Simulation analysis of low back forces in Snatch and Clean & Jerk movements via digital human modelling.

BACKGROUND: Weightlifting is an Olympic sport for dynamic strength and power, and requires the execution of different lifting techniques It is important to analyze the forces subjected to the lower back during weightlifting movements to prevent injuries. Digital Human Modeling (DHM) is a powerful tool that can be used to analyze and optimize the performance of humans while doing their work or activities. OBJECTIVE: The purpose of this study is to present a simulation analysis of the lower back forces during the execution of two weightlifting techniques: Snatch (SN) and Clean & Jerk (CJ), with different loads and for both genders. METHODS: Digital Human modelling through JACK simulation package was used analyze the forces exerted on the lumbosacral area (L5-S1) of the lower back in order to determine the risk for low back injuries. The level of compression and shear forces recommended by the literature have been set as thresholds. The simulaitons were performed in male and female models, with loads from 20-100 kg. RESULTS: The results show that any weight higher than 60 kg in both movements poses risk for the weightlifters in terms of compression and shear forces. It has been observed that weightlifters can lift greater loads in the CJ technique compared to the SN technique. Furthermore, females are able to lift higher loads with lower risk of injuries. CONCLUSION: Weightlifting is a high-risk activity due to the high levels of shear and compression forces that the body is exposed to during the lifting techniques. Digital Human Modeling holds significant value due to their ability to facilitate the exploration of diverse conditions within a safe environment, devoid of any potential harm to human subjects.

Evaluation of Reaction Time during the One-Leg Balance Activity in Young Soccer Players: A Pilot Study.

This study's aim was two-fold: (i) to test the intra-session reliability of the one-leg balance activity test; and (ii) to assess the influence of age on reaction time (RT) and the differences between dominant and non-dominant feet. Fifty young soccer players with an average age of 12.4 ± 1.8 years were divided into two groups: younger soccer players (n = 26; 11.6 ± 0.9 years) and older soccer players (n = 24; 14.2 ± 0.8 years). Each group then completed four trials (two with each leg) of the one-leg balance activity (OLBA) to evaluate RT under a single-leg stance. Mean RT and the number of hits were calculated, and the best trial was also selected. T-tests and Pearson correlations were performed for statistical analysis. Values for RT were lower, and the number of hits was higher while standing on the non-dominant foot (p = 0.01). MANOVA revealed that the "Dominant Leg" factor did not affect the multivariate composite (Pillai Trace = 0.05; F(4, 43) = 0.565; p = 0.689; Partial ETA Squared = 0.050; Observed Power = 0.174). The "Age" factor did not present an effect on the multivariate composite (Pillai Trace = 0.104; F(4, 43) = 1.243; p = 0.307; Partial ETA Squared = 0.104; Observed Power = 0.355). The results of the present investigation demonstrate that RT may be lower while standing on the non-dominant foot.

Intra-abdominal transmissible venereal tumor in a dog: a case report.

Transmissible venereal tumor (TVT) is a malignant round cell neoplasm that primarily affects the genital region of dogs. Despite being sexually transmitted, transmission can occur through contact with mucous membranes and cutaneous tissue. Although less routine, TVT has been described in several extragenital regions, such as the nasal plane, oral cavity, eyeball, eyelid, and anus. Although metastases are infrequent, they can occur in the skin, inguinal lymph nodes, liver, kidneys, spleen, intestine, heart, brain, lungs, and other organs. The clinical signs of TVT are usually related to serosanguineous secretion, intense odor, deformity, ulceration, and possibly areas of necrosis. In cases of metastases, clinical signs will depend on the affected organ. The treatment of choice for TVT is chemotherapy with vincristine. The present study aimed to report the case of a 2-year-old mixed-breed canine with intra-abdominal nodules detected by ultrasound examination, which were later diagnosed as a TVT by histopathology and immunohistochemistry.

