrangular, 9 (15%) Y-shaped, and 6 (10%) multiple-banded types were identified. The mean total LBL, MBL, AIW, CIW, LSTAI, and MSTAI were 34.94 ± 4.59 mm, 33.58 ± 5.31 mm, 29.82 ± 9.48 mm, 12.62 ± 3.95 mm, 1.29 ± 0.17 mm, and 0.90 ± 0.22 mm, respectively. The mean LBL (39.12 ± 4.29 mm), MBL (36.48 ± 3.9 mm), and CIW (37.01 ± 3.39 mm) were significantly greatest in quadrangular type (p<0.001). The mean AIW was slightly greatest in quadrangular type (p=0.069). The mean LSTAI was significantly greatest in multiple-banded type (1.45 ± 0.10 mm, p<0.001) whereas the mean MSTAI was significantly greatest in quadrangular type (1.23 ± 0.23 mm, p<0.001). CAL is quite variable regarding morphology, dimensions, and insertion features. Despite common knowledge, MSTAI and MBL of CAL can be greater than lateral counterparts in some types. To obtain complete release of CAL at acromion, the clearance of ligament fibers in an area with the dimensions of around 16 mm in mediolateral and 15 mm in anteroposterior direction, beginning from the lateral edge of acromial insertion, is recommended.

scholarly journals Anatomic Study of Subcoracoid Morphology in 418 Shoulders: Potential Implications for Subcoracoid Impingement

2017 ◽  
Vol 5 (10) ◽  
pp. 232596711773199 ◽  
Author(s):  
Anthony J. Dugarte ◽  
Rocklend J. Davis ◽  
T. Sean Lynch ◽  
Mark S. Schickendantz ◽  
Lutul D. Farrow
Keyword(s):  
Internal Rotation ◽  
Shoulder Pain ◽  
Older Patients ◽  
Morphological Changes ◽  
Young Female ◽  
Coracoid Process ◽  
Subscapularis Tendon ◽  
The Mean ◽  
Tendon Tears ◽  
Anterior Shoulder Pain

Background: Subcoracoid impingement has been implicated as a cause of anterior shoulder pain and subscapularis tendon tears. Purpose/Hypothesis: The purpose of this study was to evaluate the bony anatomy of the coracoid process and the subcoracoid space. We hypothesized that age-related changes that may contribute to subcoracoid impingement occur in the subcoracoid space. Study Design: Descriptive laboratory study. Methods: In total, 418 skeletal shoulder specimens were included in this study. We utilized 214 shoulders from a young cohort (25-35 years of age) and 204 shoulders from an older cohort (>55 years of age) for comparison. We evaluated several morphological characteristics of the coracoid process and the subcoracoid space: coracoid width, coracoid shape, coracoid thickness, and subcoracoid distance. Each coracoid was observed for the presence of spurring or other morphological changes. Results: The mean anteroposterior (AP) thickness of the coracoid tip was 7.9 and 9.4 mm in our young female and male cohorts, respectively, while the mean AP thickness was 8.1 and 9.7 mm in our older female and male cohorts, respectively. The coracoid tip was hooked in 31 of 108 young female shoulders compared with 55 of 102 older female shoulders, and the coracoid tip was hooked in 25 of 106 young male shoulders compared with 45 of 102 older male shoulders. The mean subcoracoid distance in neutral rotation was 14.8 and 12.5 mm in young and older female shoulders, respectively, while the mean subcoracoid distance in internal rotation in these same cohorts was 8.7 and 7.0 mm, respectively. The mean subcoracoid distance in neutral rotation was 14.8 and 13.3 mm in young and older male shoulders, respectively, while the mean subcoracoid distance in internal rotation was 8.6 and 8.1 mm in young and older male shoulders, respectively. Conclusion: The principal findings of our study demonstrate that anatomic changes implicated in subcoracoid impingement may be developmental and worsen with age. The subcoracoid space was narrower in our older cohort of shoulders. Additionally, these older shoulders also had a greater AP width and a more hooked coracoid compared with young shoulders. Clinical Relevance: Narrowing of the subcoracoid space has been shown to be implicated as a cause of anterior shoulder pain and subscapularis tendon tears. This is the first study to show that the morphological changes implicated in subcoracoid impingement become more prevalent with age. This may help to explain the increasing prevalence of subscapularis tendon tears in older patients. Furthermore, subcoracoid decompression may be seen as an option for older patients with anterior shoulder pain and subscapularis tendon tears.

