Functional capacity and risk of injury in CrossFit practitioners measured through smartphone apps.

BACKGROUND: CrossFit is a high intensity functional training that tends to challenge physical limits. The objectives of this study were to assess functional capacity, prevalence and risk of injury in CrossFit practitioners. METHODS: This cross-sectional, observational and prospective study evaluate the rate of injuries that occurred in CrossFit practitioners in the last 12 months and their functional capacities. The sample was given for convenience, with a total of 22 participants. Functional capacities and risk of injury were measured by functional tests using PHAST and Clinometer applications. The prevalence of injuries was cataloged using the Nordic Musculoskeletal Questionnaire. RESULTS: 5% of the injuries occurred in the neck; 9% in shoulder, hip, thighs, ankles and feet; 14% in the lumbar spine and knees. The worst functional results were for the shoulder medial rotation ROM test, where 86-95% of the athletes were classified as "Bad"; the dorsiflexion ROM test also performed poorly in 68% of athletes. CONCLUSION: This study shows that the CrossFit practice suggests that the injury prevalence is relatively low, affecting mainly knees, lumbar spine, wrists and hands. However, the risk of injuries shown by the functional musculoskeletal assessment is higher, especially in the shoulder and ankle, and it is important for the practitioner to realize a specific functional assessment before starting training.

Fast and accurate 3-D spine MRI segmentation using FastCleverSeg.

Accurate and efficient segmenting of vertebral bodies, muscles, and discs is crucial for analyzing various spinal diseases. However, traditional methods are either laborious and time-consuming (manual segmentation) or require extensive training data (fully automatic segmentation). FastCleverSeg, our proposed semi-automatic segmentation approach, addresses those limitations by significantly reducing user interaction while maintaining high accuracy. First, we reduce user interaction by requiring the manual annotation of only two or three slices. Next, we automatically Estimate the Annotation on Intermediary Slices (EANIS) using traditional computer vision/graphics concepts. Finally, our proposed method leverages improved voxel weight balancing to achieve fast and precise volumetric segmentation in the segmentation process. Experimental evaluations on our assembled diverse MRI databases comprising 179 patients (60 male, 119 female), demonstrate a remarkable 25 ms (30 ms standard deviation) processing time and a significant reduction in user interaction compared to existing approaches. Importantly, FastCleverSeg maintains or surpasses the segmentation quality of competing methods, achieving a Dice score of 94%. This invaluable tool empowers physicians to efficiently generate reliable ground truths, expediting the segmentation process and paving the way for future integration with deep learning approaches. In turn, this opens exciting possibilities for future fully automated spine segmentation.

Association between spinal alignment and biochemical composition of lumbar intervertebral discs assessed by quantitative magnetic resonance imaging.

BACKGROUND: To evaluate potential associations between spinopelvic parameters and the biochemical composition of lumbar intervertebral discs using quantitative magnetic resonance imaging in asymptomatic young adults. METHODS: Our study group comprised 93 asymptomatic volunteers aged 20-40 years (49 women and 44 men). Lumbar spine T2-weighted images and T2 relaxometry were acquired on a 1.5T MRI scanner. Spinopelvic parameters including sacral slope, pelvic tilt, pelvic incidence, lumbar lordosis, thoracic kyphosis, thoracolumbar alignment, sagittal vertical axis, spinosacral angle, C2 pelvic angle, and T1S1 and L1S1 length were measured on panoramic spine radiographs. RESULTS: Lumbar lordosis decrease correlates with discrete dehydration of nucleus pulposus at all lumbar levels. Also low values of sacral slope, pelvic tilt, pelvic incidence, thoracic kyphosis and spinosacral angle were associated with decrease of T2 relaxation times on annulus fibrosus. CONCLUSIONS: In conclusion, spinopelvic parameters presented a discrete association with lumbar disc composition and water content.

Transcranial ultrasonography as a reliable instrument for the measurement of the cerebral ventricles in rats with experimental hydrocephalus: a pilot study.

