Estudos pregressos têm investigado causas e fatores de risco para quedas e incapacidade funcional em idosos. Porém, no que se refere a fatores biomecânicos envolvidos no desempenho funcional e controle postural, a contribuição dos grupos musculares proximais de quadril e de tronco ainda recebe pouca atenção. Assim, o objetivo deste estudo foi verificar a associação entre a função muscular dos abdutores e adutores do quadril e dos extensores e flexores do tronco com o desempenho do equilíbrio semi-estático e dinâmico e da funcionalidade de idosos independentes que vivem na comunidade. Métodos: oitenta e um idosos de ambos os sexos foram submetidos à avaliação do equilíbrio e da funcionalidade por meio dos testes: (1) marcha tandem sobre a plataforma de força Balance Master (Neurocom International Inc., Clackamas, OR) para obtenção das variáveis velocidade da marcha tandem e velocidade de oscilação corporal ao final da marcha tandem; e (2) testes clínicos de apoio unipodal e Timed Up and Go (TUG). Também foram submetidos à avaliação da função muscular em dinamômetro isocinético (Biodex System 4 Pro, Nova York, EUA) por meio de 3 contrações isométricas máximas de abdução e adução do quadril e flexão e extensão do tronco para obtenção das variáveis pico de torque (PT) e taxa de desenvolvimento de força (TDF) proporcionais ao peso corporal. Após aplicação do teste de normalidade de Shapiro-Wilk, foi realizado teste de correlação de Pearson (dados com distribuição normal) e de Spearman (dados com distribuição não-normal). Para aquelas variáveis com coeficiente de correlação significativo, foi aplicado teste de regressão linear para quantificar o índice de determinação (r2) da função muscular do quadril e tronco no equilíbrio e funcionalidade de idosos. Foi adotado nível de significância de 5% (p < 0,05). Resultados: houve correlação com índice de determinação significativo do PT dos grupos musculares do quadril e do tronco sobre o desempenho dos testes de equilíbrio e funcionalidade. Em relação à TDF, foi encontrada correlação com índice de determinação significativo da TDF de abdução de quadril e de extensão de tronco sobre a velocidade de oscilação ao final da marcha tandem e sobre o TUG e também da TDF de extensão de tronco sobre o apoio unipodal. Conclusões: esses 10 achados podem ser clinicamente relevantes considerando que (1) diferentes parâmetros da função muscular (como PT e TDF) apresentam diferentes estratégias de intervenção para seu aprimoramento e que (2) problemas de equilíbrio e/ou de funcionalidade em idosos podem estar associados com comprometimentos da TDF e do PT da musculatura proximal, os quais são parâmetros passíveis de intervenção. / Previous studies have investigated causes and risk factors for falls and functional disability in the elderly. However, regarding biomechanical factors involved in the functional performance and postural control, the contribution of the proximal muscle groups of the hip and trunk still receives little attention. The objective of this study was to assess the association between muscle function of hip abductors and adductors and trunk flexors and extensors muscles with the performance of static and dynamic balance and functionality of community-dwelling older adults. Methods: eighty-one elderly of both sexes underwent assessment of balance and functionality through: (1) tandem gait test on the Balance Master force platform (Neurocom International Inc., Clackamas, OR) to obtain the variable tandem gait speed and body sway velocity in the end of tandem gait; and (2) clinical tests of single-leg stance and Timed Up and Go (TUG). The participants also underwent assessment of muscle function in isokinetic dynamometer (Biodex System 4 Pro, New York, USA) through 3 maximal isometric contractions of abduction and adduction of the hip and flexion and extension of the trunk to obtain the variables peak torque (PT) and rate of force development (RFD) in proportion to body weight. The Shapiro-Wilk normality test was performed and then, Pearson correlation test (data with normal distribution) and Spearman (data with non-normal distribution) were applied. Linear regression test was applied to quantify the determination index (r2) of muscle function of the hip and trunk in balance and functionality of the elderly for those variables with significant correlation coefficient. It was adopted a significance level of 5% (p < 0.05). Results: there was correlation with a significant determination index of PT of muscle groups of the hip and trunk in the performance of balance and functionality tests. Regarding the RFD, it was found correlation with significant determination index of RFD of the hip abduction and trunk extension in the body sway velocity in the end of tandem gait and TUG; and of RFD of the trunk extension in single-leg stance. Conclusions: These findings may be clinically relevant considering that (1) different parameters of muscle function (such as PT and RDF) have different intervention strategies for their improvement and (2) problems of balance and / or functionality in the elderly may be 12 associated with impairments of RFD and PT of proximal muscles, which are parameters that can be treated.

