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1.
Clin Interv Aging ; 14: 1555-1565, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31695344

RESUMO

Purpose: Nordic walking (NW) has been recommended as a form of exercise for clinical populations. Despite intervention programs designed to face a clinical status may last several months, no longitudinal studies have compared the effect of NW to another usual form of exercise, like walking (W). We evaluated the effects of diet combined with a long-supervised NW versus W training on body composition, aerobic capacity and strength in overweight adults. Patients and methods: Thirty-eight participants, randomized into a NW (n=19, 66±7 years, body mass index (BMI) 33±5)) and a W (n=19, 66±8 years, BMI 32±5) group, followed a diet and a supervised training routine 3 times/week for 6 months. The variables assessed at baseline, after 3 and 6 months were: anthropometric indexes (ie, BMI and waist circumference (WC)), body composition, aerobic capacity (oxygen consumption (VO2peak), peak power output (PPO), 6-min walking test (6MWT)) and strength (maximal voluntary contraction of biceps brachialis (MVCBB) and quadriceps femoris (MVCQF), chair stand and arm curl (AC)). Results: After 6 months both NW and W group decreased significantly BMI (6% and 4%, respectively) and WC (8% and 4%, respectively), but only the NW group reduced (P<0.05) total body fat (8%), android fat (14%) and leg fat (9%). After 6 months, PPO increased (P<0.05) in both groups, but VO2peak improved (P<0.05) only in the NW group (8%). After 6 months, 6MWT increased (P<0.001) in both groups and only the NW group improved (P<0.05) in MVCBB (14%), MVCQF (17%) and AC (35%). Conclusion: Our results suggest that NW can give in some relevant health parameters, greater and faster benefits than W. Thus, NW can be a primary tool to counteract the obesity and overweight state in middle-aged adults.


Assuntos
Dieta , Terapia por Exercício/métodos , Sobrepeso/terapia , Caminhada/fisiologia , Adiposidade , Idoso , Índice de Massa Corporal , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Força Muscular , Consumo de Oxigênio , Músculo Quadríceps/fisiologia , Circunferência da Cintura , Teste de Caminhada
2.
Int J Sports Med ; 40(14): 903-908, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31614383

RESUMO

Football players frequently face the occurrence of non-contact injuries. Although there are likely multiple factors that contribute to increased risk of non-contact injury, it remains a challenge to correlate all these factors. However, it is not clear how much of individual training abilities may interfere in these events. As such, the primary aim of the present study was to determine whether the reduction of functional performance of the thigh in the isokinetic knee tests, anthropometric and morbid history can establish risk factors for lower-limb musculoskeletal injuries throughout the season. The incidence of injuries and odds ratios were calculated for suspected risk factors. Hamstring/Quadriceps conventional ratio outside of the safety range (55-64%) may be involved in the occurrence of non-contact muscle injuries and the risk for any musculoskeletal injuries in the lower extremities is 16 times higher when extensor peak of torque exceeds 10% and 12 times higher when flexor peak of torque difference was greater than 10%. This kind of evaluation can result in intervention programs that may decrease the risk of lower-limb musculoskeletal injuries. Based on these results we can establish a specific and individualized exercise program for each athlete and thus protect them during the season.


Assuntos
Extremidade Inferior/lesões , Medição de Risco/métodos , Futebol/lesões , Adolescente , Adulto , Antropometria , Teste de Esforço , Músculos Isquiotibiais/lesões , Músculos Isquiotibiais/fisiologia , Humanos , Joelho/fisiologia , Ligamentos/lesões , Estudos Longitudinais , Extremidade Inferior/fisiologia , Masculino , Condicionamento Físico Humano , Músculo Quadríceps/lesões , Músculo Quadríceps/fisiologia , Fatores de Risco , Futebol/fisiologia , Coxa da Perna/fisiologia , Lesões do Menisco Tibial/fisiopatologia , Adulto Jovem
3.
Int J Sports Med ; 40(12): 779-788, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31487749

RESUMO

Static stretching (SS) can increase joint range of motion (ROM), due to neural, morphological, and physio-psychological factors. Periodized training programs (PD) (e. g., strength, power) are adopted to induce greater adaptations while avoiding overtraining. However, the effectiveness of periodized stretch training adaptations are unknown. Therefore, the objective of this study was to compare the effects of periodized and non-periodized (NP) stretching programs on flexibility, hamstrings stiffness and muscle performance. Sixteen gymnasts were allocated to either periodized or non-periodized SS training and tested pre- and post-8 weeks for countermovement jump height, hip flexors, hip extensors and dorsiflexors ROM, hamstrings stiffness and hamstrings and quadriceps peak torque. Both stretch training groups significantly and similarly increased hip extensor (33.2%), hip flexor (25.2%), and dorsiflexor (23.8%) ROM, hamstrings peak torque (7.9%) and jump height (8.1%) from pre - to post- training. Both groups decreased hamstrings stiffness across the last ten angles (32.1%). PD elicited consistently large magnitude flexibility effect size changes compared to small and moderate magnitude changes for the non-periodized. Therefore, 8-week PD and NP SS programs can decrease young gymnasts' muscle-tendon stiffness and increase muscle performance. However, effect sizes indicate that PD stretch training was more advantageous to increasing flexibility and improving performance.