O tumor venéreo transmissível (TVT) é uma neoplasia maligna de células redondas que acomete principalmente a região genital de cães. Apesar de ser sexualmente transmissível, a transmissão pode ocorrer através do contato com mucosas e tecidos da pele. Embora menos rotineiro, o TVT tem sido descrito em diversas regiões extragenitais, como plano nasal, cavidade oral, globo ocular, pálpebra e ânus. Embora as metástases sejam infrequentes, elas podem ocorrer na pele, linfonodos inguinais, fígado, rins, baço, intestino, coração, cérebro, pulmão e outros órgãos. Os sinais clínicos do TVT geralmente estão relacionados à secreção serossanguinolenta, odor intenso, deformidade, ulceração, podendo ou não haver áreas de necrose e, nos casos de metástases, os sinais clínicos vão depender do órgão acometido. O tratamento de escolha para TVT é a quimioterapia, com uso de vincristina. O presente trabalho tem como objetivo relatar o caso de um canino de dois anos de idade, sem raça definida, com nódulos intra-abdominais detectados ao exame ultrassonográfico, que posteriormente foram diagnosticados como tumor venéreo transmissível por meio de histopatologia e imunohistoquímica.

Physical Activity Time and Intensity in Physical Education During the COVID-19 Pandemic.

With the COVID-19 outbreak, schools have experienced difficulty providing moderate-to-vigorous physical activity (MVPA) to their students, which should normally account for at least 50% of children's physical education (PE) class time. We aimed to determine the intensity of physical activity (PA) within PE classes at various grade levels to compare children's in-class PA with the World Health Organization's (WHO) recommended guidelines. Thus, 301 students (1st to 12th grade) participated in the investigation. Children were evaluated during the PE classes with different typologies and durations. We assessed PA intensity using accelerometry and grouped data into either sedentary-to-light PA (SEDLI) or MVPA. Each child was assessed using both the time spent in PA (hours:minutes:seconds) and the percentage of time spent in PA versus other class activities. We found that, in the second-grade level group (fifth and sixth grades), girls spent more time in MVPA intensity than boys. Additionally, two-hour PE classes doubled the SEDLI for students in the third-grade group, and polythematic classes (those with more than one sport) promoted more MVPA level time than monothematic classes (only one sport). Concerning PA intensity during PE classes, 31-43% of the PE class total time was spent in MVPA but presented short duration and did not usually persist for 10 consecutive minutes (59% of the time). Children spent a large amount of time at the SEDLI intensity, considered insufficient for PA health benefits. Finally, to meet WHO guidelines for PA intensity, PE classes will need to increase MVPA time and reduce non-active periods between activities.

Comparison of Four Classroom-Based Strategies for Middle School Students With ADHD: A Pilot Randomized Controlled Trial.

Middle school students with ADHD often experience negative academic outcomes. To intervene, schools frequently provide services through special education or section 504. These services include strategies, such as breaks, prompting, and sensory proprioception to remove the impact of construct-irrelevant variance. Student plans rarely include strategies, such as selfmanagement, designed to teach students skills to increase independent functioning. The purpose of this study was to compare the effectiveness of four strategies on engagement, disruptive behavior, and time to initiate tasks. Fifteen sixth and seventh grade students were randomized daily to one of four conditions. Results indicated large statistically significant differences. Social validity data indicated that students found prompting and self-management helpful, but preferred breaks and sensory proprioception. This study builds on a growing empirical base that supports the prioritization of strategies to teach skills over strategies to remove the impact of ADHD on performance.

Can increased load carriage affect lower limbs kinematics during military gait?

The aim of this study was to investigate if increased load carriage, in male military personnel, can affect the lower limbs kinematics. Twelve male military volunteers from the Portuguese Army were recruited and evaluated in an unloaded and loaded gait condition. Linear kinematics and lower limbs joint angle at heel strike, midstance and toe off were calculated. The stance, swing and double support times were found to be different between load conditions (p < 0.05). There was an interaction between load and limb (p < 0.05) for joint angles, during midstance, with limbs performing different movements in the frontal plane during loaded gait. Load increase had a different effect on the right knee, with a reduction in the abduction (valgus). This study may be beneficial in offering suggestion to improve the performance of gait with load and in an attempt to help prevent possible injuries. Practitioner summary: Increased load can affect lower limbs of male soldiers at the pelvic, hip and knee angles on the frontal plane, which can alter the joint force distribution. While these alterations may indicate protective mechanics, load management procedures should be implemented along with gait monitoring to avoid negative effects in performance.

