The effect of foot position during static calibration trials on knee kinematic and kinetics during walking.

BACKGROUND: Gait analysis has been used extensively for computing knee kinematics and kinetics, in particular, in healthy and impaired individuals. One variable assessed is the external knee adduction moment (EKAM). Variations in EKAM values between investigations may be caused by changes in static standing position, especially foot placement angles which may increase or reduce any differences seen. PURPOSE OF THE STUDY: The current study aimed to explore the influence of static trial foot position on knee kinematic and kinetic variables during walking. METHODS: Twelve healthy male participants completed three different static standing trials; 1) 20-degrees toe-in, 2) 0° and 3) 20-degrees toe-out before walking at their own pace during a lower limb kinematics and kinetics assessment. First and second peak EKAM was compared between static foot position trials, as well other knee kinematic and kinetic outcomes. Repeated measures ANOVA was used with post hoc pairwise comparison to determine the differences between static foot position trials. RESULTS: The first peak of EKAM was significantly smaller in the 20o toe-out angle, than the 20o toe-in angle (p = 0.04-8.16% reduction). Furthermore, significant changes were found in peak knee kinematics and kinetics variables (adduction angle, external rotation angle, knee flexion moment external rotation moment, abduction angle and internal rotation angle) in the different positions. CONCLUSION: Modification in static foot position between study visits may result in changes especially in the 1st peak EKAM and other kinematics and kinetics variables during walking. Therefore, standardisation of static foot position should be utilised in longitudinal studies to ensure changes in EKAM are not masked or accentuated between assessments.

Comparison of hip abductor and adductor muscle performance between healthy and osteitis pubis professional footballers.

OBJECTIVE: The study aimed to compare the concentric and eccentric muscle performance of the hip abductor and adductor muscles at a high angular velocity in football players with osteitis pubis and healthy players. METHODS: A total number of 32 male football players with osteitis pubis and 20 healthy footballers were tested using an isokinetic dynamometer at a speed of 180°/s. Hip abductor and adductor peak torque/body weight, time to peak torque, acceleration, and deceleration times produced during concentric and eccentric muscle contraction modes were measured using a Biodex dynamometer. RESULTS: Football players with osteitis pubis demonstrated a significantly higher time to peak torque, acceleration, and deceleration times (p < 0.05); however, when compared to healthy athletes, there was no significant change in muscle strength. CONCLUSION: The present study showed that football players with osteitis pubis had a reduction in neuromuscular reaction. Therefore, the reaction time of these muscles is critical, and the reduction could result in magnified stresses and/or poorly distributed loads across the musculotendinous structure of the anterior pelvis, which presumably could lead to the development of osteitis pubis. Incorporate findings of the current study in clinical practice could afford critical information when evaluating the hip muscles in football players with osteitis pubis, for pre-screening, enhancing the rehabilitation programs, and guiding the decision of returning to sports after injury.

Association Between Hip Rotation and Activation of the Quadriceps and Gluteus Maximus in Male Runners.

BACKGROUND: Although running can provide health benefits, knee joint injuries are frequently reported by recreational runners. To date, the precise mechanism responsible for anterior knee pain remains elusive, and the source of symptoms is debated. Inconsistencies are found in the literature pertaining to the relationship between hip mechanics and activity in the quadriceps and gluteus maximus (GMax) during the running gait. PURPOSE/HYPOTHESIS: To investigate the correlations between hip rotation and the activity in the quadriceps and GMax during running. We hypothesized that increased hip rotation is correlated with decreased activity in these muscles. STUDY DESIGN: Descriptive laboratory study. METHODS: A cohort of 30 healthy recreational runners volunteered to participate in the study (mean ± SD age, 28.8 ± 5.66 years; height, 1.73 ± 0.05 m; mass, 69 ± 6.3 kg; body mass index, 23.02 ± 1.42 kg/m2). Surface electromyography (EMG) data were obtained from the GMax, vastus medialis obliquus (VMO), and vastus lateralis obliquus (VLO). These data were synchronized with a motion capture system during a level-surface running activity at a speed of 3.2 m/s. RESULTS: A significantly strong, negative correlation was found between the hip internal rotation angle and EMG activity of the GMax and the VMO. However, the VLO showed a significant, moderate, and positive correlation of activity with the hip internal rotation angle. CONCLUSION: The present study showed that during level-surface running, decreased GMax activity may be the cause of distal joint injuries and alteration in quadriceps muscle activity. CLINICAL RELEVANCE: Because GMax activity is important for controlling the lower body mechanics during running, evaluating GMax activity and internal hip rotation angle is important to prevent the running-related knee injuries that are linked to quadriceps deficits, such as patellofemoral pain. Additionally, clinicians and trainers should consider strengthening the GMax while rehabilitating running-related knee injuries.

Assessment of neck pain and cervical mobility among female computer workers at Hail University.

The aims of this study were to investigate the prevalence of neck pain among computer workers at Hail University, Saudi Arabia and to compare the cervical range of motion (ROM) of female computer workers suffering from neck pain to the cervical ROM of healthy female computer workers. One hundred and seventy-six female volunteers between 20 and 46 years of age were investigated. Fifty-six of these volunteers were staff members, 22 were administrators and 98 were students. The Cervical Range of Motion (CROM) instrument was used to measure the ROM of the cervical spine. A questionnaire was used to assess participants for the presence of neck pain. The data were analyzed using the Statistical Package for Social Sciences (SPSS) software, and the level of significant was set at p < .05 for all statistical tests. There was a high prevalence of neck pain (75%) among computer workers at Hail University, particularly among students. There were significant differences in cervical lateral flexion, rotation to the right side and protraction range between the pain and pain-free groups. Our results demonstrated that cervical ROM measurements, particularly cervical lateral flexion, rotation and protraction, could be useful for predicting changes in head and neck posture after long-term computer work.