The Time of Spontaneous Resolution of Monosymptomatic Nocturnal Enuresis (MNE) Is Familial

2015 ◽  
Vol 94 (4) ◽  
pp. 459-463 ◽  
Author(s):  
Ural Oguz ◽  
Aykut Aykac ◽  
Erhan Demirelli ◽  
Eyup Burak Sancak ◽  
Berkan Resorlu ◽  
...  
Keyword(s):  
Statistical Analysis ◽  
Nocturnal Enuresis ◽  
Spontaneous Resolution ◽  
Resolution Time ◽  
Mothers And Fathers ◽  
Positive Correlation ◽  
Referral Hospitals ◽  
Education Status ◽  
Monosymptomatic Nocturnal Enuresis ◽  
The Mean

Purpose: To investigate whether or not the age of spontaneous resolution of monosymptomatic nocturnal enuresis (MNE) was familial. Patients and Methods: A questionnaire was administered to more than 1,500 people, and 100 appropriate participants were identified from four referral hospitals. We included the participants who had MNE and whose parents also had MNE with spontaneous resolution. Then the association between the spontaneous resolution time of MNE in parents and that in their children was investigated. Results: The mean ages of spontaneous resolution were 10.7 (10-30 years), 9.4 (6-17 years) and 10.9 (6-18 years) in participants, their mothers and their fathers, respectively. According to the statistical analysis, there was a positive correlation between participants and both their mothers and fathers (p < 0.05). In addition, it was revealed that familial MNE history based on first- and second-degree relatives, in addition to their parents, was also associated with the increased spontaneous resolution age of MNE (p < 0.05). According to our results, gender and parents' education status were not statistically associated with the spontaneous resolution (p > 0.05). Conclusion: As a conclusion, the age of spontaneous resolution of MNE is familial. Although the exact reasons of spontaneous resolution still remain a mystery; further genetic investigations may be able to resolve this mystery.

Analysis of the breeding records of a herd of pigs

1954 ◽  
Vol 45 (1) ◽  
pp. 19-27 ◽  
Author(s):  
R. Braude ◽  
P. M. Clarke ◽  
K. G. Mitchell
Keyword(s):  
Statistical Analysis ◽  
Large White ◽  
Seasonal Differences ◽  
Significant Difference ◽  
The Mean ◽  
The Difference ◽  
Length Of Gestation

1. A survey and. statistical analysis of the records of litters born in the N.I.R.D. herd of Large White pigs over a period of 16 years are presented.2. The mean length of gestation was 114 days for both gilts and sows.3. The mean numbers of pigs born alive and born dead per litter from gilts, 10·0 and 0·2 respectively, were both significantly smaller than the corresponding figures for sows, 11·8 and O·8. No seasonal differences were found.4. The mean total losses of pigs from birth to weaning at 8 weeks were 29·5% of pigs born alive. The losses in litters from gilts, 23·0%, were significantly smaller than in litters from sows, 31·0%. The losses during the winter months both for gilts, 32·5%, and for sows, 35·9%, were significantly higher than during the summer months, 19·4% and 26·7% for gilts and sows respectively.5. Over 50% of the total losses were due to crushing by the dam, 74·1% of the losses from this cause occurring during the first 48 hr. after birth.6. The mean number of pigs weaned per litter was 8·0. The difference between the number weaned per litter from gilts, 7·7, and per litter from number of pigs was weaned per litter from sows during the summer months, 8·7, than during the winter months, 7·4.7. There was no significant difference between the number of male and of female pigs weaned.8. The mean weight at weaning was 29·9 lb., male pigs, 30·3 lb., being significantly heavier than females, 29·51b. Pigs in litters from gilts, 27·81b., were significantly lighter at weaning than those from sows, 30·0 lb., and for both gilts and sows, pigs reared during the summer months, 29·7 and 31·8 lb. respectively, were significantly heavier than those reared during the winter months, 25·9 and 28·2 lb. respectively.

scholarly journals Distances between mandibular posterior teeth and the WALA ridge in Peruvians with normal occlusion

