Gait disturbances in football, rugby players and skiers following anterior cruciate ligament reconstruction

Background. Patients who have undergone anterior cruciate ligament (ACL) reconstruction surgery may exhibit post-operative lower limb gait disturbances. Design. Laboratory in vivo controlled study. Kinematics and kinetics parameters of knee motion were measured in post-ACL reconstruction participants (n = 5; m = 4 / f = 1, age 30.6 years, height 179.2 cm, weight 80.4 kg) and control participants (n = 10; m = 6 / f = 4, age 30.3 years, height 173.5 cm, weight 65.3 kg). Kinematics and kinetics were recorded for normal gait, ‘cutting’ gait and ‘weaving’ gait (ẋ = 3 per gait type) using instrumented motion analysis and ground embedded force plates. Between groups, differences in knee joint alignment were determined in the frontal plane for normal gait,and in the coronal plane for cutting and weaving. Five of the subjects were recruited for this study had an ACL reconstruction in the past (at least two years before the test), and ten were part of a control group. Each subject performed three different tasks with both legs on a force plate: normal walking, a weaving movement, and a cutting movement. Kinematic and kinetic data were collected with four optoelectronic cameras and two force plates. Comparisons were made in the frontal plane for walking and in the coronal plane for cutting and weaving between the reconstructed knee and the contralateral, healthy knee in the late stance period. Results. There were no significant differences between the ACL reconstructed knees and the contralateral healthy knees in the walking task (p = 0.27 – 0.49). Knee coronal plane rotation showed between group similarity(cutting = 21.82° vs 11.29°, p = 0.175; weaving = 17.88 vs 21.34°, p = 0.406). Conclusions. There is an increased rotation of the knee during walking and cutting in ACL reconstructed knees when compared to the contralateral knee, although this difference was not statistically significant

Anterior cruciate ligament deficiency: rotational instability in the transverse plane. A preliminary laboratory in vivo study

Background. Rotational instability is a major feature of anterior cruciate ligament (ACL) deficiency. Few biomechanical studies have focused on the transverse plane when assessing the function of the ACL. Objective. To analyse the biomechanics of ACL deficient knees in the transverse plane under torsional conditions to detect rotational instability. Methods. Seven subjects (eight ACL deficiency) (ACLd group) and nine recreational athletes (controls) were recruited. Each performed two tasks: crossover and pivoting-jump. Biomechanical data were collected in a movement analysis laboratory. Comparisons were made for torque, rotation and torque curves in transverse plane between ACLd, contralateral knees and controls. Results. Torque curves showed and initial avoidance pattern followed by increased values in crossover task, and lesser values for ACLd group compared to controls in pivoting-jump task. Internal rotation in crossover was 19.8°, 13.7° and 19.1° for ACLd, contralateral and controls respectively (p = 0. 176). In pivoting-jump these values were 18.6°, 13.8° and 18.1° (p = 0.297). Crossover peak torque were 257, 178.4 and 184.8 Nmm for ACLd, contralateral and controls (p = 0.5), while pivoting-jump values were 238.4, 152.2 and 218 Nmm for ACLd, contralateral and controls (p = 0.288). Conclusion. Torque curve analysis identified a distinctive pattern differentiating ACLd and control group. However, no statistically significant differences were found in peak transverse plane parameters between groups

The biomechanics of running in athletes with prevous hamstring injury. A case-control study

Hamstring injury is prevalent with persistently high reinjury rates. We aim to inform hamstring rehabilitation by exploring the electromyographic and kinematic characteristics of running in athletes with previous hamstring injury. Nine elite male Gaelic games athletes who had returned to sport after hamstring injury and eight closely matched controls sprinted while lower limb kinematics and muscle activity of the previously injured biceps femoris, bilateral gluteus maximus, lumbar erector spinae, rectus femoris, and external oblique were recorded. Intergroup comparisons of muscle activation ratios and kinematics were performed. Previously injured athletes demonstrated significantly reduced biceps femoris muscle activation ratios with respect to ipsilateral gluteus maximus (maximum difference −12.5%, P = 0.03), ipsilateral erector spinae (maximum difference −12.5%, P = 0.01), ipsilateral external oblique (maximum difference −23%, P = 0.01), and contralateral rectus femoris (maximum difference −22%, P = 0.02) in the late swing phase. We also detected sagittal asymmetry in hip flexion (maximum 8°, P = 0.01), pelvic tilt (maximum 4°, P = 0.02), and medial rotation of the knee (maximum 6°, P = 0.03) effectively putting the hamstrings in a lengthened position just before heel strike. Previous hamstring injury is associated with altered biceps femoris associated muscle activity and potentially injurious kinematics. These deficits should be considered and addressed during rehabilitation.This study was partly funded by a €500 research bursary (Eastern Branch ISCP 2012)

International Society of Sports Nutrition position stand: safety and efficacy of creatine supplementation in exercise, sport, and medicine

Abstract Creatine is one of the most popular nutritional ergogenic aids for athletes. Studies have consistently shown that creatine supplementation increases intramuscular creatine concentrations which may help explain the observed improvements in high intensity exercise performance leading to greater training adaptations. In addition to athletic and exercise improvement, research has shown that creatine supplementation may enhance post-exercise recovery, injury prevention, thermoregulation, rehabilitation, and concussion and/or spinal cord neuroprotection. Additionally, a number of clinical applications of creatine supplementation have been studied involving neurodegenerative diseases (e.g., muscular dystrophy, Parkinson’s, Huntington’s disease), diabetes, osteoarthritis, fibromyalgia, aging, brain and heart ischemia, adolescent depression, and pregnancy. These studies provide a large body of evidence that creatine can not only improve exercise performance, but can play a role in preventing and/or reducing the severity of injury, enhancing rehabilitation from injuries, and helping athletes tolerate heavy training loads. Additionally, researchers have identified a number of potentially beneficial clinical uses of creatine supplementation. These studies show that short and long-term supplementation (up to 30 g/day for 5 years) is safe and well-tolerated in healthy individuals and in a number of patient populations ranging from infants to the elderly. Moreover, significant health benefits may be provided by ensuring habitual low dietary creatine ingestion (e.g., 3 g/day) throughout the lifespan. The purpose of this review is to provide an update to the current literature regarding the role and safety of creatine supplementation in exercise, sport, and medicine and to update the position stand of International Society of Sports Nutrition (ISSN)