[« My joints are cracking, is it serious doctor ? ¼ A review about sounds produced by joints]. / « Mes articulations craquent, c'est grave docteur ? ¼ Les bruits articulaires en question.

The sounds produced by joints are a common source of questioning for doctors and their patients. Two major types are identified : cracks and crepitus. Few investigations have been carried out on these manifestations, while they potentially have clinical implications, especially for patellar crepitus in patellofemoral osteoarthrosis, and may generate anxiety. Knuckle cracking appears to be caused by the sudden and temporary occurrence of an intra-articular gaseous cavity, called tribonucleation. Other researches on these sounds are focused on the knees and their links with osteoarthritis, as well as on the spine. Many questions still arise but it seems important to talk about it with patients without trivializing them.

Les bruits produits par les articulations sont une source de questionnements pour les médecins et leurs patients. Deux principaux types sont identifiés, les craquements et les grincements. Peu d'investigations ont été réalisées sur ces manifestations fréquentes alors qu'elles présentent potentiellement une implication clinique, notamment pour les grincements patellaires dans l'arthrose fémoro-patellaire, et qu'elles peuvent générer de l'anxiété. Les craquements des doigts semblent être provoqués par l'apparition soudaine et temporaire d'une cavité gazeuse intra-articulaire, appelée tribonucléation. Les autres recherches sur ces bruits se portent principalement sur les genoux et leurs liens avec l'arthrose, ainsi que sur le rachis. De nombreuses questions subsistent, mais il est nécessaire d'en parler avec les patients sans les banaliser.

[What do we know about the exercise-related transient abdominal pain ?] / Que sait-on sur le « point de côté ¼ lié à l'effort ?

Exercise-related transient abdominal pain or « side stitch ¼ is a very common problem among athletes, whatever their level of participation. This pain may be present in different areas of the abdomen, even in the shoulder, usually well localized, and described as cramping or stabbing depending on the severity. The etiology is still debated, with many possible theories. It is a benign problem but other pathologies, often more severe, must be excluded in case of any atypical presentation. There are simple preventive measures recommended. This pain usually disappears within minutes by slowing or stopping the effort and / or using different methods without scientific validation until now.

La douleur abdominale transitoire liée à l'effort ou « point de côté ¼ est un problème fréquemment rencontré chez les sportifs, qu'ils soient débutants ou confirmés. Cette douleur peut être présente dans différentes zones de l'abdomen, voire même les épaules, le plus souvent bien localisée, décrite comme une crampe ou « coup de couteau ¼ selon la sévérité. L'étiologie est encore débattue, avec de multiples théories possibles. Il s'agit d'un problème bénin mais d'autres pathologies, souvent plus graves, doivent être exclues devant toute présentation atypique. Il existe des mesures préventives simples à conseiller. Cette douleur disparaît généralement en quelques minutes en ralentissant ou stoppant l'effort et / ou à l'aide de différentes méthodes, sans validation scientifique à ce jour.

Measurement of the dynamics in ski jumping using a wearable inertial sensor-based system.

Dynamics is a central aspect of ski jumping, particularly during take-off and stable flight. Currently, measurement systems able to measure ski jumping dynamics (e.g. 3D cameras, force plates) are complex and only available in few research centres worldwide. This study proposes a method to determine dynamics using a wearable inertial sensor-based system which can be used routinely on any ski jumping hill. The system automatically calculates characteristic dynamic parameters during take-off (position and velocity of the centre of mass perpendicular to the table, force acting on the centre of mass perpendicular to the table and somersault angular velocity) and stable flight (total aerodynamic force). Furthermore, the acceleration of the ski perpendicular to the table was quantified to characterise the skis lift at take-off. The system was tested with two groups of 11 athletes with different jump distances. The force acting on the centre of mass, acceleration of the ski perpendicular to the table, somersault angular velocity and total aerodynamic force were different between groups and correlated with the jump distances. Furthermore, all dynamic parameters were within the range of prior studies based on stationary measurement systems, except for the centre of mass mean force which was slightly lower.

[Fatigue and reduction in motor performance in sportspeople or overtraining syndrome]. / Fatigue et réduction de la performance motrice chez le sportif, syndrome de surentraînement.

The main goal of training activities is to improve motor performance. After strenuous workouts, it is physiological to experience fatigue, which relieves within two weeks, and then induce an improvement in motor capacities. An overtraining syndrome is diagnosed when fatigue is postponed beyond two weeks, and affects mainly endurance athletes. It is a condition of chronic fatigue, underperformance and an increased vulnerability to infection leading to recurrent infections. The whole observed spectrum of symptoms is physiological, psychological, endocrinogical and immunological. All play a role in the failure to recover. Monitoring of athletes activities helps to prevent the syndrome with days with no sports. Rest, patience and empathy are the only ways of treatment options.

