Effects of Acute Ingestion of Guarana (Paullinia Cupana) on Soccer Player Performance: A Randomized, Cross-over, Placebo-Controlled Study.

OBJECTIVE: To investigate the acute effects of ingesting a beverage containing guarana (Paullinia cupana) seed powder on performance during field tests related to physical capacities that are determinants of soccer performance, such as lower limb power, sprint, agility, and the capacity to carry out intermittent exercise. METHODS: The study was conducted using a randomized, crossover, and counterbalanced design, with a beverage containing guarana or placebo administered in a double-blind manner. Twenty-seven under-17 soccer players of a professional soccer club performed a battery of tests 60 min after the ingestion of guarana (3 g of the fruit seed powder) or placebo. Trials were performed with a 7-day washout period. The battery of tests included a countermovement jump test, sprints of 10 and 20 m, an Illinois agility test, and a Yo-Yo Intermittent Recovery Test level 1 (YYIR1). RESULTS: Guarana ingestion did not improve countermovement jump, sprints, or agility (p > 0.05). However, guarana ingestion increased the distance covered in the YYIR1, compared with placebo ingestion (p = 0.01). CONCLUSION: Acute ingestion of guarana improves the capacity to perform intermittent exercise in soccer players but seems to be ineffective to improve lower limb power, sprint, and agility.

Usability and effects on gait of an optimized schoolchildren backpack.

BACKGROUND: Backpacks used by children is a global concern, because may cause musculoskeletal discomforts and pain. OBJECTIVE: The purpose of this study was to test the usability and effects on gait kinematics wearing the Trunkpack versus a traditional backpack and no backpack. METHODS: Twenty-four children (9 to 11 years old) from a public school participated in this study. The usability was evaluated after a five-week testing period using a questionnaire. Gait kinematics was evaluated (Vicon) when the children were wearing a standard backpack, an optimized backpack (Trunkpack), and no backpack. Both backpacks were loaded with 10% of body weight. RESULTS: Was observed more trunk, hip and knee flexion when the children carried a standard backpack in comparison using the Trunkpack and not carrying a backpack (p < 0.01). The Trunkpack and no backpack were similar. The Trunkpack was well accepted by the schoolchildren (81% positive responses), 79% liked the head opening, 88% liked the waist straps, and 83% liked the facility to put and take objects in and out of the Trunkpack. CONCLUSION: Trunkpack requires less postural adjustments during gait than a standard backpack. Gait kinematics with the Trunkpack was comparable to the gait without carrying a backpack.

Evaluation isometric and isokinetic of trunk flexor and extensor muscles with isokinetic dynamometer: A systematic review.

OBJECTIVE: To systematically review the literature analyzing the reliability and characteristics of the protocols of isokinetic and isometric evaluation of the trunk flexor and extensor muscles with isokinetic dynamometer. METHODS: This is a systematic review using PubMed, CENTRAL, LILACS, PEDro and SCOPUS databases, searching the oldest records up to December 2019. The risk of bias, the methodological quality and the level of evidence were evaluated using the COSMIN checklist. RESULTS: Fourteen articles have met the criteria and have been included in this study. All the articles performed an isometric or isokinetic evaluation of the trunk muscles with the isokinetic dynamometer and presented an analysis of the protocol's reliability using the intraclass correlation coefficient. Five articles had excellent reliability (0.93-0.98). Most of the studies presented doubtful and inconsistent psychometric values for reliability, because they used a short period between tests. The level of evidence to the fourteen selected articles for reliability was moderate. CONCLUSIONS: Although the studies present limitations in methodological quality, it was possible to identify highly reliable patterns in the parameters employed and to present recommendations for the assessment of trunk flexor and extensor muscles in the isokinetic dynamometer, both for assessment in the sitting position and orthostatic.

Accuracy of the Applied Kinesiology Muscle Strength Test for Sacroiliac Dysfunction.

Objective To investigate the accuracy of the applied kinesiology muscle strength test for sacroiliac dysfunction and compared it with four validated orthopedic tests. Methods This is a cross-sectional accuracy survey developed at a private practice in the city of Manaus, Brazil, during February 2017. The sample consisted of 20 individuals, with a median age of 33.5 years. Four tests were applied: distraction, thigh thrust, compression and sacral thrust, and the diagnosis was confirmed when three of these tests were positive. Soon after, the applied kinesiology test was applied to the piriformis muscle. Results The prevalence of sacroiliac joint dysfunction was of 45%; the thigh thrust test had the highest specificity, and the sacral thrust test had the highest sensitivity. The applied kinesiology test presented good results (sensitivity: 0.89; specificity: 0.82; positive predictive value: 0.80; negative predictive value: 0.82; accuracy: 0.85; and area under the receiver operating characteristic [ROC] curve: 0.85). Conclusion The applied kinesiology muscle strength test, which has great clinical feasibility, showed good accuracy in diagnosing sacroiliac joint dysfunction and greater discriminatory power for the existing dysfunction in comparison to other tests.

Accuracy of the Applied Kinesiology Muscle Strength Test for Sacroiliac Dysfunction / Acurácia do teste de força muscular da cinesiologia aplicada para disfunção sacroilíaca

Abstract Objective To investigate the accuracy of the applied kinesiology muscle strength test for sacroiliac dysfunction and compared it with four validated orthopedic tests. Methods This is a cross-sectional accuracy survey developed at a private practice in the city of Manaus, Brazil, during February 2017. The sample consisted of 20 individuals, with a median age of 33.5 years. Four tests were applied: distraction, thigh thrust, compression and sacral thrust, and the diagnosis was confirmed when three of these tests were positive. Soon after, the applied kinesiology test was applied to the piriformis muscle. Results The prevalence of sacroiliac joint dysfunction was of 45%; the thigh thrust test had the highest specificity, and the sacral thrust test had the highest sensitivity. The applied kinesiology test presented good results (sensitivity: 0.89; specificity: 0.82; positive predictive value: 0.80; negative predictive value: 0.82; accuracy: 0.85; and area under the receiver operating characteristic [ROC] curve: 0.85). Conclusion The applied kinesiology muscle strength test, which has great clinical feasibility, showed good accuracy in diagnosing sacroiliac joint dysfunction and greater discriminatory power for the existing dysfunction in comparison to other tests.

Resumo Objetivo Investigar a acurácia do teste de força muscular da cinesiologia aplicada para disfunção sacroilíaca, comparando-o com quatro testes ortopédicos validados. Métodos Trata-se de uma pesquisa transversal de acurácia desenvolvida em uma clínica particular da cidade de Manaus no mês de fevereiro de 2017. A amostra teve 20 indivíduos, com mediana de idade 33,5 anos. Foram aplicados quatro testes: distração, thigh thrust, compressão e thrust sacral, e o diagnóstico foi confirmado quando três destes testes deram positivo. Logo após, foi aplicado o teste da cinesiologia aplicada para o músculo piriforme. Resultados A prevalência de disfunção da articulação sacroilíaca observada foi de 45%, tendo o teste thigh thrust alta especificidade, e o teste thrust sacral, alta sensibilidade. O teste da cinesiologia aplicada obteve bons resultados (sensibilidade: 0,89; especificidade: 0,82; valor preditivo positivo: 0,80; valor preditivo negativo: 0,82; acurácia: 0,85; área abaixo da curva de característica de operação do receptor [COR]: 0,85). Conclusão O teste de força muscular da cinesiologia aplicada, de grande viabilidade clínica, mostrou ter boa acurácia no diagnóstico da disfunção da articulação sacroilíaca, e maior poder discriminatório da disfunção existente, em comparação aos demais testes.