2017 ◽  
Vol 22 (6) ◽  
pp. 56-60 ◽  
Author(s):  
Carla Y. Kong-Zárate ◽  
Marcos J. Carruitero ◽  
Will A. Andrews
Keyword(s):  
Age Groups ◽  
Test Results ◽  
Posterior Teeth ◽  
Normal Occlusion ◽  
Tooth Type ◽  
The Mean ◽  
Student’S T ◽  
Mandibular Posterior Teeth ◽  
Digital Caliper ◽  
Student’S T Test

ABSTRACT Objective: The purposes of this investigation were to determine the horizontal distances between the mandibular posterior teeth and the WALA ridge in a sample of Peruvians with normal occlusion and to compare them by tooth type, sex, arch side, and age groups. Methods: 65 dental casts of subjects with normal occlusion were collected. Posterior teeth, except for third molars, were evaluated. The horizontal distances between the occluso-gingival midpoints of the buccal surfaces (FA points) of each tooth and the WALA ridge were measured using a modified digital caliper. The values between each different tooth type within the sample were compared using the ANOVA and Scheffe tests, while comparisons by sex, arch side and age groups, using the Student’s t-test. Results: The mean distances in the sample was 0.96 mm for first premolars, 1.45 mm for second premolars, 2.12 mm for first molars and 2.55 mm for second molars. Statistically significant differences between each of the four tooth types were found. There were no significant differences found between sex, arch side and age groups. Conclusion: The horizontal distances between the mandibular posterior teeth and the WALA ridge increased progressively from the first premolars to the second molars in Peruvians with normal occlusion. The WALA ridge was a good landmark to evaluate the positions of posterior teeth in Peruvians with normal occlusion.

scholarly journals Decrease in white blood cell counts after thiopentone barbiturate therapy for refractory intracranial hypertension: A common complication

2013 ◽  
Vol 04 (S 01) ◽  
pp. S31-S34 ◽  
Author(s):  
Shin Yi Ng ◽  
Ki Jinn Chin ◽  
Tong Kiat Kwek
Keyword(s):  
Statistical Analysis ◽  
Blood Cell ◽  
Intracranial Hypertension ◽  
White Blood Cell ◽  
Retrospective Review ◽  
T Test ◽  
Barbiturate Coma ◽  
Barbiturate Therapy ◽  
The Mean ◽  
Wbc Count

ABSTRACT Background: Leucopenia has been reported after induction of thiopentone barbiturate therapy for refractory intracranial hypertension. However, the incidence and characterisitics are not well described. Aims: We performed a retrospective review to describe the incidence and characteristics of leucopenia after induction of thiopentone barbiturate therapy. Setting and Design: Our centre is a national referral centre for neurotrauma and surgery in a tertiary medical institution.Materials and Methods: We performed a retrospective review of all patients who received thiopentone barbiturate therapy for refractory intracranial hypertension during an 18 month period from January 2004 to June 2005 in our neurosurgical intensive care unit. Statistical Analysis Used: Statistical analysis was performed using SPSS version 15.0. All data are reported as mean ± standard deviation or median (interquartile range). The Chi square test was used to analyze categorical data and student t test done for comparison of means. For paired data, the paired t?test was used.-test was used. Results: Thirty eight (80.9%) out of 47 patients developed a decrease in white blood cell (WBC) count after induction of thiopentone barbiturate coma. The mean decrease in WBC from baseline to the nadir was 6.4 × 10 9 /L (P <lt; 0.001) and occurred 57 (3-147) h after induction. The mean nadir WBC was 8.6 < 3.6 × 10 9 /L. Three (6.4%) patients were leucopenic, with a WBC count of 2.8, 3.1, and 3.6 < 10 9 /L. None of them were neutropenic. We did not find an association between decrease in WBC count and clinical diagnosis of infection. We did not find any association between possible risk factors such as admission GCS, maximum ICP prior to induction of barbiturate coma, APACHE II score, total duration and dose of thiopentone given, and decrease in WBC count. Conclusions: Decrease in WBC count is common, while development of leucopenia is rare after thiopentone barbiturate coma. Regular monitoring of WBC counts is recommended.

