The analysis of validity and repeatability of the prototype for measuring isometric muscle strength has shown to be good or excellent, depending on the knee joint angle analyzed. The new instrument, which presents a relative low cost and easiness of transportation when compared with an isokinetic dynamometer, is valid and provides consistent data concerning isometric strength of knee extensors and, for this reason, can be used for practical, clinical, and research purposes.
Background/aimThe purpose of this study was to compare the isokinetic peak torque profiles from the quadriceps and hamstrings muscles during concentric and eccentric contractions in elite Brazilian soccer players across different field positions and age categories. Our hypothesis was that soccer players from different field positions are subjected to different ageing-related effects on their isokinetic peak torque.MethodsThis is a retrospective study based on professional elite-level soccer players between the years 2009 and 2019. It included 570 adult males who played for at least 5 years on first or second Brazilian divisions. Playing positions were divided as: goalkeepers, defenders, sidebacks, midfielders and forwards. Age categories were also divided as: G1 (17–20 years old), G2 (21–24 years old), G3 (25–28 years old), G4 (29–32 years old) and G5 (33 years old or more).ResultsThe results indicate a moderate effect of age (F(4545)=8.197; p<0.001; η2=0.057) and a small effect of playing position (F(4545)=2.993; p<0.05; η2=0.021) on torque of concentric extensors; mainly from midfielders and goalkeepers with 29 years or more.ConclusionsSoccer players from different field positions are subjected to different ageing related effects on their muscular performance during their career special attention should be given to these players to avoid reduction in physical performance.
Objective: To assess the diagnostic validity of an isokinetic testing to detect partial injuries on the anterior cruciate ligament (ACL). Design: Prospective diagnostic study. Settings: Orthopedic clinic, physiotherapy clinic, orthopedic hospital, and diagnostic/image clinic. Participants: Consecutive patients (n = 29) with unilateral knee complaint submitted to physical examination, magnetic resonance images (MRIs), and isokinetic testing prior to surgery of ACL reconstruction. Interventions: Not applicable. Main Outcome Measures: The isokinetic torque curves data from extensor and flexor muscles were converted to frequency domain by fast Fourier transformation and compared with healthy contralateral limb. Differences were categorized as unstable knees and these conclusions were compared with patient’s physical examinations (doctor’s conclusion on ACL integrity) and MRIs (as the radiologist conclusions on ACL integrity). After surgery, all intraoperatively confirmed partial injured patient’s data were collected. The diagnostic accuracy measures to compare the conclusions of all 3 professionals included sensitivity, specificity, positive predictive value, negative predictive value, disease prevalence, positive likelihood ratio, and accuracy—all using a confidence interval of 95%. Results: Compared with MRI, the sensitivity of isokinetic test for an ACL partial injury was 90.00%, specificity 83.33%, positive predictive value 52.94%, negative predictive value 97.56%, and accuracy 84.48%. Compared with physical examination, the sensitivity of isokinetic test for an ACL partial injury was 85.71%, specificity 78.43%, positive predictive value 35.29%, negative predictive value 97.56%, and accuracy 79.31%. Conclusions: This method of isokinetic data analysis through fast Fourier transformation can be used to improve diagnostic accuracy of a difficult detection injury. Even present, a partial ACL injury can produce a stable knee during isokinetic testing and could be used to detect candidates for conservative treatment based on strengthening exercises, reducing surgery risks, and financial and social impact on patient’s life.
Background/AimDifferent authors have tried to correlate the peak isokinetic torque values with the incidence of soccer match injuries. However, due to the wide variety of assessment testing protocols, such an inference becomes difficult. This study aimed to verify the capacity of an isokinetic test to establish injury risk reference values for hamstring strain injuries.MethodsA retrospective cohort study based on isokinetic data and clinical records from the last 10 years was conducted in 582 Brazilian elite-professional soccer players, who were subjected to the same isokinetic test protocol, machine, and tester. A Multivariate Logistic Regression Analysis for Complex Data Sampling was used to generate injury risk statistical indexes.ResultsMultivariate regression analysis of both legs provided important data to identify the cut-off values of Concentric Peak Torque (181.82 Newton/*metres), Concentric Work (236.23 watts) and Concentric Power (130.11 joules).ConclusionsThe injury risk indexes indicate that an increase of just one Newton unit in CPT (Concentric Peak Torque) and CJ (Concentric Power) above those cut-off values, can reduce the risk of future injuries by 2% and 2.7%, respectively.
