Stretching the spines of gymnasts: a review

Gymnastics is noted for involving highly specialized strength, power, agility and flexibility. Flexibility is perhaps the single greatest discriminator of gymnastics from other sports. The extreme ranges of motion achieved by gymnasts require long periods of training, often occupying more than a decade. Gymnasts also start training at an early age (particularly female gymnasts), and the effect of gymnastics training on these young athletes is poorly understood. One of the concerns of many gymnastics professionals is the training of the spine in hyperextension-the ubiquitous 'arch' seen in many gymnastics positions and movements. Training in spine hyperextension usually begins in early childhood through performance of a skill known as a back-bend. Does practising a back-bend and other hyperextension exercises harm young gymnasts? Current information on spine stretching among gymnasts indicates that, within reason, spine stretching does not appear to be an unusual threat to gymnasts' health. However, the paucity of information demands that further study be undertaken

ATHENA detector proposal - a totally hermetic electron nucleus apparatus proposed for IP6 at the Electron-Ion Collider

ATHENA has been designed as a general purpose detector capable of delivering the full scientific scope of the Electron-Ion Collider. Careful technology choices provide fine tracking and momentum resolution, high performance electromagnetic and hadronic calorimetry, hadron identification over a wide kinematic range, and near-complete hermeticity.This article describes the detector design and its expected performance in the most relevant physics channels. It includes an evaluation of detector technology choices, the technical challenges to realizing the detector and the R&D required to meet those challenges

Hemodynamic responses during and after multiple sets of stretching exercises performed with and without the Valsalva maneuver

OBJECTIVE: This study investigated the acute hemodynamic responses to multiple sets of passive stretching exercises performed with and without the Valsalva maneuver. METHODS: Fifteen healthy men aged 21 to 29 years with poor flexibility performed stretching protocols comprising 10 sets of maximal passive unilateral hip flexion, sustained for 30 seconds with equal intervals between sets. Protocols without and with the Valsalva maneuver were applied in a random counterbalanced order, separated by 48-hour intervals. Hemodynamic responses were measured by photoplethysmography pre-exercise, during the stretching sets, and post-exercise. RESULTS: The effects of stretching sets on systolic and diastolic blood pressure were cumulative until the fourth set in protocols performed with and without the Valsalva maneuver. The heart rate and rate pressure product increased in both protocols, but no additive effect was observed due to the number of sets. Hemodynamic responses were always higher when stretching was performed with the Valsalva maneuver, causing an additional elevation in the rate pressure product. CONCLUSIONS: Multiple sets of unilateral hip flexion stretching significantly increased blood pressure, heart rate, and rate pressure product values. A cumulative effect of the number of sets occurred only for systolic and diastolic blood pressure, at least in the initial sets of the stretching protocols. The performance of the Valsalva maneuver intensified all hemodynamic responses, which resulted in significant increases in cardiac work during stretching exercises

Influência do alongamento dos músculos isquiostibial e retofemoral no pico de torque e potência máxima do joelho

O alongamento muscular é utilizado nas práticas desportivas para aumentar a flexibilidade muscular e amplitude articular, mas estudos mostram que pode produzir efeitos deletérios na produção de força muscular. A proposta deste estudo foi verificar a influência imediata e tardia do alongamento dos músculos isquiostibiais e retofemoral, por meio da facilitação neuromuscular proprioceptiva (FNP), no pico de torque e potência máxima do joelho. Quinze jovens sedentárias foram distribuídas em três grupos: GA, submetidas a 12 sessões de alongamento durante quatro semanas; GB, a apenas uma sessão de alongamento imediatamente antes da avaliação final; e GC, à mobilização articular passiva do joelho, de forma a não alongar. Todas as participantes foram avaliadas quanto à amplitude de movimento (ADM) de flexão e extensão do joelho, e à dinamometria isocinética, antes e após a intervenção, mensurando-se ADM, pico de torque (PT) e potência máxima (PM) do joelho. Observou-se diferença entre as médias dos três grupos na ADM após a intervenção (p0,05). Os grupos GA e GB apresentaram melhoras na ADM e apenas o grupo GC apresentou melhora significativa em todas as variáveis isocinéticas (pMuscle stretching is often used in sports practice in order to increase muscle flexibility and joint range of motion. However, many studies have shown that muscle torque production may be reduced after stretching. The purpose of this work was to assess immediate and late effects of stretching, by proprioceptive neuromuscular facilitation (PNF) techniques, on knee peak torque and maximum power. Fifteen young sedentary female subjects were evenly distributed into three groups: AG, submitted to 12 PNF stretching sessions along four weeks; BG, submitted to only one stretching session just before the final evaluation; and GC, submitted to passive knee mobilization so as not to produce muscle stretching. All of them were assessed, before and after the four-week study, as to knee range of motion (ROM) flexion and extension, as well as to isokinetic dynamometry; variables analysed were knee ROM, peak torque and maximum power. Significant mean ROM differences were found between the three groups (p0.05). A and B groups showed increased ROM at the post-test, and only the C group showed significant increase in all isokinetic variables (p<0.05). Results then suggest that PNF stretching, performed with adequate duration and intensity, may be done before sports practice with no decrease in muscle strength