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The use of accelerometers is discussed to evaluate standing vertical jump. Two accelerometers, mounted on each ankle and connected to a wearable system, were used for signal acquisition, and a piezoelectric platform was used to verify the results. Fifty-one subjects were enrolled, subdivided into a group of healthy subjects and 2 groups who had different surgery for Achilles tendon rupture. Each subject performed 5 countermovement and 5 squat jumps; 11 subjects also performed 5 countermovement jumps with voluntary leg rotations during the flight phase. A training set was used to assess signal processing, and a validation set was used to verify its accuracy. A peak detection algorithm was developed to quantify flight time from the acceleration modulus, and its results were compared with platform data. The Pearson correlation coefficient of ankle accelerations and the integral of each signal were adopted to describe, respectively, the movement coordination and the limbs rotation during the flight time. The flight times obtained from the accelerometers and force plate were highly correlated (Spearman's coefficient >0.95); they were compared, for each jump, and the maximum mean error, for subject, was 4.8%. The movement coordination was in good agreement with subjects' clinical features and with the different jump phases. The signal integral presented significant differences, among jumps, related to leg rotations (p < 0.0005). The method proposed allows the monitoring of standing vertical jump using the fight time and gives information on the legs coordination and on the motor strategies of the lower limbs. Therefore, it can be used to obtain performance reference also outside labs, both in clinical and sport settings. KEY WORDS accelerometer, flight time, performance, movement coordination, Achilles tendon rupture

Abstract Background In overhead sports like volleyball, the onset of a rotator cuff tendinopathy due to functional overload is a common observation. An angiofibroblastic etiopathogenesis has been hypothesized, whereby a greater anaerobic metabolism occurs in critical zones of the tendon with a lower degree of vascularization; this would induce collagen and extracellular matrix degradation, that could then trigger a compensatory neovascularization response. We performed a clinical observational study of 80 elite volleyball players, monitoring the perfusion values of the supraspinatus tendons by oximetry. Results No statistically significant differences were found between the oximetry data and age, sex or years of sports activity, nor when comparing the right and left arm or the dominant and non-dominant arm. A statistically significant difference was found for the dominant arm values in relation to the competitive role, higher values being obtained in outside hitters (62.7%) than middle hitters (53.7%) (p = 0.01), opposite hitters (55.5%) (p = 0.02) and libero players (54.4%) (p = 0.008), whereas there were no differences in setters (56.2%) (p > 0.05). Conclusions The different tendon vascularization values found in players with different roles in the team may be attributed to a response to the specific biomechanical demands posed by the different overhead throwing roles.

Abstract Background Total knee arthroplasty (TKA) is often associated with a severe local inflammatory reaction which, unless controlled, leads to persistent pain up to one year after surgery. Standard and accelerated rehabilitation protocols are currently being implemented after TKA, but no consensus exists regarding the long-term effects. Biophysical stimulation with pulsed electromagnetic fields (PEMFs) has been demonstrated to exert an anti-inflammatory effect, to promote early functional recovery and to maintain a positive long-term effect in patients undergoing joint arthroscopy. The aim of this study was to evaluate whether PEMFs can be used to limit the pain and enhance patient recovery after TKA. Methods A prospective, randomized, controlled study in 30 patients undergoing TKA was conducted. Patients were randomized into experimental PEMFs or a control group. Patients in the experimental group were instructed to use I-ONE stimulator 4hours/day for 60days. Postoperatively, all patients received the same rehabilitation program. Treatment outcome was assessed using the Knee Society Score, SF-36 Health-Survey and VAS. Patients were evaluated pre-operatively and one, two, six and 12 months after TKA. Joint swelling and Non Steroidal Anti Inflammatory Drug (NSAID) consumption were recorded. Comparisons between the two groups were carried out using a two-tail heteroschedastic Student’s t-test. Analysis of variance for each individual subject during the study was performed using ANOVA for multiple comparisons, applied on each group, and a Dunnet post hoc test. A p value Results Pre-operatively, no differences were observed between groups in terms of age, sex, weight, height, Knee-Score, VAS, SF-36 and joint swelling, with the exception of the Functional Score. The Knee-Score, SF-36 and VAS demonstrated significantly positive outcomes in the I-ONE stimulated group compared with the controls at follow-ups. In the I-ONE group, NSAID use was reduced and joint swelling resolution was more rapid than in controls. The effect of I-ONE therapy was maintained after use of the device was discontinued. Conclusions The results of the study show early functional recovery in the I-ONE group. I-ONE therapy should be considered after TKA to prevent the inflammatory reaction elicited by surgery, for pain relief and to speed functional recovery. Trial registration Current Controlled Trials ISRCTN10526056