Gerald Gremion

Lausanne University Hospital | CHUV · Département de l'appareil locomoteur (DAL)

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...

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 physica...

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...

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 afte...

When neovascularization is present in chronic tendinosis, sclerotherapy may be useful. This study's objective was to evaluate the short-and long-term clinical efficacy of sclerotherapy and estimate the evolution of Achilles and patellar tendinosis among athletes using ultrasound. All the patients who underwent sclerotherapy in our department from 2...

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...

La utilizacion de sustancias susceptibles de mejorar el rendimiento es un fenomeno ampliamente extendido. Su prevalencia se estima en alrededor del 2% en los adolescentes y se situa en mas del 60% en ciertos deportes, como la halterofilia. Por desgracia, esta practica omnipresente ha deslustrado el espiritu de competicion, de manera que se ha mostr...

Objectives: Running is known to exert a positive impact on overall health. Its potential harm or benefit on knee osteoarthritis (OA) has, however, not been thoroughly explored, mainly due to lack of quantifiable metric to link running derived parameters with OA-related biomechanics. This study sought to investigate whether joint space width (JSW),...

Objective Approximately 42% of Europeans never practice physical activity (PA) or sports and 40% spend more than 5:30 per day in a sitting position. The objective of this literature review is to identify the necessary means to promote PA and tools available for physicians to advise and prescribe a suitable AP. Material/patients and methods Electro...

La douleur abdominale transitoire liée à l'effort ou « point de côté » 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 » selon la s...

Poor governance of sport, in particular all the policy implications that take the place of sport are causing many negative headlines in the press today. We have to do with doping, corruption, violence, rigging the competition, trafficking of players and all this corresponds to only the visible part of the iceberg. Sports ethics must be promoted to...

The present study proposes a method based on ski fixed inertial sensors to automatically compute spatio-temporal parameters (phase durations, cycle speed and cycle length) for the diagonal stride in classical cross-country skiing. The proposed system was validated against a marker-based motion capture system during indoor treadmill skiing. Skiing m...

Chronic aerobic exercise has been shown to increase exercise efficiency, thus allowing less energy expenditure for a similar amount of work. The extent to which skeletal muscle mitochondria play a role in this is not fully understood, particularly in an elderly population. The purpose of this study was to determine the relationship of exercise effi...

Tendinopathy is one of the most common diagnosis in sports. Knowledges about their etiology, the repair process to their diagnosis and their treatment have improved thanks to the development of imaging, especially ultra- sound. The disorder whose etiology could be mechanical or degenerative can cause long- term disability and sometimes the end of t...

Introduction: Self-induced myofascial release (SMR) is a new technique to treat soft tissues restrictions (MacDonald et al., 2013). It consists for an individual to exert pressure on the soft tissues with his own body mass using a foam roller (a dense cylindrical pipe with a diameter of 10 to 15 centimeters and a length of 30 to 60 centimeters). B...

Electrically assisted bicycles (EAB) are an emerging transportation modality, increasingly used in Switzerland (about 50 000 during 2013 1) and in the world 2 with different interesting characteristics. Fist it’s ecological, without any CO2 emission, poor consumption of energy, soundless and fighting against traffic jam. Secondly, human power is ne...

Whole-body vibration (WBV) is a new exercise method, with good acceptance among sedentary subjects. The metabolic response to WBV has not been well documented. 3 groups of male subjects, inactive (SED), endurance (END) and strength trained (SPRINT) underwent a session of side-alternating WBV composed of three 3-min exercises (isometric half-squat,...

Patellofemoral pain syndrome (PFPS) is one of the most frequent cause of anterior knee pain in adolescents and adults. Due to its complex etiology, which is multifactorial and still poorly understood, its management is a major challenge for the practitioner. The diagnosis is made primarily on the history and clinical examination of the knee, but al...

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...

Context: Sarcopenia is thought to be associated with mitochondrial (Mito) loss. It is unclear whether the decrease in Mito content is consequent to aging per se or to decreased physical activity. Objectives: The objective of the study was to examine the influence of fitness on Mito content and function and to assess whether exercise could improv...

