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1.
PLoS One ; 17(6): e0269103, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35700158

RESUMO

In older adults, the quantitative decline of the quadriceps femoris is associated with the augmentation of difficulty in the execution of a stand-up task. However, it is unclear whether the cross-sectional areas (CSAs) of individual thigh muscles differ between older adults who can stand up from a 40-cm-height chair on a single leg and those who cannot. To investigate this, the present study determined the CSAs of individual mid-thigh muscles in 67 Japanese women aged 60-77 years by using a magnetic resonance imaging method. Participants were asked to stand up from a 40-cm-height chair on a single leg, and those who could and could not stand up without leaning back and maintain a standing posture for 3 seconds on a single leg were allocated into the successful group (SG, n = 40) and unsuccessful group (USG, n = 27), respectively. Only the CSA of the adductors (sum of the adductor longus and adductor magnus) was significantly smaller in USG compared to SG. When CSA was expressed relative to the two-third power of body mass, the values for the four heads of the quadriceps femoris and biceps femoris long head, as well as the adductors, were significantly lower in USG than in SG. The current results indicate that in terms of the value relative to body mass, the reduced CSAs of the adductors and biceps femoris long head, as well as the four heads of the quadriceps femoris, are associated with the failure of attempts to stand up from a 40-cm-height chair on a single leg in older women. This may be due to the anatomical function of the two muscle groups, which contributes to hip extension movement involved in transitioning from a sitting position to a standing position during the stand-up task.


Assuntos
Perna (Membro) , Coxa da Perna , Idoso , Feminino , Humanos , Japão , Músculo Esquelético/fisiologia , Músculo Quadríceps/diagnóstico por imagem , Músculo Quadríceps/fisiologia , Coxa da Perna/fisiologia
2.
J Biomech ; 135: 111019, 2022 04.
Artigo em Inglês | MEDLINE | ID: mdl-35248802

RESUMO

A better understanding of deep hip muscle function is needed to establish whether retraining and strengthening these muscles is a worthwhile target for rehabilitation. This study aimed to determine the contribution of the deep hip muscles to the direction of hip loading in the acetabulum. Hip contact forces were calculated during walking and squatting for 12 participants (age: 24 ± 4 yrs, 4 females) using electromyography-informed neuromusculoskeletal modelling. Models were configured with different deep hip muscle activation levels: deep hip muscles (piriformis, obturator internus and externus, gemellus superior and inferior, and quadratus femoris) informed by intramuscular electromyography measurements (i.e., normal activation; assisted activation) and simulated with zero (no activation) or maximal (maximal activation) activation. The angle between the hip contact force and the vector from the femoral head to the acetabular center (hip contact force angle) was calculated for all configurations, where lower angles equated to hip loading directed towards the acetabular center. The position and spread of acetabular loading during both tasks were calculated for all configurations and compared using a within-participant analysis of variance via statistical parametric mapping (P < 0.05). Maximal activation resulted in lower hip contact force angles and more anterior-inferior oriented, albeit a slightly reduced, spread of acetabular loading compared to assisted activation and no activation. Results suggest that, if activated maximally, the deep hip muscles can change the direction of hip loading away from commonly damaged areas of acetabular cartilage. Targeted training of these muscles may be relevant for individuals with hip pathology who present with unfavorable regional loading and/or cartilage lesions.


Assuntos
Quadril , Coxa da Perna , Acetábulo , Adulto , Eletromiografia , Feminino , Quadril/fisiologia , Articulação do Quadril/fisiologia , Humanos , Masculino , Músculo Esquelético/fisiologia , Coxa da Perna/fisiologia , Adulto Jovem
3.
Int J Sports Physiol Perform ; 17(5): 774-779, 2022 05 01.
Artigo em Inglês | MEDLINE | ID: mdl-35235903

RESUMO

PURPOSE: This study aimed to investigate the level of muscle activity during sprint running using T2-weighted magnetic resonance imaging. METHODS: Fourteen male sprinters (age 21.2 [4.0] y; height 171.8 [4.2] cm, weight 65.5 [5.3] kg, 100-m personal record 11.01 [0.41] s; mean [SD]) performed 3 sets of three 60-m round-trip sprints. Before and after the round-trip sprints, 3 T magnetic resonance imaging scans were performed to obtain the T2 values of the 14 athletes' lower-extremity muscles. RESULTS: After the 60-m round-trip sprints, the T2 value of the gluteus maximus, long head of biceps femoris, semitendinosus, semimembranosus, adductor brevis, adductor longus, adductor magnus, and gracilis increased significantly. The rate of change in the T2 values before and after the 60-m round-trip sprints was notably higher in the semitendinosus and gluteus maximus than in the other muscles. CONCLUSIONS: These findings demonstrate the specific physiological metabolism of the lower-extremity muscles during fast sprinting. There are particularly high levels of muscle activity in the gluteus maximus and semitendinosus during sprint performance.