Assuntos
Desempenho Atlético/fisiologia , Ginástica/fisiologia , Exercícios de Alongamento Muscular/métodos , Músculo Esquelético/fisiologia , Criança , Elasticidade , Teste de Esforço/métodos , Feminino , Músculos Isquiotibiais/fisiologia , Articulação do Quadril/fisiologia , Humanos , Músculo Quadríceps/fisiologia , Amplitude de Movimento Articular/fisiologia , Torque
4.
Gait Posture ; 73: 315-322, 2019 09.
Artigo em Inglês | MEDLINE | ID: mdl-31419759

RESUMO

BACKGROUND: Muscle co-contraction is an accepted clinical measure to quantify the effects of aging on neuromuscular control and movement efficiency. However, evidence of increased muscle co-contraction in old compared to young adults remains inconclusive. RESEARCH QUESTION: Are there differences in lower-limb agonist/antagonist muscle co-contractions in young and old adults, and males and females, during walking and stair use? METHODS: In a retrospective study, we analyzed data from 20 healthy young and 19 healthy old adults during walking, stair ascent, and stair descent at self-selected speeds, including marker trajectories, ground reaction force, and electromyography activity. We calculated muscle co-contraction at the knee (vastus lateralis vs. biceps femoris) and ankle (tibialis anterior vs. medial gastrocnemius) using the ratio of the common area under a muscle pairs' filtered and normalized electromyography curves to the sum of the areas under each muscle in that pair. RESULTS: Old compared to young adults displayed 18%-22% greater knee muscle co-contractions during the entire cycle of stair use activities. We found greater (17%-29%) knee muscle co-contractions in old compared to young adults during the swing phase of walking and stair use. We found no difference in ankle muscle co-contractions between the two age groups during all three activities. We found no difference in muscle co-contraction between males and females at the knee and ankle joints for all three activities. SIGNIFICANCE: Based on our findings, we recommend clinical evaluation to quantify the effects of aging through muscle co-contraction to include the knee joint during dynamic activities like walking and stair use, and independent evaluation of the stance and swing phases.


Assuntos
Articulação do Tornozelo/fisiologia , Marcha/fisiologia , Articulação do Joelho/fisiologia , Contração Muscular/fisiologia , Músculo Esquelético/fisiologia , Subida de Escada/fisiologia , Fatores Etários , Tornozelo/fisiologia , Eletromiografia , Feminino , Músculos Isquiotibiais/fisiologia , Voluntários Saudáveis , Humanos , Joelho , Masculino , Músculo Quadríceps/fisiologia , Estudos Retrospectivos , Adulto Jovem
5.
J Sports Sci ; 37(21): 2506-2512, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31362579

RESUMO

The study assesses the test-retest reliability of movement and physiological measures during a simulated rugby match that employed activities performed in a stochastic order. Twenty male rugby players (21.4 ± 2.1 y) completed two trials of a 2 × 23 min rugby movement simulation protocol during which the order of events was performed in a stochastic order, with 7-10 days between trials. Movement characteristics, heart rate (HR), RPE, maximum voluntary contraction (MVC), voluntary activation (VA%) of the quadriceps, Stroop test and subjective task load rating (NASA-TLX) were measured. The most reliable measures of external load was relative distance (typical error [TE] and CV% = 1.5-1.6 m min-1 and 1.4-1.5%, respectively), with all other movement characteristics possessing a CV% <5%. The most reliable measure of internal load, neuromuscular function and perceptual measures were for %HRmax (TE and CV% = 1.4-1.7% and 1.4-2.1%, respectively), MVC before (TE and CV% = 10.8-14.8 N·m and 3.8-4.6%, respectively), and average RPE (TE and CV% = 0.5-0.8 AU and 3.6-5.5%, respectively). The Stroop test, NASA-TLX and blood lactate produced the least reliable measures (CV% >5%). Future studies can confidently examine changes in several perceptual, neuromuscular, physiological and movement measures related to rugby activity using stochastic movements.


Assuntos
Desempenho Atlético/fisiologia , Desempenho Atlético/psicologia , Cognição/fisiologia , Futebol Americano/fisiologia , Futebol Americano/psicologia , Movimento/fisiologia , Músculo Quadríceps/fisiologia , Comportamento Competitivo/fisiologia , Frequência Cardíaca/fisiologia , Humanos , Ácido Láctico/sangue , Masculino , Contração Muscular/fisiologia , Percepção/fisiologia , Esforço Físico/fisiologia , Processos Estocásticos , Teste de Stroop , Análise e Desempenho de Tarefas , Adulto Jovem
6.
Eur J Appl Physiol ; 119(9): 2053-2064, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31327028