Assessing Post-Driving Discomfort and Its Influence on Gait Patterns.

Professional drivers need constant attention during long driving periods and sometimes perform tasks outside the truck. Driving discomfort may justify inattention, but it does not explain post-driving accidents outside the vehicle. This study aims to study the discomfort developed during driving by analysing modified preferred postures, pressure applied at the interface with the seat, and changes in pre- and post-driving gait patterns. Each of the forty-four volunteers drove for two hours in a driving simulator. Based on the walking speed changes between the two gait cycles, three homogeneous study groups were identified. Two groups performed faster speeds, while one reduced it in the post-steering gait. While driving, the pressure at the interface and the area covered over the seat increased throughout the sample. Preferred driving postures differed between groups. No statistical differences were found between the groups in the angles between the segments (flexed and extended). Long-time driving develops local or whole-body discomfort, increasing interface pressure over time. While driving, drivers try to compensate by modifying their posture. After long steering periods, a change in gait patterns can be observed. These behaviours may result from the difficulties imposed on blood circulation by increasing pressure at this interface.

Carnauba wax uses in food - A review.

Carnauba wax is widely used in food, due to its physico-chemical characteristics with a predominance of esters and inert and stable components. Even with so many possibilities for the use of carnauba wax in food, there are still a large number of researchers around the world searching for new applications and a demand for new products with new technologies to improve existing ones. Recently, many parts of research which focus on the use of this wax in conservation and food processing have been carried out, some of which highlight the role of this wax in the microencapsulation of flavours, in preparing edible films and super hydrophobic and biodegradable packaging. This paper discusses the use of carnauba wax in food, including the extraction process of the wax, its chemical and physical characteristics, safety aspects, national and international law and permitted uses, along with the presentation of the main scientific research conducted.

Screening for diabetes in pharmaceutical professionals in the State of Mato Grosso do Sul / Rastreamento para diabetes em profissionais farmacêuticos do Estado de Mato Grosso do Sul

Type 2 diabetes mellitus (T2DM) is a metabolic disease characterized by chronic hyperglycemia resulting from thesecretion or deficient action of insulin, accounting for more than 90% of the cases of diabetes and is associated withmacro and microvascular complications that are among the main causes of morbidity and total or partial disability in the21st century. The objective of this study was to perform the screening for T2DM in pharmaceutical professionals fromthe State of Mato Grosso do Sul (MS), Brazil. This was a descriptive study with a cross-sectional design and a quantitativeapproach, carried out with pharmacists from seven municipalities in the State of São Paulo, from March 2017 to June2018. The method used to track T2DM was the self-application of the Finnish Diabetes Risk Score (FINDRISC) instrument,which incorporates the following variables: age, BMI, waist circumference, hypertension, physical activity, diet, familyhistory of diabetes and history of glucose intolerance. One hundred and fifty-three pharmacists were included in thestudy. Of these, 127 (83.0%) were female. Considering the results of the FINDRISC instrument, 9.8%, 13.1%, 25.5%and 51.6% demonstrated high, moderate, slight and low risk, respectively, of T2DM development within the next 10years. The results indicated that approximately half (n=74; 48.4%) of the evaluated professionals demonstrated a risk ofdeveloping T2DM above the low risk classification. It is worth emphasizing the contributions of the study which orientthe pharmacists related to the possibility of altering the modifiable risk factors identified in order to significantly reduce their risk of developing T2DM