Assuntos
Corrida , Coxa da Perna , Adulto , Humanos , Extremidade Inferior/fisiologia , Imageamento por Ressonância Magnética/métodos , Masculino , Músculo Esquelético/diagnóstico por imagem , Músculo Esquelético/fisiologia , Corrida/fisiologia , Coxa da Perna/fisiologia , Adulto Jovem
4.
J Electromyogr Kinesiol ; 63: 102643, 2022 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-35189569

RESUMO

Given its tri-planar action at the hip, strengthening of gluteus maximus (GMAX) has been advocated as part of rehabilitation and injury prevention protocols for various musculoskeletal conditions. However, recruitment of GMAX during weight-bearing strengthening exercises can be challenging owing to the muscular redundancy at the hip for a given joint motion. The current study sought to determine if a 1-week activation program could result in greater GMAX recruitment during functional strengthening exercises. Pre- and post-training surface electromyography were collected from 12 healthy participants as they performed double- and single-leg squats. Between testing sessions, participants completed a GMAX activation training program consisting of isometric exercises with band resistance (twice per day for 7 days). Following the 1-week activation program, GMAX recruitment was found to increase by 57% during the double-leg squat (p = 0.005, Cohen's r = 0.73) and 53% during the single-leg squat (p = 0.006, Cohen's r = 0.70). Implementation of an initial GMAX activation program should be considered to facilitate neuromuscular adaptations that facilitate utilization of GMAX during hip strengthening exercises.


Assuntos
Contração Isométrica , Músculo Esquelético , Eletromiografia , Humanos , Contração Isométrica/fisiologia , Músculo Esquelético/fisiologia , Coxa da Perna/fisiologia , Suporte de Carga
5.
Eur J Sport Sci ; 22(6): 799-807, 2022 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-33749535

RESUMO

Muscle hypertrophy can occur non-uniformly in athletes who repetitively perform particular movements, presumably leading to a unique muscle size distribution along the length. The present study aimed to examine if sprinters have unique size distributions within the gluteus and posterior thigh muscles. Nineteen male sprinters and 20 untrained males participated in the present study. T1-weighted magnetic resonance images of the hips and right thigh were obtained in order to determine whole and regional (proximal, middle, and distal) volumes of the gluteus maximus and individual posterior thigh muscles. The results showed that the volumes of all the examined muscles relative to body mass were significantly larger in sprinters than in untrained males (all P < 0.001, d = 1.40-3.29). Moreover, the magnitude of the difference in relative volume between sprinters and untrained males was different between the regions within the gluteus maximus (P = 0.048, partial η2 = 0.187), semitendinosus (P = 0.004, partial η2 = 0.331), and adductor magnus (P = 0.007, partial η2 = 0.322), but not within the other posterior thigh muscles (P = 0.091-0.555, partial η2 = 0.025-0.176). The magnitude of the difference in relative volume between the sprinters and untrained males was greatest in the distal regions within the gluteus maximus and semitendinosus, while the proximal region within the adductor magnus. These findings indicate that sprinters have unique size distributions within the gluteus maximus, semitendinosus, and adductor magnus, which may be attributed to their competitive and training activities. HighlightsSprinters showed larger gluteus maximus and individual posterior thigh muscles than untrained males.The magnitude of difference varied within the gluteus maximus, semitendinosus, and adductor magnus.The greatest difference was found in distal regions within the gluteus maximus and semitendinosus, while proximal region within the adductor magnus.


Assuntos
Músculos Isquiossurais , Músculos Isquiossurais/fisiologia , Quadril , Humanos , Extremidade Inferior/fisiologia , Masculino , Músculo Esquelético/fisiologia , Coxa da Perna/fisiologia
6.
J Therm Biol ; 101: 103098, 2021 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-34879916

RESUMO

Although dynamic thermography skin temperature assessment has been used in medical field, scientific evidence in sports is scarce. The aim of the study was to assess changes in anterior thigh skin temperature in response to a cold stress test after a strength exercise fatiguing protocol. Ten physically active adults performed a familiarization session and two strength exercise sessions, one with dominant and the other with non-dominant lower limb. Participants performed bouts of 10 concentric and eccentric contractions of leg extensions in an isokinetic device until reaching around 30% of force loss. Infrared thermographic images were taken at baseline conditions and after the fatigue level from both thighs after being cooled using a cryotherapy system. ROIs included vastus medialis, rectus femoris, adductor and vastus lateralis. Skin temperature rewarming was assessed during 180s after the cooling process obtaining the coefficients of the following equation: ΔSkin temperature = ß0 + ß1 * ln(T), being ß0 and ß1 the constant and slope coefficients, respectively, T the time elapsed following the cold stress in seconds, and ΔSkin temperature the difference between the skin temperature at T respect and the pre-cooling moment. Lower ß0 and higher ß1 were found for vastus lateralis and rectus femoris in the intervention lower limb compared with baseline conditions (p < 0.05 and ES > 0.6). Adductor only showed differences in ß0 (p = 0.01 and ES = 0.92). The regressions models obtained showed that ß0 and ß1 had a direct relationship with age and muscle mass, but an inverse relationship with the number of series performed until 30% of fatigue (R2 = 0.8). In conclusion, fatigue strength exercise results in a lower skin temperature and a faster thermal increase after a cold stress test.