RESUMO

PURPOSE: To quantify how postural stability is modified during experimental pain while performing different cognitively demanding tasks. METHODS: Sixteen healthy young adults participated in the experiment. Pain was induced by intramuscular injection of hypertonic saline solution (1 mL, 6%) in both vastus medialis and vastus lateralis muscles (0.9% isotonic saline was used as control). The participants stood barefoot in tandem position for 1 min on a force plate. Center of pressure (CoP) was recorded before and immediately after injections, while performing two cognitive tasks: (i) counting forwards by adding one; (ii) counting backwards by subtracting three. CoP variables-total area of displacement, velocity in anterior-posterior (AP-velocity) and medial-lateral (ML-velocity) directions, and CoP sample entropy in anterior-posterior and medial-lateral directions were displayed as the difference between the values obtained after and before each injection and compared between tasks and injections. RESULTS: CoP total area ( - 84.5 ± 145.5 vs. 28.9 ± 78.5 cm2) and ML-velocity ( - 1.71 ± 2.61 vs. 0.98 ± 1.93 cm/s) decreased after the painful injection vs. Control injection while counting forward (P < 0.05). CoP total area (12.8 ± 53.9 vs. - 84.5 ± 145.5 cm2), ML-velocity ( - 0.34 ± 1.92 vs. - 1.71 ± 2.61 cm/s) and AP-velocity (1.07 ± 2.35 vs. - 0.39 ± 1.82 cm/s) increased while counting backwards vs. forwards after the painful injection (P < 0.05). CONCLUSION: Pain interfered with postural stability according to the type of cognitive task performed, suggesting that pain may occupy cognitive resources, potentially resulting in poorer balance performance.


Assuntos
Atenção/fisiologia , Joelho/fisiologia , Dor/fisiopatologia , Equilíbrio Postural/fisiologia , Postura/fisiologia , Adulto , Feminino , Humanos , Articulação do Joelho/fisiologia , Masculino , Músculo Quadríceps/fisiologia
7.
Int J Sports Med ; 40(10): 650-656, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31342480

RESUMO

Quadriceps atrophy and weakness can persist for years after anterior cruciate ligament reconstruction (ACLR). We evaluated the effectiveness of a home-based blood flow restriction (BFR) exercise program to increase quadriceps size and strength several years after ACLR. Nine adults with ACLR (5±2 yrs post-surgery, ≤90% symmetry in quadriceps size and strength) and nine uninjured controls volunteered. ACLR participants exercised at home for 25 min, 5×/wk for 4 wks (single-leg knee extension, bodyweight half-squats, walking). Blood flow in only the involved leg was restricted using a thigh cuff inflated to 50% of limb occlusion pressure. Rectus femoris and vastus lateralis thickness and knee extensor strength were measured before and after training. Baseline and post-training symmetry (involved leg/uninvolved leg) indices were compared to uninjured controls. Rectus femoris and vastus lateralis thickness and knee extensor strength in the involved leg increased by 11±5%, 10±6%, and 20±14%, respectively (all P<0.01). Compared to baseline, post-training knee extensor strength symmetry increased from 88±4 to 99±5% (P<0.01) and did not differ from uninjured controls (99±5%, P=0.95). Implementation of BFR exercise at home was feasible, safe and effective. Results extend upon early post-operative application of BFR exercise for ACLR recovery and demonstrate that BFR can improve quadriceps function long after ACLR.


Assuntos
Constrição , Terapia por Exercício/métodos , Músculo Quadríceps/irrigação sanguínea , Músculo Quadríceps/fisiologia , Fluxo Sanguíneo Regional , Adolescente , Adulto , Reconstrução do Ligamento Cruzado Anterior , Estudos de Casos e Controles , Feminino , Humanos , Joelho , Masculino , Força Muscular , Adulto Jovem
8.
J Strength Cond Res ; 33(9): 2321-2329, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31343548

RESUMO

Trexler, ET, Keith, DS, Schwartz, TA, Ryan, ED, Stoner, L, Persky, AM, and Smith-Ryan, AE. Effects of citrulline malate and beetroot juice supplementation on blood flow, energy metabolism, and performance during maximum effort leg extension exercise. J Strength Cond Res 33(9): 2321-2329, 2019-Citrulline malate (CitMal) and beetroot juice (BEET) are increasingly popular ergogenic aids, but few studies have rigorously investigated their effects on resistance exercise performance and underlying mechanisms. The current randomized, double-blind, crossover study evaluated the effects of CitMal and BEET supplementation on blood flow, metabolic efficiency, and performance during maximal isokinetic leg extension exercise. After familiarization, 27 recreationally active men (age: 22 ± 4 years) completed 3 visits in which subjects ingested a treatment beverage (CitMal [8 g], BEET [400-mg nitrate], or placebo [PLA]), followed by a 2-hour rest period, warm-up, and 5 sets of 30 concentric leg extensions. Before and after exercise, ultrasound was used to measure diameter (aDIAM) and blood flow (aBF) of the superficial femoral artery, along with cross-sectional area and echo intensity of the vastus lateralis. Plasma analytes (lactate, nitrate/nitrite [NOx], and urea nitrogen [BUN]) were also assessed at these times, and indirect calorimetry was used to measure energy expenditure and respiratory exchange ratio before and during exercise. Resting NOx values were higher in BEET (233.2 ± 1.1 µmol·L) compared with CitMal (15.3 ± 1.1, p < 0.0001) and PLA (13.4 ± 1.1, p < 0.0001). Postexercise NOx values, adjusted for resting differences, were higher in BEET (86.3 ± 1.2 µmol·L) than CitMal (21.3 ± 1.1, p < 0.0001) and PLA (18.1 ± 1.1, p < 0.0001). No other variables were affected by treatment (all p > 0.05). While BEET increased NOx, neither treatment was found to enhance performance, blood flow, metabolic efficiency, nor the hormonal response to leg extension exercise.