O diabetes mellitus tipo 2 (DM2) é uma doença metabólica caracterizada por hiperglicemia crônica, resultante dasecreção ou ação deficitária da insulina, sendo responsável por mais de 90% dos casos de diabetes e associado acomplicações macro e microvasculares que estão entre as principais causas de morbidade e incapacidade total ouparcial no século XXI. O objetivo deste estudo foi realizar o rastreamento para o DM2 em profissionais farmacêuticosdo Estado de Mato Grosso do Sul (MS), Brasil. Tratou-se de um estudo descritivo com desenho transversal e abordagemquantitativa, realizado com farmacêuticos de sete municípios do Estado de MS, no período de março de 2017 a junhode 2018. O método utilizado para o rastreamento do DM2 foi a autoaplicação do instrumento Finnish Diabetes RiskScore (FINDRISC), que incorpora as seguintes variáveis: idade, IMC, circunferência abdominal, hipertensão, atividadefísica, dieta, história familiar de diabetes e história de intolerância à glicose. Cento e cinquenta e três farmacêuticosforam incluídos no estudo. Desses, 127 (83,0%) eram do sexo feminino. Considerando os resultados do instrumentoFINDRISC, 9,8%, 13,1%, 25,5% e 51,6% apresentaram alto, moderado, pouco elevado e baixo risco, respectivamente,de desenvolvimento de DM2 nos próximos 10 anos. Os resultados apontaram que aproximadamente metade (n=74;48,4%) dos profissionais avaliados apresentou risco de desenvolver DM2 acima da classificação de baixo risco.Ressaltam-se, ainda, as contribuições deste estudo na orientação dos profissionais relacionadas à possibilidade dealteração dos fatores de risco modificáveis, a fim de reduzir de forma significativa o risco de desenvolvimento de DM2

Principal component analysis in ground reaction forces and center of pressure gait waveforms of people with transfemoral amputation.

BACKGROUND: The alterations in gait pattern of people with transfemoral amputation leave them more susceptible to musculoskeletal injury. Principal component analysis is a method that reduces the amount of gait data and allows analyzing the entire waveform. OBJECTIVES: To use the principal component analysis to compare the ground reaction force and center of pressure displacement waveforms obtained during gait between able-bodied subjects and both limbs of individuals with transfemoral amputation. STUDY DESIGN: This is a transversal study with a convenience sample. METHODS: We used a force plate and pressure plate to record the anterior-posterior, medial-lateral and vertical ground reaction force, and anterior-posterior and medial-lateral center of pressure positions of 12 participants with transfemoral amputation and 20 able-bodied subjects during gait. The principal component analysis was performed to compare the gait waveforms between the participants with transfemoral amputation and the able-bodied individuals. RESULTS: The principal component analysis model explained between 74% and 93% of the data variance. In all ground reaction force and center of pressure waveforms relevant portions were identified; and always at least one principal component presented scores statistically different (p < 0.05) between the groups of participants in these relevant portions. CONCLUSION: Principal component analysis was able to discriminate many portions of the stance phase between both lower limbs of people with transfemoral amputation compared to the able-bodied participants. CLINICAL RELEVANCE: Principal component analysis reduced the amount of data, allowed analyzing the whole waveform, and identified specific sub-phases of gait that were different between the groups. Therefore, this approach seems to be a powerful tool to be used in gait evaluation and following the rehabilitation status of people with transfemoral amputation.

Identification and Quantification of Oxidoselina-1,3,7(11)-Trien-8-One and Cyanidin-3-Glucoside as One of the Major Volatile and Non-Volatile Low-Molecular-Weight Constituents in Pitanga Pulp.