Diagnostic block and radiofrequency ablation of the acromial branches of the lateral pectoral and suprascapular nerves for shoulder pain: a 3D cadaveric study

2021 ◽  
Vol 46 (4) ◽  
pp. 305-312
Author(s):  
John Tran ◽  
Philip Peng ◽  
Anne Agur ◽  
Nimish Mittal
Keyword(s):  
Radiofrequency Ablation ◽  
Shoulder Pain ◽  
Coracoid Process ◽  
Electrode Position ◽  
Anatomical Landmarks ◽  
Ultrasound Guided ◽  
Pectoral Nerve ◽  
Diagnostic Block ◽  
Superior Surface ◽  
Capture Rates

Background and objectivesAcromial branches of the lateral pectoral and suprascapular nerves have been proposed as targets for diagnostic block and radiofrequency ablation to treat superior shoulder pain; however, the nerve capture rates of these procedures have not been investigated. The objectives of this study were to use dissection and 3D modeling technology to determine the course of these acromial branches, relative to anatomical landmarks, and to evaluate nerve capture rates using ultrasound-guided dye injection and lesion simulation.MethodsUltrasound-guided dye injections, targeting the superior surface of coracoid process and floor of supraspinous fossa, were performed (n=5). Furthermore, needles targeting the superior and posterior surfaces of the coracoid process were placed under ultrasound guidance to simulate needle electrode position (n=5). Specimens were dissected, digitized, and modeled to determine capture rates of acromial branches of lateral pectoral and suprascapular nerves.ResultsThe course of acromial branches of lateral pectoral and suprascapular nerves were documented. Dye spread capture rates: acromial branches of lateral pectoral and suprascapular nerves were captured in all specimens. Lesion simulation capture rates: (1) when targeting superior surface of coracoid process, the entire acromial branch of lateral pectoral nerve was captured in all specimens and (2) when targeting posterior surface of coracoid process, the acromioclavicular and bursal branches of acromial branch of suprascapular nerve were captured in all specimens; coracoclavicular branch was captured in 3/5 specimens.ConclusionsThis study supports the anatomical feasibility of ultrasound-guided targeting of the acromial branches of lateral pectoral and suprascapular nerves. Further clinical investigation is required.

scholarly journals Assessment and comparison of the levels of N-nitrosonornicotine and 4-(n-methyl-n –nitrosamino) -1-(3-pyridyl)-1-butanone in the saliva of tobacco chewers and non- chewers -a hospital based study

2018 ◽  
Vol 6 (2) ◽  
pp. 66
Author(s):  
Dr Harpreet Kaur Gandhoke ◽  
Dr Vasanti Lagali Jirge ◽  
Dr Anjana Bagewadi
Keyword(s):  
Statistical Analysis ◽  
Smokeless Tobacco ◽  
Statistical Difference ◽  
Study Groups ◽  
P Value ◽  
Sample Collection ◽  
Group Iii ◽  
Group I ◽  
The Mean ◽  
Tobacco Specific Nitrosamines

Background: Studies estimating the Tobacco- specific nitrosamines, (TSNA’s) which are the strongest carcinogens in the saliva oftobacco users and tobacco quitters, are limited.Objectives: To assess and compare the levels of N- nitrosamines (NNN, NNK) in the saliva of tobacco chewers and non -chewers including those who have quit the habit of tobacco use.Methods: The study included 120 patients who were divided into three groups of 40 each: Group I- Smokeless tobacco chewersGroup II- Tobacco chewers who have completely stopped the habit at least 2 weeks prior to sample collection andGroup III- non-chewers. The salivary levels of two tobacco specific nitrosamines; NNN & NNK levels were estimated in the three study groups. Statistical analysis was done by Kruskal– Wallis, one-way analysis of variance (ANOVA) test, Mann-Whitney U test. (p-value < 0.05 was considered to be statistically significant)Results: In Group I, the mean level of NNN was 651.84 ± 359.78 and mean level of NNK was 168.32 ± 131.83. In Group II, the mean level of NNN was 119.52 ± 95.05 and mean level of NNK was 42.78 ± 43.19. In Group III, the mean level of NNN was 3.44 ±6.55 and mean level of NNK was 1.98 ± 3.68. There was a statistical difference in the 3 groups with respect to mean levels of NNN and NNK.Conclusion: The study indicated that salivary tobacco-specific nitrosamines are elevated in tobacco chewers. Saliva can be used to detect TSNA’s and screen for TSNA’s during each patient’s de-addiction process.  

