Zoekresultaten

Effects of reduced relative implicit and explicit feedback on lower extremity jump-landing mechanics: a preliminary analysis

Implicit (IF) and explicit (EF) feedback are two motor learning strategies that have been demonstrated to alter biomechanical movement patterns. While both strategies have been utilized for injury prevention, it remains unclear which strategy may be more effective. PURPOSE: To examine the effects of reduced relative IF and EF feedback on lower extremity landing mechanics. METHODS: Seventeen participants (23.5±0.9 years, 1.72±0.1m, 67.7±11.5kg) were randomly assigned to three groups: IF (n=6), EF (n=5), and Control (CG) (n=6). A box-drop jump task was performed three times a week for six weeks. Testing occurred before and after 6 weeks of intervention. IF and EF were provided by ? video feedback with instructions, while CG received no feedback. IF were instructed to focus their attention outside their body, while EF were instructed to focus their attention to their lower extremities. Intervention sessions were partitioned into 100% feedback, 33% feedback, and 16.6% feedback frequency phases. Participants viewed video recordings of their task to analyze their jump-landing mechanics from both a sagittal and frontal plane cameras. Participants viewed 2 video recordings per camera, once in real-time and once in slow motion. Multivariate analysis of variance was conducted to compare differences between groups and time for hip abduction angle (HA), knee abduction moment (KAM), and knee flexion angle (KF). RESULTS: No statistically significant difference (p>0.05) was found for: HA (CG:pre=-9.85±5.3, post=-7.36±8.65; IF:pre=-4.17±2.67, post=-7.52±5.27; EF:pre=-5.68±6.12, post=-5.98±5.43), KAM (CG:pre=-0.5±0.3, post=-0.34±0.13; IF:pre=-0.5±0.21, post=-0.48±0.13; EF:pre=-0.48±0.12, post=-0.46±0.26), and KF (CG:pre=-92.26±9.12, post=-100.33±15.2; IF:pre=-106.37±16.34, post=-103.45±19.97; EF:pre=-100.32±11.4, post=-112.4±18.22). CONCLUSION: We did not find statistically significant differences for any dependent measures between groups from pre to post-test. It should be noted that IF HA slightly decreased from pre to post-test whereas it increased for CG. For KAM, CG was lower on post-test comparing to IF and EF. EF and CG trended to decrease from pre to post-test, while IF slightly increased KF. Our preliminary findings partially support that implicit and explicit feedback alters lower body mechanics while jumping.

Lower limb orthoses

Background: Osteoarthritis (OA) is the most common rheumatic disease of the musculoskeletal system, with the knee as the most affected joint. The number of people with OA of the knee is likely to increase due to the ageing society and the obesity epidemic. The predominant clinical symptom of knee OA is pain, which is described as worsening by activity and relieving by rest. Knee instability has been recognized as an important clinical feature in persons with knee OA. Pain and knee instability are associated with limitations in performing daily activities. Non-pharmacological options in the management of knee OA consist of education, weight loss, exercise, braces and physical therapy. Knee bracing has been recommended by the Osteoarthritis Research Society International (OARSI). Valgus knee braces designed to decrease loads on the medial compartment of the knee for patients with varus alignment are the most common. It has been shown however, that valgus bracing may have little or no effect on pain and physical functioning, and adherence to this treatment in patients with knee OA is low.Because of ease of use and access, lack of complications and low cost, soft knee braces are commonly used in persons with knee OA. However, the evidence for efficacy of soft knee bracing on pain and activity limitations in knee OA is limited. Therefore, it is important to strengthen the evidence of using a soft brace to reduce pain and activity limitations as well as to evaluate the efficacy of soft knee bracing on knee instability in persons with knee OA. There is also debate about the effectiveness of soft braces in other affected joints of the lower extremity and in conditions other than OA such as rheumatoid arthritis.Objectives: The aim of the study will be to evaluate the effect of wearing a soft brace on dynamic knee instability in patients with OA of the knee.Methods: Persons with knee OA and self-reported knee instability from the Amsterdam Osteoarthritis cohort participated in a single-session lab-experimental study. A within-subject design was used, comparing no brace versus brace, and comparing a non-tight versus a tight brace (standard fit). The primary outcome measure was dynamic knee instability, expressed by the Perturbation Response (PR), i.e., a biomechanics based measure reflecting deviation in the mean knee varus-valgus angle after a controlled mechanical perturbation, standardized to the mean (SD) varus-valgus angle during level walking. Linear mixed-effect model analysis was used to evaluate the effect of a brace on dynamic knee instability.Results: The wearing of a soft brace reduced the knee instability significantly during perturbed walking. Results will also be presented from the literature search and from the lab-experimental study.Conclusion: Wearing a soft brace reduces dynamic knee instability in patients with knee OA. However, longitudinal studies are needed to evaluate the clinical implications of wearing a soft brace.