The pulp of pitanga (Eugenia uniflora L.) is used to prepare pitanga juice. However, there are no reports on the identification and quantification of the main constituents in pitanga pulp. The aim of this study was to identify and quantify the major volatile and non-volatile low-molecular-weight constituents of the pulp. Isolation of volatile compounds was performed by solvent-assisted flavor evaporation technique. Characterization of the main volatile and non-volatile constituents was performed by GC-MS, LC-MS and NMR spectroscopy. For quantitative measurements, the main volatile compound needed to be isolated from pitanga pulp to obtain a commercially not available reference standard. Cyanidin-3-glucoside was determined as one of the most abundant non-volatile pulp compound yielding 53.8% of the sum of the intensities of all ions detected by LC-MS. Quantification of cyanidin-3-glucoside in pitanga pulp resulted in a concentration of 344 ± 66.4 µg/mL corresponding to 688 ± 133 µg/g dried pulp and 530 ± 102 µg/g fruit. For the volatile fraction, oxidoselina-1,3,7(11)-trien-8-one was identified as the main volatile pulp constituent (27.7% of the sum of the intensities of all ions detected by GC-MS), reaching a concentration of 89.0 ± 16.9 µg/mL corresponding to 1.34 ± 0.25 µg/g fresh pulp and 1.03 ± 0.19 µg/g fruit. The results provide quantitative evidence for the occurrence of an anthocyanin and an oxygenated sesquiterpene as one of the major volatile and non-volatile low-molecular-weight compounds in pitanga pulp.

Influence of wedges on lower limbs' kinematics and net joint moments during healthy elderly gait using principal component analysis.

The elderly are susceptible to many disorders that alter the gait pattern and could lead to falls and reduction of mobility. One of the most applied therapeutical approaches to correct altered gait patterns is the insertion of insoles. Principal Component Analysis (PCA) is a powerful method used to reduce redundant information and it allows the comparison of the complete waveform. The purpose of this study was to verify the influence of wedges on lower limbs' net joint moment and range of motion (ROM) during the gait of healthy elderly participants using PCA. In addition, discrete values of lower limbs' peak net moment and ROM were also evaluated. 20 subjects walked with no wedges (control condition) and wearing six different wedges. The variables analyzed were the Principal Components from joint net moments and ROM in the sagittal plane in the ankle and knee and joint net moments in frontal plane in the knee. The discrete variables were peak joint net moments and ROM in sagittal plane in knee and ankle. The results showed the influence of the wedges to be clearer by analyzing through PCA methods than to use discrete parameters of gait curves, where the differences between conditions could be hidden.

Pitanga (Eugenia uniflora L.) fruit juice and two major constituents thereof exhibit anti-inflammatory properties in human gingival and oral gum epithelial cells.

Pitanga, Eugenia uniflora L., is a tropical fruit, which may be consumed as juice. While beneficial health effects of Eugenia uniflora L. leaf extracts have extensively been studied, limited data are available on an anti-inflammatory potential of pitanga juice. The aim of the presented study was to investigate anti-inflammatory properties of pitanga juice with regards to a prevention of inflammation-related periodontal diseases. For this purpose, six healthy volunteers swirled pitanga juice, containing 35% pitanga pulp, for 10 min. Thereafter, oral gum epithelial cells were harvested using a sterile brush and stimulated with lipopolysaccharides from Porphyromonas gingivalis (PG-LPS) for 6 h. Furthermore, human gingival fibroblasts (HGF-1) were used to elucidate the anti-inflammatory potential of pitanga juice constituents, cyanidin-3-glucoside and oxidoselina-1,3,7(11)-trien-8-one, in juice representative concentrations of 119 µg ml(-1) and 30 µg ml(-1), respectively. For the first time, an anti-inflammatory impact of pitanga juice on gingival epithelial cells was shown by means of an attenuation of IL-8 release by 55 ± 8.2% and 52 ± 11% in non-stimulated and PG-LPS-stimulated cells, respectively. In addition, both cyanidin-3-glucoside and oxidoselina-1,3,7(11)-trien-8-one reduced the LPS-stimulated CXCL8 mRNA expression by 50 ± 15% and 37 ± 18% and IL-8 release by 52 ± 9.9% and 45 ± 3.7% in HGF-1 cells, when concomitantly incubated with 10 µg ml(-1)PG-LPS for 6 h, revealing an anti-inflammatory potential of the volatile compound oxidoselina-1,3,7(11)-trien-8-one for the first time.