Assuntos
Resposta ao Choque Frio , Exercício Físico/fisiologia , Fadiga/fisiopatologia , Temperatura Cutânea , Coxa da Perna/fisiologia , Adulto , Feminino , Humanos , Masculino , Termografia , Adulto Jovem
7.
J Physiol Anthropol ; 40(1): 13, 2021 Sep 30.
Artigo em Inglês | MEDLINE | ID: mdl-34593041

RESUMO

BACKGROUND: The primary aim of this study was to investigate whether using the extracellular water/intracellular water (ECW/ICW) index and phase angle combined with segmental-bioimpedance analysis (BIA) improved the model fitting of skeletal muscle volume (SMV) estimation. The secondary aim was to compare the accuracy of segmental-BIA with that of ultrasound for estimating the quadriceps SMV measured with MRI. METHODS: Seventeen young men (mean age, 23.8 ± 3.3 years) participated in the study. The T-1 weighted images of thigh muscles were obtained using a 1.5 T magnetic resonance imaging (MRI) scanner. Thigh and quadriceps SMVs were calculated as the sum of the products of anatomical cross-sectional area and slice thickness of 6 mm across all slices. Segmental-BIA was applied to the thigh region, and data on the 50-kHz bioelectrical impedance (BI) index, ICW index, ECW/ICW index, and phase angle were obtained. The muscle thickness index was calculated as the product of the mid-thigh muscle thickness, determined using ultrasound, and thigh length. The standard error of estimate (SEE) of the regression equation was calculated to determine the model fitting of SMV estimation and converted to %SEE by dividing the SEE values by the mean SMV. RESULTS: Multiple regression analysis indicated that the combination of 50-kHz BI and the ECW/ICW index or phase angle was a significant predictor when estimating thigh SMV (SEE = 7.9 and 8.1%, respectively), but were lower than the simple linear regression (SEE = 9.4%). The ICW index alone improved the model fitting for the estimation equation (SEE = 7.6%). The model fitting of the quadriceps SMV with the 50-kHz BI or ICW index was similar to that with the skeletal muscle thickness index measured using ultrasound (SEE = 10.8, 9.6 and 9.7%, respectively). CONCLUSIONS: Combining the traditionally used 50-kHz BI index with the ECW/ICW index and phase angle can improve the model fitting of estimated SMV measured with MRI. We also showed that the model suitability of SMV estimation using segmental-BIA was equivalent to that on using ultrasound. These data indicate that segmental-BIA may be a useful and cost-effective alternative to the gold standard MRI for estimating SMV.


Assuntos
Impedância Elétrica , Músculo Esquelético , Coxa da Perna , Adulto , Antropologia Física , Composição Corporal/fisiologia , Humanos , Imageamento por Ressonância Magnética , Masculino , Músculo Esquelético/anatomia & histologia , Músculo Esquelético/diagnóstico por imagem , Músculo Esquelético/fisiologia , Coxa da Perna/anatomia & histologia , Coxa da Perna/diagnóstico por imagem , Coxa da Perna/fisiologia , Adulto Jovem
8.
BMC Pregnancy Childbirth ; 21(1): 646, 2021 Sep 23.
Artigo em Inglês | MEDLINE | ID: mdl-34556074

RESUMO

BACKGROUND: High rates of adverse pregnancy outcomes globally raise the need to understand risk factors and develop preventative interventions. The Pregnancy Outcomes in the Era of Universal Antiretroviral Treatment in Sub-Saharan Africa (POISE Study) was a prospective, observational cohort study conducted from 2016 to 2017 in Blantyre, Malawi. We examine the associations between indicators of nutritional status, specifically mid-thigh circumference (MTC) and body-mass index (BMI), and adverse pregnancy outcomes, low birth weight (LBW), preterm birth (PTB), and small-for-gestational age (SGA), in a cohort of HIV-infected and HIV-uninfected women. METHODS: Sociodemographic, clinical, laboratory, and maternal height, weight and MTC data were collected immediately before or after delivery at the Queen Elizabeth Central Hospital (QEHC) and 4 affiliated health centers in Blantyre, Malawi. LBW was defined as birth weight < 2.5 kg; PTB as gestational age < 37 weeks using Ballard score; and SGA as birth weight < 10th percentile for gestational age. Descriptive, stratified, and multivariable logistic regression were conducted using R. RESULTS: Data from 1298 women were analyzed: 614 HIV-infected and 684 HIV-uninfected. MTC was inversely associated with LBW (adjusted odds ratio [aOR] = 0.95, p = 0.03) and PTB (aOR 0.92, p < 0.001), after controlling for HIV status, age, socioeconomic status and hemoglobin. The association between MTC and SGA was (aOR 0.99, p = 0.53). Similarly, higher BMI was significantly associated with lower odds of PTB (aOR 0.90, p < 0.001), LBW (aOR 0.93, p = 0.05), and SGA (aOR 0.95, p = 0.04). CONCLUSIONS: We observed an inverse relationship between MTC and adverse pregnancy outcomes in Malawi irrespective of HIV infection. MTC performs comparably to BMI; the ease of measuring MTC could make it a practical tool in resource-constrained settings for identification of women at risk of adverse pregnancy outcomes.