Assuntos
Beta vulgaris , Citrulina/análogos & derivados , Sucos de Frutas e Vegetais , Malatos/farmacologia , Substâncias para Melhoria do Desempenho/farmacologia , Adolescente , Adulto , Citrulina/farmacologia , Estudos Cross-Over , Suplementos Nutricionais , Método Duplo-Cego , Metabolismo Energético/efeitos dos fármacos , Exercício/fisiologia , Artéria Femoral/diagnóstico por imagem , Humanos , Masculino , Nitratos/administração & dosagem , Nitratos/sangue , Nitritos/sangue , Raízes de Plantas , Músculo Quadríceps/irrigação sanguínea , Músculo Quadríceps/fisiologia , Fluxo Sanguíneo Regional/efeitos dos fármacos , Ultrassonografia , Adulto Jovem
9.
Muscle Nerve ; 60(4): 433-436, 2019 10.
Artigo em Inglês | MEDLINE | ID: mdl-31330047

RESUMO

INTRODUCTION: The sarcolemmal resting membrane potential (RMP) affects muscle excitability, contractility, and force generation. However, there are limited In vivo data on the normal RMP of the human sarcolemma between muscles. We hypothesize that the in vivo RMP may differ between human muscles with different physiological roles. METHODS: Muscle velocity recovery cycles were recorded from a proximal antigravity muscle, the rectus femoris, and compared with paired recordings from a distal non-antigravity muscle, the tibialis anterior, in 34 normal individuals. RESULTS: Significant differences in muscle relative refractory period (3.55 millseconds vs 3.87 milliseconds, P = .002), early supernormality (14.22% vs 10.50%, P < .0001), and late supernormality (5.43% vs 3.50%, P < .0001) were observed. DISCUSSION: The results strongly suggest a less negative RMP in tibialis anterior vs rectus femoris and attest to intermuscle differences in normal excitability and physiology. This novel finding employing an in vivo methodology highlights the need for muscle-specific normative data in future studies.


Assuntos
Potenciais da Membrana/fisiologia , Músculo Quadríceps/fisiologia , Período Refratário Eletrofisiológico/fisiologia , Sarcolema/fisiologia , Adulto , Idoso , Idoso de 80 Anos ou mais , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Músculo Esquelético/fisiologia , Valores de Referência , Adulto Jovem
10.
Phys Ther Sport ; 39: 120-125, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31349092

RESUMO

OBJECTIVES: To compare the effects of conventional (constant load) eccentric training and isokinetic eccentric training on quadriceps muscle mass, strength and functionality of recreational athletes following partial meniscectomy. DESIGN: Randomized controlled trial. SETTING: XXXX, Brazil. PARTICIPANTS: 32 recreational male athletes (∼27 years old) who underwent partial meniscectomy performed a 6-week quadriceps strength training program in one of the experimental groups: conventional group (CG) or icokinetic group (IG). MAIN OUTCOME MEASURES: Quadriceps muscle mass, strength, and patients' objective and self-reported function. RESULTS: Both groups enhanced muscle mass, strength and functionality outcomes. The IG presented higher increases than CG for muscle mass (ES = 0.99-1.41), strength (ES = 1.48-2.35), and Lysholm score (ES = 1.0). The magnitude-based inference supports that results 'very likely' or 'almost certainly' favour IG compared to CG for all outcomes, except for the single leg hop test (i.e., between-group similar change). CONCLUSION: After partial meniscectomy, isokinetic eccentric training is more effective than conventional eccentric training to restore quadriceps muscle mass, strength, and functional capacity.


Assuntos
Meniscectomia , Força Muscular/fisiologia , Músculo Quadríceps/diagnóstico por imagem , Músculo Quadríceps/fisiologia , Treinamento de Resistência/métodos , Adulto , Humanos , Escore de Lysholm para Joelho , Imagem por Ressonância Magnética , Masculino
11.
Int J Sports Med ; 40(9): 555-562, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31291650

RESUMO

We aimed to determine whether blood flow restriction (BFR) alters the characteristics of individual motor units during low-intensity (LI) exercise. Eight men (26.0±3.8 yrs) performed 5 sets of 15 knee extensions at 20% of one-repetition maximum (with and without BFR). Maximal isometric voluntary contractions (MVC) were performed before and after exercise to quantify force decrement. Submaximal isometric voluntary contractions were additionally performed for 18 s, matching trapezoidal target-force trajectories at 40% pre-MVC. EMG activity was recorded from the vastus lateralis muscle. Then, signals were decomposed to extract motor unit recruitment threshold, firing rates and action potential amplitudes (MUAP). Force decrement was only seen after LI BFR exercise (-20.5%; p<0.05). LI BFR exercise also induced greater decrements in the linear slope coefficient of the regression lines between motor unit recruitment threshold and firing rate (BFR: -165.1±120.4 vs. non-BFR: -44.4±33.1%, p<0.05). Finally, there was a notable shift towards higher values of firing rate and MUAP amplitude post-LI BFR exercise. Taken together, our data indicate that LI BFR exercise increases the activity of motor units with higher MUAP amplitude. They also indicate that motor units with similar MUAP amplitudes become activated at higher firing rates post-LI BFR exercise.


