ABSTRACT Objective: Fatigue of the ankle’s stabilizing muscles may influence the performance of functional activities and postural control. The purpose of this study was to evaluate the performance of healthy young adults using functional jump tests and static posturography control under pre- and post-fatigue conditions of the ankle invertor and evertor muscles. Methods: Thirty physically active healthy male and female (15 male and 15 female) volunteers (24.3 years) were enrolled in this prospective cross-sectional study. Participants performed tests on one day under a non-fatigued state of invertor and evertor muscles and on the second day in a fatigued state. Tests included static posturography on a force platform in a bipedal stance with eyes open and closed and in one-legged support with eyes open and functional jump tests (figure-of-8, side hop, 6-m crossover hop, and square hop). Fatigue of the ankle invertor and evertor muscles was induced using isokinetic dynamometry with 30 repetitions at 120°/s. Results: Participants had an average age of 24.3 years (SD ± 2.08), the height of 1.73 m (SD ± 0.08), and a weight of 68.63 kg (SD ± 10.29). The average Body Mass Index (BMI) was 22.88 (SD ± 2.46). A decrease in performance was observed in functional activities and postural control under all conditions after the induction of muscle fatigue, except for the speed at a bipedal stance with eyes open. Conclusions: Functional jump tests are low cost and useful for clinical practice and evaluation of the effects of muscle fatigue and could be used in clinical practice.

OBJECTIVES: To evaluate the clinical characteristics, ground reaction force (GRF), and function of the plantar muscles and dorsiflexors of the ankle in runners with and without Achilles tendinopathy (AT) and in non-runners. METHODS: Seventy-two participants (42 men, 30 women; mean age: 37.3±9.9 years) were enrolled in this cross-sectional study and divided into three groups: AT group (ATG, n=24), healthy runners’ group (HRG, n=24), and non-runners’ group (NRG, n=24). Both ankles were evaluated in each group. The American Orthopedic Foot and Ankle Society (AOFAS) Ankle-Hindfoot Scale was used for clinical and functional evaluation. GRF was evaluated using force plates and muscle strength was evaluated using an isokinetic dynamometer. RESULTS: The AOFAS scores were lower in the ATG. The strike impulse was higher in the ATG than in the HRG and NRG. However, GRF was similar among the groups. The ATG exhibited lower total work at 120°/s speed than the HRG. The peak torque in concentric dorsiflexion was lower in the NRG than in the ATG and HRG. The peak torque and total work in concentric plantar flexion were lower in the NRG than in the ATG. The peak torque and total work in eccentric plantar flexion were lower in the NRG than in the ATG and HRG. CONCLUSION: Runners with AT showed higher strike impulse, lower muscle strength of the plantar flexors, and higher clinical and functional damage.

RESUMO O novo coronavírus, que causa a doença infecciosa denominada COVID-19 pela Organização Mundial de Saúde, foi notificado em dezembro, na China. As principais manifestações clínicas dos pacientes infectados são febre, tosse e dispneia. Esses pacientes têm propensão a desenvolver alterações cardíacas, miopatia difusa, diminuição da função pulmonar, diminuição da força muscular inspiratória e deterioração da capacidade funcional. Assim sendo, é esperado que os pacientes afetados pela COVID-19 sofram sequelas musculoesqueléticas em decorrência do processo inflamatório e perda de massa muscular causada pela imobilidade, que geram incapacidades motoras ainda não quantificáveis. Existe a necessidade de entender as implicações clínicas causadas pela COVID-19 para elaborar melhores estratégias de reabilitação para esses pacientes. O objetivo deste estudo foi realizar uma análise reflexiva no que tange ao impacto da COVID-19 nos sistemas imunológico, neuromuscular e musculoesquelético e no processo de reabilitação. Trata-se de uma análise reflexiva, desenvolvida no Laboratório do Estudo do Movimento do Instituto de Ortopedia e Traumatologia da Faculdade de Medicina da Universidade de São Paulo, SP, Brasil. Nesta análise, fizemos uma reflexão sobre os seguintes tópicos relacionados com a COVID-19: mecanismos imunológicos, impacto no sistemas neuromuscular e musculoesquelético e reabilitação dos pacientes. Nível de evidência V; Opinião do especialista.