Effect of hip flexion angle on hamstring optimum length after a single set of concentric contractions.

The eccentric contraction mode was proposed to be the primary stimulus for optimum angle (angle at which peak torque occurs) shift. However, the training range of motion (or muscle excursion range) could be a stimulus as important. The aim of this study was to assess the influence of the training range of motion stimulus on the hamstring optimum length. It was hypothesised that performing a single set of concentric contractions beyond optimal length (seated at 80° of hip flexion) would lead to an immediate shift of the optimum angle to longer muscle length while performing it below (supine at 0° of hip flexion) would not provide any shift. Eleven male participants were assessed on an isokinetic dynamometer. In both positions, the test consisted of 30 consecutive knee flexions at 4.19 rad · s⁻¹. The optimum angle was significantly shifted by ∼15° in the direction of longer muscle length after the contractions at 80° of hip flexion, while a non-significant shift of 3° was found at 0°. The hamstring fatigability was not influenced by the hip position. It was concluded that the training range of motion seems to be a relevant stimulus for shifting the optimum angle to longer muscle length. Moreover, fatigue appears as a mechanism partly responsible for the observed shift.

Process Optimization and Efficacy Assessment of Standardized PRP for Tendinopathies in Sports Medicine: Retrospective Study of Clinical Files and GMP Manufacturing Records in a Swiss University Hospital.

Platelet-rich plasma (PRP) preparations have recently become widely available in sports medicine, facilitating their use in regenerative therapy for ligament and tendon affections. Quality-oriented regulatory constraints for PRP manufacturing and available clinical experiences have underlined the critical importance of process-based standardization, a pre-requisite for sound and homogeneous clinical efficacy evaluation. This retrospective study (2013-2020) considered the standardized GMP manufacturing and sports medicine-related clinical use of autologous PRP for tendinopathies at the Lausanne University Hospital (Lausanne, Switzerland). This study included 48 patients (18-86 years of age, with a mean age of 43.4 years, and various physical activity levels), and the related PRP manufacturing records indicated a platelet concentration factor most frequently in the range of 2.0-2.5. The clinical follow-up showed that 61% of the patients reported favorable efficacy outcomes (full return to activity, with pain disappearance) following a single ultrasound-guided autologous PRP injection, whereas 36% of the patients required two PRP injections. No significant relationship was found between platelet concentration factor values in PRP preparations and clinical efficacy endpoints of the intervention. The results were in line with published reports on tendinopathy management in sports medicine, wherein the efficacy of low-concentration orthobiologic interventions appears to be unrelated to sport activity levels or to patient age and gender. Overall, this study confirmed the effectiveness of standardized autologous PRP preparations for tendinopathies in sports medicine. The results were discussed in light of the critical importance of protocol standardization for both PRP manufacturing and clinical administration to reduce biological material variability (platelet concentrations) and to enhance the robustness of clinical interventions (comparability of efficacy/patient improvement).

Current Status of PRP Manufacturing Requirements & European Regulatory Frameworks: Practical Tools for the Appropriate Implementation of PRP Therapies in Musculoskeletal Regenerative Medicine.

Providing accurate and up-to-date practical tools enabling oversight of platelet-rich plasma (PRP) legislation and of the appropriate standards to be implemented for its manufacture and use in Europe is a demanding task. This is due to rapid medico-technological advancements, slowness and disparity in legislation updates and enforcement between member states, and many reported gray-zone practices, notably for autologous PRP use. The levels of risk associated with blood manipulation processes generally dictate the manufacturing requirements for PRP preparations, which have gradually shifted toward good manufacturing practices (GMP) for standardization and overall quality enhancement. This work firstly outlines Western European and Swiss legislation for PRP products/preparations, providing key simplified information and recommendations for medical doctors seeking to implement this biological-based therapy for safe use in hospital settings, clinics, or private offices. This work secondly shows the importance of PRP-based product manufacturing standardization, which subsequently enables sound clinical evaluation of therapeutic interventions. Although the applicable legal bases provide guidelines for GMP manufacturing infrastructure and basic process design, paramount importance is set on the definition of workflows, technical specifications, and key parameters for PRP preparation and delivery. Overall, the development of simple and robust technologies and processes for PRP preparation is critical for guaranteeing the high therapeutic quality of the intervention, in collaboration with qualified GMP manufacturing platforms. Importantly, this work aims to serve as a practical tool for clinicians based in Western Europe who are willing to appropriately (i.e., administratively and technically) implement autologous PRP treatments in musculoskeletal regenerative medicine workflows, to ensure they make informed and optimal regulatory or process-based decisions.

Automatic measurement of key ski jumping phases and temporal events with a wearable system.