Assuntos
Potenciais de Ação , Constrição , Músculo Quadríceps/fisiologia , Treinamento de Resistência , Adulto , Humanos , Contração Isométrica , Masculino , Fluxo Sanguíneo Regional , Adulto Jovem
12.
Eur J Appl Physiol ; 119(9): 2065-2073, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31332518

RESUMO

PURPOSE: To investigate the effects of acute experimental knee joint pain on maximum force generation and rate of force development (RFD) of the quadriceps muscle during isometric and dynamic muscle activations. METHODS: The right knee of 20 healthy people was injected with hypertonic saline to create an acute pain experience. Measurements of maximum knee extensor torque during isometric, concentric, and eccentric contractions were undertaken using a Biodex dynamometer. The RFD was also examined during the isometric contractions. Quadriceps muscle activity was obtained using electromyography (EMG). The outcome measures were obtained at baseline, during pain, and after knee pain had resolved. RESULTS: Maximum joint torque and peak EMG were significantly reduced during pain, but there were no differences across the three types of contraction. The maximum RFD and rate of EMG rise were also reduced during pain, primarily at 50-100 ms post-contraction onset. The RFD and EMG rise were largely unaffected at later time periods following contraction onset (150-200 ms). CONCLUSIONS: Acute joint pain has a similar impact on isometric and isokinetic contractions despite differences in neural control strategies. Joint pain also impairs rapid muscle activation and the RFD. These findings are important for people with musculoskeletal pain as it likely contributes to impairments in joint function in these populations.


Assuntos
Contração Isométrica/fisiologia , Joelho/fisiologia , Contração Muscular/fisiologia , Força Muscular/fisiologia , Dor/fisiopatologia , Músculo Quadríceps/fisiologia , Adolescente , Adulto , Eletromiografia/métodos , Exercício/fisiologia , Feminino , Humanos , Articulação do Joelho/fisiologia , Masculino , Pessoa de Meia-Idade , Movimento/fisiologia , Torque , Adulto Jovem
13.
J Strength Cond Res ; 33(8): 2145-2152, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31344011

RESUMO

Hintzy, F, Gregoire, N, Samozino, P, Chiementin, X, Bertucci, W, and Rossi, J. Effect of thigh-compression shorts on muscle activity and soft-tissue vibration during cycling. J Strength Cond Res 33(8): 2145-2152, 2019-This study examined the effects of different levels of thigh compression (0, 2, 6, and 15 mm Hg) in shorts on both vibration and muscle activity of the thigh during cycling with superimposed vibrations. Twelve healthy males performed a 18-minute rectangular cycling test per shorts condition (randomized cross-over design) on a specifically designed vibrating cycloergometer. Each test was composed of 2 intensity levels (moderate then high) and 3 vibration frequencies of 18.3, 22.4, and 26.3 Hz, corresponding to cadences of 70, 85, and 100 rpm, respectively. Muscle vibrations were measured with 2 triaxial accelerometers located before and on the lower-body compression garment, to quantify, respectively, the input and output vibrations, and vastus lateralis muscle activity was measured using surface electromyography. Both vibration and electromyography signals were measured throughout the tests and quantified using root-mean-square analyses. The study showed that the use of a thigh-compression shorts at 6-15 mm Hg significantly reduced both the vibration transmissibility to the thigh and the muscle activity, with higher effect size at higher superimposed vibrations. The thigh-compression shorts garment therefore seems to be 1 way to dampen vibrations transmitted to the cyclists and then to reduce the negative consequences of these vibrations on muscles.


Assuntos
Ciclismo/fisiologia , Bandagens Compressivas , Músculo Esquelético/fisiologia , Coxa da Perna/fisiologia , Vibração , Adulto , Eletromiografia , Humanos , Masculino , Fenômenos Fisiológicos Musculoesqueléticos , Modalidades de Fisioterapia , Músculo Quadríceps/fisiologia , Adulto Jovem
14.
Gait Posture ; 73: 74-79, 2019 09.
Artigo em Inglês | MEDLINE | ID: mdl-31302335