PURPOSES: Demonstrate that transcranial ultrasonography (TUS) scanning is viable and useful as a diagnostic method in experimental hydrocephalus, as well as to compare measurements of cerebral and ventricular width obtained from TUS scans of hydrocephalic rats with post-mortem anatomical specimens, aiming for the development of accurate criteria to establish ventricular enlargement and progression of hydrocephalus subsequently. METHODS: Thirty-five male Wistar rats were used. Following hydrocephalus induction, they underwent a transcranial ultrasound scan to measure cerebral and ventricular dimensions, in the fourth and 21 post-induction days. By the end of the experiments, measurements obtained from TUS scans were compared with actual values as seen in the post-mortem specimens of each animal. RESULTS: Ventricular dilation could be clearly visualized in hydrocephalic animals. We performed intraclass correlation coefficient and linear regression analyses that have demonstrated a precise correlation between measurements of TUS scans and post-mortem specimens; we have found a similarity of 0,95 for the cerebral diameter and 0,97 for ventricular width. CONCLUSIONS: Transcranial ultrasonography is a useful and reliable diagnostic tool for experimental hydrocephalus; also, it can be used to assess the progression of ventriculomegaly in animal models of hydrocephalus.

Concordance in prediction body fat percentage of Brazilian women in reproductive age between different methods of evaluation of skinfolds thickness.

OBJECTIVE: To assess the utility of bioimpedance (BIA) and skinfolds thickness (SF) in body fat percentage measuring (%BF) compared to the reference method dual-energy x-ray absorptiometry (DXA) in Brazilian reproductive age women, as well as to estimate of inter- and intra-observer precision for SF. SUBJECTS AND METHODS: 170 women aged 18-37 years with BMI between 18 and 39.9 kg/m2 were selected for this cross-sectional study. Body density was evaluated through equations proposed by Jackson, Pollock and Ward (1980) (EqJPW) and Petroski (1995) (EqPET), and %BF was estimated by BIA, DXA and Siri's formula (1961). The SF were measured by two separate observers: A and B (to determine inter-observer variability), who measured the folds at three times with 10-minute interval between them (to determine intra-observer variability - we used only observer A). RESULTS: The %BF by DXA was higher than those measured by SF and BIA (p<0.01, for all) of 90 volunteers. The Lin coefficient of agreement was considered satisfactory for %BF values obtained by EqJPW and BIA (0.55) and moderate (0.76) for sum of SF (ΣSF) values obtained by EqJPW and EqPET. No agreement was observed for the values obtained by SF (EqJPW and EqPET), BIA and DXA. Analysis of inter- and intra-observer of 59 volunteers showed that different measures of SF thickness met acceptability standards, as well as the % BF. CONCLUSION: BIA and SF measurements may underestimate %BF compared with DXA. In addition, BIA and SF measurements are not interchangeable with DXA. However, our results suggest the equation proposed by Jackson, Pollock and Ward (three skinfolds) compared to BIA are interchangeable to quantify the %BF in Brazilian women in reproductive age. Furthermore, our results show acceptable accuracy for intra- and inter-observer skinfold measurements. Arch Endocrinol Metab. 2020;64(3):257-68.

Spinopelvic sagittal balance: what does the radiologist need to know?

Sagittal balance describes the optimal alignment of the spine in the sagittal plane, resulting from the interaction between the spine and lower limbs, via the pelvis. Understanding sagittal balance has gained importance, especially in the last decade, because sagittal imbalance correlates directly with disability and pain. Diseases that alter that balance cause sagittal malalignment and may trigger compensatory mechanisms. Certain radiographic parameters have been shown to be clinically relevant and to correlate with clinical scores in the evaluation of spinopelvic alignment. This article aims to provide a comprehensive review of the literature on the spinopelvic parameters that are most relevant in clinical practice, as well as to describe compensatory mechanisms of the pelvis and lower limbs.

O equilíbrio sagital descreve o alinhamento ideal da coluna vertebral no plano sagital, sendo resultante da interação entre a coluna e os membros inferiores, por meio da bacia. O entendimento do equilíbrio sagital ganhou importância principalmente na última década, uma vez que o desequilíbrio sagital se correlaciona diretamente com incapacidade e dor. Doenças que alterem este equilíbrio podem causar mal alinhamento sagital e desencadear mecanismos compensatórios, os quais tentam restaurar a postura ereta. A literatura relata parâmetros radiográficos clinicamente relevantes, que possuem relação estabelecida com escores clínicos, para avaliar o alinhamento espinopélvico. Este artigo tem como objetivo fornecer uma ampla revisão da literatura sobre os parâmetros espinopélvicos mais relevantes na prática clínica, e descrever os mecanismos compensatórios da pelve e membros inferiores.

