The aim of this study was to examine the diff erences of landing phase biomechanics between the players who had anterior cruciate ligament (ACL) reconstruction and healthy participants during single leg drop vertical jump. In this study, 11 soccer players who had anterior cruciate ligament reconstruction (aged 23.0±3.6 years, height 177±5.0 cm, weight 83.8±11.7 kg) and 9 healthy soccer players(aged 22.2±2.4 years, height 178±3.0 cm, weight 74.3±6.1 kg) participated voluntarily. During the data collection phase three high speed cameras synchronized to each other and force plate were used. Visual analysis programme and MATLAB were used to calculate kinetic and kinematic variables. Landing techniques of the subjects' were examined by fl exion angle of knee, ground reaction force and moment parameters. The statistical analyses of the measured results were performed by t-test and Pearson Correlation analysis. According to the results, it was determined that peak vertical ground reaction force exhibited significant phase diff erences (p=0.00, and p=0.00, respectively) between the groups. Obtained results can be explained with "quadriceps avoidance" motion pattern which is characterized by decreased quadriceps activity and lower external knee fl exion moment in an eff ort to control anterior translation of the tibia in subjects with ACL reconstruction. A better understanding of the diff erent phases during single-leg landings can shed a light on mechanism of non-contact anterior crucaite ligament injuries therefore future researches should assess how phase diff erences aff ect drop vertical jump performance.

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The 3-m backward walk test (3MBWT) is used to evaluate neuromuscular control, proprioception, protective reflexes, fall risk, and balance. The aim of the present study was to determine the test–retest reliability of the 3MBWT in patients with primary total knee arthroplasty (TKA). Twenty-eight patients with primary TKA, operated by the same surgeon, were included in this study. Patients performed trials for 3MBWT twice on the same day. Between the first and second trials, patients waited for an hour on sitting position to prevent fatigue. The 3MBWT showed an excellent test–retest reliability in this study. Intraclass correlation coefficient (ICC) for 3MBWT was 0.97. The standard error of measurement and smallest real difference at the 95% confidence level for 3MBWT were 1.06 and 2.94, respectively. The 3MBWT has an excellent test–retest reliability in patients with primary TKA. It is an effective and reliable tool for measuring dynamic balance and participant falls. As a clinical test, the 3MBWT is easy to score, requires little space, has no cost, needs no special equipment, and can be applied in a short time as part of the routine medical examination.

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BACKGROUND: Isokinetic exercise is used to reduce strength imbalance and to enhance performance. OBJECTIVE: The aim of this study was to investigate the acute effects of a single bout of eccentric isokinetic exercise on hemorheology (erythrocyte deformability and aggregation), total oxidant/antioxidant status (TOS/TAS) and oxidative stress index (OSI) in active individuals. METHODS: The study comprises 11 active, healthy, male subjects (mean age of 19.45 ± 0.31 years, BMI 22.05 ± 0.51 kg/m2). They performed single, unilateral eccentric contractions of knee flexors and extensors with dominant leg on a dynamometer. Isokinetic hamstring, quadriceps strength were recorded at eccentric (30, 120° s−1) angular velocities. Eight active age-matched healthy male subjects were included as a control group, who did not receive exercise. Blood samples were obtained before, immediately after and two days after the exercise session. Hemorheological parameters were measured by an ektacytometer. TOS/TAS were determined using a commercial kit. RESULTS: A session of eccentric isokinetic exercise did not affect erythrocyte deformability and oxidative stress indices, whereas red blood cell (RBC) aggregation was increased initially and returned to pre-exercise levels after two days following exercise. CONCLUSION: Our results suggest that, increased RBC aggregation following an acute bout of isokinetic exercise may result in increased plasma skimming that augments tissue perfusion and clearance of metabolites within a period of two days following exercise.