A Functional Agility Short-Term Fatigue Protocol Changes Lower Extremity Mechanics

The purpose of this study was to evaluate the effects of a functional agility fatigue protocol on lower extremity biomechanics between two unanticipated tasks (stop-jump and sidestep). The subjects consisted of fifteen female collegiate soccer athletes (19 ± 0.7 years, 1.67 ± 0.1 m, 61.7± 8 kg) free of lower extremity injury. Participants performed five trials of stop-jump and sidestep tasks. A functional short-term agility protocol was performed, and immediately following participants repeated the unanticipated running tasks. Lower extremity kinematic and kinetic values were obtained pre and post fatigue. Repeated measures analyses of variance were conducted for each dependent variable with an alpha level set at 0.05. Knee position post-fatigue had increased knee internal rotation (11.4 ± 7.5 degrees vs. 7.9 ± 6.5 degrees p = 0.011) than pre-fatigue, and a decreased knee flexion angle (-36.6 ± 6.2 degrees vs. -40.0 ± 6.3 degrees, p = 0.003), as well as hip position post-fatigue had decreased hip flexion angle (35.5 ± 8.7 degrees vs. 43.2 ± 9.5 degrees, p = 0.002). A quick functional fatigue protocol altered lower extremity mechanics of Division I collegiate soccer athletes during landing tasks. Proper mechanics should be emphasized from the beginning of practice/game to aid in potentially minimizing the effects of fatigue in lower extremity mechanics

Two Different Fatigue Protocols and Lower Extremity Motion Patterns During a Stop-Jump Task

Context: Altered neuromuscular control strategies during fatigue probably contribute to the increased incidence of non-contact anterior cruciate ligament injuries in female athletes. Objective: To determine biomechanical differences between 2 fatigue protocols (slow linear oxidative fatigue protocol [SLO-FP] and functional agility short-term fatigue protocol [FAST-FP]) when performing a running-stop-jump task. Design: Controlled laboratory study. Setting: Laboratory. Patients or Other Participants: A convenience sample of 15 female soccer players (age = 19.2 ± 0.8 years, height = 1.67± 0.05m, mass = 61.7 + 8.1 kg) without injury participated. Intervention(s): Five successful trials of a running–stop-jump task were obtained prefatigue and postfatigue during the 2 protocols. For the SLO-FP, a peak oxygen consumption (V˙o2peak) test was conducted before the fatigue protocol. Five minutes after the conclusion of the V˙o2peak test, participants started the fatigue protocol by performing a 30-minute interval run. The FAST-FP consisted of 4 sets of a functional circuit. Repeated 2 (fatigue protocol) × 2 (time) analyses of variance were conducted to assess differences between the 2 protocols and time (prefatigue, postfatigue). Main Outcome Measure(s): Kinematic and kinetic measures of the hip and knee were obtained at different times while participants performed both protocols during prefatigue and postfatigue. Results: Internal adduction moment at initial contact (IC) was greater during FAST-FP (0.064 ± 0.09 Nm/kgm) than SLO-FP (0.024±0.06 Nm/kgm) (F1,14 = 5.610, P= .03). At IC, participants had less hip flexion postfatigue (44.7°±8.1°) than prefatigue (50.1°± 9.5°) (F1,14 = 16.229, P= .001). At peak vertical ground reaction force, participants had less hip flexion postfatigue (44.7°± 8.4°) than prefatigue (50.4°± 10.3°) (F1,14 = 17.026, P=.001). At peak vertical ground reaction force, participants had less knee flexion postfatigue (−35.9°± 6.5°) than prefatigue (−38.8°± 5.03°) (F1,14 = 11.537, P= .001). Conclusions: Our results demonstrated a more erect landing posture due to a decrease in hip and knee flexion angles in the postfatigue condition. The changes were similar between protocols; however, the FAST-FP was a clinically applicable 5-minute protocol, whereas the SLO-FP lasted approximately 45 minutes

Fatores determinantes na variação dos preços dos produtos contratados por pregão eletrônico

A pesquisa buscou avaliar quais os fatores determinantes na variação dos preços dos produtos comprados através de pregão eletrônico. Para atingir os objetivos, testou-se a relação da variação dos preços com as variáveis: número de fornecedores, especificidade dos ativos, frequência das transações, quantidade, oportunismo dos agentes, tempo de existência e faturamento da empresa ganhadora e número de lances da disputa. Foram realizadas correlação de Pearson e regressão linear múltipla, com o intuito de explorar as relações entre as variáveis e construir um modelo para medir a variação dos preços. As variáveis número de fornecedores, especificidade dos ativos, quantidade e frequência das transações apresentaram um poder de explicação conjunta de 67,4% das variações dos preços. Assim, os órgãos públicos devem desenvolver ações que busquem maximizar o efeito destas variáveis com o objetivo de reduzir os preços pagos