We propose a new method, based on inertial sensors, to automatically measure at high frequency the durations of the main phases of ski jumping (i.e. take-off release, take-off, and early flight). The kinematics of the ski jumping movement were recorded by four inertial sensors, attached to the thigh and shank of junior athletes, for 40 jumps performed during indoor conditions and 36 jumps in field conditions. An algorithm was designed to detect temporal events from the recorded signals and to estimate the duration of each phase. These durations were evaluated against a reference camera-based motion capture system and by trainers conducting video observations. The precision for the take-off release and take-off durations (indoor < 39 ms, outdoor = 27 ms) can be considered technically valid for performance assessment. The errors for early flight duration (indoor = 22 ms, outdoor = 119 ms) were comparable to the trainers' variability and should be interpreted with caution. No significant changes in the error were noted between indoor and outdoor conditions, and individual jumping technique did not influence the error of take-off release and take-off. Therefore, the proposed system can provide valuable information for performance evaluation of ski jumpers during training sessions.

A new conservative-dynamic treatment for the acute ruptured Achilles tendon.

INTRODUCTION: There is a trend towards surgical treatment of acute ruptured Achilles tendon. While classical open surgical procedures have been shown to restore good functional capacity, they are potentially associated with significant complications like wound infection and paresthesia. Modern mini-invasive surgical techniques significantly reduce these complications and are also associated with good functional results so that they can be considered as the surgical treatment of choice. Nevertheless, there is still a need for conservative alternative and recent studies report good results with conservative treatment in rigid casts or braces. PATIENTS/METHOD: We report the use of a dynamic ankle brace in the conservative treatment of Achilles tendon rupture in a prospective non-randomised study of 57 consecutive patients. Patients were evaluated at an average follow-up time of 5 years using the modified Leppilahti Ankle Score, and the first 30 patients additionally underwent a clinical examination and muscular testing with a Cybex isokinetic dynamometer at 6 and 12 months. RESULTS: We found good and excellent results in most cases. We observed five complete re-ruptures, almost exclusively in case of poor patient's compliance, two partial re-ruptures and one deep venous thrombosis complicated by pulmonary embolism. CONCLUSION: Although prospective comparison with other modern treatment options is still required, the functional outcome after early ankle mobilisation in a dynamic cast is good enough to ethically propose this method as an alternative to surgical treatment.

Measure of efficiency and knee isokinetic strength in bike messengers and non-cyclist athletes.

BACKGROUND: Gross efficiency in cycling (GE) seems correlated with lower-body strength. This study investigated GE at four different pedaling rates and its relationship with an isokinetic strength test in bike messengers (BM) and experienced athletes non-bike messengers (NBM). METHODS: Eight BM and eight NBM completed a maximal incremental test to determine maximal aerobic power (MAP) and maximal oxygen consumption (V̇O2max). GE, V̇O2, heart rate (HR) and blood lactate concentration (BLC) were measured at different cadences (60, 70, 90 and 100 rpm) during an efficiency test at 50% of MAP and participants then performed an isokinetic test of the right knee. RESULTS: A difference in GE (except at 90 rpm), BLC and MAP/kg was found in favor of BM. The most efficient cadence was 60 rpm in both groups. Increased cadence resulted in decreased GE and increased HR and V̇O2 in both groups. BLC only increased in the NBM. We found no relationships between GE at different cadence, peak torque relative to bodyweight and muscle fatigability. CONCLUSIONS: This study is the first investigating performance and efficiency among BM. At equivalent power output, BM show a better GE than NBM. Those results are in line with previously described analysis in cyclists and explained by better aerobic capacity and training status. Isokinetic knee maximal strength and fatigability were not linked with GE, and thus does not appear appropriate for evaluating GE in cycling.

From Sedentary and Physical Inactive Behaviours to an Ultra Cycling Race: A Mixed-Method Case Report.

In faculties of health sciences, almost 30% of nursing students exercise less than once a week. This mixed-method case report presents the 38-month evolution of the physiological and psychological health parameters of a sedentary and physically inactive nursing student. During this period, she first took part in a one-semester institutional physical activity (PA) program that was offered by her university before being selected for participation in the Race Across America (RAAM) with a university relay team. In the four months leading up to the RAAM, she followed a cycling training program. After the RAAM, she was followed-up for the next 28 months. The results showed that each phase of the study had an important impact on the subject and showed that sedentary and physical inactive behaviours are reversible. Institutional PA programs, including training education in addition to concurrent strength and endurance training, can lead to physiological and psychological health improvements. For some individuals, participating in an athletic challenge can improve motivation and long-term adherence to PA participation. An individualised approach should be considered in future interventions that aim to promote PA participation. In the specific context of a university of health sciences, this kind of initiative could positively influence the general population's health by empowering students to become role models towards PA promotion.