ABSTRACT The new coronavirus, which causes the infectious disease named COVID-19 by the World Health Organization (WHO), was notified in 2020 in China. The main clinical manifestations in infected patients are fever, cough and dyspnoea. These patients are prone to developing cardiac changes, diffuse myopathy, decreased pulmonary function, decreased inspiratory muscle strength, and a deterioration in functional capacity. Thus, it is expected that patients affected by COVID-19 will suffer musculoskeletal consequences as a result of the inflammatory process and loss of muscle mass caused by immobility, generating motor incapacities that are not yet quantifiable. It is important to understand the clinical implications caused by COVID-19, in order to have better rehabilitation strategies for these patients. The aim of this study was to conduct a reflective analysis of the impact of COVID-19 on the immune, neuromuscular and musculoskeletal systems, and its rehabilitation process. This is a reflexive analysis, developed in the Laboratory for the Study of Movement of the Institute of Orthopaedics’ and Traumatology, at the Universidade de São Paulo School of Medicine, SP, Brazil. In this analysis, we reflect on the following topics related to COVID-19: immunological mechanisms, impact on the neuromuscular and musculoskeletal systems, and the rehabilitation of patients. Level of evidence V; Opinion of the specialist.

RESUMEN El nuevo coronavirus, que causa la enfermedad infecciosa llamada COVID-19 por la Organización Mundial de la Salud, fue notificado en diciembre en China. Las principales manifestaciones clínicas de los pacientes infectados son fiebre, tos y disnea. Esos pacientes son propensos a desarrollar cambios cardíacos, miopatía difusa, disminución de la función pulmonar, disminución de la fuerza muscular inspiratoria y deterioro de la capacidad funcional. Por lo tanto, se espera que los pacientes afectados por COVID-19 sufran secuelas musculoesqueléticas debido al proceso inflamatorio y pérdida de masa muscular causada por la inmovilidad, que generan discapacidades motoras aún no son cuantificables. Es necesario comprender las implicaciones clínicas causadas por COVID-19 para elaborar mejores estrategias de rehabilitación para estos pacientes. El objetivo de este estudio fue realizar un análisis reflexivo sobre el impacto de COVID-19, en los sistemas inmunitario, neuromuscular y musculoesquelético y en el proceso de rehabilitación. Es un análisis reflexivo, desarrollado en el Laboratorio del Estudio de Movimiento del Instituto de Ortopedia y Traumatología, Facultad de Medicina, Universidad de São Paulo, SP. En este análisis, reflexionamos sobre los siguientes temas relacionados con COVID-19: mecanismos inmunológicos, impacto en los sistemas neuromuscular y musculoesquelético y la rehabilitación de los pacientes. Nivel de evidencia V; Opinión de expertos.

OBJECTIVES: This study sought to analyze the extent of motor adaptation in ankle plantar flexors and dorsiflexors among older drivers during clinical isokinetic testing. METHODS: One hundred older adults (70.4±5.7 years) participated in two bilateral ankle plantar flexor and dorsiflexor isokinetic assessments at 30°/sec. Peak torque (PTQ), PTQ adjusted for body weight (PTQ/BW), and total work (TW) were analyzed. RESULTS: On the dominant side, PTQ/BW and TW were significantly greater for the second plantar flexion test than were those for the first such test (p<0.001), whereas PTQ, PTQ/BW, and TW (p<0.001) were significantly greater for the second dorsiflexion test than were those for the first such test. On the non-dominant side, plantar flexion PTQ and TW were significantly lower for the second test than were those for the first test (p<0.001). CONCLUSION: Older drivers demonstrated better performance with the dominant limb on the second test. The low variability in test execution showed the existence of a motor adaptation effect for the tested movements, despite the short recovery period between the assessments.