Biomechanical Evaluation of Glenoid Reconstruction With an Implant-Free J-Bone Graft for Anterior Glenoid Bone Loss

2017 ◽  
Vol 45 (12) ◽  
pp. 2849-2857 ◽  
Author(s):  
Leo Pauzenberger ◽  
Felix Dyrna ◽  
Elifho Obopilwe ◽  
Philipp R. Heuberer ◽  
Robert A. Arciero ◽  
...  
Keyword(s):  
Bone Graft ◽  
Bone Grafting ◽  
Humeral Head ◽  
External Rotation ◽  
Glenoid Defect ◽  
Contact Patterns ◽  
Grafting Technique ◽  
The Mean ◽  
The Creation ◽  
Glenoid Reconstruction

Background: The anatomic restoration of glenoid morphology with an implant-free J-shaped iliac crest bone graft offers an alternative to currently widely used glenoid reconstruction techniques. No biomechanical data on the J-bone grafting technique are currently available. Purpose: To evaluate (1) glenohumeral contact patterns, (2) graft fixation under cyclic loading, and (3) the initial stabilizing effect of anatomic glenoid reconstruction with the implant-free J-bone grafting technique. Study Design: Controlled laboratory study. Methods: Eight fresh-frozen cadaveric shoulders and J-shaped iliac crest bone grafts were used for this study. J-bone grafts were harvested, prepared, and implanted according to a previously described, clinically used technique. Glenohumeral contact patterns were measured using dynamic pressure-sensitive sensors under a compressive load of 440 N with the humerus in (a) 30° of abduction, (b) 30° of abduction and 60° of external rotation, (c) 60° of abduction, and (d) 60° of abduction and 60° of external rotation. Using a custom shoulder-testing system allowing positioning with 6 degrees of freedom, a compressive load of 50 N was applied, and the peak force needed to translate the humeral head 10 mm anteriorly at a rate of 2.0 mm/s was recorded. All tests were performed (1) for the intact glenoid, (2) after the creation of a 30% anterior osseous glenoid defect parallel to the longitudinal axis of the glenoid, and (3) after anatomic glenoid reconstruction with an implant-free J-bone graft. Furthermore, after glenoid reconstruction, each specimen was translated anteriorly for 5 mm at a rate of 4.0 mm/s for a total of 3000 cycles while logging graft protrusion and mediolateral bending motions. Graft micromovements were recorded using 2 high-resolution, linear differential variable reluctance transducer strain gauges placed in line with the long leg of the graft and the mediolateral direction, respectively. Results: The creation of a 30% glenoid defect significantly decreased glenohumeral contact areas ( P < .05) but significantly increased contact pressures at all abduction and rotation positions ( P < .05). Glenoid reconstruction restored the contact area and contact pressure back to levels of the native glenohumeral joint in all tested positions. The mean (±SD) force to translate the humeral head anteriorly for 10 mm (60° of abduction: 31.7 ± 12.6 N; 60° of abduction and 60° of external rotation: 28.6 ± 7.6 N) was significantly reduced after the creation of a 30% anterior bone glenoid defect (60° of abduction: 12.2 ± 6.8 N; 60° of abduction and 60° of external rotation: 11.4 ± 5.4 N; P < .001). After glenoid reconstruction with a J-bone graft, the mean peak translational force significantly increased (60° of abduction: 85.0 ± 8.2 N; 60° of abduction and 60° of external rotation: 73.6 ± 4.5 N; P < .001) compared with the defect state and baseline. The mean total graft protrusion under cyclical translation of the humeral head over 3000 cycles was 138.3 ± 169.8 µm, whereas the mean maximal mediolateral graft deflection was 320.1 ± 475.7 µm. Conclusion: Implant-free anatomic glenoid reconstruction with the J-bone grafting technique restored near-native glenohumeral contact areas and pressures, provided secure initial graft fixation, and demonstrated excellent osseous glenohumeral stability at time zero. Clinical Relevance: The implant-free J-bone graft is a viable alternative to commonly used glenoid reconstruction techniques, providing excellent graft fixation and glenohumeral stability immediately postoperatively. The normalization of glenohumeral contact patterns after reconstruction could potentially avoid the progression of dislocation arthropathy.