Assuntos
Tamanho Corporal/fisiologia , Estado Nutricional/fisiologia , Complicações na Gravidez/epidemiologia , Coxa da Perna , Adulto , Feminino , Idade Gestacional , Infecções por HIV , Humanos , Recém-Nascido de Baixo Peso , Recém-Nascido , Malaui/epidemiologia , Masculino , Gravidez , Resultado da Gravidez/epidemiologia , Nascimento Prematuro/epidemiologia , Estudos Prospectivos , Coxa da Perna/fisiologia , Adulto Jovem
9.
Med Sci Sports Exerc ; 53(10): 2140-2151, 2021 10 01.
Artigo em Inglês | MEDLINE | ID: mdl-33935234

RESUMO

PURPOSE: This study aimed to determine the best muscle size index of muscle strength by establishing if incorporating muscle architecture measurements improved the human muscle size-strength relationship. The influence of calculating muscle force and the location of anatomical cross-sectional area (ACSA) measurements on this relationship were also examined. METHODS: Fifty-two recreationally active men completed unilateral isometric knee extension strength assessments and magnetic resonance imaging scans of the dominant thigh and knee to determine quadriceps femoris size variables (ACSA along the length of the femur, maximum ACSA (ACSAMAX), and volume (VOL)) and patellar tendon moment arm. Ultrasound images (two sites per constituent muscle) were analyzed to quantify muscle architecture (fascicle length, pennation angle) and, when combined with VOL (from magnetic resonance imaging), facilitated calculation of quadriceps femoris effective PCSA (EFFPCSA) as potentially the best muscle size determinant of strength. Muscle force was calculated by dividing maximum voluntary torque by the moment arm and addition of antagonist torque (derived from hamstring EMG). RESULTS: The associations of EFFPCSA (r = 0.685), ACSAMAX (r = 0.697), or VOL (r = 0.773) with strength did not differ, although qualitatively VOL explained 59.8% of the variance in strength, ~11%-13% greater than EFFPCSA or ACSAMAX. All muscle size variables had weaker associations with muscle force than maximum voluntary torque. The association of strength-ACSA at 65% of femur length (r = 0.719) was greater than for ACSA measured between 10%-55% and 75%-90% (r = -0.042-0.633) of femur length. CONCLUSIONS: In conclusion, using contemporary methods to assess muscle architecture and calculate EFFPCSA did not enhance the muscle strength-size association. For understanding/monitoring muscle size, the major determinant of strength, these findings support the assessment of muscle volume, which is independent of architecture measurements and was most highly correlated with strength.


Assuntos
Força Muscular , Músculo Quadríceps/anatomia & histologia , Músculo Quadríceps/fisiologia , Adulto , Humanos , Joelho/diagnóstico por imagem , Joelho/fisiologia , Imageamento por Ressonância Magnética , Masculino , Ligamento Patelar/fisiologia , Músculo Quadríceps/diagnóstico por imagem , Coxa da Perna/anatomia & histologia , Coxa da Perna/diagnóstico por imagem , Coxa da Perna/fisiologia , Torque , Ultrassonografia , Adulto Jovem
10.
PLoS One ; 16(4): e0249670, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33819316

RESUMO

Hip extensor muscle size is related to sprint running performance. However, the mechanisms underlying this relationship remain unclear. To gain insights into this issue, the present study examined the relationships between the individual hip extensor sizes, spatiotemporal variables (step frequency and length, and their determinants), and sprint velocity during maximal velocity sprinting. Magnetic resonance images of the hip and right thigh were obtained from 26 male sprinters to determine the volumes of the gluteus maximus, individual hamstrings and adductors, and gracilis. Muscle volumes were normalized to their respective body mass and recorded as relative muscle volumes. The sprinters performed a 100-m sprint with their maximal effort. Their sprint motions were recorded using cameras to calculate the mean sprint velocity and the spatiotemporal variables at 50-60 m interval. The sprint velocity was significantly correlated with the relative volume of the semitendinosus (r = 0.497, P = 0.010), but not with the volumes of the other examined muscles. The relative volume of semitendinosus significantly correlated with the stance distance (r = 0.414, P = 0.036) and the stance distance adjusted by the stance time (r = 0.490, P = 0.011). Moreover, there were significant correlations between the stance distance and step length (r = 0.592, P = 0.001), and between the step length and sprint velocity (r = 0.509, P = 0.008). These results suggest that the semitendinosus contributes to attaining long stance distance and thereby high sprint velocity during maximal velocity sprinting.