O objetivo do presente estudo foi comparar os efeitos da manipulação da ordem dos exercícios de força e aeróbico durante o treinamento concorrente na hidroginástica sobre as variáveis neuromusculares e cardiorrespiratórias de mulheres jovens e pósmenopáusicas. No estudo I, 26 mulheres jovens (25,12 ± 2,94 anos) foram aleatoriamente divididas em dois grupos de treinamento: força-aeróbico (FA) (n=13) e aeróbico-força (AF) (n=13). Para o estudo II, 21 mulheres pós-menopáusicas (57,14 ± 2,43 anos) foram divididas, também aleatoriamente, em dois grupos: força-aeróbico (FA) (n=10) e aeróbico-força (AF) (n=11). Em ambos os estudos os sujeitos realizaram o treinamento concorrente no meio aquático, duas vezes na semana durante 12 semanas, executando ambos os tipos de exercícios (aeróbico e força) na mesma sessão de treinamento. O treinamento de força foi realizado com séries em máxima velocidade e o treinamento aeróbico foi executado na frequência cardíaca do segundo limiar ventilatório. Todas as variáveis foram avaliadas antes e após o período de treinamento. Para análise dos dados foi utilizado o teste ANOVA para medidas repetidas com fator grupo (α=0,05). No estudo I, com as mulheres jovens, houve um aumento significativo da força muscular dinâmica máxima, avaliada através do teste de 1 repetição máxima (1RM), de todos os grupos musculares analisados (flexão e extensão de cotovelos e joelhos) após o período de treinamento. O grupo FA apresentou maiores ganhos da força muscular dinâmica máxima dos extensores de joelho em comparação ao grupo AF (43,58 ± 14,00% vs. 27,01 ± 18,05%, respectivamente). Após o treinamento houve um aumento do pico de torque isométrico (PT), avaliado no dinamômetro Biodex, de todos os grupos musculares avaliados (exceção PT extensores de cotovelo), sem diferença entre os grupos FA e AF. Além disso, após o treinamento, houve um aumento significativo da taxa de produção máxima e em diferentes janelamentos (50, 100, 250 ms), durante a contração isométrica voluntária máxima (CIVM) de extensão de joelho, sem diferença entre os grupos FA e AF. Houve um aumento significativo da amplitude máxima isométrica do sinal eletromiográfico (EMG), após o treinamento, dos músculos bíceps braquial e vasto lateral, sem diferença entre os grupos FA e AF. Além disso, observou-se uma diminuição significativa da amplitude submáxima isométrica do sinal EMG dos músculos bíceps braquial em 40% da CIVM, do vasto lateral em 40 e 80% da CIVM e do reto femoral em 80% da CIVM, sem diferença entre os grupos FA e AF após as 12 semanas de treinamento. Após o treinamento, houve um aumento significativo da espessura muscular do bíceps braquial, braquial, vasto medial e reto femoral, sem diferença entre os grupos FA e AF. O percentual de ganho da espessura muscular do vasto lateral e vasto intermédio diferiu significativamente entre os grupos, com maiores ganhos para o grupo que treinou na ordem FA em comparação a ordem AF (vasto lateral: 10,00 ± 7,64% vs. 5,28 ± 3,42%, vasto intermédio: 11,58 ± 5,36% vs. 4,40 ± 3,77%, respectivamente). Para os saltos, após o treinamento, houve um aumento significativo da altura do countermovement jump, sem diferença entre os grupos FA e AF. Por fim, ainda em relação ao estudo I, após o treinamento, houve um aumento significativo do consumo de oxigênio de pico (VO2pico) e referente ao primeiro limiar ventilatório (VO2LV1), sem diferença entre os grupos FA e AF. No estudo II, com as mulheres pós-menopáusicas, após o treinamento, houve um aumento significativo da força muscular dinâmica máxima dos flexores e extensores de cotovelo, sem diferença entre os grupos FA e AF. Para o teste de 1RM de extensão de joelhos, foi observado que o grupo FA apresentou maiores ganhos de força em comparação ao grupo AF (34,62 ± 13,51% vs. 14,16 ± 13,68%). Após o treinamento, houve um aumento significativo do PT dos flexores e extensores de joelho, sem diferença entre os grupos FA e AF. Além disso, houve um aumento significativo da taxa de produção máxima e também nos diferentes janelamentos (50, 100, 250 ms), durante a CIVM de extensão de joelho, sem diferença entre os grupos FA e AF. Houve um aumento significativo da amplitude máxima isométrica do sinal EMG dos músculos vasto lateral e reto femoral, sem diferença entre os grupos FA e AF após 12 semanas de treinamento. Também houve uma diminuição significativa da amplitude submáxima isométrica do sinal EMG do músculo reto femoral em 40% da CIVM, sem diferença entre os grupos FA e AF após o treinamento. Após o treinamento, houve um aumento significativo da espessura muscular de todos os músculos analisados, sem diferença entre os grupos FA e AF (exceto reto femoral). Por fim, no estudo II, após o treinamento, houve um aumento significativo do consumo de oxigênio referente ao segundo limiar ventilatório (VO2LV2), sem diferença entre os grupos FA e AF. Em suma, a ordem exercícios de força seguidos dos exercícios aeróbicos otimizou os ganhos de força muscular dinâmica máxima dos extensores de joelho tanto