In vitro bioaccessibility of copper, iron, zinc and antioxidant compounds of whole cashew apple juice and cashew apple fibre (Anacardium occidentale L.) following simulated gastro-intestinal digestion.

Considering the lack of research studies about nutrients' bioaccessibility in cashew apple, in this study the whole cashew apple juice and the cashew apple fibre were submitted to simulated in vitro gastrointestinal digestion. The samples were analysed before and after digestion and had their copper, iron, zinc, ascorbic acid, total extractable phenols and total antioxidant activity assessed. As a result, for the whole cashew apple juice, the content of copper and iron minerals bioaccessible fraction were 15% and 11.5% and for zinc this level was 3.7%. Regarding the cashew apple fibre, the bioaccessible fraction for these minerals was lower than 5%. The ascorbic acid, total extractable polyphenols and total antioxidant activity bioaccessible fraction for whole cashew apple juice showed bioaccessibility percentages of 26.2%, 39% and 27%, respectively, while for the cashew apple fibre, low bioaccessibles levels were found. The bioacessible percentage of zinc, ascorbic acid and total extractable polyphenols were higher in cashew apple juice than cashew apple fibre.

Accuracy and repeatability of the gait analysis by the WalkinSense system.

WalkinSense is a new device designed to monitor walking. The aim of this study was to measure the accuracy and repeatability of the gait analysis performed by the WalkinSense system. Descriptions of values recorded by WalkinSense depicting typical gait in adults are also presented. A bench experiment using the Trublu calibration device was conducted to statically test the WalkinSense. Following this, a dynamic test was carried out overlapping the WalkinSense and the Pedar insoles in 40 healthy participants during walking. Pressure peak, pressure peak time, pressure-time integral, and mean pressure at eight-foot regions were calculated. In the bench experiments, the repeatability (i) among the WalkinSense sensors (within), (ii) between two WalkinSense devices, and (iii) between the WalkinSense and the Trublu devices was excellent. In the dynamic tests, the repeatability of the WalkinSense (i) between stances in the same trial (within-trial) and (ii) between trials was also excellent (ICC > 0.90). When the eight-foot regions were analyzed separately, the within-trial and between-trials repeatability was good-to-excellent in 88% (ICC > 0.80) of the data and fair in 11%. In short, the data suggest that the WalkinSense has good-to-excellent levels of accuracy and repeatability for plantar pressure variables.

Plantar pressures and ground reaction forces during walking of individuals with unilateral transfemoral amputation.

OBJECTIVE: To describe and compare the plantar pressures, temporal foot roll-over, and ground reaction forces (GRFs) between both limbs of subjects with unilateral transfemoral amputation and with those of able-bodied participants during walking. We also verify the relevance of a force plate and a pressure plate to discriminate changes in gait parameters of subjects with limb loss. DESIGN: Cross-sectional study. SETTING: Biomechanics laboratory. SUBJECTS: A total of 14 subjects with unilateral transfemoral amputation and 21 able-bodied participants. METHODS: We used a force plate and a pressure plate to assess biomechanical gait parameters while the participants were walking at their self-selected gait speed. MAIN OUTCOME MEASUREMENTS: We measured plantar pressure peaks in 6 foot regions and the instant of their occurrence (temporal foot roll-over); and GRF peaks and impulses of anterior-posterior (braking and propulsive phases), medial-lateral, and vertical (load acceptance and thrust phases) components. RESULTS: The thrust, braking, and propulsive peaks, and the braking and propulsive impulses, were statistically significantly lower in the amputated limb than in the sound limb (P < .05) and in able-bodied participants (P < .05). In the amputated limb, we observed higher pressure peaks in the lateral rearfoot and medial and lateral midfoot, and lower values in the forefoot regions compared to those in the other groups (P < .05). The temporal foot roll-over showed statistically significant differences among the groups (P < .05). CONCLUSIONS: The plantar pressures, temporal foot roll-over, and GRFs in subjects with unilateral transfemoral amputation showed an asymmetric gait pattern, and different values were observed in both of their lower limbs as compared with those of able-bodied subjects during walking. The force plate and pressure plate were able to determine differences between participants in gait pattern, suggesting that both plantar pressure and GRF analyses are useful tools for gait assessment in individuals with unilateral transfemoral amputation. Because of the convenience of pressure plates, their use in the clinical context for prosthetic management appears relevant to guide the rehabilitation of subjects with lower limb amputation.