Statistical analysis of nematode counts from interlaboratory proficiency tests

Nematology ◽  
2014 ◽  
Vol 16 (2) ◽  
pp. 229-243 ◽  
Author(s):  
Wim Van Den Berg ◽  
Olaf Hartsema ◽  
Loes J.M.F. Den Nijs
Keyword(s):  
Statistical Analysis ◽  
Proficiency Test ◽  
Meta Analysis ◽  
Proficiency Tests ◽  
Free Living ◽  
Accuracy And Precision ◽  
Mean And Variance ◽  
The Mean ◽  
Interaction Variance

A series of proficiency tests on potato cyst nematode (PCN; ) and free-living stages of Meloidogyne and Pratylenchus () were investigated to determine the accuracy and precision of the nematode counts and to gain insights into possible trends and potential improvements. In each test, each participating laboratory received ten samples of soil collected from naturally infested fields and well mixed before distribution. The variance between the counts from the ten samples, estimated per test and laboratory, was constant for PCN cysts and free-living stages of Meloidogyne spp. and Pratylenchus spp. during the period monitored. However, during the initial years, the variance between the samples showed a downward trend for PCN living juveniles. The variance between the laboratories, estimated per test, was constant for PCN cysts over the period 1994-2010. For PCN living juveniles the variance between laboratory means declined from 1994-2000 and from 2000 it was more or less constant, which coincided with the introduction of a well-described new methodology. For Meloidogyne spp. and Pratylenchus spp., from 1998-2005 the variance between laboratory means was more or less constant or increased. From 2006, all participating laboratories incubated the organic matter and the variance between the laboratories was stable and below the levels observed during 2003-2005. After discarding data from initial years with unstable variances of the nematode counts, a meta-analysis was carried out on the remaining data using HGLMs to model the mean and variance of the counts simultaneously. The within-laboratory variance for the ten samples and the interaction variance of test and laboratory were estimated and combined to percentage coefficient of variation (%CV) per laboratory. For PCN cysts, %CV per laboratory ranged from 12.6 to 41.6 and for PCN juveniles in sandy soil from 24.4 to 67.4 and in loamy soil from 37.9 to 102.0. For Meloidogyne spp., %CV ranged from 53.2 to 84.4 and for Pratylenchus spp. from 24.3 to 90.6. The quality of a proficiency test is largely defined by random distribution of the nematodes over the samples allocated, statistical analysis of the data and communication of the results to participating laboratories. This study provides insights into the accuracy and precision at laboratories in recent years and the effect of concerted actions during the period in which the proficiency tests were conducted.

scholarly journals Effects of Pre-Activation with Variable Intra-Repetition Resistance on Throwing Velocity in Female Handball Players: A Methodological Proposal

2021 ◽  
Vol 77 (1) ◽  
pp. 235-244
Author(s):  
Darío Martínez-García ◽  
Ángela Rodríguez-Perea ◽  
Álvaro Huerta-Ojeda ◽  
Daniel Jerez-Mayorga ◽  
Daniel Aguilar-Martínez ◽  
...  
Keyword(s):  
Statistical Analysis ◽  
Repeated Measures ◽  
Initial Velocity ◽  
Acute Effect ◽  
Rest Interval ◽  
Maximum Voluntary Isometric Contraction ◽  
Variable Resistance ◽  
Ball Velocity ◽  
The Mean ◽  
The Individual

Abstract The purpose of this study was to investigate the acute effect of pre-activation with Variable Intra-Repetition Resistance and isometry on the overhead throwing velocity in handball players. Fourteen female handball players took part in the study (age: 21.2 ± 2.7 years, experience: 10.9 ± 3.5 years). For Post-Activation Potentiation, two pre-activation methods were used: (I) Variable Intra-Repetition Resistance: 1 x 5 maximum repetitions at an initial velocity of 0.6 m·s-1 and a final velocity of 0.9 m·s-1; (II) Isometry: 1 x 5 s of maximum voluntary isometric contraction. Both methods were "standing unilateral bench presses" with the dominant arm, using a functional electromechanical dynamometer. The variable analysed was the mean of the three overhead throws. Ball velocity was measured with a radar (Stalker ATS). The statistical analysis was performed using ANOVA with repeated measures. No significant differences were found for either method (variable resistance intra-repetition: p = 0.194, isometry: p = 0.596). Regarding the individual responses, the analysis showed that 86% of the sample increased throwing velocity with the variable resistance intra-repetition method, while 93% of the sample increased throwing velocity with the isometric method. Both the variable intra-repetition resistance and isometric methods show improvements in ball velocity in female handball players. However, the authors recommend checking individual responses, since the results obtained were influenced by the short rest interval between the pre-activation and the experimental sets.

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