em mulheres jovens quanto em mulheres pós-menopáusicas, bem como a espessura muscular do quadríceps em mulheres jovens quando comparada com a ordem inversa (aeróbico-força). / The aim of the present study was to compare the effects of the intra-session exercise order (i.e., resistance-aerobic or aerobic-resistance) during water-based concurrent training on the neuromuscular and cardiorespiratory variables in young and postmenopausal women. Twenty-six young women (25.12 ± 2.94 years) were randomly assigned into two groups in study I: resistance-aerobic (RA) (n=13) and aerobicresistance (n=13). For study II, twenty-one postmenopausal women were also randomly assigned into two groups: resistance-aerobic (RA) (n=10) and aerobic-resistance (n=11). In both studies the subjects performed the water-based concurrent training two times a week during 12 weeks, performing both resistance and aerobic training in the same session. The resistance training was performed with sets at maximal effort and the aerobic training with exercises at heart rate corresponding to the second ventilatory threshold. All variables were evaluated before and after training. A repeated measure ANOVA with group factor was used to analyze the data of the present study (α=0.05). After training in study I, with the young women, there was a significant increase in the maximal dynamic strength in all muscle groups (elbow and knee flexors and extensors) evaluated using the one-repetition maximal test (1RM). The RA group presented grater relative gains of the knee extensors maximal dynamic strength compared to the AR group (43.58 ± 14.00% vs. 27.01 ± 18.05%, respectively). After training there was a significant increase of the maximal isometric peak torque (PT) of all muscle groups (except elbow extensor PT) evaluated using the Biodex dynamometer, with no difference between RA and AR groups. In addition, after training there was a significant increase of the maximal rate of force development (RFD) and of the RFD at different windows (50, 100, 250 ms) during the knee extension maximal isometric voluntary contraction (MIVC), with no difference between RA and AR groups. There was a significant increase of the maximal isometric electromyography (EMG) activity of biceps brachii and vastus lateralis after training, with no difference between RA and AR groups. Moreover, the submaximal isometric EMG activity of biceps braachi at 40% of MIVC, the submaximal isometric EMG activity of vastus lateralis at 40% and 80% of MIVC and the submaximal isometric EMG activity of rectus femoris at 80% of MIVC showed lower values after training, with no difference between RA and AR groups. After training, there was a significant increase of the muscle thickness of biceps brachii, brachialis, vastus medialis and rectus femoris, with no difference between RA and AR groups. The relative gains of the muscle thickness of the vastus lateralis and vastus intermedius were greater for the RA group compared to the AR group (vastus lateralis: 10.00 ± 7.64% vs. 5.28 ± 3.42%, vastus intermedius: 11.58 ± 5.36% vs. 4.40 ± 3.77%, respectively). The height of the countermovement jump improved after training, with no difference between RA and AR groups. In addition, the peak oxygen uptake (VO2peak) and corresponding to the first ventilatory threshold (VO2VT1) showed significant increases after training, with no difference between RA and AR groups. In study II, with the postmenopausal women, there was a significant increase in the maximal dynamic strength of the elbow flexors and extensors, with no difference between RA and AR groups. The knee extensors 1RM in the RA group showed greater increases than the AR group (34.62 ± 13.51% vs. 14.16 ± 13.68%). After training, there were significant increases of the knee flexors and extensors PT, with no difference between RA and AR groups. In addition, there was a significant increase in the knee extension maximal RFD and in the knee extension RFD at different windows (50, 100, 250 ms), with no difference between RA and AR groups. Moreover, there were increases of the maximal isometric EMG activity of vastus lateralis and rectus femoris, with no difference between RA and AR groups. Furthermore, the submaximal isometric EMG activity of rectus femoris at 40% of MIVC showed lower values after training, with no difference between RA and AR groups. Also, there were significant increases of the muscle thickness of all muscles evaluated, with no difference between RA and AR groups (except rectus femoris). Significant increase was also observed in the oxygen uptake corresponding to the second ventilatory threshold (VO2VT2) after training, with no difference between RA and AR groups. In summary, the intra-session exercise order with resistance exercises prior to aerobic exercises optimizes the knee extensors maximal dynamic strength gains in young and postmenopausal women, as well as the quadriceps femoris muscle thickness in young women when compared to the inverse order (i.e., aerobic-resistance).