Abstract 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 senso...

This article reviews the evidence-based ergogenic potential adverse effects of the most common products in use by recreational and elite athletes today. This is an aggressively marketed and controversial area of sports medicine wordwide. It is therefore important for the scientific societies, clinicians, dieticians sports federations to be well ver...

Take-off, the most important phase in ski jumping, has been primarily studied in terms of spatio-temporal parameters; little is known about its motor control aspects. This study aims to assess the inter-segment coordination of the shank-thigh and thigh-sacrum pairs using the continuous relative phase (CRP). In total 87 jumps were recorded from 33 a...

Abstract 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 o...

Purpose: The effects of β(2)-agonists on human skeletal muscle contractile properties, particularly on slow fibers, are unclear. Moreover, it remains to be ascertained whether central motor drive (CMD) during voluntary contractions could counter for eventual contractile alterations induced by β(2)-agonists. This study investigated central and peri...

Objectifs L’analyse de la littérature sur le sujet permet de faire le point sur les effets réellement démontrés de la pratique des étirements. Ils existent un certains nombre de résultats contradictoires. Actualités Les étirements musculaires plus communément appelés ‘‘stretching’’ font partie intégrante de la culture physique et du domaine de la...

Aims : Muscle stretching is used by manual therapists as a tool for diagnosis and treatment. Proper learning and specific technicity are needed to improve their expertise. Context: Literature reviews on muscle stretching exercises (known as stretching) showed results going against common beliefs. No effect on injury prevention, no warming, and dec...

Doping prevalence among recreational sports is evaluated between 5% and 15%, and is more frequent among men. Substances used are stimulants, anabolic steroids, narcotics, corticosteroids and diuretics. The percentage of use of these different products shows a large variation between studies. Doping substance access is easy through internet and fitn...

Three-dimensional analysis of the entire sequence in ski jumping is recommended when studying the kinematics or evaluating performance. Camera-based systems which allow three-dimensional kinematics measurement are complex to set-up and require extensive post-processing, usually limiting ski jumping analyses to small numbers of jumps. In this study,...

The sports clinician faces multiple treatment options when dealing with overload injuries, and it is important to evaluate their outcomes. Multiple scores exist, some clincian rated (CRO), others patient rated (PRO), the latter being currently favoured. This review presents some of these scores and we selected the ones we feel are the most appropri...

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 perfor...

Several studies have shown that in diabetic patients, the glycemic profile was disturbed after intra-articular injection of corticosteroids. Little is known about the impact of epidural injection in such patients. The goal of this study was double, at first comparing the glycaemic profile in diabetic patients after a unique injection of 80 mg of ac...

Electrically assisted bicycles (EAB) are an emerging transportation modality favored for environmental reasons. Some physical effort is required to activate the supporting engine, making it a potential active commuting option. We hypothesized that using an EAB in a hilly city allows sedentary subjects to commute comfortably, while providing a suffi...

This article reviews the literature regarding gastrointestinal disturbances in particular in runners. The lower intestinal problems of motility and blood loss are discussed. These problems are directly related to running. These symptoms, especially diarrhea are common and can impact adversely both performance and the health of the athlete. Most cas...

Whole body vibration (WBV) is an increasingly popular modality of muscle training, especially in sedentary subjects. We hypothesised that the vigorous muscle contractions elicited by WBV can cause muscle damage expressed as an elevation in muscle enzymes. Twenty inactive subjects, ten male and ten female, aged 22.7 ± 2.6, BMI 22.4 ± 2.1 were includ...

The study examined the effects of an oral acute administration of the β2-agonist salbutamol (Sal) (6 mg) vs. placebo on muscle strength and fatigability in 12 non-asthmatic recreational male athletes in a randomized double-blind protocol. Contractile properties of the right quadriceps muscle were measured during electrical stimulations, i.e. twitch...

During recovery from a maximal or submaximal aerobic exercise, augmentation of central (aortic) systolic pressure by reflected pressure waves is blunted in healthy humans. However, the extent to which reflected pressure waves modify the central pulse in diastole in these conditions remains unknown. We evaluated systolic and diastolic central reflec...