RESUMO

BACKGROUND: Lower extremity movement asymmetries may lead to re-injury and knee osteoarthritis after anterior cruciate ligament (ACL) reconstruction surgery. However, there is no consensus regarding the effect of quadriceps strength asymmetry on lower extremity movement asymmetry after ACL reconstruction. RESEARCH QUESTION: What is the relationship between quadriceps strength asymmetry and asymmetries in lower extremity kinematics and kinetics during walking in individuals who underwent ACL reconstruction surgery?. METHODS: Isometric quadriceps strength, kinematic, and kinetic data during walking were collected from 24 men with unilateral ACL reconstruction. Knee joint angles and moments were reduced. Pearson correlation coefficients between asymmetry in selected knee biomechanics and isometric quadriceps strength asymmetry were determined. RESULTS: The isometric quadriceps strength of the injured leg was significantly lower than that of the uninjured leg (P < 0.001). Knee flexion angles and knee extension moments were smaller in the injured leg than that in the uninjured leg during both loading response (P = 0.007, P = 0.047) and mid-stance phases (P = 0.005, P = 0.028). Isometric quadriceps strength asymmetry was significantly correlated with asymmetry in the peak knee flexion angle during loading response and mid-stance phases (r = -0.48, P = 0.017, r = -0.48, P = 0.017). Isometric quadriceps strength asymmetry was also significantly correlated with asymmetry in the peak knee extension moment during the mid-stance phase (r = -0.44, P = 0.033). SIGNIFICANCE: Individuals with ACL reconstruction demonstrate knee movement asymmetry in the sagittal plane. Isometric quadriceps strength asymmetry is significantly correlated with asymmetry in knee flexion angles during the early stance phase and knee extension moments during the mid-stance phase. Rehabilitation programs should emphasise eccentric exercise to beneficially modify quadriceps neuromuscular control.


Assuntos
Lesões do Ligamento Cruzado Anterior , Reconstrução do Ligamento Cruzado Anterior , Articulação do Joelho/fisiologia , Força Muscular/fisiologia , Músculo Quadríceps/fisiologia , Caminhada/fisiologia , Adulto , Lesões do Ligamento Cruzado Anterior/fisiopatologia , Lesões do Ligamento Cruzado Anterior/cirurgia , Fenômenos Biomecânicos , Humanos , Contração Isométrica/fisiologia , Traumatismos do Joelho/fisiopatologia , Traumatismos do Joelho/cirurgia , Masculino , Suporte de Carga/fisiologia , Adulto Jovem
15.
J Strength Cond Res ; 33(10): 2595-2601, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31356511

RESUMO

Delgado, J, Drinkwater, EJ, Banyard, HG, Haff, GG, and Nosaka, K. Comparison between back squat, Romanian deadlift, and barbell hip thrust for leg and hip muscle activities during hip extension. J Strength Cond Res 33(10): 2595-2601, 2019-This study compared muscle activities of vastus lateralis (VL), biceps femoris (BF), and gluteus maximus (GM) during the back squat (SQ), Romanian deadlift (RDL), and barbell hip thrust (BHT) exercises performed with the same load (60 kg) and at one repetition maximum (1RM). Eight men with a minimum of 1 year's lower-body strength training experience performed the exercises in randomized order. Before each exercise, surface electromyography (EMG) was recorded during a maximal voluntary isometric contraction (MVIC) and then used to normalize to each muscle's EMG during each trial. Barbell hip thrust showed higher GM activity than the SQ (effect size [ES] = 1.39, p = 0.038) but was not significantly different from RDL (ES = 0.49, p = 0.285) at 1RM. Vastus lateralis activity at 1RM during the SQ was significantly greater than RDL (ES = 1.36, p = 0.002) and BHT (ES = 2.27, p = 0.009). Gluteus maximus activity was higher during MVIC when compared with the 60 kg load for the SQ (ES = 1.29, p = 0.002) and RDL (ES = 1.16, p = 0.006) but was similar for the BHT (ES = 0.22, p = 0.523). There were no significant differences in GM (ES = 0.35, p = 0.215) and BF activities (ES = 0.16, p = 0.791) between 1RM and MVIC for the SQ. These findings show that the RDL was equally as effective as the BHT for isolating the hip extensors, while the SQ simultaneously activated the hip and knee extensors.


Assuntos
Músculos Isquiotibiais/fisiologia , Músculo Esquelético , Músculo Quadríceps/fisiologia , Treinamento de Resistência/métodos , Levantamento de Peso/fisiologia , Adolescente , Adulto , Nádegas , Eletromiografia , Exercício/fisiologia , Quadril , Humanos , Contração Isométrica , Masculino , Distribuição Aleatória , Adulto Jovem
16.
Medicina (Kaunas) ; 55(8)2019 Jul 26.
Artigo em Inglês | MEDLINE | ID: mdl-31357518