Concordance in prediction body fat percentage of Brazilian women in reproductive age between different methods of evaluation of skinfolds thickness

ABSTRACT Objective To assess the utility of bioimpedance (BIA) and skinfolds thickness (SF) in body fat percentage measuring (%BF) compared to the reference method dual-energy x-ray absorptiometry (DXA) in Brazilian reproductive age women, as well as to estimate of inter- and intra-observer precision for SF. Subjects and methods 170 women aged 18-37 years with BMI between 18 and 39.9 kg/m2 were selected for this cross-sectional study. Body density was evaluated through equations proposed by Jackson, Pollock and Ward (1980) (EqJPW) and Petroski (1995) (EqPET), and %BF was estimated by BIA, DXA and Siri's formula (1961). The SF were measured by two separate observers: A and B (to determine inter-observer variability), who measured the folds at three times with 10-minute interval between them (to determine intra-observer variability - we used only observer A). Results The %BF by DXA was higher than those measured by SF and BIA (p<0.01, for all) of 90 volunteers. The Lin coefficient of agreement was considered satisfactory for %BF values obtained by EqJPW and BIA (0.55) and moderate (0.76) for sum of SF (ΣSF) values obtained by EqJPW and EqPET. No agreement was observed for the values obtained by SF (EqJPW and EqPET), BIA and DXA. Analysis of inter- and intra-observer of 59 volunteers showed that different measures of SF thickness met acceptability standards, as well as the % BF. Conclusion BIA and SF measurements may underestimate %BF compared with DXA. In addition, BIA and SF measurements are not interchangeable with DXA. However, our results suggest the equation proposed by Jackson, Pollock and Ward (three skinfolds) compared to BIA are interchangeable to quantify the %BF in Brazilian women in reproductive age. Furthermore, our results show acceptable accuracy for intra- and inter-observer skinfold measurements. Arch Endocrinol Metab. 2020;64(3):257-68

Protocolo intensivo de reabilitação para o desenvolvimento neuropsicomotor em uma criança com microcefalia: um estudo de caso / Intensive rehabilitation protocol for neuropsychomotor development in a child with microcephaly: a case report

A microcefalia é uma doença de origem multifatorial podendo ser desenvolvida de forma congênita ou por causas ambientais. Ela atinge os ossos da calota craniana, causando o fechamento prematuro das fontanelas, no qual restringe o espaço interno do crânio, que em consequência afeta o crescimento e desenvolvimento normal do encéfalo, levando a disfunções neuropsicomotoras leves, moderadas ou graves. Desta forma, este estudo tem como objetivo avaliar o desenvolvimento neuropsicomotor de uma criança com microcefalia, antes e após um protocolo fisioterapêutico intensivo. Trata-se de relato de caso no qual foram avaliados os marcos motores e os níveis de função apresentados pelo paciente, antes e após um protocolo fisioterapêutico intensivo, realizado por um período de 30 dias consecutivos. Foram obtidos importantes resultados no controle de cervical, alinhamento de cabeça em linha média, manuseio de objetos, elevação das mãos à boca e alinhamento postural. Desta forma, conclui-se que o protocolo fisioterapêutico intensivo é uma alternativa eficaz que auxilia e potencializa o desenvolvimento neuropsicomotor da criança

Microcephaly is a multifactorial disease that can be developed congenitally or due to environmental causes. It affects the skullcap bones, causing premature fontanelles closure, in which it restricts the internal skull space, which consequently affects the growth and normal development of the brain, leading to mild, moderate or severe neuropsychomotor disorders. Thus, this study aims to evaluate the neuropsychomotor development of a child with microcephaly, before and after an intensive physical therapy protocol. This is a case report in which the motor milestones and function levels were evaluated before and after an intensive physical therapy protocol performed for a consecutive 30 days period. Important results were obtained in cervical control, midline head alignment, object handling, lifting hands to mouth and postural alignment. Thus, it is concluded that the intensive physical therapy protocol is an effective alternative that helps and enhances the child's neuropsychomotor development

Effective Parameters for Gait Analysis in Experimental Models for Evaluating Peripheral Nerve Injuries in Rats.