Assuntos
Quadril/fisiologia , Músculos Psoas/fisiologia , Corrida/fisiologia , Desempenho Atlético/fisiologia , Fenômenos Biomecânicos , Nádegas/fisiologia , Músculo Grácil/fisiologia , Músculos Isquiossurais/fisiologia , Humanos , Imageamento por Ressonância Magnética/métodos , Masculino , Músculo Esquelético/fisiologia , Coxa da Perna/fisiologia , Tronco/fisiologia , Adulto Jovem
11.
J Orthop Surg (Hong Kong) ; 29(1): 23094990211003349, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33779410

RESUMO

BACKGROUND: The posterior approach (PA) is the most commonly used surgical approach for total hip arthroplasty (THA), but the proximity of the sciatic nerve may increase the likelihood of sciatic nerve injury (SNI). Gluteus maximus tenotomy can be performed to prevent SNI because tenotomy increases the distance between the femoral neck and sciatic nerve and prevents compression of the sciatic nerve by the gluteus maximus tendon (GMT) during hip movements. We aimed to kinematically compare the postoperative hip extensor forces of patients who have and have not undergone gluteus maximus tenotomy to determine whether there is a difference in hip extensor strength. METHODS: Seventy-two patients who underwent gluteus maximus tenotomy during THA were included in the group 1, and 86 patients who did not undergo tenotomy were included in group 2. The Harris hip score, body mass index and hip extensor forces were measured both preoperatively, and 6 months after surgery with an isokinetic dynamometer and compared. RESULTS: The mean age was 64.6 ± 2.3 years in group 1 and 63.8 ± 2.1 in group 2. Mean body mass index was 25.7 ± 1.1 in group 1, and 25.5 ± 1.3 in group 2. Baseline Harris hip score (HHS) was 42.36 ± 12 in group 1 and 44.07 ± 9.4 in group 2 (p = 0.31), whereas it was 89.1 ± 7.8 and 88.4 ± 8.1 at 6 months after surgery, respectively. Baseline hip extensor force (HEF) was 2 ± 0.4 Nm/kg in group 1, and 2.1 ± 0.7 Nm/kg in group 2 (p = 0.28), while it was 2.4 ± 0.6 Nm/kg, and 2.5 ± 0.5 Nm/kg, respectively at 6 month follow-up (p = 0.87). Both groups had significantly improved HHS and HEF when comparing baseline and postoperative measurements (p < 0.0001). No cases of sciatic nerve palsy were noted in group 1, whereas there were two (2.32%) cases in group 2, postoperatively. CONCLUSION: The release of the GMT during primary hip arthroplasty performed with the PA did not lead to significant decrease in hip extension forces. Hip extensor strength improves after THA regardless of tenotomy. Gluteus maximus tenotomy with repair does not reduce muscle strength and may offer better visualization.


Assuntos
Artroplastia de Quadril/métodos , Resistência à Flexão/fisiologia , Articulação do Quadril/fisiologia , Neuropatia Ciática/prevenção & controle , Tenotomia , Idoso , Fenômenos Biomecânicos , Nádegas/cirurgia , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Força Muscular/fisiologia , Músculo Esquelético/cirurgia , Procedimentos Cirúrgicos Reconstrutivos , Nervo Isquiático/lesões , Tendões/fisiologia , Tendões/cirurgia , Tenotomia/efeitos adversos , Tenotomia/métodos , Coxa da Perna/fisiologia , Resultado do Tratamento
12.
Int J Sports Med ; 42(9): 803-811, 2021 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-33440446

RESUMO

The study aimed to compare the effect of performing the same or different exercises for a muscle group on resistance training (RT) sessions on muscle hypertrophy at different sites along muscle length. Twenty-two detrained men (23.3±4.1 years) were randomly allocated to the following groups: a group that performed the same exercises in all training sessions (N-VAR=11) or one that varied the exercises for the same muscle groups (VAR=11). All were submitted to 3 weekly sessions for nine weeks. Muscle thickness was assessed at the proximal, middle, and distal sites of the lateral and anterior thigh, elbow flexors, and extensors by B-mode ultrasound. The VAR group significantly increased all the sites analyzed (P<0.05). Furthermore, the proximal site of the lateral thigh showed a larger relative increase when compared to the middle site (P<0.05). In contrast, the N-VAR group were not revealed significant improvements only for the middle site of the lateral thigh and the proximal site of the elbow flexors (P>0.05). Our results suggest that to perform different resistance exercises can induce hypertrophy of all sites assessed in detrained young men.


Assuntos
Força Muscular , Músculo Esquelético/crescimento & desenvolvimento , Treinamento de Força/métodos , Adaptação Fisiológica , Adulto , Cotovelo/fisiologia , Humanos , Masculino , Coxa da Perna/fisiologia , Ultrassonografia , Adulto Jovem
13.
Phys Ther Sport ; 47: 7-14, 2021 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-33099093

RESUMO

OBJECTIVES: To observe isolated lumbopelvic-hip complex (LPHC) stability and muscle activity using the Seated Trunk Control Test (STCT) and evaluate the relationship between LPHC stability and 2-dimensional kinematics during movements. DESIGN: Descriptive Study. SETTING: Laboratory. PARTICIPANTS: 22 healthy participants (12F, 10M, 23.5 ± 3.1yrs, 173.0 ± 9.0 cm, 76.1 ± 10.7 kg). MAIN OUTCOME MEASURE(S): Time to first error and number of errors, and muscle activity of the abdominals, erector spinae, and gluteus medius were recorded during the STCT. Lateral trunk movement, hip and knee frontal plane projection angles, hip and knee flexion during single leg squats and single leg drop vertical jumps were measured. Pearson r correlations were calculated among STCT performance, muscle activity, and 2-dimensional kinematics. RESULTS: Number of errors was moderately correlated to hip and knee flexion during single leg squatting (r = 0.456-0.649, p < 0.05). Number of errors and time to first error were moderately correlated to knee-frontal plane projection angle and hip flexion respectively during single leg drop vertical jumping (r = 0.463-0.515, p < 0.05). CONCLUSIONS: Decreased LPHC stability relates to decreased sagittal plane motion during single leg squatting and increased frontal plane motion during single leg drop vertical jumping. Pairing the STCT with 2-dimensional kinematic analysis can demonstrate influence of LPHC function.