La mise en place d’une prothèse de genou (PTG) apporte des bénéfices reconnus pour les patients souffrant d’arthrose du genou. Une grande attention est accordée à la qualité de l’intervention chirurgicale et à la prise en charge rééducative. Ces mesures permettent une bonne récupération dans la grande majorité des cas. Cependant, malgré la sédation...

To assess the effectiveness of pulsed signal therapy in the treatment of knee osteoarthritis (Kellgren II or III). A randomized, double-blind controlled clinical trial. The first 95 patients sent to the clinic with knee osteo-arthritis were selected and randomized into treatment with pulsed signal therapy or conventional physiotherapy. Assessment i...

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 complica...

Reconstruction of the central aortic pressure wave from the noninvasive recording of the radial pulse with applanation tonometry has become a standard tool in the field of hypertension. It is not presently known whether recording the radial pulse on the dominant or the nondominant side has any effect on such reconstruction. We carried out radial ap...

Exercise is classically associated with muscular soreness, presenting one to two days later, delayed onset muscular soreness. Blood muscle enzymes and protein elevations are characteristic, and may cause renal failure. Creatin phosphokinase peak appears on the fourth day and depends on exercise type and individual parameters. This effect is attenua...

Sportliche Betatigung fuhrt klassischerweise nach ein bis zwei Tagen zu Gliederschmerzen, allgemein bekannt als Muskelkater. Gleichzeitig sind die Muskelenzyme und -proteine im Serum erhoht, was zur Beeintrachtigung der Nierenfunktion fuhren kann. Die Konzentration der Kreatinkinase (CK) ist am vierten Tag am hochsten und die Hohe ist von der Art d...

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 minim...

The prevalence of diabetes is constantly growing and an ever increasing number of diabetics travel to moderate (1500-2000 m, 5000-6500 ft.) or high altitude (>2500 m, >8000 ft) for recreational purposes. Stays at moderate altitude are very well tolerated for a majority of diabetics, but can be limited by hypoxia or equipment failure due to freezing...

Sudden cardiac death in a young athlete is a tragic and marking event, even though the media attention it gets is more important than its incidence (1-2/100000 per year). The main etiology is hypertrophic cardiomyopathy, followed by coronary artery anomalies. Sometimes signs of myocarditis are found at autopsy. The pre-participation examination rec...

La mort subite d'origine cardiaque chez le jeune athlète est marquante, tragique et souvent médiatisée, dont l'impact est plus important que son incidence (1–2/100000 par an). L'étiologie principale est la cardiomyopathie hypertrophique, suivie des anomalies coronariennes. On retrouve parfois une myocardite à l'autopsie. Les recommandations d'exame...

Significant changes in body composition occur during lifetime. This longitudinal study (8.0 +/- 0.8 yrs) in a cohort of healthy sedentary and physically active men (n = 78) and women (n = 53), aged 20 to 74 yr describes: 1) the longitudinal changes in weight and body composition and 2) their associations with age and physical activity. Method: Fat-...

The net mechanical efficiency of positive work (ηpos) has been shown to increase if it is immediately preceded by negative work. This phenomenon is explained by the storage of elastic energy during the negative phase and its release during the subsequent positive phase. If a transition time (T) takes place, the elastic energy is dissipated into hea...

Chronic exertional compartment syndrome (CECS) of the leg is a pathological condition often related to overuse in subject who engage repetitive physical activities. Fascial release is the mainstay of surgical management. The purpose of this study was to evaluate the results obtained with a double incision decompressive fasciotomy. Eighteen consecut...

Since 1980, according to several authors, it is accepted that increasing flexibility of a muscle-tendon unit allows a better performance and decreases sports injuries. Stretching is regularly included in warm-up and in cooling-down. However, there are contradictory findings in the literature. In contrast, since 1990, there's evidence suggesting tha...

It is generally accepted that increasing the flexibility of a muscle-tendon unit allows a better performance and decreases the number of injuries. Stretching is regularly included in warm-up and in cooling-down exercises. However, contradictory findings have been reported in the literature. Since 1980, several authors have suggested that stretching...