OBJECTIVE: Chronic constriction injury (CCI) of the sciatic nerve is a peripheral nerve injury widely used to induce mononeuropathy. This study used machine learning methods to identify the best gait analysis parameters for evaluating peripheral nerve injuries. METHODS: Twenty-eight male Wistar rats (weighing 270±10 g), were used in the present study and divided into the following 4 groups: CCI with 4 ligatures around the sciatic nerve (CCI-4L; n=7), a modified CCI model with 1 ligature (CCI-1L; n=7), a sham group (n=7), and a healthy control group (n=7). All rats underwent gait analysis 7 and 28 days postinjury. The data were evaluated using Kinovea and WeKa software (machine learning and neural networks). RESULTS: In the machine learning analysis of the experimental groups, the pre-swing (PS) angle showed the highest ranking in all 3 analyses (sensitivity, specificity, and area under the receiver operating characteristics curve using the Naive Bayes, k-nearest neighbors, radial basis function classifiers). Initial contact (IC), step length, and stride length also performed well. Between 7 and 28 days after injury, there was an increase in the total course time, step length, stride length, stride speed, and IC, and a reduction in PS and IC-PS. Statistically significant differences were found between the control group and experimental groups for all parameters except speed. Interactions between time after injury and nerve injury type were only observed for IC, PS, and IC-PS. CONCLUSION: PS angle of the ankle was the best gait parameter for differentiating nonlesions from nerve injuries and different levels of injury.

Relationship of spinal alignment with muscular volume and fat infiltration of lumbar trunk muscles.

Fat infiltration and atrophy of lumbar muscles are related to spinal degenerative conditions and may cause functional deficits. Spinal alignment exerts biomechanical influence on lumbar intervertebral discs and joints. Our objective was to evaluate if spinopelvic parameters correlate with the lumbar muscle volume and fat infiltration. This is an observational, prospective and cross-sectional study. Ninety-three asymptomatic adult aged 20-40 years were included. Lumbar lordosis (LL), thoracic kyphosis (TK), pelvic incidence (PI), pelvic tilt (PT), sacral slope (SS), thoracolumbar alignment (TL), sagittal vertical axis (SVA), C2-pelvic angle (CPA), spinosacral angle (SSA), lack of lordosis (PI-LL), L1S1 and T1S1 length were measured on panoramic spine radiographs. Lumbar axial T1-weighted and In- and Out-Phase images were obtained on 1.5T MRI scanner and were used to extract the muscle volumes and fat fractions of multifidus, erector spinae, and psoas. All muscle volumes were higher in men than women (p<0.05). The fat fraction was higher in the multifidus and erector spinae in women (p<0.05). Multifidus volume was weakly correlated with PT (R = 0.22), PI (R = 0.22), LL (R = 0.34) and CPA (R = 0.29). Erectors spinae volume were correlated with CPA (R = 0.21). Psoas volume correlated with TK (R = 0.21), TL (R = 0.27) and SVA (R = -0.23). The lumbar muscle volumes showed a moderated correlation with T1S1 length (R = 0.55 to 0.62). Spinopelvic parameters showed correlation with lumbar muscle volumes but not with muscle fat infiltration on asymptomatic young adults.

Hyperbaric oxygen therapy reduces astrogliosis and helps to recovery brain damage in hydrocephalic young rats.

PURPOSE: We investigated the possible beneficial effects that hyperbaric oxygen therapy could offer in different brain structures affected by ventriculomegaly in pup rats submitted to experimental hydrocephalus. METHODS: Seven-day-old Wistar rats were submitted to hydrocephalus by intracisternal injection of 10% kaolin into the cisterna magna. The animals were divided into four groups: control (n = 5); control with HBOT (3ATA/2 h/day) (n = 5); untreated hydrocephalic (n = 10); hydrocephalic treated with HBOT (3ATA/2 h/day) (n = 10). The treatment with HBOT was performed daily for 14 days post-induction of hydrocephalus. To evaluate the response to treatment, behavioral tests (open field, Morris water maze, and activity monitor) were performed. After 14 days, the animals were euthanized, and the brain was removed for histological (hematoxylin-eosin and solochrome-cyanine) and immunohistochemical (GFAP and Ki-67) studies. RESULTS: The hyperbaric treatment, although not causing changes in ventricular enlargement, resulted in a significant improvement in the behavioral performance (p = 0.0001), with greater agility and exploration of the environment, preservation of spatial memory, and greater learning capacity (p = 0.0001). Through the immunohistochemical study, the astrocytic activity (glial fibrillary acidic protein) in the corpus callosum (p = 0.0001) and in the germinative matrix (p = 0.0033) was significantly reduced as compared to that in the H group. CONCLUSION: The results suggest that hyperbaric treatment bettered the behavioral performance and offered benefits to the structures affected by the ventricular increase helping to recover the brain damages. In this way, the HBOT it can be considered an adjuvant therapy for the treatment of hydrocephalus.