Assuntos
Quadril/fisiologia , Extremidade Inferior/fisiologia , Pelve/fisiologia , Tronco/fisiologia , Adulto , Fenômenos Biomecânicos , Teste de Esforço/métodos , Feminino , Humanos , Joelho/fisiologia , Região Lombossacral/fisiologia , Masculino , Movimento , Força Muscular , Músculo Esquelético/fisiologia , Postura , Amplitude de Movimento Articular , Coxa da Perna/fisiologia , Adulto Jovem
14.
J Sports Med Phys Fitness ; 61(5): 645-655, 2021 May.
Artigo em Inglês | MEDLINE | ID: mdl-33146489

RESUMO

BACKGROUND: There is currently limited evidence available to support the use of the isometric mid-thigh pull (IMTP) within professional soccer. The aim of this study was to analyze the association between IMTP variables, with common markers of athletic performance capability. METHODS: Eleven professional development soccer players (age: 20±2 years, stature: 1.82±0.10 m, mass: 76.4±12.8 kg) performed IMTP, 5 m and 10 m accelerations, maximal sprint speed (MSS), countermovement jump (CMJ), and the 505 change of direction test (COD). RESULTS: Relative and absolute peak force (PF) and force at 50, 100, 150 and 200 ms values were measured during the IMTP. Relative F150, F200, PF displayed large to very large correlations with MSS (r=0.51, r=0.66, and r=0.76 respectively), while absolute PF also displayed a large correlation with MSS (r=0.57). Relative and absolute PF showed large correlations with CMJ height (r=0.54 and r=0.55 respectively). Relative F150 and F200 highlighted large correlations with COD ability (r=-0.68 and r=-0.60 respectively). Relative F200 and PF had a large negative correlation with 10 m acceleration (r=-0.55 and r=-0.53 respectively). CONCLUSIONS: This study provides an important contribution to knowledge within the area of IMTP testing in professional soccer by evidencing the prominence of the isometric force generating capacity as an underpinning factor in relation to athletic capability.


Assuntos
Desempenho Atlético/fisiologia , Comportamento Competitivo/fisiologia , Força Muscular , Músculo Esquelético/fisiologia , Futebol/fisiologia , Coxa da Perna/fisiologia , Aceleração , Teste de Esforço , Humanos , Contração Isométrica , Adulto Jovem
15.
Phys Ther Sport ; 47: 53-58, 2021 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-33197873

RESUMO

OBJECTIVE: The objective was to establish normative data for hip strength, flexibility, and stiffness in male soccer athletes and to investigate the effect of age and limb dominance on these variables. DESIGN: Cross-sectional. SETTING: Soccer team physical therapy department. PARTICIPANTS: A total of 293 asymptomatic male soccer athletes were assessed. Elite youth players aged 15-17 years and professional adult players aged 18-29 years old. MAIN OUTCOME MEASURES: Rectus femoris, iliopsoas, hamstring muscle flexibility, passive hip stiffness, and isometric hip strength were measured using a goniometer, inclinometer, and handheld dynamometer, respectively. Descriptive and mixed analyses of variance were used as statistical procedures. RESULTS: The dominant limb had lower iliopsoas (P = 0.010) and rectus femoris (P = 0.003) flexibility and higher external rotators torque compared to the non-dominant limb (P = 0.006) in both age groups. In adult athletes, the dominant limb had lower hip stiffness than the non-dominant limb (P = 0.002). Adults had higher hip external rotator torque than younger athletes (P < 0.0001). No differences were observed for hamstrings flexibility and hip extensors torque. CONCLUSION: This study provided normative data of hip strength, flexibility, and stiffness for youth and adult male soccer athletes. In addition, there were no clinically relevant inter-limb differences.