Wound infection following implant removal of foot, ankle, lower leg or patella; a protocol for a multicenter randomized controlled trial investigating the (cost-)effectiveness of 2 g of prophylactic cefazolin compared to placebo (WIFI-2 trial)

Background: Elective implant removal (IR) after fracture fixation is one of the most common procedures within (orthopedic) trauma surgery. The rate of surgical site infections (SSIs) in this procedure is quite high, especially below the level of the knee. Antibiotic prophylaxis is not routinely prescribed, even though it has proved to lower SSI rates in other (orthopedic) trauma surgical procedures. The primary objective is to study the effectiveness of a single intravenous dose of 2 g of cefazolin on SSIs after IR following fixation of foot, ankle and/or lower leg fractures. Methods: This is a multicenter, double-blind placebo controlled trial with a superiority design, including adult patients undergoing elective implant removal after fixation of a fracture of foot, ankle, lower leg or patella. Exclusion criteria are: an active infection, current antibiotic treatment, or a medical condition contraindicating prophylaxis with cefazolin including allergy. Patients are randomized to receive a single preoperative intravenous dose of either 2 g of cefazolin or a placebo (NaCl). The primary analysis will be an intention-to-treat comparison of the proportion of patients with a SSI at 90 days after IR in both groups. Discussion: If 2 g of prophylactic cefazolin proves to be both effective and cost-effective in preventing SSI, this would have implications for current guidelines. Combined with the high infection rate of IR which previous studies have shown, it would be sufficiently substantiated for guidelines to suggest protocolled use of prophylactic antibiotics in IR of foot, ankle, lower leg or patella. Trial registration Nederlands Trial Register (NTR): NL8284, registered on 9th of January 2020, https://www.trialregister.nl/trial/8284

Jump landing characteristics predicts lower extremity injuries in indoor team sports

The aim of this study is to investigate the predictivevalue of landing stability and technique togain insight into risk factors for ankle and kneeinjuries in indoor team sport players. Seventyfivemale and female basketball, volleyball orkorfball players were screened by measuringlanding stability after a single-leg jump landingand landing technique during a repeated countermovement jump by detailed 3-dimensional kinematicsand kinetics. During the season 11 acuteankle injuries were reported along with 6 acuteand 7 overuse knee injuries by the teams’ physicaltherapist. Logistic regression analysis showedless landing stability in the forward and diagonaljump direction (OR 1.01–1.10, p ≤ 0.05) in playerswho sustained an acute ankle injury. Furthermorelanding technique with a greater ankle dorsiflexionmoment increased the risk for acuteankle injury (OR 2.16, p ≤ 0.05). A smaller kneeflexion moment and greater vertical groundreaction force increased the risk of an overuseknee injury (OR 0.29 and 1.13 respectively,p ≤ 0.05). Less one-legged landing stability andsuboptimal landing technique were shown inplayers sustaining an acute ankle and overuseknee injury compared to healthy players. Determiningboth landing stability and technique mayfurther guide injury prevention programs.

The relation of asymmetry in power and balance in the lower extremities

COVID 19 Conspiracy Thinking Across the World

Presentatie van het manuscript 'COVID 19 Conspiracy Thinking Across the World ' door Annemarie Walter en Hugo Drochon bij REPRESENT, Research Centre for the Study of Parties and Democracy van de Universiteit van Nottingham, op 24 maart 2021.