RESUMO

Background and Objectives: This study considered the use of a generalized additive multilevel model to describe the joint-angle-specific functional hamstring to quadriceps ratio (H:Q ratio) in the knee, using all of the available truly isokinetic data within the range. Materials and Methods: Thirty healthy male basketball players aged 15.0 (1.4) years (average stature = 180.0 cm, SD = 11.1 cm; average body mass = 71.2, SD = 14.9 kg) years were considered. All players considered had no history of lower extremity musculoskeletal injury at the time of testing or during the 6 months before testing, and had been engaged in formal basketball training and competition for 5.9 (2.4) years. Moments of force of the reciprocal concentric and eccentric muscular actions for the knee extensors and flexors assessed by isokinetic dynamometry at 60°âˆ™s-1 were used. Results: Maximum moments of force were attained at different angle positions for knee extension. For knee flexion, it was apparent that there was an ability to maintain high levels of moment of force between 30° and 60° in the concentric muscular action, corresponding to the concentric action of the hamstrings. However, for the eccentric knee flexion, corresponding to the quadriceps action, there was a marked peak of moment of force at about 55°. The functional H:Q ratio for the knee extension was non-linear, remaining higher than 1.0 (i.e., point of equality) from the beginning of the extension until approximately 40° of the knee extension, leveling off below the point of equality thereafter. On average, the functional H:Q ratio for the knee flexion did not attain 1.0 across the range of motion. The functional H:Q ratio for the knee in the present sample peaked at 20° and 80°, declining between these angle positions to below 0.50 at about 0.54. Conclusions: Estimating the form of the non-linear relationship on-the-fly using a generalized additive multilevel model provides joint-angle-specific curves and joint-angle-specific functional H:Q ratio patterns, allowing the identification and monitoring of strength development, with potential implications for injury and performance.


Assuntos
Atletas/estatística & dados numéricos , Músculos Isquiotibiais/fisiologia , Músculo Quadríceps/fisiologia , Amplitude de Movimento Articular/fisiologia , Adolescente , Análise de Variância , Basquetebol/estatística & dados numéricos , Brasil , Humanos , Joelho/fisiologia , Masculino , Força Muscular/fisiologia
17.
J Sports Sci Med ; 18(2): 198-206, 2019 06.
Artigo em Inglês | MEDLINE | ID: mdl-31191088

RESUMO

The present systematic review aimed to analyze the activation of the muscles involved in the barbell hip thrust (BHT) and its transfer to sports activities that include horizontal displacement. A search of the current literature was performed using the PubMed, SPORTDiscuss, Scopus and Google Scholar databases. The inclusion criteria were: (a) descriptive studies, (b) physically trained participants, (c) analyzed muscle activation using normalized EMG signals or as a percentage of maximal voluntary isometric contraction (MVIC) and (d) acute or chronic transfer of the BHT to horizontal displacement activity. Twelve articles met the inclusion criteria and the following results were found: 1) neuromuscular activation: hip extensor muscles (gluteus maximus and biceps femoris) demonstrated greater activation in the BHT compared to the squat. The straight bar deadlift exercise demonstrated greater biceps femoris activation than BHT; 2) Regardless of the BHT variation and intensity used, the muscle excitation sequence is gluteus maximus, erector spinae, biceps femoris, semitendinosus, vastus lateralis, gluteus medius, vastus medialis and rectus femoris; 3) acute transfer: four studies demonstrated a significant improvement in sprinting activities after BHT exercise; 4) as for the chronic transfer: two studies demonstrated improvement of the sprint time, while other two studies failed to present such effect. We concluded that: a) the mechanics of BHT favors greater activation of the hip extensor muscles compared to more conventional exercises; b) regardless of the variation of BHT used, the muscle excitation sequence is gluteus maximus, erector spinae, hamstrings, and quadriceps femoris; c) the acute transfer of the post-activation potentiation of the BHT is significant, improving the sprinting time; and d) despite training with BHT submaximal loads can improve sprint times, further investigations are needed.


Assuntos
Músculos Isquiotibiais/fisiologia , Músculos Paraespinais/fisiologia , Músculo Quadríceps/fisiologia , Levantamento de Peso/fisiologia , Fenômenos Biomecânicos , Nádegas , Quadril , Humanos , Contração Isométrica , Postura , Coxa da Perna
18.
Sports Health ; 11(4): 316-323, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31194624

RESUMO

BACKGROUND: Individuals who experience a subsequent ipsilateral anterior cruci (cruciate)ate ligament (ACL) reinjury may use hazardous muscle activation strategies after primary ACL reconstruction (ACLR). The purpose of this study was to compare electromyograms (EMGs) of the quadriceps, hamstrings, and gastrocnemius muscles during a dynamic hopping task among individuals with a single ACL injury (ACLx1), individuals who went on to have secondary ipsilateral ACL injury (ACLx2), and individuals who have never sustained an ACL injury (ACLx0). HYPOTHESIS: We expected that individuals who went on to experience a secondary ACL injury would use less quadriceps muscle activity as compared with individuals who experienced a single ACL injury. STUDY DESIGN: Cross-sectional study. LEVEL OF EVIDENCE: Level 3. METHODS: Fourteen individuals that were returned to play post-ACLR and 7 non-ACL-injured individuals participated. Individuals who had undergone an ACLR were placed into groups depending on whether they had experienced a secondary ipsilateral ACL reinjury postprimary ACLR. EMG data of the vastus lateralis, biceps femoris, and lateral gastrocnemius were measured during 2 phases of a single-leg dynamic hopping task: preactivity (100 ms prior to ground contact) and reactivity (250 ms post-ground contact). Processed EMG data were compared across groups using 1-way analyses of variance, with post hoc independent t tests where appropriate (P ≤ 0.05). RESULTS: At preactivity, ACLx1 (0.48% ± 0.2%max) was found to use significantly more hamstring activity than ACLx2 (0.20% ± 0.1%max, P = 0.018), but not than ACLx0 (0.38% ± 0.1%max, P > 0.05). At reactivity, both ACL groups were found to use less quadriceps activity than ACLx0 (ACLx1: 0.38% ± 0.1%max, P = 0.016; ACLx2: 0.40% ± 0.1%max, P = 0.033; ACLx0: 0.58% ± 0.1%max), but not than each other (P > 0.05). CONCLUSION: Quadriceps muscle activity during landing was diminished in all ACL participants as compared with participants who had never sustained an ACL injury. Individuals who did not experience a secondary ipsilateral ACL reinjury (ACLx1) used greater levels of hamstring activity prior to landing. CLINICAL RELEVANCE: The higher hamstring activity in patients who did not experience a secondary injury may be interpreted as a protective mechanism that is used to dynamically stabilize the reconstructed limb.