Assuntos
Atletas , Quadril/fisiologia , Força Muscular , Futebol , Adolescente , Adulto , Fatores Etários , Estudos Transversais , Lateralidade Funcional , Humanos , Masculino , Dinamômetro de Força Muscular , Músculo Esquelético/fisiologia , Músculo Quadríceps/fisiologia , Coxa da Perna/fisiologia , Torque , Adulto Jovem
16.
Sports Health ; 13(2): 136-144, 2021 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-33337984

RESUMO

BACKGROUND: Thigh muscle weakness after anterior cruciate ligament reconstruction (ACLR) can persist after returning to activity. While resistance training can improve muscle function, "nonfunctional" training methods are not optimal for inducing transfer of benefits to activities such as walking. Here, we tested the feasibility of a novel functional resistance training (FRT) approach to restore strength and function in an individual with ACLR. HYPOTHESIS: FRT would improve knee strength and function after ACLR. STUDY DESIGN: Case report. LEVEL OF EVIDENCE: Level 5. METHODS: A 15-year-old male patient volunteered for an 8-week intervention where he performed 30 minutes of treadmill walking, 3 times per week, while wearing a custom-designed knee brace that provided resistance to the thigh muscles of his ACLR leg. Thigh strength, gait mechanics, and corticospinal and spinal excitability were assessed before and immediately after the 8-week intervention. Voluntary muscle activation was evaluated immediately after the intervention. RESULTS: Knee extensor and flexor strength increased in the ACLR leg from pre- to posttraining (130 to 225 N·m [+74%] and 44 to 88 N·m [+99%], respectively) and increases in between-limb extensor and flexor strength symmetry (45% to 92% [+74%] and 47% to 72% [+65%], respectively) were also noted. After the intervention, voluntary muscle activation in the ACLR leg was 72%, compared with the non-ACLR leg at 75%. Knee angle and moment during late stance phase decreased (ie, improved) in the ACLR leg and appeared more similar to the non-ACLR leg after FRT training (18° to 14° [-23.4] and 0.07 to -0.02 N·m·kg-1·m-1 [-122.8%], respectively). Corticospinal and spinal excitability in the ACLR leg decreased (3511 to 2511 [-28.5%] and 0.42 to 0.24 [-43.7%], respectively) from pre- to posttraining. CONCLUSION: A full 8 weeks of FRT that targeted both quadriceps and hamstring muscles lead to improvements in strength and gait, suggesting that FRT may constitute a promising and practical alternative to traditional methods of resistance training. CLINICAL RELEVANCE: FRT may serve as a viable approach to improve knee strength and function after ACL reconstruction.


Assuntos
Lesões do Ligamento Cruzado Anterior/cirurgia , Reconstrução do Ligamento Cruzado Anterior/reabilitação , Terapia por Exercício/métodos , Joelho/fisiologia , Força Muscular , Treinamento de Força/métodos , Adolescente , Basquetebol/lesões , Fenômenos Biomecânicos , Braquetes , Desenho de Equipamento , Marcha/fisiologia , Músculos Isquiossurais/fisiologia , Humanos , Ligamentos Laterais do Tornozelo/lesões , Masculino , Tratos Piramidais/fisiologia , Músculo Quadríceps/fisiologia , Coxa da Perna/fisiologia
17.
Sports Biomech ; 20(3): 344-359, 2021 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-30707089

RESUMO

Analyses of segment kinetic energy (KE) can provide the most appropriate means of exploring sequential movements. As the reliability associated with its measurement has not been reported, the aim of this study was to examine the test-retest reliability of segment KE measures in the golf swing. On two occasions, seven male golfers hit five shots with three different clubs. Body segment inertia parameters were estimated for 17 rigid bodies and 3D kinematic data were collected during each swing. The magnitude and timing of peak total, linear and angular kinetic energies were then calculated for each rigid body and for four segment groups. Regardless of club type, KE was measured with high reliability for almost all rigid bodies and segment groups. However, significantly larger magnitudes of peak total (p = 0.039) and linear (p = 0.021) lower body KE were reported in test 2 than in test 1. The high reliability reported in this study provides support for the use of analyses of segment kinetic energy. However, practitioners should pay careful attention to the identification of anatomical landmarks which define the thigh, pelvis and thorax as this was the main cause of variability in repeated measures of segment kinetic energy.


Assuntos
Pontos de Referência Anatômicos/fisiologia , Fenômenos Biomecânicos/fisiologia , Golfe/fisiologia , Adulto , Humanos , Cinética , Masculino , Movimento/fisiologia , Ossos Pélvicos/fisiologia , Reprodutibilidade dos Testes , Equipamentos Esportivos , Coxa da Perna/fisiologia , Tórax/fisiologia
18.
J Sports Med Phys Fitness ; 61(1): 18-26, 2021 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-32936567

RESUMO

BACKGROUND: The effects of a reduced or mildly elevated exercising muscle temperature on the graded exercise test (GXT) performance have yet to be studied. The present study clarified the effects of a range of exercising muscle temperatures on GXT performance in a temperate environment. METHODS: Eight male subjects (age: 24.0±0.5 years old; height: 175±2 cm; weight: 64.8±2.0 kg; peak oxygen consumption [V̇O2peak]: 51.1±2.4 mL/kg/min) performed 4 GXTs at different exercising muscle temperatures using a cycle-ergometer in a temperate environment (24.1±0.2 °C). The exercise began at 0.3 kilopond (kp) with 60 revolutions per minute (rpm) and increased 0.3 kp every minute until volitional exhaustion. Subjects passively cooled (averaged deep thigh and calf temperature [Tmm], cold: 31 °C or cool: 33 °C) or warmed (Tmm; warm: 35 °C or hot: 37 °C) the exercising muscle using water perfusion pants throughout the test. The peak oxygen consumption (V̇O2peak), exercise time to exhaustion (TTE), heart rate (HR), tympanic (Tty) and mean body temperature (Tb), and total sweat loss were also measured. RESULTS: No significant differences were observed in the V̇O2peak or TTE among the 4 conditions; however, the HR, Tb, and total sweat loss were significantly higher (P<0.05) under warming conditions than cooling conditions. CONCLUSIONS: These results suggest that although the cardiovascular and thermoregulatory strain is higher under warming conditions than cooling conditions, the exercising muscle temperature does not affect the performance of a GXT lasting approximately 15 min in a temperate environment.