Respostas anti-inflamatórias ao exercício terapêutico na osteoartrite de joelho: uma revisão sistemática / Anti-inflammatory responses to therapeutic exercise in knee osteoarthritis: a systematic review

Introdução: A osteoartrite (OA) de joelho atinge 10% da população mundial com idade de 60 anos ou mais. Citocinas, prostaglandinas e enzimas como IL-6, TNF-α, PCR, metaloproteínases, entre outras, são responsáveis por desencadear o processo inflamatório na articulação, degradação da cartilagem, formação de edema, incapacidades funcionais e dor. Embora o processo de degradação da cartilagem articular seja considerado de difícil reversão, sabe-se que pode ser estabilizado ou prevenido com o exercício físico. Objetivo: realizar uma revisão sistemática acerca dos efeitos de exercícios terapêuticos sobre o processo inflamatório em indivíduos com osteoartrite de joelho. Métodos: Foi realizada uma busca por artigos originais e em inglês e publicados em periódicos com fator de impacto indexados na base de dados Pubmed. Resultados: Foram encontrados 211 artigos originais, e 16 foram selecionados por se enquadrarem nos critérios de inclusão estabelecidos. Conclusão: O exercício terapêutico promoveu redução dos níveis séricos de citocinas pró-inflamatórias, em especial IL-6, TNF e PCR. Protocolos de exercícios de fortalecimento associados a exercícios aeróbios e dieta alimentar mostraram ser a combinação mais eficaz na redução da resposta inflamatória. O uso de medicamentos associados não interfere nos benefícios do exercício terapêutico na OA de joelho. (AU)

Introduction: Knee Osteoarthritis (OA) reaches 10% of the population aged 60 or older. Cytokines, prostaglandins and enzymes such as IL-6, TNF-α, PCR, metalloproteinases, and others are responsible for triggering the inflammatory process in joint, cartilage degradation, edema formation, functional disability and pain. Although the process of articular cartilage degradation is considered difficult to reverse, it is known that may be stabilized or prevented with physical exercise. Objective: to perform a systematic review about the effects of exercise therapy on the inflammatory process in individuals with knee osteoarthritis. Methods: A search was performed for original articles in English and published in journals with impact factor indexed in Pubmed database. Results: 211 original articles found, 16 were selected since they fit the established inclusion criteria. Conclusion: The exercise therapy promoted reduction of serum levels of pro-inflammatory cytokines, especially IL-6, TNF and PCR. Strengthening exercises protocols associated with aerobic and diet, showed to be the most effective combination in reducing the inflammatory response. The use of associated medications does not interfere with the therapeutic benefits of exercise on knee OA. (AU)

Lumbar intervertebral discs T2 relaxometry and T1ρ relaxometry correlation with age in asymptomatic young adults.

BACKGROUND: To investigate the detection of intervertebral disc (IVD) composition aging-related changes using T2 and T1ρ relaxometry in vivo in asymptomatic young adults. METHODS: We recruited ninety asymptomatic and young adults (42 men and 48 women) between 20 and 40 years old. T2 and T1ρ lumbar spine mappings were acquired using 1.5 T magnetic resonance imaging (MRI) scanner. Two independent observers manually segmented 450 lumbar discs in all slices. They also performed sub region segmentation of annulus fibrosus (AF) and nucleus pulposus (NP) at the central MRI sagittal slices. RESULTS: There was no difference between men and women for T2 (P=0.37) or T1ρ relaxometry (P=0.97). There was a negative correlation between age (20-40 years) and IVD T2 relaxation time of the whole disc (r=-0.30, P<0.0001), NP (r=-0.20 to -0.51, P<0.05) and posterior AF (r=-0.21 to -0.31, P<0.05) at all lumbar disc levels. There was no statistical correlation between aging and IVD T1ρ relaxation both for NP and AF. CONCLUSIONS: T2 relaxometry detected gradual IVD dehydration in the first two decades of adulthood. We observed no significant variation of T1ρ or volumetry with aging in our study group. Our results suggest that T2 mapping may be more appropriate to detect early IVD aging changes.