OBJETIVOS: Avaliar fatores associados com acidentes de trânsito com motocicletas. MÉTODOS: Foram avaliadas 285 vítimas de acidente de motocicleta em São Paulo. Os dados foram coletados em plantões nas unidades de emergência. Foram coletadas informações sobre: condições das vítimas, uso de equipamentos de segurança, condições de estrada e veículo. RESULTADOS: As vítimas eram principalmente homens jovens (92%); 23% usavam a motocicleta para o trabalho (média: 8 horas por dia); 45% possuíam a motocicleta por menos de dois anos; 77% tinham habilitação para dirigir; 33% tinham menos de quatro anos de habilitação; 31% tinham feito curso de direção defensiva. Lesões graves foram identificadas em 67% dos motoristas não habilitados. Houve politraumatismo em 9% das vítimas e traumatismo craniano em 5% da população avaliada. Fraturas de membros inferiores ocorreram mais frequentemente do em membros superiores (17% contra 12%). A maioria usava capacetes (90%), mas apenas 18% usava capacete, botas e jaqueta. Dosagens positivas de álcool (7%) e drogas (14%) foram vistas e totalizaram 21% de todas as vítimas. A maioria dos acidentes ocorreu como consequência de imprudência (88%), durante o dia (67%) e sem chuva (94%). CONCLUSÃO: A maioria dos acidentes envolve vítimas do sexo masculino, adultos, que usam a motocicleta como meio de transporte e não consideram equipamentos de segurança, condução defensiva e o consumo de álcool e drogas fatores importantes para prevenção dos acidentes.

OBJECTIVE: To evaluate the factors associated with traffic motorcycles accidents. METHODS: The sample consisted of 285 motorcycle accident victims in São Paulo. Data were collected from 24-hour emergency service shifts regarding: conditions of the victims, security equipment, road and vehicle conditions. RESULTS: Victims were mostly young men (92%); 23% used the motorcycle for work (average: 8 hours per day); 45% had owned a motorcycle for less than two years; 77% were licensed motorcycle drivers; 33% had less than four years of qualification; 31% had attended a course of defensive driving. Severe lesions were identified in 67% of the unlicensed drivers. Polytrauma occurred in 9% head trauma in 5% of the entire population. Lower limb fractures occurred more frequently than upper limb (17% vs. 12%). Most wore helmets (90%) but only 18% wore helmet, boots and jacket. Positive readings for alcohol (7%) and drugs (14%) occurred in 21% of victims. Most accidents occurred as a consequence of imprudence (88%), during the day (67%), in dry weather conditions (94%). A side impact was registered in 48% of cases; 80% of motorcycles had an engine capacity up to 250 cc. In 51% of the accidents the person responsible for the accident was the driver of the other vehicle in the accident. CONCLUSION: Most accidents involve motorcyclists who are young male adults, use the motorcycle as a means of transport and do not consider safety, defensive driving and the use of alcohol and drugs as important factors.

OBJECTIVES: In post-menopausal women with osteoporosis, insufficient vitamin D levels decrease calcium fixation in the bones and calcium transport in the sarcoplasmic reticulum, which impairs muscle strength, possibly leading to detrimental consequences for the preservation of functional capacity and postural balance, fall prevention, and fracture risk. The aim of this study was to evaluate the association between vitamin D levels and knee muscle strength, postural balance and functional mobility among postmenopausal women with osteoporosis. METHODS: This cross-sectional study included 63 osteoporotic older women (aged 60.6±3.1 years). The subjects completed the Timed Up and Go Test to measure functional mobility, and postural balance was assessed on the AccuSway Plus portable force platform. Maximal strength was tested using an isokinetic dynamometer for knee flexion and extension. The subjects were assessed as a group and were divided into quartiles according to their vitamin D levels. Clinicaltrials.gov: NCT02771834. RESULTS: Vitamin D status was independently associated with the normalized peak torque of the knee extensors (β=0.59; p=0.04) and Timed Up and Go Test (β=-0.07; p<0.001). No between-group differences were observed in the demographic and clinical variables or postural balance; however, significant differences were observed in the Timed Up and Go Test, and the group with the highest vitamin D levels exhibited better performance than the group with the lowest vitamin D levels (p<0.001). CONCLUSION: The serum vitamin D levels were independently associated with normalized knee extension strength and functional mobility in postmenopausal women with osteoporosis.