Assuntos
Exercício Físico/fisiologia , Adulto , Desempenho Atlético/fisiologia , Temperatura Corporal/fisiologia , Regulação da Temperatura Corporal/fisiologia , Temperatura Baixa , Teste de Esforço , Frequência Cardíaca/fisiologia , Humanos , Perna (Membro) , Masculino , Sudorese , Temperatura , Coxa da Perna/fisiologia , Adulto Jovem
19.
Eur J Sport Sci ; 21(2): 204-212, 2021 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-32050853

RESUMO

AbstractThis study investigated the effects of whole body vibration (WBV) training combined with blood flow restriction (BFR) on muscle fitness. Twenty physically inactive adults were randomly assigned to a WBV + BFR group (8 men and 2 women) and a WBV group (8 men and 2 women). The participants in the WBV group were subjected to 10 sets of intermittent WBV exercise 20 min/day, 3 days/week, for 8 weeks. The participants in the WBV + BFR group received the same WBV treatment, but the proximal portion of their thighs was compressed using inflatable cuffs. Dual-energy X-ray absorptiometry estimated thigh muscle mass, one repetition maximal (1RM) leg press, and muscle endurance were measured before and after the training programme. The results indicated that thigh muscle mass significantly increased (3%) after the 8-week training period only in the WBV + BFR group. Meanwhile, 1RM leg press and muscle endurance significantly increased in both groups after training (p < 0.05). Analysis of covariance revealed that the increase in 1RM leg press and muscle endurance was significantly higher (p < 0.05) in the WBV + BFR group than the WBV group (leg press: 11.1%. vs. 4.37%; muscle endurance: 48.84% vs. 15.19%, respectively). In conclusion, exposure to regular WBV + BFR training can increase thigh muscle mass, maximal strength, and muscle endurance compared with exposure to WBV training alone. WBV + BFR training appears to be a feasible strategy for improving muscle mass, strength, and endurance in previously untrained participants.


Assuntos
Exercício Físico/fisiologia , Força Muscular/fisiologia , Músculo Esquelético/irrigação sanguínea , Músculo Esquelético/fisiologia , Fluxo Sanguíneo Regional/fisiologia , Vibração , Adaptação Fisiológica , Adulto , Terapia Combinada , Constrição , Feminino , Humanos , Masculino , Coxa da Perna/irrigação sanguínea , Coxa da Perna/fisiologia , Torniquetes
20.
J Sports Sci Med ; 20(4): 626-634, 2021 12.
Artigo em Inglês | MEDLINE | ID: mdl-35321144

RESUMO

Despite its beneficial effects on flexibility and muscle soreness, there is still conflicting evidence regarding dose-response relationships and underlying mechanisms of foam rolling (FR). This study aimed to investigate the impact of different FR protocols on tissue perfusion and tissue stiffness. In a randomized crossover trial, two FR protocols (2x1 min, 2x3 min) were applied to the right anterior thigh of twenty healthy volunteers (11 females, 25 ± 4 years). Tissue perfusion (near infrared spectroscopy, NIRS) and stiffness (Tensiomyography, TMG and Myotonometry, MMT) were assessed before and after FR application. Variance analyses revealed a significant interaction of FR duration and tissue perfusion (F [1,19] = 7.098, p = 0.015). Local blood flow increased significantly from pre to post test (F [1,19] = 7.589, p = 0.013), being higher (Δ +9.7%) in the long-FR condition than in the short-FR condition (Δ +2.8%). Tissue stiffness (MMT) showed significant main effects for time (F [1,19] = 12.074, p = 0.003) and condition (F [1,19] = 7.165, p = 0.015) with decreases after short-FR (Δ -1.6%) and long-FR condition (Δ -1.9%). However, there was no time*dose-interaction (F [1,19] = 0.018, p = 0.895). No differences were found for TMG (p > 0.05). FR-induced changes failed to exceed the minimal detectable change threshold (MDC). Our data suggest that increased blood flow and altered tissue stiffness may mediate the effects of FR although statistical MDC thresholds were not achieved. Longer FR durations seem to be more beneficial for perfusion which is of interest for exercise professionals designing warm-up and cool-down regimes. Further research is needed to understand probable effects on parasympathetic outcomes representing systemic physiological responses to locally applied FR stimulations.


Assuntos
Exercício de Aquecimento , Estudos Cross-Over , Feminino , Humanos , Masculino , Perfusão , Amplitude de Movimento Articular/fisiologia , Coxa da Perna/fisiologia
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