Assuntos
Lesões do Ligamento Cruzado Anterior/fisiopatologia , Lesões do Ligamento Cruzado Anterior/cirurgia , Reconstrução do Ligamento Cruzado Anterior , Traumatismos em Atletas/fisiopatologia , Traumatismos em Atletas/cirurgia , Músculos Isquiotibiais/fisiologia , Músculo Esquelético/fisiologia , Músculo Quadríceps/fisiologia , Adolescente , Adulto , Estudos Transversais , Eletromiografia , Teste de Esforço , Feminino , Humanos , Masculino , Força Muscular , Recidiva , Volta ao Esporte , Adulto Jovem
19.
BMC Res Notes ; 12(1): 366, 2019 Jun 28.
Artigo em Inglês | MEDLINE | ID: mdl-31253181

RESUMO

OBJECTIVE: The present study reports the on-field screening of a population of young soccer players in the pursuit of alterations in gait using a portable and low-cost gait analysis system composed of a Wii Balance Board and a webcam. RESULTS: Recordings of motion of the lower extremities along with vertical ground reaction force (GRF) were used to quantify coefficients of symmetry for the overall GRF and the forces exerted by the quadriceps femori and acting on the anterior cruciate ligament (ACL). Data show that, in face of a quite homogeneous symmetry of GRF during left and right stance phases of gait, quadriceps and ACL exert and are subjected to left-right asymmetrical forces that might prelude, especially in young athletes, later alterations of gait.


Assuntos
Ligamento Cruzado Anterior/fisiologia , Atletas , Custos e Análise de Custo , Lateralidade Funcional/fisiologia , Marcha/fisiologia , Fisiologia/economia , Fisiologia/instrumentação , Músculo Quadríceps/fisiologia , Adolescente , Adulto , Fenômenos Biomecânicos , Feminino , Humanos , Masculino , Adulto Jovem
20.
Scand J Med Sci Sports ; 29(10): 1591-1603, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31169924

RESUMO

Oxidative stress is associated with disease severity and limb muscle dysfunction in COPD. Our main goal was to assess the effects of exercise training on systemic oxidative stress and limb muscle dysfunction in older people with COPD. Twenty-nine outpatients with COPD (66-90 years) were randomly assigned to a 12-week exercise training (ET; high-intensity interval training (HIIT) plus power training) or a control (CT; usual care) group. We evaluated mid-thigh muscle cross-sectional area (CSA; computed tomography); vastus lateralis (VL) muscle thickness, pennation angle, and fascicle length (ultrasonography); peak VO2 uptake (VO2peak ) and work rate (Wpeak ) (incremental cardiopulmonary exercise test); rate of force development (RFD); maximal muscle power (Pmax ; force-velocity testing); systemic oxidative stress (plasma protein carbonylation); and physical performance and quality of life. ET subjects experienced changes in mid-thigh muscle CSA (+4%), VL muscle thickness (+11%) and pennation angle (+19%), VO2peak (+14%), Wpeak (+37%), RFD (+32% to 65%), Pmax (+38% to 51%), sit-to-stand time (-24%), and self-reported health status (+20%) (all P < 0.05). No changes were noted in the CT group (P > 0.05). Protein carbonylation decreased among ET subjects (-27%; P < 0.05), but not in the CT group (P > 0.05). Changes in protein carbonylation were associated with changes in muscle size and pennation angle (r = -0.44 to -0.57), exercise capacity (r = -0.46), muscle strength (r = -0.45), and sit-to-stand performance (r = 0.60) (all P < 0.05). The combination of HIIT and power training improved systemic oxidative stress and limb muscle dysfunction in older people with COPD. Changes in oxidative stress were associated with exercise-induced structural and functional adaptations.


Assuntos
Treinamento Intervalado de Alta Intensidade , Estresse Oxidativo , Doença Pulmonar Obstrutiva Crônica/terapia , Músculo Quadríceps/fisiologia , Adaptação Fisiológica , Idoso , Idoso de 80 Anos ou mais , Teste de Esforço , Feminino , Humanos , Masculino , Força Muscular , Consumo de Oxigênio , Desempenho Físico Funcional , Carbonilação Proteica , Músculo Quadríceps/fisiopatologia , Qualidade de Vida
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