Overtraining, a decrease in performance despite training that does not disappear after 2 weeks of relative rest, accompanied by symptoms like fatigue, anorexia, and muscle and joint pain, mood changes and feeling burnt out or stale is a frequent syndrome in endurance athletes. It is generally the result of excessive activity from training and compe...

Endurance training modifies the thermoregulatory control of skin blood flow, as manifested by a greater augmentation of skin perfusion for the same increase in core temperature in athletes, in comparison with sedentary subjects. In this study, we tested the hypothesis that a component of this adaptation might reside in a higher ability of cutaneous...

The adaptation of the skeleton to the dynamic mechanical stresses is known since the middle of the XIXth century. In contrast to the bone degradation related to pathological conditions (e.g. osteoporosis), no reliable data are known for healthy young or mature people practising a physiological sport with varying intensity. This triggered us to carr...

Energy restriction and physical activity are major components of weight reduction programs. Energy restriction is known to affect the sympathetic nervous system activity and to reduce several components of energy expenditure, including the stimulation of energy expenditure elicited by mental stress. The effect of physical activity on this parameter...

The best feedback of an individuals physical condition is to obtain a measurement of his maximum oxygen-intake (VO2max). A group of Finnish researchers, R. Laukkanen et al., established a formula, based on a «walking-test», permitting the evaluation of a persons physical condition. The aim of this particular study is to compare the validity of thei...

Strenuous training can be associated with amenorrhea leading to amenorrhea-related accelerated bone loss. Insufficient calorie energy, calcium, and/or protein intakes can also be frequently encountered in women with intense training, possibly contributing to bone loss. Long-distance runners with or without regular menses (age range 19-37 yr) were p...

The so called «zone» dietary concept, designed in North America, was adopted by some individuals in Switzerland (e.g. therapists, coaches, athletes, etc.). This dietary concept is in conflict with the diets Usually recommended to athletes (i.e. a carbohydrate-rich diet) and uses rationales which sound scientific but which can seriously mislead indi...

Africa is the source of one of the great mysteries in the sport science. Why is it that sprinting and jumping events are dominated by African-Americans whose genetic origins are from the west coast of Africa, whereas East African, especially Kalenjin-speaking Kenyans from the Rift Valley province, bestride the distance running events? Reduced to it...

Zusammenfassung Die Bedeutung und Zahl der Athletinnen ist in diesem Jahrhundert deutlich gewachsen. Diese gesteigerte Teilnahme an körperlichen Aktivitäten hat zur signifikanten Verbesserung des Gesundheitszustands und der körperlichen Fitness geführt. Regelmäßiges Krafttraining hat einen vorteilhaften Effekt auf die Knochendichte. Ermüdendes Tra...

The prominence and number of female athletes has grown dramatically during this century. This increased participation in physical activity has led to significant health benefits and improved physical fitness. Regular weight-bearing exercise has a beneficial effect on the bone mineral density (BMD). But strenuous training can affect the female repro...

Calcifying tendonitis is a very common and often asymptomatic disease. The evolution is divided into three distinct stages. The therapeutic approach should be based upon the assessment of the symptoms in conjunction with the findings in radiographs. Since the beginning of this year we gathered experience with the application of extracorporal shock...

In sport competition sometimes we observe training practices, lacking of scientific foundations, which are not without dangers for the athlete. These methods, which are not sensu stricto doping, may later promote the use of forbidden substances. This is the case of vitamins' injections or use of other perfusions. Physicians in charge of First Divis...

To determine the influence of functional electrical stimulation (FES) on subluxation and shoulder pain in hemiplegic patients. Controlled study of 24 months' duration beginning in the first month after onset of stroke. One hundred twenty hemiplegic patients with both subluxed and painful shoulder were followed for rehabilitation before and after di...

Sports is considered as an activity able to improve the fitness of the population. Unfortunately, physical activity can also be the cause of many running-related injuries requiring medical treatment. In order to prevent the risk of musculoskeletal pain and disability in the lower extremity, a good running shoe which provides cushioning, support, st...