POLYPHENOLS AND ANTIOXIDANT ACTIVITY OF CASHEW NUTS FROM CONVENTIONAL AND ORGANIC CULTIVATION IN DIFFERENT STAGES OF PROCESSING

This research aimed to determine the total extractable polyphenols and the antioxidant activity of cashew nut obtained from conventional and organic cultivation. The study was performed with cashew nuts collected at four stages of processing: after shelling, before peeling, after peeling and during packaging. The antioxidant activity was measured by the methods with the radicals ABTS•+ and DPPH• and by the ß-carotene/linoleic acid system. The nuts collected in the steps after shelling and before peeling presented higher antioxidant activity than those collected after peeling and during packaging. Little variation occurred in the content of total extractable polyphenols and antioxidant activity by ABTS•+ and DPPH• assays between the two cultivation methods studied.

Characterization and antioxidant activity of cashew nut bran in different stages of processing

The present work aimed to characterize the cashew nut bran during several stages of processing, withemphasis in the quantifi cation of total extractable polyphenols and total antioxidant activity. The cashewnut bran was analyzed for the following parameters: water activity, total acidity, pH, moisture, ash, lipids,proteins, carbohydrates, total extractable polyphenolsand total antioxidant activity by the methods ABTS•+ and DPPH•. There was a decrease in the water activityand moisture in cashew nut bran during processing. The highest values of total extractable polyphenolsand antioxidant activity were observed in raw bran due to peel adhered in these nuts.

Cocontraction and economy of triathletes and cyclists at different cadences during cycling motion.

The purpose of this study was to compare the cycling technique of triathletes and cyclists on the basis of the cocontraction of selected muscles of the lower limbs and economy at different cadences. The economy (EC) and percent cocontraction from nine triathletes and eight cyclists were compared at 60, 75, 90 and 105 rpm cadences. Tests were performed on two separate days. The maximal oxygen uptake was measured and the second ventilatory threshold (VO(2VT)) was estimated on the first day using a stationary bicycle. On the second day the four different cadences were tested at approximately 5% below the VO(2VT). The EMG activity of the rectus femoris (RF), biceps femoris (BF) and vastus lateralis (VL) was recorded and the EMG signal was normalized using the 60 rpm dynamic contraction. The percent cocontractions were calculated from RF/BF and VL/BF muscles. The EC was also calculated. The results showed that cyclists were significantly more economic, indicating that they exerted more power with less VO(2), and presented significantly lower percent cocontraction than triathletes (p<0.05). Thus, the results suggest that the cyclists had a better technique than the triathletes. The simultaneous use of the percent cocontraction and economy seems to be a good performance indicator for cyclists and triathletes.

Effective force and economy of triathletes and cyclists.

The effective force applied on the crank, the index of pedalling effectiveness, and the economy of movement at 60, 75, 90, and 105 rev/min cadences were examined in nine cyclists and eight triathletes. Tests were performed on two days. Maximal oxygen uptake was measured and the second ventilatory threshold was estimated on day 1 using a stationary bicycle. On day 2, the four different cadences were tested at about 5% below the second ventilatory threshold. A strain gauge instrumented clip-less pedal mounted on the bicycle enabled us to measure the normal and tangential forces exerted on the pedal, while the pedal and crank angles were monitored with the aid of a video system. Based on this information, the effective force and the index of pedalling effectiveness were calculated. Cyclists produced significantly more effective force and a higher index of pedalling effectiveness at 60 and 75 rev/min and were significantly more economic at all cadences than triathletes. The significant and positive correlation between effective force and economy at all cadences suggests that improvement of the effective force would reflect on economy.