ObjectiveTo analyse rider’s subjective responses after a standardised bicycle ergonomic adjustment method.MethodsExperimental study of 160 healthy, amateur mountain bikers analysed previously and 30 days after a bike-fitting session. The main outcome measures were subjective comfort level (Feeling Scale, FEEL), fatigue (OMINI Scale) and pain (Visual Analogue Scale, VAS).ResultsAll variables demonstrated statistical significance between groups pre and post bike-fit session (p<0001). FEEL, OMNI and VAS-knee demonstrated large effect sizes (d=1.30; d=1.39 and d=0.86, respectively). VAS-hands, VAS-neck and VAS-back indicated moderate effect size (d=0.58; d=0.52 and d=0.43, respectively). VAS-groin and VAS-ankle indicated a small size effect (d=0.46 and d=0.43, respectively).ConclusionsOverall discomfort, fatigue and pain in healthy mountain biker adults improved according to all three scales. The major improvements in pain levels were detected on the knee, hands, back and neck compared with presession values. Groin and ankle pain had smaller improvements but were still significant. Future clinical trials should address the bias effects of this experimental study.
Background: Kinematic analysis aimed toward scientific investigation or professional purposes is commonly unaffordable and complex to use. Objective: The purpose of this study was to verify concurrent validation between a cycling-specific 3D camera and the gold-standard 3D general camera systems. Methods: Overall, 11 healthy amateur male triathletes were filmed riding their bicycles with Vicon 3D cameras and the Retul 3D cameras for bike fitting analysis simultaneously. All 18 kinematic measurements given by the bike fitting system were compared with the same data given by Vicon cameras through Pearson correlation (r), intraclass correlation coefficients (ICC), standard error measurements (SEM), and Bland–Altman (BA) analysis. Confidence intervals of 95% are given. Results: A very high correlation between cameras was found on six of 18 measurements. All other presented a high correlation between cameras (between 0.7 and 0.9). In total, six variables indicate a SEM of less than one degree between systems. Only two variables indicate a SEM higher than two degrees between camera systems. Overall, four measures indicate bias tendency according to BA. Conclusions: The cycling-specific led-emitting 3D camera system tested revealed a high or very high degree of correlation with the gold-standard 3D camera system used in laboratory motion capture. In total, 14 measurements of this equipment could be used in sports medicine clinical practice and even by researchers of cycling studies.
Background. It is well known that periods of inactivity generate a loss of muscle strength, a fundamental component of sports performance in soccer. However, little information is available on the decrease in strength levels in professional soccer players after the quarantine lockdown that occurred during the COVID-19 pandemic. Aim. To compare the isokinetic peak torque profiles of professional soccer players from different teams before and after the quarantine period generated by COVID-19. Methods. A retrospective observational study was performed using data collected from two different professional elite-level soccer teams just before and immediately after the COVID-19 quarantine period. One team gave individual instructions to its players for conditioning maintenance at home during the quarantine period, while the other team used regular video calls to maintain the player’s conditioning status on home training. The main outcomes were the mean peak torque of knee extensors and flexors, from concentric and eccentric contractions of each playing position. Analysis. A two-way ANOVA analysis was used to compare peak torque before and after the quarantine period and between both teams’ strategies, showing a statistically significant reduction in eccentric knee flexor peak torque from the team that did not have remote monitoring. Conclusions. Remote monitoring programs are recommended so that athletes are less affected by the deleterious effects of confinement.
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