OBJECTIVE: To assess the postural control and flexibility of obese subjects before and both six and 12 months after bariatric surgery. To verify whether postural control is related to flexibility following weight reductions resulting from bariatric surgery. METHODS: The sample consisted of 16 subjects who had undergone bariatric surgery. All assessments were performed before and six and 12 months after bariatric surgery. Postural balance was assessed using an Accusuway¯ portable force platform, and flexibility was assessed using a standard chair sit and reach test (Wells’ chair). RESULTS: With the force platform, no differences were observed in the displacement area or velocity from the center of pressure in the mediolateral and anteroposterior directions. The displacement speed from the center of pressure was decreased at the six month after the surgery; however, unchanged from baseline at 12 months post-surgery. Flexibility increased over time according to the three measurements tested. CONCLUSIONS: Static postural balance did not change. The velocity of postural adjustment responses were increased at six months after surgery. Therefore, weight loss promotes increased flexibility. Yet, improvements in flexibility are not related to improvements in balance.

OBJECTIVE: The aim of this study was to evaluate the vertical component of the ground reaction force, plantar pressure, contact area of the feet and double-support time using static and dynamic (gait) baropodometry before and after bariatric surgery. METHODS: Sixteen individuals with a body mass index of between 35 and 55 were evaluated before and after bariatric surgery. Thirteen patients (81.3%) were female and three (18.8%) male and their average age was 46±10 (21-60) years. An FSCAN system (version 3848) was used for baropodometric analyses (1 km/h and 3 km/h). The peak plantar pressure and ground reaction force were measured for the rear foot and forefoot. The double-support time and foot contact area were measured during gait. RESULTS: There were reductions in the ground reaction force in the forefoot and rear foot and in the foot contact area in all evaluations and of the double-support time at 3 km/h, as well as a significant reduction in the body mass index at six months post-surgery. The peak pressure did not vary at 1 km/h and at 3 km/h, reductions in peak pressure were observed in the left and right rear feet and left forefoot. CONCLUSIONS: Weight loss after bariatric surgery resulted in decreases in the ground reaction force and contact area of the foot. Plantar pressure was decreased at 3 km/h, especially in the forefoot. There was an increase in rhythm because of a reduction in the double-support time at 3 km/h.

OBJECTIVES: To analyze muscle strength and exercise intensity adaptation to resistance training in older women with knee osteoarthritis and total knee arthroplasty. METHODS: Twenty-three community-dwelling women were divided into the following groups: older, with knee osteoarthritis and total knee arthroplasty in the contralateral limb (OKG; N= 7); older, without symptomatic osteoarthritis (OG; N= 8); and young and healthy (YG; N= 8). Muscle strength (1-repetition maximum strength test) and exercise intensity progression (workload increases of 5%-10% were made whenever adaptation occurred) were compared before and after 13 weeks of a twice-weekly progressive resistance-training program. RESULTS: At baseline, OKG subjects displayed lower muscle strength than those in both the OG and YG. Among OKG subjects, baseline muscle strength was lower in the osteoarthritic leg than in the total arthroplasty leg. Muscle strength improved significantly during follow-up in all groups; however, greater increases were observed in the osteoarthritic leg than in the total knee arthroplasty leg in OKG subjects. Greater increases were also seen in the osteoarthritic leg of OKG than in OG and YG. The greater muscle strength increase in the osteoarthritic leg reduced the interleg difference in muscle strength in OKG subjects, and resulted in similar posttraining muscle strength between OKG and OG in two of the three exercises analyzed. Greater exercise intensity progression was also observed in OKG subjects than in both OG and YG subjects. CONCLUSIONS: OKG subjects displayed greater relative muscle strength increases (osteoarthritic leg) than subjects in the YG, and greater relative exercise intensity progression than subjects in both OG and YG. These results suggest that resistance training is an effective method to counteract the lower-extremity strength deficits reported in older women with knee osteoarthritis and total knee arthroplasty.