No description available.

Monitoring tests are commonly used to assess weightlifter’s preparedness for competition. Although various monitoring tests have been used, it is not clear which test is the strongest indicator of weightlifting performance. Therefore, the purpose of this study was to (1) determine the relationships between vertical jump, isometric mid-thigh pull (IMTP) and weightlifting performance; and (2) compare vertical jumps to IMTP as monitoring tests of weightlifting performance in a large cohort of male and female weightlifters. Methods: Fifty-two competitive weightlifters (31 males, 21 females) participated in squat and countermovement jump testing (SJ, CMJ), and IMTP testing performed on force plates. All laboratory testing data was correlated to a recent competition where the athletes had attempted to peak. Results: Squat jump height (SJH) was the strongest correlate for men and women with the Sinclair Total (r = 0.686, p ≤ 0.01; r = 0.487, p ≤ 0.05, respectively) compared to countermovement jump height (r = 0.642, p ≤ 0.01; r = 0.413, p = 0.063), IMTP peak force allometrically scaled to body mass (r = 0.542, p ≤ 0.01; r = −0.044, p = 0.851) and rate of force development at 200 ms (r = 0.066, p = 0.723; r = 0.086, p = 0.711), respectively. Further, SJH was a stronger correlate of relative weightlifting performance compared to IMTP peak force in females (p = 0.042), but not male weightlifters (p = 0.191). Conclusions: Although CMJ and IMTP are still considered strong indicators of weightlifting performance, SJH appears to be the most indicative measure of weightlifting performance across a wide-range of performance levels. Thus, SJH can be used as a reliable measure to monitor weightlifting performance in male and female weightlifters.

Certain variables: peak aerobic power (PAP), running economy, and lactate threshold, act as limiting factors for endurance running. However, all of the mechanisms underlying high-level endurance running are not completely clear. Alterations in maximum and explosive strength P27 have been shown to effect positive changes in endurance performance, likely by altering P28 running economy. If strength related factors affect running economy, then this should be evident in the running performance of long-distance runners and perhaps PAP. The purpose of this study was to examine the relationships between peak isometric strength (IPF), explosive strength (rate of force development, RFD), PAP and 3 k performance (3KT) among 5 female and 7 male (n = 12) X-country runners. Force-time curve analysis was conducted for each (2 trials) isometric pull and averaged for analyses. IPF and RFD from 0 - 200 ms were determined from appropriate curves. IPFs were normalized using an allometric (IPFa) scaling equation: absolute force/ (body mass (kg)0.67). ICCs were previously shown to be > 0.9. Relationships were established with Pearson's r; statistical differences with at-Test (p < 0.05). !PF, IPFa and RFD were not different between sexes. PAP was statistically greater in males. Correlations were: PAP vs 3KT (r = -0.92); !PF vs PAP (r = 0.58), 3KT (r = -0.66); IPFa vs PAP (r = 0.45), 3KT (r = 0.45). RFD vs PAP (r = 0.58), 3KT (r = -0.65). Results indicate that strength characteristics correlate moderately to strongly with PAP and 3KT. Data suggests that strong.

Explosive strength, a function of rate of force development (RFD), is a primary determinant for the amount of peak force that can be produced in critical sport performance time periods ( e.g. foot contact time). Evidence indicates that maximum strength and RFD are correlated. However, the characteristics of this relationship are not well established among athletes. This study examined the relationship of peak isometric force (IPF) and RFD from a mid-thigh pull, among male and female track and field athletes. Athletes were 12 sprinters (S), 10 jumpers (JP) and 12 cross-country runners (XC). Force-time curve analysis was conducted for each (2 trials) isometric pull and averaged for analyses. IPF and RFD from 0 - 200 ms were determined from appropriate curves. IPFs were normalized using an allometric (IPFa) scaling equation: absolute force/ (body mass (kg)0.67). ICCs were previously shown to be > 0.9. Relationships were established with Pearson's r; statistical differences with a Bonferroni adjusted t-Test. IPF, IPFa and RFD were greater in males than females for S and JP but not for XC. IPF, IPFa and RFD were greater for S and JP compared to XC. Similar relationships of IPF to RFD were noted among groups S(r = 0.85), JP (r = 0.87), XC (r = 0.88). Among males, n = 19, the relationship ofIPF to RFD was r = 0.89 and was somewhat higher compared to females, n = 15, (r = 0.78). Overall (n = 34) relationship between IPF and RFD was r = 0.90. These data indicate a strong relationship between maximum strength and "explosiveness" that is independent.