Association Between Lumbar Spine Sagittal Alignment and L4-L5 Disc Degeneration Among Asymptomatic Young Adults.

STUDY DESIGN: Cross-sectional observational study on the relationship between the degrees of disc degeneration and sagittal alignment in asymptomatic healthy individuals. OBJECTIVE: This study sought to determine whether the sagittal spine alignment subtype is related to the prevalence of lumbar disc degeneration. SUMMARY AND BACKGROUND DATA: Sagittal balance and spinopelvic parameters might be risk factors for disc degeneration. METHODS: A total of 70 asymptomatic participants (36 women and 34 men) without regular physical activity were categorized according to the four subtypes of sagittal alignment proposed by Roussouly. All participants underwent magnetic resonance imaging of the lumbar spine (1.5T) and panoramic radiography of the spine. The degree of disc degeneration was graded using T2-weighted images according to the Pfirrmann classification. Spinopelvic parameters and vertebral curvatures were measured on digital panoramic radiographs using Surgimap software. Interobserver analyses for the Pfirrmann classification and spinopelvic parameters were assessed using the weighted Kappa and intraclass correlation coefficient (ICC), respectively. RESULTS: The Kappa associated with disc degeneration classification was 0.79 (95% confidence intervals 0.72-0.87). The ICCs were excellent, with small confidence intervals for all spinopelvic parameters. The type II group (flat lordosis) showed a higher frequency of degenerated discs at L4-L5 (P = 0.03) than the type IV group (long and curved lumbar spine). No significant differences in disc degeneration were observed among the four subtypes at the other disc levels. We found a negative, moderate correlation between the spinopelvic parameters and the occurrence of disc degeneration in the type II group. CONCLUSION: The Roussouly subtype II sagittal alignment is significantly associated with disc degeneration at L4-L5 in asymptomatic young adults. Our results support the hypothesis that spinal sagittal alignment plays a role in early disc degeneration. LEVEL OF EVIDENCE: 3.

Respostas fisiológicas ao exercício físico em atletas cadeirantes com lesão medular / Physiological responses to exercise in wheelchair athletes with spinal cord injury

Introdução: Atletas com lesão medular apresentam redução da sua capacidade aeróbia global, em comparação com indivíduos não portadores de deficiência. Porém, seu treinamento tem sido realizado igual ao de um atleta sadio, desconsiderando suas particularidades. Objetivo: Identificar o que tem sido relatado pela literatura nos últimos anos envolvendo a capacidade aeróbia de atletas cadeirantes com lesão medular. Métodos: Foi realizada uma revisão sistemática por meio de busca de artigos originais em inglês publicados e indexados na base de dados PubMed. Resultados: Foram encontrados 44 artigos originais, e destes, apenas 17 se enquadraram nos critérios de inclusão desta pesquisa. Conclusão: O nível da lesão e o grau de mobilidade afetaram diretamente a capacidade aeróbia dos esportistas. Atletas cadeirantes apresentaram VO2 pico e potência aeróbia semelhantes a dos atletas saudáveis, e FCmáx maior. Atletas cadeirantes de modalidades esportivas de esforço contínuo exibiram melhor capacidade aeróbia que atletas de esforços intermitentes.

Introduction: Athletes with spinal cord injury have overall aerobic capacity reduced, compared with non-disabled individuals. However, their training has been conducted the same way as a healthy athlete, disregarding their peculiarities. Objective: To identify what has been reported in the literature in recent years involving the aerobic capacity of wheelchair athletes with spinal cord injury. Methods: A systematic review by searching for original articles published in English and indexed in the PubMed database was performed. Results: Forty-four original articles were found and of these only 17 met our criteria for inclusion and exclusion of this research. Conclusion: The lesion level and the mobility degree directly affect the aerobic capacity of these athletes. Wheelchair athletes have VO2peak and aerobic power similar to healthy athletes, and higher HRmax. Wheelchair athletes in sports that require continuous effort exhibited better aerobic capacity than athletes in sports requiring only intermittent effort.