Participating In The Race Across AMerica In A Team Of Eight Cyclists: Do Not Neglect Crew Preparation.

BACKGROUND: The Race Across AMerica (RAAM) is considered as one of the longest, and most difficult cycling races in the world. It can be performed in solo or in relay of two, four or eight persons. PURPOSE/METHOD: The aim of the present study was to investigate several physiological, perceptual and psychological responses before, during and after RAAM in a team of eight amateur cyclists. Because logistics of all team is demanding and complex, crew members have followed the same testing procedure. RESULTS: The main result is that parameters were globally not altered to a greater extent in cyclists than in crew members over the course of the RAAM, and that all variables returned to pre-race levels 1 week after the end of the race in both groups. In crew, body fat was decreased (p < 0.05) at mid-race (Mid) vs 1 week before the RAAM (Pre) (-1.5%) and total body water was increased (p < 0.05) at Mid vs Pre (+2.5%). In pre-relay quadriceps strength in cyclists was significantly lower (p < 0.05) at Mid vs Pre (41.6 ± 9.1 vs 45.0 ± 11.2 N, d = 0.36). Therefore, performing the race with eight well-prepared amateur cyclists seems to decrease potential risks on health. In crew, quadriceps strength remained stable at each assessment time but general fatigue increased all along the race. Anger was increased (p < 0.05) at Mid vs Pre in crew. CONCLUSION: The most important message of this study is that crew members for a team of eight require adequate and sufficient preparation and training. Roles and responsibilities need to be thoroughly defined; individuals need to know each other beforehand and they must be prepared for sleep deprivation. The results of this study show the importance of the preparation of two teams: crew members, as well as cyclists.

Gait analysis following single-shot hyaluronic acid supplementation: a pilot randomized double-blinded controlled trial.

OBJECTIVES: Viscosupplementation with new-generation, polyol-containing, cross-linked hyaluronic acid (HA) gels reduces joint inflammation in patients with knee osteoarthritis. Gait analysis is a complementary outcome measure to standard patient-reported scores and physical measures for testing the effect of HA injection. This three-arm, prospective, randomized, controlled, double-blind, feasibility pilot study investigated which gait parameters are more sensitive following a single bolus injection of polyol-containing HA for knee osteoarthritis. METHODS: Twenty-two patients with Ahlbäck grade II-III knee osteoarthritis were randomly allocated into three groups: (1) HA + mannitol (n = 9), (2) HA + sorbitol (n = 5), and (3) saline placebo (n = 8). Patients were assessed by blinded observers prior to injection and at 4 weeks post-injection (4W). Outcome measures included the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), Knee Society score (KSS), EuroQol in five-dimensions (EQ-5D), VAS pain, and VAS stiffness. Gait was assessed over 30 m using a portable inertial-based data logger (Physilog®). RESULTS: Differences between 4W and baseline were statistically significant for the mannitol-containing viscosupplement, with a median increase of 0.076 m/s on gait speed (p = 0.039), 0.055 m on stride length (p = 0.027), and 15 points on the KSS (p = 0.047). In contrast, the HA + sorbitol and saline groups demonstrated no significant changes from baseline to 4W in any gait parameters or self-reported outcome measures (all p > 0.3). The observed increase in gait speed is approximately 13% greater than the mean difference between healthy subjects and those with knee osteoarthritis, is clinically important, and thus is a sensitive gait parameter. CONCLUSIONS: This study demonstrated gait speed and stride length are the most relevant gait parameters to investigate when assessing the effect of polyol-containing HA viscosupplementation. This study supports the need for a larger, randomized, controlled, clinical trial to assess the effect of a single-bolus HA injection versus multiple injections in people with knee osteoarthritis using both gait performance and self-reported parameters of knee function. TRIAL REGISTRATION: This study was retrospectively registered at clinicaltrials.gov on August 20, 2018, and assigned #NCT03636971. LEVEL OF EVIDENCE: I.

[Whole-body vibration training: fact or fiction?]. / Plate-forme de vibration: efficacité ou science-fiction?

Vibration platforms are a new type of fitness equipment promoted for multiples effortless benefits, encompassing muscle strengthening to cosmetic effects, in a minimum of time. Beyond its trendy aspects, positive effects have been observed on strength, body balance and bone mineral density in aged home residents or post-menopausal women. Only minimal or no effects have been found in young sedentaries or athletes. The diversity of vibration settings and modes render the establishment of guidelines for their optimal use difficult. Contraindications are multiple but relative. Sports including vibrations might benefit, or for the sake of proprioceptive rehabilitation. Obese and limited-mobility persons are for the time being the most adequate target population for their use.