The purpose of this monitoring study was to investigate how alterations in training affect changes in force-related characteristics and weightlifting performance. Subjects: Seven competitive weightlifters participated in the study. Methods: The weightlifters performed a block style periodized plan across 20 weeks. Force plate data from the isometric mid-thigh pull and static jumps with 0 kg, 11 kg, and 20 kg were collected near the end of each training block (weeks 1, 6, 10, 13, 17, and 20). Weightlifting performance was measured at weeks 0, 7, 11, and 20. Results: Very strong correlations were noted between weightlifting performances and isometric rate of force development (RFD), isometric peak force (PF), peak power (PP), and jump height (JH). Men responded in a more predictable manner than the women. During periods of higher training volume, RFD was depressed to a greater extent than PF. JH at 20 kg responded in a manner reflecting the expected fatigue response more so than JH at 0 kg and 11 kg. Conclusions: PF appears to have been more resistant to volume alterations than RFD and JH at 20 kg. RFD and JH at 20 kg appear to be superior monitoring metrics due to their “sensitivity.”

Le conflit fémoro-acétabulaire (femoroacetabular impingement, FAI) est une pathologie mécanique de la hanche qui peut causer des douleurs et limitations fonctionnelles. Le but de cette thèse était d’étudier la fonction musculaire au niveau de la hanche chez des patients présentant un FAI symptomatique. La fonction musculaire de la hanche a été évaluée, dans un premier temps, chez des patients avant qu’ils ne subissent une opération. Ces patients démontraient un déficit de force qui pourrait être expliqué par de l’inhibition musculaire. Cependant, ce déficit de force n’était pas associé à une plus grande fatigabilité musculaire. Dans un deuxième temps, les altérations de force musculaire ont été évaluées chez des patients ayant subi une arthroscopie de la hanche. Après l’opération, les patients récupéraient un niveau de force normal au niveau de tous les groupes musculaires de la hanche excepté les fléchisseurs. Le cas d’un joueur de hockey sur glace ayant subi une chirurgie ouverte aux deux hanches pour traiter un FAI bilatéral a aussi été décrit. On a démontré que la déhiscence de la bandelette iléo-tibiale pouvait survenir après chirurgie, empêcher l’augmentation de force musculaire des abducteurs de la hanche, et retarder la reprise du sport. Enfin, un protocole d’évaluation du taux de développement de la force normalisé, variable permettant d’estimer l’inhibition musculaire de la hanche, a été proposé chez des sujets sains. La fiabilité et reproductibilité des résultats ont été montrées au niveau des adducteurs, rotateurs externes, et fléchisseurs de la hanche. Ces résultats montrent que ces patients ont une fonction musculaire altérée au niveau de la hanche, qui est toutefois récupéré après une opération. / Femoroacetabular impingement (FAI) is a pathomechanical process of the hip joint, which could lead to hip pain and functional disability. Aim of this thesis was to investigate hip muscle function in patients with a symptomatic FAI. Hip muscle function was first investigated before patients underwent any surgical treatment for managing FAI. It was shown that they present with reduced hip muscle strength (i.e., muscle weakness), probably due to hip muscle inhibition. Nevertheless, hip muscle weakness was not associated with exaggerated hip muscle fatigue. Hip muscle strength recovery was then evaluated in a series of patients after hip arthroscopy to treat FAI. These patients demonstrated a good recovery for all hip muscle groups, except for hip flexors. The case of a professional ice hockey player who underwent bilateral hip open surgeries for treating bilateral FAI was also documented. This report showed that iliotibial band dehiscence could occur after hip open surgery, thereby preventing hip abductor strength increase during rehabilitation and delaying the return to sport. In addition, the assessment of the rate of force development scaling factor for the hip muscles was evaluated in a group of healthy adults. This parameter seems to be promising for the evaluation of hip muscle inhibition. The testing protocol was feasible and reproducible for hip adductors, external rotators and flexors. Taken as a whole, these findings show that patients with symptomatic FAI demonstrate an impaired hip muscle function, which is however mainly resolved after surgical treatment.

No description available.

No description available.